A N EPIDEMIOLOGICAL CROSS - SECTIONAL STUDY OF LEISURE - TIME PHYSICAL ACTIVITY IN INDIVI DUALS WITH AN ANXIETY DISORDER: RELATIONSHIP TO 30 - DAY FUNCTIONING MEASURED BY THE WORLD HEALTH ORGANIZATION DISABILITY ASSESSMENT SCALE (WHO - DAS II) By Ashley R. Strong A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of Epidemiology - Master of Science 2015 ABSTRACT A N EPIDEMIOLOGICAL CROSS - SECTIONAL STUDY OF LEISURE - TIME PHYSICAL ACTIVITY IN INDIVI DUALS WITH AN ANXIETY DISORDER: RELATIONSHIP TO 30 - DAY FUNCTIONING MEASURED BY THE WORLD HEALTH ORGANIZATION DISABILITY ASSESSMENT SCALE (WHO - DAS II) By Ashley R. Strong Objectives: To see how leisu re - time physical activity impacts previous 30 - day functio ning for those with an anxiety disorder. Methods: I ndividuals who participated in the Nationa l Survey of American Life me e t ing criteria for an anxiety disorder (n = 548) were included in this analysis. The dependent variable s were the WHO - DAS II categorie s , which measured previous 30 - day functioning in six differe nt categories. The independent variable was leisure - time physical activity. Results: As the level of leisure - time physical activity increased, the odds of having at least some impairment did not decrease. Rarely participating in leisure - time physical activity had a significant protective effect against at least some impairment in the cognition, role impairment, and social interaction categories . Additionally, there was no protective effect for tho se who often or sometimes participated in leisure - time physical activity in the cognition, mobility, or role functioning categories. Discussion: Based on this study, public health of ficials should note that promoting leisure - time physical activity may not be the best strategy to improve daily functioning for those with an anxiety disorder. Consequently, p ublic health experts should continue to explore other constructive ways to improve daily functioning and quality of life for those who suffer from anxiety disorder s of one type or another. Keywords: Anxiety disorders, leisure - time physical acti vity, impairment iii TABLE OF CONTENTS LIST OF TABLES .......................... .............................. .......... ........................... .................... .......................... i v LIST OF FIGURES .............................................................. .............................. ............................................ . v KEY TO ABBREVIATIONS ................................................ ............................ ........................................... .... . . vi INTRODUCTION................................................................. ....................... ............................................. ...... 1 Generalized Anxie ty Disorder (GAD)................................... .......................................... ................ 3 Social Anxiety Disorder (Social Phobia)....................... .......................................... ........................ 3 Agorap hobia......................................................... .......................................... ............................... 4 Panic Disorder................................................ .......................................... ........... .......................... 4 Adult Separation Anxiety Disorder............... .......................................... ....................................... 5 Post - Traumatic Stress Disorder.................................... ....................... ................... ....................... 6 Anxiety Disorders, Daily Function, Physic al Activity and Mental Illnes s . ................................. . ..... . 7 METHODS..................................................................................... ........ ..................................... . ...... .......... 9 Description of the Sample (NSAL). ........................................................................ ...... . ................ 9 Anxiety Diagnosis...................................... .................... ........................................ ..... . ................. 9 Dependent Variable (WHO - DAS II Categories)............... ........................................ .. . ................... 9 Independent Variable (Leisure - Time Physica l Activity)....... ........................................ ................ 1 0 Covariates............................................................ ................. ....................................... ............... 1 0 Inclusion and Exclusion Cri teria........................... ........ ....................................... .......... .............. 1 0 Analyses................................................................ ....................................... .............................. . 1 1 RESULTS........................................................... .......................................... ............................................... 1 3 Demographics............................................................................... . ...................................... ....... 1 3 Anxiety Disorder Diagnoses........................ ....................................... ......................................... 1 5 Impairment.................................................. ....... ................................ ........................................ 1 6 WHO - DAS II Self Care.................................... ........................................ ....................................... 1 7 WHO - DAS II Cognition................ ................... .......................................... ..................................... 1 8 WHO - DAS II Physical Mobility...................... .......................................... ....... ............................... 1 9 WHO - DAS II Role Impairment............................. .......................................... ......................... ...... 2 0 WHO - DAS II Social Interaction............................ .......................................... ... ............................ 2 2 WH O - DAS II Out of Role...................................... .......................................... ............................... 2 4 DISCUSSION ...................................................................... . ...................................... ..... ............................. 2 6 Strengths............................................................... .......................................... .......................... ... 2 8 Limitations.......................................................... .... .......................................... ............................ 2 9 Conclusion......................................................... .......................................... .. .. ............................. 2 9 REFERENCES .................. .................................................. .................. ............................................. ............ 3 1 iv LIST OF TABLES Table 1a . Descriptive S tatistics by Race/Ethnicity G roup ( n = 5 4 8 ) ... ...... . . .......................... .......... ........... 1 4 Table 1b . Descriptive S tatistics for A nxiety D isorders by Race/Ethnicity G roup .. ..... . . ............................ ... 1 5 Table 2 . World Health Organization Disability Assessment Scales - II number and percent ( unweighted n, weighted %) with at least some impairment among those meeting criteria fo r a 12 - month anxiety disorder. ..... ..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .... 1 6 Table 3 . WHO - DAS II Self - Care Model.................................... ..................... .................................... .......... 1 7 Table 4 . WHO - DAS II C ognition Model.................................... ............ ..................................... .................. 1 8 Table 5 . WHO - DAS II Physical Mobility Model........................ ................ ..................................... .............. 1 9 Table 6a . WHO - DAS II Role Impairment Model...................... ............... ..................................... ............... 