Measuring physical activity with the behavioral risk factor surveillance system.

PURPOSE AND METHODS: Because regular physical activity reduces the risk of premature death and disability, accurate methods of population-based measurement are important for public health surveillance efforts such as those based on the Behavioral Risk Factor Surveillance System (BRFSS). The present study: 1) briefly reviews and compares currently available methods to measure physical activity using BRFSS data, 2) describes physical activity patterns in the United States using these state-aggregated measures, and 3) provides suggestions on future directions for practitioners and researchers. Using a random-digit dialing, telephone survey, we collected data for noninstitutionalized adults aged 18 yr and older. We analyzed BRFSS data for 1996 from 50 states and the District of Columbia and Puerto Rico (N = 124,085). Based on recent literature and public health priorities, we developed eight different physical activity indices (one vigorous and seven moderate). These varied in their threshold for duration, kcal expenditure, and in frequency and intensity of activity. RESULTS: Using different algorithms, the population prevalence of moderate physical activity ranged from about 20% to 38%. Only 20% of adults met the Healthy People 2000 definition for regular, sustained activity (> or =30 min of moderate activity per day for at least 5 d x wk(-1)). CONCLUSIONS: Considerable progress is needed if the United States is to reach the current public health goal for regular physical activity. Standardized approaches to analyzing and collecting physical activity data are essential for public health surveillance, policy making, and communication to the public.

Reliability and validity issues concerning large-scale surveillance of physical activity.

The BRFSS is our major source of population-based information on physical activity in the United States. The top priority for the immediate future should be to make sure that the information obtained from the BRFSS in its current form is both reliable and valid. As outlined in this report, this task could be completed in relatively short time frame and at reasonable cost in terms of both financial and human resources. The development of an additional module to assess light-to-moderate activity and strength is currently underway with support from the CDC. As suggested in this report, this task may prove to be extremely difficult, or it may be difficult to develop an instrument of this type given the constraints of a population based telephone survey. The current focus on the health benefits of moderate activity and the interest in tracking this type of activity behavior on a population basis as it relates to national physical activity objectives both argue in favor of developing a physical activity assessment instrument that provides a valid and reliable measurement of moderate activity. Given the complexity and uncertainty of this task it is important to develop a procedure that will allow for periodic evaluation of progress and the potential for success to minimize the risk of making a considerable financial investment in an instrument that may be of limited utility.

The quantity and quality of physical activity among those trying to lose weight.

BACKGROUND: Regular exercise to elicit caloric expenditure is an important component for achieving weight loss. The Healthy People 2000 objectives recommend regular sustained physical activity lasting 30 minutes, five days per week (Objective 1.3) particularly for weight loss. Moreover, this recommendation has been restated for weight loss and overall health benefits in the Centers for Disease Control and Prevention / American College of Sports Medicine (CDC/ACSM) statement and Surgeon General's Report (SGR) on Physical ActivitY and Health. Thus, we sought to identify the relative quality, and quantity of physical activity among people trying to lose weight. DESIGN: Cross-sectional self-reported data from the West Virginia Behavioral Risk Factor Surveillance System (BRFSS) were used. The BRFSS is a state-based telephone survey of adults that uses a multistage cluster design based on the Waksberg method of random-digit dialing. Data froM 2769 men and 4490 women were obtained from the 1992, 1994, and 1996 surveys. RESULTS: Half (49.6%) of individuals trying to lose weight did not engage in any physical activity. Further, only 15% of respondents trying to lose weight reported exercising regularly. Nevertheless, those trying to lose weight were more likely (OR [odds ratio] = 1.3; 95% CI [confidence interval], 1.14, 1.51, p < 0.001) to exercise regularly than those not trying to lose weight. In particular, women trying to lose weight were significantly more likely (OR = 1.45; 95% CI, 1.22,1.74, p < 0.001) to exercise regularly than women not trying to lose weight. Conversely, men trying to lose weight were no more likely to exercise regularly (p = .23) than men not trying to lose weight. Among respondents who were using exercise for weight loss, only 14.7% were expending > or =1000 kcal/week and 18.2% were expending > or =500 kcal/week. Weekly expenditure rates of > or =1000 kcal/week were more likely to occur among men (17%) than women (13.8%), in younger age groups, and among those with higher educational attainment. CONCLUSION: These data suggest that while certain individuals trying to lose weight are more likely to engage in regular physical activity, most persons trying to lose weight have not adopted regular physical activity as part of their weight loss practice. These results suggest that public health efforts to effectively integrate physical activity into weight control practices of West Virginians have been minimally successful.