2 1 Table 6b . Role Impairment Interaction between LTPA and Sex......... ..................................... .............. .... 2 1 Table 7a . WHO - DAS II Social Interaction Model.................... ...................... ..................................... ......... 2 3 Table 7b . Social Interaction Impairment Inter action between LTPA and MDD.... ................................ .... . 2 3 Table 8a . WHO - DAS II Out of Role Model............................. .................. .................................... ............. . 2 5 Table 8b . Out of Role Impairment Interaction between LTPA and Sex............ ............................... ...... ... . 2 5 v LIST OF FIGURES Figure 1 . I nclusion and E xclusion F l o w C h a r t ..... ................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .................... 1 1 vi KEY TO ABBREVIATIONS CDC Centers for Disease Control and Prevention BMI Body Mass Index DA LYs Disability - Adjusted Life Years DSM - V Diagnostic and Statistical Manual of Mental Disorders GAD Generalized Anxiety Disorder LTPA Leisure - Time Physical Activity MDD Major Depressive Disorder NSAL National Survey of American Life PTSD Post - Traumatic Stress Disorder WHO World Health Organization WHO - DAS II World Health Organization Disability Assessment Scale II WMH - CIDI World Mental Health Composi te International Diagnostic Interview YLD Years of Life Lived with Disability 1 I N T R O D U C T I O N Anxiety disorders are chronic and disabling illnesses that interfere with daily functioning, and cause great burden not only in the US, but on a global scale. In 2010, epidemiologic research classified anxiety disorders as the si xth leading cause of disability in terms of years of life lived with disability (YLD) in high - , middle - , and low - income countries. 1 On an international scale, anxiety disorders account for 390 disability - adjusted life years (DALYs) per 100,000 persons. These disorders include, but are not restricted to, Generalized Anxiety Disorder (GAD), Social Anxiety Disorder, Agoraphobia, Separation Anxiety, and Specific Phobias. The highest burden of these disorders is seen in males and females between the ages of 15 and 34 years, with 65% of the DALYS accounted for by females. In 2010, global costs of mental il lnesses were estimated to be $2.5 trillion; ( two - thirds of which are indirect costs ) , and are projected to increase to at least $6 trillion by 2030. 2 According to the World Economic Forum, mental health costs are estimated to be the largest source of global economic burden among non - communicable diseases, higher than cardiovascular disease, cancer, and diabetes. 2 According to The Centers for Disease Control and Prevention ( CDC ) , anx iety disorders are the most common types of mental disorders in the United States. 3 In the 1990s, the estimated annual cost of anxiety disorders was $42.3 billion in the United States. 4 In 2006, The Agency of Healthcare Research and Quality estimated ment al health care costs to be $57.5 billion . 5 The majority of these costs are not due to cost of care, but are a result of unemployment and a variety of indirect costs related to chro nic disability. Anxiety disorders have an estimated lifetime prevalence of g reater than 15%, while the 12 - month prevalence for any anxiety disorder is greater than 10%. In any given year in the United States, anxiety disorders affect ap proximately 40 million individuals who are 18 years or older ; t his accounts for 18% of the Unite d States population. 6 2 According to the WHO, "mental illnesses are the leading causes of disability adjusted life years (DALYs) worldwide". 7 Additionally, according to The Anxiety and Depression Association of America, approximately only one - third of thos e with an anxiety disorder receive treatment, even though anxiety disorders are very treatable. Therefore, it is important to understand anxiety disorders and to pursue strategies that address their clinical and public health ramifications. In the contex t of these challenges, the purpose of this study is to examine the effects of leisure - time physical activity on previ ous 30 - day functioning for individuals who have a clinically diagnosed an xiety disorder. Specifically, t his study examine s how various leve ls of leisu re - time physical activity a ffect previous 30 - day functioning, and also examine s those aspects of functioning that are affected by leisure - time physical activity , while controlling for demographic and environmental factors. Anxiety disorders are different from normal, everyday fear and anxiety. 8 While f ear is a respo nse to an observable threat, anxiety is the antici pation of future threat. A ccording to the DSM - 5, "anxiety disorders include disorders that share features of excessive fear and anxie ty and related behavioral disturbances". 8 Anxiety disorders differ from these normative responses of fear and anxiety by being excessive and persistent, usually lasting six months or longer. There are different types of anxiety disorders, which can be dif f erentiated from one another relative to different situations and/ or the object ( s ) that provoke : fear, anxiety, and avoidance behavior. What follows is a review and epidemiology of multiple anxiety disorders (Generalized Anxiety Disorder, Social Anxiety Dis order, Agoraphobia, Panic Disorder, Adult Separation Disorder, and Post - Traumatic Stress Disorder), how they impact day - to - day functioning, and current research that examines the a ffect of physical activity on anxiety disorders. 3 Generalized Anxiety Disord er (GAD) The fundamental feature of GAD is that anxiety and worry are excessive concerning a multitude of life activities and events. 8 Additionally, there are three characteristics that distinguish GAD from everyday anxiety. First, individuals with GAD ha ve worries that are excessive and also significantly interfere with daily functioning. Second, worries in individuals with GAD are distressing, invasive, persistent, and have a longer duration than normal anxiety. Third, unlike with everyday worries, indiv iduals with GAD often report physical symptoms, such as restlessness or muscle tension, in response to constant worrying. Those with GAD often report social and occupational impairment, along with other important areas of functioning. The lifetime morbid r isk of GAD is 9.0%. 9 In the United States, the 12 - month prevalence of GAD is 2.9% among adults. In other countries, the 12 - month prevalence ranges from 0.4% to 3.6%. 10 Additionally, women are twice as likely to be diagnosed with GAD, with prevalence of GAD diagnosis peaking in the middle ages of life. 9 , 11 It has also been reported that individuals of European descent experience GAD more often than non - European s . 10 Social Anxiety Disorder (Social Phobia) Social anxiety disorder is distinguished by intense f ear or anxiety of social situations, where the individual fears they will be negatively assessed by others. 8 Social situations nearly always cause fear or anxiety, which often leads to avoiding these social situations altogether, or tolerating them with in tense fear and anxiety. Fear of social situations can also lead to anticipatory anxiety, which occurs far in advance of the upcoming social situation. The fear and anxiety in social anxiety disorder is excessive compared to the actual risk, and has to last for at least six months to be diagnosed with Social Anxiety Disorder. In the United States, the 12 - month prevalence is estimated to be 7%. 6 , 9 In older adults, the 12 - month prevalence ranges from 2 - 5%. 9 , 12 The prevalence is higher in American Indians, with lower prevalence rates in Asian, Latino, African American, and Afro - Caribbean individuals when compared to 4 non - Hispanic whites. 10 In the general population, rates of social anxiety disorder are higher in women compared to men (OR ranging from 1.5 - 2.2). 13 Agoraphobia Agoraphobia is defined by striking, or extreme fear and anxiety brought on by anticipated or actual exposure to a variety of feared situations. 8 These situations can include, but are not limited to, using public transportation, being in open s paces or enclosed spaces, being in a crowd, or being away from the home alone. When in these situations, individuals with agoraphobia experience fear and anxiety almost every time, along with thoughts that something horrible might happen. Individuals with agoraphobia may also experience a full or limited panic attack as a result of the fear and anxiety. The feared situations also cause the individual to actively avoid the situation, or endure it with severe fear or anxiety. Avoidance at the most severe stat e can result in the agoraphobic individual being completely homebound. Additionally, to be diagnosed with agoraphobia, the anxiety, fear, or avoidance, must be excessive in relation to the true danger of the situation. Agoraphobia must also be persistent, and cause significant social, occupational or other functional impairment. Approximately 1.7% of adolescents and adults every year are diagnosed with agoraphobia. 9 , 14 Incidence of agoraphobia peaks in late adolescence and early adulthood, with females twic e as likely to experience agoraphobia compared to males. 14 Lastly, prevalence rates of agoraphobia do not seem to differ between cultural and racial groups. 10 Panic Disorder Panic disorder is defined as "recurrent unexpected panic attacks". 8 Panic attacks consist of a sudden rush of powerful fear or discomfort, and crest within minutes. During a panic attack, four or more physical or cognitive symptoms must transpire out of 13 possible symptoms found in the DSM - V. Symptoms include: pounding or accelerated heart rate, sweating, shaking, chest pain, shortness of 5 breath, feelings of choking, nausea, chills or heat sensations, light - headedness or dizziness, paresthesias, fear of losing control, derealization, and fear of dying. Panic attacks can be unexpected, when there is no clear trigger, or expected, if there is an obvious trigger for the attack. Attacks can also vary greatly in frequency and severity. The severity and number of symptoms also vary from one panic attack to the next. 15 Having an expected panic attack does not eliminate a panic disorder diagnosis. However, for diagnosis, more than one unexpected panic attack is required. Individuals with panic disorder may change their behavior to avoid panic attacks, such as limiting daily activities and avoidi ng agoraphobic situations. A separate diagnosis of agoraphobia is given if agoraphobia is present. In the United States, the 12 - month prevalence of panic disorder varies between 2 - 3% in adolescents and adults. 6,9,16 Rates of panic disorder seem to gradual ly increase during adolescence, and crest during adulthood. 15 Lower rates of panic disorder are reported in Latinos, Caribbean blacks, African Americans, and Asian Americans, when compared with non - Latino whites. 10 Whereas, American Indians report signific antly higher rates of panic disorder. Additionally, females are affected more than men with a rate of 2:1. 6 Adult Separation Anxiety Disorder Separation anxiety disorder can occur at any age, but the focus will be on adult separation anxiety disorder. The fundamental feature of separation anxiety disorder is excessive anxiety or fear as a result of anticipated or present separation from an attachment figure or the home. 8 The anxiety expressed by the individual will be excessive, and may exceed expectations based on the developmental level of the individual. Adults with separation anxiety disorder may worry about the safety of their attachment figures, usually their children and spouses. These individuals, especially when separated, experience marked distres s and need to know their attachment figures' current location, and need to stay in touch with them. This may cause significant disruption in work or social life, due to constantly 6 contacting their significant other. They also fear being alone, and leaving the house by themselves due to separation fears. To be diagnosed, this disorder must cause significant social, academic, occupational, or other functional distress or impairment. In the United States, the 12 - month prevalence of adult separation anxiety dis order ranges from 0.9 - 1.9%. 6,9,17 Post - Traumatic Stress Disorder Post - Traumatic Stress Disorder (PTSD) is defined as exposure to one or more traumatic events, such as exposure to war, physical assault, or sexual assault, resulting in the development of characteristic symptoms. 8 Symptoms include intrusive events related to the traumatic event, which can be re - experienced in multiple ways, such as recurring and intrusive memories of the event, flashbacks, or recurring dreams related to the event. Those wit h PTSD deliberately avoid any stimuli associated with the trauma. Stimuli could be thoughts and memories, talking about the event, objects, activities, certain people, or situations. Heightened sensitivity to possible threats is what helps distinguishes P TSD from other disorders. The projected lifetime risk for PTSD in the United States is 8.7%, with a twelve - month prevalence of approximately 3.5%. 6,18 After adjusting for traumatic exposure and demographics, compared to non - Latino whites, PTSD is reported at higher rates among Latinos, African Americans, and American Indians, while lower rates are reported among Asian Americans. 19, 20 Additionally, females have higher prevalence rates of PTSD across the lifespan, and also experience it for a longer duratio n, compared to males. 6, 18 Higher rates of PTSD are also found among veterans, and others with a vocation with increased risk of traumatic exposure. PTSD has been seen to impair functioning in social, educational, physical health, and occupational areas. L astly, lower estimates of approximately 0.5% - 1.0% are found in Europe, and most Asian, Latin American, and African countries. 20 7 Anxiety Disorders, Daily Fun ction, Physical Activity and Mental Illness Approximately 29% of individuals in the United State s will experience some type of anxiety disorder in their lifetime. 6 In addition, anxiety disorders have an immense impact on daily - functioning, affecting social and family relationships, educational and occupational success, and overall quality of life. 21 These disorders are also associated with indirect costs, such as lost work days or productivity, and direct costs due to increased use of health care. 22 These costs can create a huge economic burden for individuals suffering from an anxiety disorder. Anxie ty disorders are also exceedingly prevalent in our population, cause chronic disease, and cause a tremendous decrease in daily - function. Therefore, it is important to understand the epidemiology of these disorders, how they relate to each other, and what c an be done from a public health perspective to help prevent and treat them. Physical activity is known to protect against diseases such as coronary heart disease, hypertension, diabetes, obesity, certain cancers, and all - cause mortality. 23 However, the r elationship between physical activity and mental illness has been less well studied. 24 Previous studies have suggested that physical activity may have beneficial effects and reduce symptoms of numerous mental disorders. However, very few large scale, popul ation - based studies have been conducted examining the relationship between physical activity and mental health. 25 The cross - sectional studies that have been done have established a negative association between regular physical activity and symptoms of anxi ety and depression. The main limitation to the majority of the cross - sectional and longitudinal studies that have been completed is that they used anxiety and depression symptoms instead of a clinical diagnosis. Clinical trials have also examined a dose - r esponse relationship between physical activity and mental disorders. 26 Results suggest that the amount, more than the frequency of physical activity , appears to be strong ly associated with its therapeutic effects. 27 Additionally, once an adequate level of physical activity is reached, the remission and response rates can be equivalent to other treatments for depression, such as cognitive behavioral therapy or medication. 