Prevalence of physical inactivity and its relation to social class in U.S. adults: results from the Third National Health and Nutrition Examination Survey, 1988-1994.

PURPOSE: This study examines the prevalence of physical inactivity during leisure time in a national representative sample of U.S. adults. METHODS: Data were obtained from the Third National Health and Nutrition Examination Survey, conducted between 1988 and 1994. A total of 18,825 adults aged 20 yr and older participated in a home interview where information about physical activity, education, income, occupation, employment, and labor force participation was obtained. RESULTS: The prevalence of physical inactivity among U.S. adults was 23%, with more women (28%) than men (17%) reporting being inactive during their leisure time. Additionally, inactivity is more common among in social class such as persons who are less educated, living below the poverty line, living in households with income below 20,000 dollars, and who are retired. In every category of social class, women experienced a higher prevalence of physical inactivity than men. CONCLUSIONS: We conclude that social class is associated with physical inactivity and that more research is needed to better understand the effect that other social and environmental factors have on sedentary behaviors in our society.

Prevalence of attempting weight loss and strategies for controlling weight.

CONTEXT: Overweight and obesity are increasing in the United States. Changes in diet and physical activity are important for weight control. OBJECTIVES: To examine the prevalence of attempting to lose or to maintain weight and to describe weight control strategies among US adults. DESIGN: The Behavioral Risk Factor Surveillance System, a random-digit telephone survey conducted in 1996 by state health departments. Setting The 49 states (and the District of Columbia) that participated in the survey. PARTICIPANTS: Adults aged 18 years and older (N = 107 804). MAIN OUTCOME MEASURES: Reported current weights and goal weights, prevalence of weight loss or maintenance attempts, and strategies used to control weight (eating fewer calories, eating less fat, or using physical activity) by population subgroup. RESULTS: The prevalence of attempting to lose and maintain weight was 28.8% and 35.1 % among men and 43.6% and 34.4% among women, respectively. Among those attempting to lose weight, a common strategy was to consume less fat but not fewer calories (34.9% of men and 40.0% of women); only 21.5% of men and 19.4% of women reported using the recommended combination of eating fewer calories and engaging in at least 150 minutes of leisure-time physical activity per week. Among men trying to lose weight, the median weight was 90.4 kg with a goal weight of 81.4 kg. Among women, the median weight was 70.3 kg with a goal weight of 59.0 kg. CONCLUSIONS: Weight loss and weight maintenance are common concerns for US men and women. Most persons trying to lose weight are not using the recommended combination of reducing calorie intake and engaging in leisure-time physical activity 150 minutes or more per week.

Cardiovascular disease risk factors and preventive practices among adults--United States, 1994: a behavioral risk factor atlas. Behavioral Risk Factor Surveillance System State Coordinators.