8 There is a growing body of literature suggesting that physical activity can be of impo rtance to mental health in addition to physical health. A recent longitudinal study suggests high levels of leisure - time physical activity could decrease the risk of developing mental illness problems. 24 Leisure - time physical activity can be defined as exe rcise not related to household chores, occupation, or transportation. 28 The relationship between physical activity and mental health, however, is more complicated than the relationship between physical activity and physical health. The physical activity an d mental health relationship varies greatly by activity type, individual demographics, and psychological condition. Therefore, more research needs to be done to help define this relationship. Previous research on this topic has mainly focused on the asso ciation between physical activity and mental disorders, with a focus on depression, or depression and anxiety. 29 There are no studies that specifically examine the association between anxiety disorders and physical activity without depression or other me nt al disorders. This study include s all available subtypes of anxiety in the National Survey of American Life (NSAL) to examine how leisure - time physical activity affects previous 30 - day functioning in those with a clinically diagnosed anxiety disorder. It e xamine s those aspects of functioning that are affected by various levels of leisure - time physical activity in terms of previous 30 - day functioning using to the World Health Organization Disability Assessment Scale (WHO - DAS II). H1: I hypothesize that as t he level of leisure - time physical activity increases, the odds of having at least some i mpairment will decrease. H2: I hypothesize that those who partake in leisure - time physical activity rarely or never will be more likely to have at least some impairment in each functioning category compared to those who partake in leisure - time physical activity often or sometimes. H3: I hypothesize that there will be a protective effect for those who partake in leisure - time physical activity often or sometimes, especial ly in the cognition, mobility, and role functioning categories. 9 M E T H O D S Description of the Sample (NSAL) A n analysis of existing data will be completed using the National Survey of American Life (NSAL). The NSAL is an integrated national househ old probability sample survey with a sample size of 6,082 adults, 18 years and older. 30 This survey includes 3,570 African - Americans, 891 non - Hispanic whites, and 1,621 blacks of Caribbean descent. Data were collected in 48 states between January 2001 and November 2002, with an overall response rate of 71.5%. The NSAL was designed to collect data from African - American and Afro - Caribbean populations of the US, and compare them to white participants from the same neighborhoods. Data was collected on mental di sorders, emotional, mental, and physical states, as well as potential risk and protective factors to examine racial and ethnic differences. Anxiety Diagnosis A modified version of the World Mental Health Composite International Diagnostic Interview (WMH - C IDI) was used to make diagnoses based on the Diagnostic and Statistical Manual (DSM - IV - TR) criteria for mental disorders. 31 Participants who endorsed a DSM - IV, 12 - month diagnosis of the following anxiety disorders were included in this study: Generalized A nxiety Disorder (n=102), Social Anxiety Disorder (n=231), Agoraphobia without panic disorder (n=72), Agoraphobia with panic disorder (n=47), Panic Disorder (n=113), Adult Separation Anxiety Disorder (n=84), and PTSD (n=138). Specific phobias were not inclu ded because no information was available in the NSAL on specific phobias. Anxiety disorders in this study are reported as "met criteria" or "did not meet criteria " so they are not stratified by severity. Dependent Variable (WHO - DAS II Categories) The Wo rld Health Organization Disability Assessment Schedule II (WHO - DAS II) is an instrument that was designed to measure previous 30 - day functioning and disability among diverse cultures and populations . 32,33 This assessment is based on the International Class ification of Functioning, Disability, 10 and Health framework. 34 The WHO - DAS II assessment is comprised of 32 items, which examine six functional domains of daily life. The six domains include: self - care, cognition, physical mobility, role impairment, social interaction, and time out of role. As a result, this assessment generates six individual domain scores. 35 During the assessment, participants are asked to state the intensity of difficulty when performing the domain activity. Additionally, for every item, participants have to approximate the level of disability for the previous 30 days using a five - point scale. 36 All scores are calculated and can range from 0 - 100, with h igher scores representing more disability. The WHO - DAS II will allow for an analysis of specific functioning domains across levels of leisure - time physical activity. Previous research evaluating the WHO - DAS II categories suggest s acceptable internal consistency and test - retest reliability. 34 Independent Variable (Leisure - T ime P hysical A ctivi ty) Leisure - time physical activity will be measured using the question: "how often do you engage in active sports or exercise?" Possible responses to this question are: often, sometimes, rarely, or never. Scores for leisure - time physical activity will be coded: 1 = never, 2 = rarely, 3 = sometimes, and 4 = often. Therefore, a higher number will represent more physical activity. The reference category used for analyses was the "often" category. The "often" category was used as the reference group because it is an extreme value, and also because it represents the most normative group. Covariates The covariates that will be included in the analysis are: self - reported BMI, household income, education level, self - report of physical health, city type, and DSM - I V Major Depressive Disorder. Inclusion and Exclusion C riteria To be included in this study, individuals m ust be 18 - years of age or older, and meet criteria for a 12 - month diagnosis of one of the following anxiety disorders: generalized anxiety disorder, social phobia, agoraphobia with or without panic disorder, panic disorder, adult separation anxiety disorder, or 11 PTSD. Individuals were excluded from this study if they did not meet the inclusion criteria. Additionally, those with missing information on co variates, or the dependent or independent variables , were excluded from all analyses (Figure 1.). Analyse s Analyses will be performed in STATA 13.1. Weights were designed specifically for the NSAL to account for the complex sampling procedure, and wi ll be used for this analysis. The dependent variable is the WHO - DAS II score, which was coded as a dummy variable, 0=no impairment, and 1=at least some impairment. If the WHO - DAS II score was recorded as a 0 it was recoded to 0. If the WHO - DAS II score was recorded as greater than 0, then it was recoded NSAL N = 6,082 Excluded n = 5,409 Did not meet criteria for an anxiety disorder Included n = 673 Met criteria for an anxiety disorder Excluded n = 125 Missing information Final analytical sample n = 548 Met all inclusion criteria Figure 1. Inclusion and Exclusion Flow Chart 1 2 as a 1. The independent variable is a categorical variable: Leisure - time physical activity, which can be answered as: often, sometimes, rarely, or never. Multivariable models will be built for each WHO - DAS I I category of impairment using the seven step purposeful selection procedure described by Hosmer, Lemeshow, and Sturdivant. 37 Significant variables will be noted and added in as interaction terms with leisure - time physical activity to examine effects of ef fect modification. Logistic regression will be used to compute odds ratios as well as 95% confidence intervals for each WHO - DAS II category. T - tests and Pearson Chi - square tests will also be computed to look for statistically significant differences. 13 R ES ULTS Demographics The demographics of the sample are describ ed in Table 1 a . There were 548 participants from the NSAL who met the inclusion criteria. Race/ethnic groups were divided into African Ame rican (n=336), Non - Latino Whites (n=74) , and Afro - Caribbean and Hispanic (n=138) . The statistics used for Table 1a. and 1b. tested each variable to see if there were differences between any of the three racial /ethnic groups. This table only tests for differences between the three groups, it doe s not test for race to race differences. Differences betw een the three racial/ethnic groups were found for BMI (p = 0.006), Education (p = 0.01), and City Type (p = 0.008). This sample consisted of 402 women (73.36%), and 146 men (26.64%). Thus, i n this s ample women were 2.75 times more likely to meet criteria for an anxiety disorder. The majority of the sample was between the ages of 25 and 44. 14 African - American n = 336 Non - Latino Whites n = 74 All Other Hisp/ Afro - Caribbean n = 138 P - Value SEX 0.20 Male 39 (53.28) 80 (29.72) 27 (39.20) Female 99 (46.72) 256 (70.28) 47 (60.80) AGE 0.2 0 < 24 72 (24.10) 3 (8.99) 36 (29.59) 25 - 44 155 (43.75) 36 (50.87) 69 (53.37) 45 - 54 66 (19.73) 19 (18.07) 20 (7.57) > 55 43 (12.42) 16 (22.07) 13 (9.46) BMI 0.006* < 18.5 7 (2.48) 0 (0) 1 (0.88) 18.5 - 24.9 89 (25.57) 29 (47.49) 53 (21.94) 25.0 - 29.9 94 (27.24) 18 (22.09) 43 (42.16) 30.0 - 34.9 82 (25.60) 15 (20.33) 20 (6.86) > 35 64 (19.12) 12 (10.09) 21 (28.17) EDUCATION 0.01* 0 - 11 Years 112 (31.05) 13 (13.63) 25 (24.96) 12 Years 116 (34.16) 22 (37.65) 41 (25.14) 13 - 15 Years 66 (22.17) 17 (17.27) 40 (26.50) > 16 Years 42 (12.62) 22 (31.45) 32 (23.40) Physical Health Rating 0.82 Very Good 117 (31.57) 26 (38.30) 60 (42. 02) Good 105 (34.06) 23 (29.32) 43 (34.41) Fair 86 (26.39) 19 (23.40) 27 (20.44) Poor 28 (7.99) 6 (8.97) 8 (3.13) MDD12 0.54 Met Criteria 66 (19.99) 20 (24.90) 26 (17.86) Did Not Meet Criteria 270 (80.01) 54 (75.10) 112 (82.14) City Type 0.008* Rural Area 62 (16.64) 25 (38.43) 17 (8.18) Small Town 62 (17.73) 16 (17.29) 18 (18.20) Small City 53 (14.24) 11 (11.16) 12 (9.75) Suburb of City 24 (8.32) 8 (16.57) 17 (14.48) Large City 129 (41.31) 12 (14.92) 71 (47.55) Other 6 (1. 76) 2 (1.63) 3 (1.84) Household Income 0.45 < 17,999 161 (39.41) 23 (33.31) 40 (23.87) 18,000 - 31,999 80 (25.22) 18 (21.30) 41 (28.08) 32,000 - 54,999 65 (22.03) 16 (20.80) 31 (24.23) > 55,000 30 (13.34) 17 (24.60) 26 (23.82) LTPA 0.48 Often 89 (26.61) 20 (26.79) 37 (21.71) Sometimes 89 (27.14) 26 (30.38) 42 (31.50) Rarely 66 (20.47) 11 (14.15) 36 (35.34) Never 92 (25.78) 17 (28.67) 23 (11.46) *indicates p < 0.05 Table 1a. Descriptive S tatis tics by Race/Et hnicity G roup ( n = 548). unweighted n (weighted %) 15 Anxiety Disorder Diagnoses Table 1 b . summarize s counts and weighted percentages fo r all anxiety disorder diagnosis categories. Differences between racial/ethnic groups were only seen for social anxiety (p = 0.002), and agoraphobia without panic disorder (p = 0.046). Data was not available on Adult Separation Anxiety Disorder and PTSD fo r Non - Latino Whites. The most common diagnoses were Social Anxiety Disorder, PTSD, and Generalized Anxiety Disorder. African - American Non - Latino Whites All Other Hisp/ Afro - Caribbean P - Value Generalized Anxiety 0.13 Met Criteria 57 (16.79) 23 (29.37) 22 (14.98) Social Anxiety 0.002* Met Criteria 123 (37.02) 51 (66.80) 57 (34.96) Agoraphobia w/o Panic 0.046* Met Criteria 52 (15.20) 5 (5.71) 15 (12.93) Agoraphobia w/ Panic 0.14 Met Criteria 34 (9.19) 3 (2.99) 10 (5.04) Panic Disorder 0.19 Met Criteria 66 (17.41) 20 (25.76) 27 (17.57) Adult Separation Anxiety 0.23 Met Criteria 58 (17.99) NA 26 (12.30) PTSD 0.82 Met Criteria 102 (30.52) NA 36 (33.16) Table 1b. Descriptive S tatistics for A nxiety D isorders by Race/Ethnicity G roup . unweighted n (weighted %) *indicates p < 0.05 16 Impai rment Table 2 . illustrate s the unweighted number and weighted percent with at least some impairment among those meeting criteria for a 12 - month anxiety disorder. The out of role category has the largest number of participants for each racial group with a t least some impairment. There is no significant difference between racial groups for all WHO - DAS II categories. n % p - value SELF CARE 0.28 All Other Hisp/Afro - C 10 3.73 African American 28 7.98 Non - Latino Whites 10 12.93 COGNITION 0.28 All Other Hisp/Afro - C 45 31.06 African American 107 32.99 Non - Latino Whites 30 43.4 PHYSICAL MOBILITY 0.59 All Other Hisp/Afro - C 44 30.37 African American 121 36.91 Non - Latino Whites 28 31.11 ROLE IMPAIRMENT 0.63 All Other Hisp /Afro - C 68 44.66 African American 194 57.63 Non - Latino Whites 46 52.53 SOCIAL INTERACTION 0.06 All Other Hisp/Afro - C 31 20.93 African American 86 24.98 Non - Latino Whites 28 40.13 OUT OF ROLE 0.61 All Other Hisp/Afro - C 77 50.66 African American 209 62.48 Non - Latino Whites 49 56.85 Table 2. World Health Organization Disability Assessment Scales - II number and percent ( unweighted n, weighted %) with at least some impairment among those meeting criteria for a 12 - month anxiety disorder. *indicates p < 0.05 17 WHO - DAS II Self Care The odds of having at least some impairment in the self - care category for those who sometimes partake in LTPA are 7.6 3 (1.17 - 49.87) times larger (p=0.03) than that of tho se who partake in often LTPA (Table 3 .). Additionally, the odds of having at least some impairment in the self - care category for those who self reported fair physical health are 5.7 4 (1.97 - 16.76) times larger than that of those who self reported very good physical health (p=0.002). OR Linearized SE p - value 95% CI LL 95% CI UL LTPA Often REF Sometimes* 7.63 7.18 0.03 1.17 49.87 Rarely 3.73 3.31 0.14 0.63 21.96 Never 6.39 6.47 0.07 0.85 48.19 Physical Health Rate Very Good REF Goo d 1.20 0.80 0.79 0.32 4.51 Fair* 5.74 3.08 0.002 1.97 16.76 Poor 3.14 2.35 0.13 0.70 14.01 Table 3. WHO - DAS II Self Care Model. *Indicates p < 0.05 18 WHO - DAS II Cognition After adjusting for age, self - rated physical health, Major Depressive Disorder, and city type, t he odds of having at lea st some impairment in the cognitive category for those who rarely partake in LTPA are 90% times smaller (p=0.006 ) than that of those who partake in often LTPA (Table 4 .). Additionally, there was a significant interaction between self - rated physical health and LTPA that was included in the model . OR Linearized SE p - value 95% CI LL 95% CI UL LTPA Often REF Sometimes 2.15 1.19 0.17 0.72 6.49 Rarely* 0.1 0.08 0.006 0.02 0.51 Never 1.48 1.69 0.73 0.15 14.4 Age 18 - 24 REF 25 - 44 0.82 0 .32 0.61 0.37 1.79 45 - 54 1.08 0.45 0.85 0.47 2.5 55+ 0.36 0.23 0.11 0.11 1.26 Physical Health Rate Very Good REF Good 1.38 0.76 0.55 0.46 4.13 Fair 2.95 1.76 0.07 0.9 9.68 Poor 2.58 3.69 0.51 0.15 44.53 Major Depressive Disorder Met Criteria REF Did not meet criteria* 0.46 0.16 0.03 0.23 0.91 City Type Rural Area REF Small Town 0.68 0.28 0.35 0.3 1.54 Small City 1.8 0.72 0.15 0.81 4.01 Suburb of City* 3.65 1.82 0.01 1.35 9.88 Large City 1.07 0.33 0.83 0.58 1.97 Ot her 0.57 0.53 0.55 0.09 3.72 Table 4. WHO - DAS II Cognition Model. *i ndicates p < 0.05 19 WHO - DAS II Physical Mobility A fter controlling for confounders there is no significant association between LTPA and physical mobility impairment (Table 5 ). However, as the self report of physical health gets worse, the odds of having at least some impairment in the physical mobility category increase. The odds of having at least some impairment in the physical mobility category for those who self rated their physical health as good are 3.21 times larger than that of those w ho self rated their physical health as very good (p=0.02). The odds of having at least some impairment for those who self rated their physical health as fair are 4.67 times greater compared to those who self rated their physical health as very good (p=0.00 4 ). The odds of having at least some impairment for those who self rated their physical health as poor are 60.48 times larger than that of those who self rated their physical health as very good (p<0.001) . OR Linearized SE p - value 95% CI LL 95% CI UL L TPA Often REF Sometimes 1.6 0.6 0.22 0.76 3.38 Rarely 0.85 0.45 0.76 0.29 2.46 Never 1.5 0.65 0.35 0.63 3.56 Physical Health Rate Very Good REF Good* 3.21 1.56 0.02 1.22 8.45 Fair* 4.67 2.41 0.004 1.67 13.08 Poor* 60.48 44.88 <0. 