UNLABELLED: PROBLEM/CONDITIONS: Cardiovascular disease (CVD), including coronary heart disease (CHD) and stroke, is the leading cause of death in the United States, and state rates of CVD vary by state and by region of the country. Several behavioral risk factors (i.e., overweight, physical inactivity, smoking, hypertension, and diabetes mellitus) and preventive practices (i.e., weight loss and smoking cessation) are associated with the development of CVD and also vary geographically. This summary displays and analyzes geographic variation in the prevalences of selected CVD risk factors. REPORTING PERIOD: 1994 (1992 for prevalence of hypertension). DESCRIPTION OF SYSTEM: The Behavioral Risk Factor Surveillance System (BRFSS) is a state-based random-digit-dialing telephone survey of noninstitutionalized adults aged > or =18 years; 50 states and the District of Columbia participated in BRFSS in 1994, and 48 states and the District of Columbia participated in 1992. METHODS: Several different analyses were conducted: a) analysis of state risk factor and preventive practice prevalences by sex and race (i.e., black and white); b) mapping; c) cluster analysis; d) correlations of state prevalence rates by sex and race; and e) regression of state risk factor prevalences on state CHD and stroke mortality rates. RESULTS: Mapping the prevalence of selected CVD risk factors and preventive health practices indicates substantial geographic variation for black and white men and women, as confirmed by cluster analysis. Data for blacks are limited by small sample size, especially in western states. Geographic clustering is found for physical inactivity, smoking, and risk factor combinations. Risk factor prevalences are generally lower in the West and higher in the East. White men and white women are more similar in state risk factor rates than other race-sex pairs; white women and black women ranked second in similarity. State prevalences of physical inactivity and hypertension are strongly associated with state mortality rates of CVD. INTERPRETATION: Geographic patterns of risk factor prevalence suggest the presence (or absence) of sociocultural environments that promote (or inhibit) the given risk factor or preventive behavior. Because the risk factors examined in this summary are associated with CVD, further exploration of the reasons underlying observed geographic patterns might be useful. The BRFSS will continue to provide geographic data about cardiovascular health behaviors with a possible emphasis on more data-based small- area analyses and mapping. This will permit states to more adequately monitor trends that affect the burden of CVD in their regions and the United States. Mapping also facilitates the exploration of patterns of morbidity, health-care use, and mortality, as well as the epidemiology of risk factors. Finally, by identifying those segments of the population with high levels of these risk factors and lower levels of the preventive health practices, public health personnel can better allocate resources and target intervention efforts for the prevention of CVD.

Injury rates from walking, gardening, weightlifting, outdoor bicycling, and aerobics.

PURPOSE: The objective of this survey was to estimate the frequency of injuries associated with five commonly performed moderately intense activities: walking for exercise, gardening and yard work, weightlifting, aerobic dance, and outdoor bicycling. METHODS: National estimates were derived from weighted responses of over 5,000 individuals contacted between April 28 and September 18, 1994, via random-digit dialing of U.S. residential telephone numbers. Self-reported participation in these five activities in the late spring and summer of 1994 was common, ranging from an estimated 14.5 +/- 1.2% of the population for aerobics (nearly 30 million people) to 73.0 +/- 1.5% for walking (about 138 million people). RESULTS: Among participants, the activity-specific 30-d prevalence of injury ranged from 0.9 +- 0.5% for outdoor bicycle riding to 2.4 +- 1.3% for weightlifting. The estimated number in the 30 d of people injured in the 30 d before their interview ranged from 330,000 for outdoor bicycle riding to 2.1 million for gardening or yard work. Incidence rates for injury causing reduced participation in activity were 1.1 +/- 0.5x100 participantsx30 d for walking, 1.1 +/- 0.4 for gardening, and 3.3 +/- 1.9 for weightlifting. During walking and gardening, men and women were equally likely to be injured, but younger people (18-44 yr) were more likely to be injured than older people (45 + yr). Injury rates were low, yet large numbers of people were injured because participation rates were high. Most injuries were minor, but injuries may reduce participation in these otherwise beneficial activities. CONCLUSIONS: Additional studies to confirm the magnitude of the problem, to identify modifiable risk factors, and to recommend methods to reduce the frequency of such injuries are needed.

Physical activity among persons with disabilities--a public health perspective.

Regular physical activity, sports participation, and active recreation are essential behaviors for the prevention of disease, promotion of health, and maintenance of functional independence. This health behavior is essential for persons with and without disabilities. Population-based surveys have consistently demonstrated that persons with disabilities are less likely to be physically active, compared to persons without such limitations. However, these observations are based on relatively few surveys and are dependent on physical activity assessment methods that may not be sensitive and specific enough for persons with disabilities. Studies clearly demonstrate that many persons, representing a variety of selected disabilities, can adapt to increased levels of physical activity, as evidenced by alterations in various components of physical fitness. More importantly, other studies consistently provide evidence that participation in regular physical activity among persons with selected impairments and disabilities results in improved functional status and quality of life. Further efforts are critically needed in the area of the development of physical activity assessment methodology for persons with disabilities. Methods need to be developed that will provide survey researchers and those in public health the capacity to measure and monitor activity patterns of persons with disabilities. This information is important not only for public health officials but also health policy analysts, service providers, and disability advocacy groups. Further understanding of the role of physical activity in the maintenance of function and independence among persons with disabilities is needed. The understanding of environmental and social barriers to physical activity among persons with disabilities needs further exploration. Finally, physical activity determinants research among persons with disabilities, including the role of assistive technology as well as maximizing the intrinsic capacity of functional anatomy and physiology, needs to be addressed.