001 13.76 265.86 City Type Rural Area REF Small Town 1.96 1.12 0.25 0.62 6.13 Small City* 2.75 1.25 0.03 1.12 6.79 Suburb of City 1.38 0.92 0.63 0.36 5.2 Large City 1.27 0.6 0.62 0.5 3.23 Other 2.47 2.44 0.36 0.34 17.69 Table 5. WHO - DAS II Physical Mobility Model. *indicates p < 0.05 20 WHO - DAS II Role Im pairment After adjusting for age, self rated physical health, Major Depressive Disorder, and income, t he odds of having at least some impairment in the role impairment category for those who rarely partake in LTPA are 93% times smaller (p=0.02) compared t o those who often partake in LTPA (Table 6 a .). Additionally, there were interactions between LTPA and income, self rated physical health, and sex that were accounted for in the model . Thus, the effect of LTPA on role impairment is different for different v alues of income, self rated physical health, and sex. T here was a significant interaction between LTPA and Gender (Table 6b.) . Shown in Table 6b, females have a protective advantage for the role impairment category, and the odds of having at least some imp airment are significantly smaller for the women who participate in LTPA less. 21 Male Female LTPA Adjusted OR (95% CI) p - value Adjusted OR (95% CI) p - value Often REF Sometimes 0.74 ( - 0.32, 1.80) 0.17 0.98 (0.21, 1.76) 0.01* Rarely 0.20 ( - 0.11, 0.52) 0.21 0.78 (0. 23, 1.33) 0.005* Never 1.42 ( - 0.37, 3.21) 0.12 0.55 (0.13, 0.98) 0.01* OR Linearized SE p - value 95% CI LL 95% CI UL LTPA Often REF Sometimes 0.77 0.93 0.83 0.07 8.61 Rarely* 0.07 0.08 0.02 0.01 0.69 Never 2.71 2.81 0.34 0. 34 21.48 Age 18 - 24 REF 25 - 44 1.6 0.66 0.26 0.71 3.65 45 - 54* 3.21 1.48 0.01 1.27 8.07 55+ 0.65 0.36 0.44 0.22 1.96 Physical Health Rate Very Good REF Good 1.81 0.96 0.27 0.63 5.2 Fair* 3.51 2 0.03 1.12 10.97 Poor 2.67 3.16 0.41 0 .25 28.4 Major Depressive Disorder Met Criteria REF Did not meet criteria* 0.47 0.13 0.009 0.27 0.82 Income < 17,999 REF 18,000 - 31,999 2.11 1.15 0.18 0.71 6.24 32,000 - 54,999* 11.1 8 0.001 2.64 46.74 55,000+ 1.06 0.6 0.92 0.34 3.3 Sex Male REF Female 2.06 0.97 0.13 0.81 5.25 Table 6a. WHO - DAS II Role Impairment Model. *indicates p < 0.05 Table 6b. Role Impairment Interaction between LTPA and Sex. *indicates p < 0.05 22 WHO - DAS II Social Interaction Afte r adjusting for age , education, self rated physical health, and Major Depressive Disorder, t he odds of having at least some impairment in the soc ial interaction category for those who sometimes partake in LTPA are 83% times smaller (p=0.04) compared to those who often partake in LTPA (Table 7 a .). While, the odds of having at least some impairment in the social interaction category for those who rar ely partake in LTPA are 94% times smaller (p=0.01) compared to those who often partake in LTPA. There was also a significant interaction between LTPA and MDD that was added to the model (Table 7b.) . The odds of having at least some impairment are 4.29 time s larger (p = 0.03) for those who partake in LTPA sometimes, and did not meet criteria for MDD. Additionally, for social interaction impairment, increasing in age is a protective factor. As participants age d the odds of having at least some impairment de creases. The odds of having at least some impairment for those ages 25 - 44 are 60% times smaller (p=0.03) compared to that of those aged 18 - 24. The odds of having at least some impairment for those ages 45 - 54 are 77% times smaller (p=0.004) compared to that of those aged 18 - 24. While the odds of having at least some impairment for those ages 55 and older are 84% times smaller (p<0.001) compared to that of those aged 18 - 24. 23 OR Linearized SE p - value 95% CI LL 95% CI UL LTPA Often REF Som etimes* 0.17 0.15 0.04 0.03 0.95 Rarely* 0.06 0.06 0.01 0.01 0.50 Never 0.23 0.22 0.12 0.04 1.49 Age 18 - 24 REF 25 - 44* 0.4 0.17 0.03 0.18 0.92 45 - 54* 0.23 0.11 0.004 0.08 0.61 55+* 0.16 0.08 <0.001 0.06 0.42 Education 0 - 11 Years REF 12 Years 1.23 0.7 0.72 0.39 3.84 13 - 15 Years 1.85 0.82 0.17 0.76 4.49 >=16 Years* 4.81 2.56 0.004 1.67 13.89 Physical Health Rate Very Good REF Good 0.83 0.37 0.68 0.35 2.00 Fair 2.74 1.63 0.10 0.83 9.00 Poor 1.98 1.65 0.42 0.37 10.45 Major Depressive Disorder Met Criteria REF Did not meet criteria* 0.02 0.01 <0.001 0.005 0.09 Met Criteria for MDD Did Not Meet Criteria for MDD LTPA Adjusted OR (95% CI) p - value Adjusted OR (95% CI) p - value Often REF Sometimes 0.1 7 ( - 0.12, 0.46) 0.24 4.29 (0.37, 8.21) 0.03* Rarely 0.06 ( - 0.07, 0.19) 0.34 1.53 ( - 0.04, 3.10) 0.06 Never 0.23 ( - 0.19, 0.65) 0.29 9.66 ( - 2.43, 21.75) 0.12 Table 7a. WHO - DAS II S ocial Interaction Model. *indicates p < 0.05 Table 7b. Social Interaction Impairment Interaction between LTPA and MDD. *indicates p < 0.05 24 WHO - DAS II Out of Role After adjusting for age, self rated physical health, Major Depressive D isorder, income, and sex, there were still no significant associations between LTPA and out of role impairment (Table 8a .). However, never partaking in LTPA compared to often LTPA is trending toward significance (p=0.06). There were also significant intera ctions between LTPA and income, and LTPA and sex added to the multivariable model. On the other hand , each self reported level of physical health increases the odds of impairment when compared to very good reported health. In addition , t he odds of having a t least some impairment in the out of role category for those ages 45 - 54 are 2.75 times larger (p=0.03) compar ed to that of those aged 18 - 24. The odds of having at least some impairment in this category for those who partake in LTPA sometimes and are fema le are 1.06 times larger than that of those who partake in often LTPA (Table 8b.) . However, the odds of having at least some impairment are 31% times, and 45% times smaller for the women who participate in LTPA rarely or never, respectively. 25 OR Linearized SE p - value 95% CI LL 95% CI UL LTPA Often REF Sometimes 0.74 0.75 0.77 0.1 5.54 Rarely 0.34 0.34 0.29 0.05 2.5 Never 5.3 4.74 0.06 0.89 31.55 Age 18 - 24 REF 25 - 44 1.63 0.66 0.23 0.73 3.65 45 - 54* 2.75 1.26 0.03 1.1 6. 87 55+ 0.52 0.27 0.22 0.18 1.48 Physical Health Rate Very Good REF Good* 2.83 1.17 0.01 1.24 6.45 Fair* 8.71 3.64 <0.001 3.79 20.04 Poor* 4.04 2.6 0.03 1.12 14.62 Major Depressive Disorder Met Criteria REF Did not meet criteria* 0.49 0.16 0.03 0.25 0.94 Income < 17,999 REF 18,000 - 31,999 2.37 1.93 0.29 0.47 12.05 32,000 - 54,999* 6.43 4.54 0.01 1.57 26.31 55,000+ 0.92 0.61 0.9 0.25 3.45 Sex Male REF Female 1.32 0.85 0.66 0.37 4.75 Male Female LTPA Adjusted OR (95% CI) p - value Adjusted OR (95% CI) p - value Often REF Sometimes 0.62 ( - 0.41, 1.65) 0.24 1.06 (0.14, 1.99) 0.025* Rarely 0.28 ( - 0.16, 0.71) 0.22 0.69 (0.16, 1.22) 0.01* Never 1.01 ( - 0.49, 2.51) 0.19 0.55 (0.05, 1.04) 0.03* Table 8a. WHO - DAS II Out of Role Model. *indicates p < 0.05 Table 8b. Out of Role Impairment Interaction betwee n LTPA and Sex. *indicates p < 0.05 26 D I S C U S S I O N H1: I hypothesize d that as the level of leisure - time physical activity increases , the odds of having at least some i mpairment will decrease. As the level of leisure - time physical activity increased, the odds of having at least some impairment did not d ecrease. Thus, this hypothesis is rejected. In the self - care category, the odds of impairment were highest for the sometimes category when compared to the often category. H2: I hypothesize d that those who partake in leisure - time physical activity rarely or never will be more likely to have at least some impairment in each functioning category compared to those who partake in leisure - time physical activity often or sometimes. Rarely participating in leisure - time physical activity had a significant protec tive effect against at least some impairment in the cognition, role impairment, and social interaction categories. In the social interaction category, sometimes partaking in leisure - time physical activity also had a significant protective effect against at least some impairment. Thus, this hypothesis is rejected. However, in the self care and the out of role categories, never participating in leisure - time physical activity was trending towards significance for increasing the odds of impairment in those cate gories. H3: I hypothesize d that there will be a protective effect for those who partake in leisure - time physical activity often or sometimes, especially in the cognition, mobility, and role functioning categories. There was not a protective effect for th ose who participated in leisure - time physical activity often or sometimes in the cognition, mobility, or role functioning categories. Thus, this hypothesis is rejected. However, there was a protective effect for those who participated in leisure - time physi cal activity sometimes in the social interaction category. Results of this study suggest that among those with an anxiety disorder, LTPA is associated with the self - care, cognition, role impairment, and social interaction categories of the WHO - DAS II. It is those 27 who sometimes partake in LTPA who are at an increased risk of self care impairment compared to those who often partake in LTPA. Also, the odds of having at least some cognitive impairment are smaller for those who rarely partake in LTPA than that of those who partake in often LTPA. Additionally, the odds of having role impairment is significantly smaller for those who rarely partake in LTPA compared to those who partake in often LTPA. For the role impairment category, females have a protective adva ntage compared to males, and the odds of having at least some impairment are smaller for the women who participate in LTPA less. Lastly, the odds of having social interaction impairment among those who rarely or sometimes partake in LTPA are significantly smaller compared to those who often partake in LTPA. For the social interaction category, t he odds of having at least some impairment are larger for those who partake in LTPA sometimes, and did not meet criteria for MDD. According to these findings , those who never partake in LTPA are neither protected nor at an increased risk for impairment. In addition to the self rated physical health measures, other variables such as age , income, and MDD diagnosis also seem to greatly affect the association between LT PA and impairment . Not meeting the criteria for MDD significantly reduces the odds of impairment for the cognition, role impairment, social interaction, and out of role categories. This result is concurrent with previous literature, which states that those with depression or depressive symptoms may not partake in physical activity due to apathy or low levels of energy. 38 For the social interaction category, being greater than ages 18 - 24 significantly reduces the odds for impairment, and continues to reduces the odds of impairment as age increases. However, those between the ages of 45 - 54 have an increased odds of at least some impairment for the role impairment and out of role categories. To my knowledge, this is the first study of physical activity and anx iety disorders, which focuses specifically on anxiety disorders, in addition to examining the relationship between physical activity and previous 30 - day functioning. Previous research on physical activity and mental health mainly focus on the prevalence or number of symptoms of anxiety and depressive disorders. This previous research 28 suggests that leisure - time physical activity is associated with lower prevalence of anxiety and mood disorders. 25 Other research suggests that light physical activity, and mode rate to vigorous physical activity is associated with lower rates of reported symptoms of anxiety and depression. 29 These findings are very informative, however, the dependent variable in this study is quite different compared to previous literature. Rath er than addressing the prevalence , or the number of symptoms associated with anxiety disorders, this study looked at impairment in previous 30 - day functioning. The results of this study are intriguing. Perhaps individuals with an anxiety disorder do not pa rtake in LTPA because it makes them too anxious. The sample of this study includes those with agoraphobia, panic disorder, and social anxiety. These anxiety disorders can result in avoiding people, places, and certain situations, such as leaving the house. Another possibility is that individuals with an anxiety disorder are sicker than a normal population, and are therefore, not as inclined to participate in physical activity. The results of this study are curious , which could in part be due to the unique all anxiety sample . Future studies should try using the "never" cat egory as the reference category to see if it clarifies and simplifies the interpretation. Future studies should also try grouping often, sometimes, and rarely together, and compare it to t he never category to see if this has an impact on the results. LTPA could also be made binary by combining often and sometimes, as well as rarely and never together. Further research should be done using a cohort design to better assess the impact of p hysi cal activity on functioning, and include a larger sample of individuals with anxiety disorders. Strengths The strengths of this study should be noted . First, this sample was from the National Survey of American Life (NSAL), which is a national household probability sample survey. Second, a modified version of the World Mental Health Composite International Diagnostic Interview (WMH - CIDI) was used to make diagnoses based on the Diagnostic and Statistical Manual (DSM - IV - TR) criteria for mental 29 disorders. Th us, clinical diagnoses were assessed rather than anxiety symptoms, which results in more accurate but conservative estimates. Additionally, seven different types of anxiety disorders were included in the analysis. Third, the NSAL was a very detailed surve y, thus a wide range of potential confounders could be accounted for. Lastly, this is the first study to use the WHO - DAS II to look at the effect of leisure - time physical activity on previous 30 - day functioning for those with a clinically diagnosed anxiety disorder. Limitations When interpreting these results it is important to take into account the limitations of this study. First, including only those with an anxiety disorder resulted in a relatively small sample size of 548. Thus, for some of the analy ses small cell sizes and statistical power were problematic, which led to large standard errors and confidence intervals. Examining a larger dataset would increase power and reduce small cell sizes. S econd, the NSAL sample was designed to assess African A mericans and Afro - Caribbeans. It would be interesting to do the same study with a larger sample with a wide r range of races. Since the sample size was relatively small the distribution of males to females was also disproportionate. Third, this is a cross - s ectional study , so no temporal association can be established . Lastly, only one question, which was self - reported, was used to measure the amount of physical activity. The physical health rating was also self reported. Thus, for future research a better me thod for measuring physical activity is needed. Conclusion In 2010, anxiety disorders were classified as the sixth leading cause of disability, in terms of years of life lived with disability (YLD) in high - , middle - , and low - income countries. 1 Additionall y, in any given year in the United States, anxiety disorders affect approximately 40 million Americans who are 18 years or older. 