Associations between physical activity and other health behaviors in a representative sample of US adolescents.

OBJECTIVES: This study examined the associations between physical activity and other health behaviors in a representative sample of US adolescents. METHODS: In the 1990 Youth Risk Behavior Survey, 11631 high school students provided information on physical activity; diet; substance use; and other negative health behaviors. Logistic regression analyses examined associations between physical activity and other health behaviors in a subset of 2652 high-active and 1641 low-active students. RESULTS: Low activity was associated with cigarette smoking, marijuana use, lower fruit and vegetable consumption, greater television watching, failure to wear a seat belt, and low perception of academic performance. For consumption of fruit, television watching, and alcohol consumption, significant interactions were found with race/ethnicity or sex, suggesting that sociocultural factors may affect the relationships between physical activity and some health behaviors. CONCLUSIONS: Low physical activity was associated with several other negative health behaviors in teenagers. Future studies should examine whether interventions for increasing physical activity in youth can be effective in reducing negative health behaviors.

Changes in cardiovascular disease knowledge and behavior in a low-education population of African-American and white adults.

OBJECTIVE: Racial differences in secular changes in cardiovascular disease risk factor knowledge and behaviors were assessed among adults with low levels of education throughout a community-wide cardiovascular disease prevention program. METHODS: Four independent cross-sectional telephone surveys were conducted with the random-digit-dialing technique in 1987, 1988, 1989, and 1991 in a biracial South Carolina community. Community-wide cardiovascular disease intervention programs were initiated in 1988 and continued through 1990. Changes in the prevalence of cardiovascular risk factor knowledge, dietary fat intake, leisure-time physical activity, smoking, and cholesterol screening behavior were compared between African-American and white respondents in a population subset with less than 12 years of education using analysis of covariance regression techniques. RESULTS: Mean intake of high fat foods was lower in 1991 than in 1987 among both white and African-American respondents; the trend for lower mean intake began in 1989 among African-American adults. Prevalence of the correct exercise knowledge was higher in 1988 than in 1987 for both groups, but this trend was maintained only among white respondents. However, prevalence of leisure-time physical activity did not change significantly between 1987 and 1991. Prevalence of cholesterol level knowledge and screening behavior increased over time among both groups; however, greater increasing trends between 1987 and 1991 were observed among white adults. CONCLUSIONS: Favorable secular changes in fat intake, exercise knowledge, cholesterol level knowledge, and cholesterol screening behavior were observed among both race groups during a time period that coincided with community-wide intervention efforts and messages. Greater changes in most of these behaviors and knowledge were observed among white adults suggesting that health behavior messages may not have reached all segments of this community.

Health promotion practices among physicians.

Personal belief concerning both the validity of health promotion and the physician's ability to influence patient behavior may affect how much effort a physician spends on health promotion strategies. We assessed these beliefs through a mail survey to physicians practicing in a predominantly rural southern state in 1987 (n = 83) and 1991 (n = 96). Response rates in both studies exceeded 75%. The instrument was obtained from similar studies conducted in Massachusetts in 1981 and Maryland in 1983. Between 1987 and 1991 we found slight improvements in the perceived importance of many health behaviors, but significant improvement was observed in the importance of reducing intake of dietary saturated fat (66% in 1987 to 80% in 1991; P < .05). Less than 10% of the physicians thought they could be "very successful" in modifying patients' behaviors. However, in 1991 physicians perceived that their ability to be "very successful" in helping patients to modify their behavior would increase threefold (8%-24% for exercise; 4%-18% for smoking) if given appropriate support. Although the type of appropriate support was not identified, the credibility of physician's advice in promoting health changes is important. These results suggest that efforts should be made to provide support to physicians who are inclined to discuss health behavior changes with their patients. Medical Subject Headings (MeSH): dietary fats, exercise, patient education, physician's practice patterns, smoking.