6 Thus, anxiety disorders are highly prevalent, and are chronic conditions that impact quality of life. Therefore, public healt h efforts need to be taken to find effective ways to help prevent 30 and treat these disorders. Public health focus shoul d not only include treating symptoms, but should also focus on helping individual s attain greater functionality by reducing impairments th at lead to a l ower quality of life. This study focused on the functionality aspect of treatment, by examining the association between physical activity and previous 30 - day functioning for those with an anxiety disorder. T he results presented here imply t hat leisure - time physical activity does impact various categories of previous 30 - day functioning for those with a clinically diagnosed anxiety disorder. However, compared to those who partake in LTPA often, those who never partake in LTPA are neither prote cted nor at an increased risk for impairment. Based on this study, public health of ficials should note that promoting leisure - time physical activity may not be the best approach to improve daily functioning for those with an anxiety disorder. Public health experts should research other possible ways to improve daily functioning and quality of life for those with an anxiety disorder. 31 REFERENCES 32 REFERENCES 1. Baxter AJ, Vos T, Scott KM, Ferrari AJ, Whiteford HA. The global burden of anxiety disorders in 2010. Psychol Med. 2014;:1 - 12. 2 . Bloom DE, Cafiero ET, Jané - Llopis E, Abrahams - Gessel S, Bloom LR, Fathima S, Feigl AB, Gaziano T, Mowafi M, Pandya A, Prettner K, Rosenberg L, Seligman B, Stein A, Weinstein, C. (2011). The Global E conomic Burden of Non - communicable Diseases. Geneva: World Economic Forum. 3. Kessler RC, Aguilar - Gaxiola S, Alonso J, Chatterji S, Lee S, Ormel J, Ustün TB, Wang PS. The global burden of mental disorders: an update from the WHO World Mental Health (WMH) s urveys. Epidemiol Psichiatr Soc 2009;18(1):23 33. 4 . Greenberg PE, Sisitsky T, Kessler RC, Finkelstein SN, Berndt ER, Davidson JR, Ballenger JC, Fyer AJ. The economic burden of anxiety disorders in the 1990s. J Clin Psychiatry 1999;60(7):427 35. 5 . Soni, A nita. The Five Most Costly Conditions, 1996 and 2006: Estimates for the U.S. Civilian Noninstitutionalized Population. Statistical Brief #248. July 2009. Agency for Healthcare Research and Quality, Rockville, MD. 6 . Kessler RC, Chiu WT, Demler O, Walters E E. Prevalence, severity, and comorbidity of twelve - month DSM - IV disorders in the National Comorbidity Survey Replication (NCS - R). Archives of General Psychiatry , 2005 Jun;62(6):617 - 27. 7 . World Health Organization. (WHO 2011a). Global status report on non - communicable diseases 2010. Geneva: WHO. 8 . The Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM 5 ; American Psychiatric Association, 2013). 9 . Kessler RC, Petukhova M, Sampson NA, et al: Twelve - month and lifetime prevalence and lifetime morbid risk of anxiety and mood disorders in the US. Int J Methods Psychiatr Res 21(3):169 184, 2012. 10 . Lewis - Fernández R, Hinton DE, Laria AJ, et al: Culture and the anxiety disorders: recommendations for DSM - V. Depress Anxiety 27(2):212 229, 2010. 11 . Seedat S , Scott KM , Angermeyer MC , et al: Cross - national associations between gender and mental disorders in the World Health Organization World Mental Health Surveys . Arch Gen Psychiatry 66 ( 7 ): 785 795 , 2009. 12 . Mohlman J , Bryant C , Lenze EJ , et al: Impr oving recognition of late life anxiety disorders in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition : observations and recommendations of the Advisory Committee to the Lifespan Disorders Work Group . Int J Geriatr Psychiatry 27 ( 6 ): 549 55 6 , 2012 10.1002/gps.2752. 33 13 . Fehm L , Pelissolo A , Furmark T , Wittchen HU : Size and burden of social phobia in Europe . Eur Neuropsychopharmacol 15 ( 4 ): 453 462 , 2005. 14 . Wittchen HU , Gloster AT , Beesdo - Baum K , et al: Agoraphobia : a review of the diagnostic classificatory position and criteria . Depress Anxiety 27 ( 2 ): 113 133 , 2010. 15 . Craske MG , Kircanski K , Epstein A , et al: Panic disorder : a review of DSM - IV panic disorder and proposals for DSM - V . Depress Anxiety 27 ( 2 ): 93 112 , 2010. 16 . Goodwin RD , Faravell i C , Rosi S , et al: The epidemiology of panic disorder and agoraphobia in Europe . Eur Neuropsychopharmacol 15 ( 4 ): 435 443 , 2005. 17 . Shear K , Jin R , Ruscio AM , et al: Prevalence and correlates of estimated DSM - IV child and adult separation anxiety disorder in the National Comorbidity Survey Replication . Am J Psychiatry 163 ( 6 ): 1074 1083 , 2006. 18 . Kessler RC , Berglund P , Demler O , et al: Lifetime prevalence and age - of - onset distributions of DSM - IV disorders in the National Comorbidity Survey Replication . Arch Gen Psychiatry 62 ( 6 ): 593 602 , 2005a. 19 . Beals J , Manson SM , Shore JH , et al: The prevalence of posttraumatic stress disorder among American Indian Vietnam veterans : disparities and context . J Trauma Stress 15 ( 2 ): 89 97 , 2002. 20 . Hinton D , Lewis - Fernández R : The cross - cultural validity of posttraumatic stress disorder : implications for DSM - 5 . Depress Anxiety 28 ( 9 ): 783 801 , 2011 . 21 . Mendlowics MV, Stein MB. Quality of life in individuals with anxiety disorders. American Journal of Psychiatry 2000;157:669 - 6 82. 22 . Stein MB, Roy - Byrne PP, Craske MG, et al. Functional impact and health utility of anxiety disorders in primary care outpatients. Med Care 2003;12:34 - 43. 23 . Ströhle A, Höfler M, Pfister H, et al. Physical activity and prevalence and incidence of me ntal disorders in adolescents and young adults. Psychol Med. 2007;37(11):1657 - 66. 24 .Sanchez - villegas A, Ara I, Guillén - grima F, Bes - rastrollo M, Varo - cenarruzabeitia JJ, Martínez - gonzález MA. Physical activity, sedentary index, and mental disorders in the SUN cohort study. Med Sci Sports Exerc. 2008;40(5):827 - 34. 25 . Ten have M, De graaf R, Monshouwer K. Physical exercise in adults and mental health status findings from the Netherlands mental health survey and incidence study (NEMESIS). J Psychosom Res. 20 11;71(5):342 - 8. 26 . Dunn AL, Trivedi MH, O'Neal HA. Physical activity dose response effects on outcomes of depression and anxiety. Med Sci Sports Exerc. 2001;33(6 suppl):S587 - 97. 27 . Dunn AL, Trivedi MH, Kampert JB, et al. Exercise treatment for depression : efficacy and dose response. Am J Prev Med. 2005;28 - 1 - 8. 28 . Torres ER, Sampselle CM, Ronis DL, Neighbors HW, Gretebeck KA. Leisure - time physical activity in relation to depressive symptoms in African - Americans: results from the National Survey of America n Life. Prev Med. 2013;56(6):410 - 12. 34 29 . Jonsdottir IH, Rödjer L, Hadzibajramovic E, Börjesson M, Ahlborg G. A prospective study of leisure - time physical activity and mental health in Swedish health care workers and social insurance officers. Prev Med. 201 0;51(5):373 - 77. 30 . Heeringa, S.G., Wagner, J., Torres, M., Duan, N., Adams, T., Berglund, P., 2004. Sample designs and sampling methods for the Collaborative Psychiatric Epidemiology Studies (CPES). Int. J. Methods Psychiatr. Res. 13, 221 - 240. 31 . http:// www.rcgd.isr.umich.edu/prba/nsal 32 . World Health Organization (WHO). (2000) World Health Organization: Disability Assessment Schedule II (WHO - DAS II) , Geneva, WHO. 33 . Galindo - garre F, Hidalgo MD, Guilera G, Pino O, Rojo JE, Gómez - benito J. Modeling the W orld Health Organization Disability Assessment Schedule II using non - parametric item response models. Int J Methods Psychiatr Res. 2015;24(1):1 - 10. 34 . Von korff M, Crane PK, Alonso J, et al. Modified WHODAS - II provides valid measure of global disability b ut filter items increased skewness. J Clin Epidemiol. 2008;61(11):1132 - 43. 35 . Chwastiak LA, Von Korff M. Disability in depression and back pain evaluation of the World Health Organization Disability Assessment Schedule (WHO DAS II) in a primary care setti ng. Journal of Clinical Epidemiology. 2003;56:507 - 514. 36 . Luciano JV, Ayuso - mateos JL, Aguado J, et al. The 12 - item World Health Organization Disability Assessment Schedule II (WHO - DAS II): a nonparametric item response analysis. BMC Med Res Methodol. 201 0;10:45. 37 . Jr. DW, Lemeshow S, Sturdivant RX. Applied Logistic Regression. John Wiley & Sons; 2013. 38 . Azevedo da silva M, Singh - manoux A, Brunner EJ, et al. Bidirectional association between physical activity and symptoms of anxiety and depression: the Whitehall II study. Eur J Epidemiol. 2012;27(7):537 - 46.