Leisure-time physical activity among US adults. Results from the Third National Health and Nutrition Examination Survey.

BACKGROUND: The prevalence of no leisure-time physical activity (LTPA) among US adults is estimated to be between 24% and 30%. Such information, however, usually does not include prevalence estimates for non-Hispanic blacks, Mexican Americans, and the elderly. OBJECTIVE: To assess the prevalence of participation in leisure-time physical activity among US adults. METHODS: Between 1988 and 1991, 9488 adults aged 20 years and older were interviewed in their home as part of the third National Health and Nutrition Examination Survey. A clinic examination in a mobile center was also included. Mexican Americans, non-Hispanic blacks, and the elderly were oversampled to produce reliable estimates for these groups. Questions were asked about the type and frequency of physically active hobbies, sports, and exercises. RESULTS: The prevalence of no LTPA for US adults aged 20 years or older from 1988 through 1991 was 22%. The rate was higher in women (27%) than in men (17%). Mexican-American men (33%) and women (46%) and non-Hispanic black women (40%) had the highest rates of no LTPA. Participation in moderate to vigorous LTPA five or more times per week decreased with age, with the largest decreases observed among non-Hispanic black men and women. In almost all subpopulations, gardening and/or yard work and walking were stated as the two top LTPAs of choice. CONCLUSIONS: Many Americans are inactive or irregularly active during their leisure time. Rates of inactivity are greater for women, older persons, non-Hispanic blacks, and Mexican Americans. Intervention strategies meant to promote lifetime physical activities among all Americans represents a major health priority.

Anabolic-steroid use, strength training, and multiple drug use among adolescents in the United States.

OBJECTIVE: This study examined the relationships between anabolic-steroid use and the use of other drugs, sports participation, strength training, and school performance among a nationally representative sample of US high school students. DESIGN: Randomized survey data from the 1991 Centers for Disease Control and Prevention Youth Risk Behavior Survey. SETTING: Public and private schools in the 50 United States and District of Columbia. PATIENTS: A total of 12,272 9th through 12th grade students. MAIN OUTCOME MEASURED: Prevalence of anabolic-steroid use. RESULTS: The frequency of anabolic-steroid use was significantly associated with the frequency of use of cocaine, the use of other drugs such as amphetamines and heroin, tobacco smoking, and alcohol use. The weighted prevalences of anabolic-steroid use were higher among male (4.08%) than female students (1.2%). Students living in the South (3.46%) reported higher prevalences than students in the Midwest (3.0%), West (2.02%), or Northeast (1.71%). Students with self-perceived below-average academic performances (5.10%) and students reporting injected drug use also reported higher anabolic-steroid use (51.57%). Based on a multiple logistic regression, the following variables were found to be significant predictors of anabolic-steroid use: injectable drug use (odds ratio [OR], 17.86), use of other drugs (OR, 4.19), male gender (OR, 2.79), alcohol use (OR, 1.38), and strength training (OR, 1.73). The variables that were significantly associated with anabolic-steroid use varied by gender and by region of the country. CONCLUSION: These data suggest that adolescent anabolic-steroid users in this country are more likely to engage in strength training, injected drug use, and the use of multiple drugs, even after controlling for sports participation and poorer academic performance. These data confirm previous findings of an association between multiple drug use and anabolic-steroid use. Also, engaging in strength-training exercises continued to be associated with anabolic-steroid use after controlling for drug use and other predictors.

The epidemiology of walking for exercise: implications for promoting activity among sedentary groups.

The relative contribution of walking to overall leisure-time physical activity participation rates was studied among respondents from the 45 states that participated in the 1990 Behavioral Risk Factor Surveillance System (n = 81,557). The percentages of low income, unemployed, and obese persons who engaged in leisure-time physical activity (range = 51.1% to 57.7%) were substantially lower than the percentage among the total adult population (70.3%). In contrast, the prevalence of walking for exercise among these sedentary groups (range = 32.5% to 35.9%) was similar to that among the total population (35.6%). Walking appears to be an acceptable, accessible exercise activity, especially among population subgroups with a low prevalence of leisure-time physical activity.

Changes in blood cholesterol awareness: final results from the South Carolina Cardiovascular Disease Prevention Project.

We examined changes in five indicators of blood cholesterol awareness in two comparable biracial communities in South Carolina. One community received three years of cholesterol education and intervention activities implemented by a state health department and the other served as a comparison. Cross-sectional, interviewer-administered, random digit-dialed telephone surveys of 11,070 adults 18 years and older were conducted in 1987, 1988, 1989, and 1991. Changes in community levels of knowledge, preventive behavior, risk awareness, and treatment were assessed and compared between the two communities with analysis of covariance techniques that adjusted for age, race, and sex. Significant increases in knowledge, behavior, and risk awareness were observed for most groups defined by race, sex, or age in both communities. Significant net intervention increases between 1987 and 1991 were seen for knowledge of good cholesterol level (+16.4%, P < .001); behavioral action of ever having blood cholesterol checked (+18.6%, P < .001); and knowledge of personal level of blood cholesterol (+16.0%, P < .01). These results suggest that a community-wide blood cholesterol screening and education program can be effective in increasing blood cholesterol knowledge, risk awareness, and preventive behavior, thus serving as part of a public health strategy to lower and treat high blood cholesterol levels in a community.

The association between leisure-time physical activity and dietary fat in American adults.

Relations between leisure-time physical activity and dietary fat were examined in a population-based probability sample of 29,672 adults in the 1990 Behavioral Risk Factor Surveillance System. Consumption of 13 high-fat food items and participation in physical activities were measured, and fat and activity scores were calculated. Dietary fat and physical activity were strongly and inversely associated. This association was independent of nine other demographic and behavioral risk factors. Etiologic researchers should consider that diet and physical activity can potentially confound each other, and creators of public health messages that target one behavior should consider including the other.

Physical activity and public health. A recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine.

OBJECTIVE: To encourage increased participation in physical activity among Americans of all ages by issuing a public health recommendation on the types and amounts of physical activity needed for health promotion and disease prevention. PARTICIPANTS: A planning committee of five scientists was established by the Centers for Disease Control and Prevention and the American College of Sports Medicine to organize a workshop. This committee selected 15 other workshop discussants on the basis of their research expertise in issues related to the health implications of physical activity. Several relevant professional or scientific organizations and federal agencies also were represented. EVIDENCE: The panel of experts reviewed the pertinent physiological, epidemiologic, and clinical evidence, including primary research articles and recent review articles. CONSENSUS PROCESS: Major issues related to physical activity and health were outlined, and selected members of the expert panel drafted sections of the paper from this outline. A draft manuscript was prepared by the planning committee and circulated to the full panel in advance of the 2-day workshop. During the workshop, each section of the manuscript was reviewed by the expert panel. Primary attention was given to achieving group consensus concerning the recommended types and amounts of physical activity. A concise "public health message" was developed to express the recommendations of the panel. During the ensuing months, the consensus statement was further reviewed and revised and was formally endorsed by both the Centers for Disease Control and Prevention and the American College of Sports Medicine. CONCLUSION: Every US adult should accumulate 30 minutes or more of moderate-intensity physical activity on most, preferably all, days of the week.

Community intervention and trends in dietary fat consumption among black and white adults.

OBJECTIVE: This study assessed whether a state public health department could effectively implement an affordable nutrition intervention program at the community level. DESIGN: Cross-sectional data were collected via telephone surveys of 9,839 adults, aged 18 years or older, in 1987, 1989, and 1991 in two South Carolina communities. Nutrition education programs began in 1988 in one community. The other community served as a comparison site. We assessed and compared changes in community levels of dietary fat and weekly meat consumption, salt use, and nutrition promotion awareness with analysis of covariance regression techniques that included race, sex, and age as covariates. RESULTS: We observed favorable changes in most eating behaviors and levels of awareness in both communities. The intervention community experienced greater absolute changes that the comparison community in use of animal fats (-8.9% vs -4.0%; P = .02) and liquid or soft vegetable fats (+8.4% vs +3.6%; P = .04), and in awareness of restaurant nutrition information (+33.0% vs +19.4%; P = .0001). Although the primary type of dietary fat used differed between black and white respondents, we observed significant change among both groups. CONCLUSIONS: These results suggest that community-wide nutrition education programs may have augmented regional or national changes in dietary behavior among white and black adults in the intervention community.