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Biomedical subjects

C A Macera

Publications and source records attributed to C A Macera.

At least 19 recordsLinked to original sources
PubMed2001

Association among physical activity level, cardiorespiratory fitness, and risk of musculoskeletal injury.

To help public health practitioners promote physical activities with a low risk of injury, this study determined the relation among type and duration of physical activity, cardiorespiratory fitness, and musculoskeletal injury in a sample of adults enrolled in the Aerobics Center Longitudinal Study. Subjects included 4,034 men and 967 women who underwent a baseline physical examination between 1970 and 1985 and who returned a mailed follow-up survey in 1986. At baseline, a treadmill graded exercise test was used to measure cardiorespiratory fitness. At follow-up, subjects reported injuries and type and duration of physical activity in the preceding 12 months. Polytomous logistic regression was used to estimate the association among physical activity type and duration, cardiorespiratory fitness, and injury. The risk of sustaining an activity-related injury increased with higher duration of physical activity per week and cardiorespiratory fitness levels. Results suggest that cardiorespiratory fitness may be a surrogate for unmeasured components of physical activity, such as exercise intensity. Among walkers, increasing duration of activity per week was not associated with an increased risk of injury. Results suggest that, for most adults, walking is a safe form of physical activity associated with a lower risk of injury than running or sport participation.

Adult↗
PubMed2001

Television watching, energy intake, and obesity in US children: results from the third National Health and Nutrition Examination Survey, 1988-1994.

OBJECTIVES: To examine the relationship between television watching, energy intake, physical activity, and obesity status in US boys and girls, aged 8 to 16 years. METHODS: We used a nationally representative cross-sectional survey with an in-person interview and a medical examination, which included measurements of height and weight, daily hours of television watching, weekly participation in physical activity, and a dietary interview. Between 1988 and 1994, the Third National Health and Nutrition Examination Survey collected data on 4069 children. Mexican Americans and non-Hispanic blacks were oversampled to produce reliable estimates for these groups. RESULTS: The prevalence of obesity is lowest among children watching 1 or fewer hours of television a day, and highest among those watching 4 or more hours of television a day. Girls engaged in less physical activity and consumed fewer joules per day than boys. A higher percentage of non-Hispanic white boys reported participating in physical activity 5 or more times per week than any other race/ethnic and sex group. Television watching was positively associated with obesity among girls, even after controlling for age, race/ethnicity, family income, weekly physical activity, and energy intake. CONCLUSIONS: As the prevalence of overweight increases, the need to reduce sedentary behaviors and to promote a more active lifestyle becomes essential. Clinicians and public health interventionists should encourage active lifestyles to balance the energy intake of children.

Adolescent↗
PubMed2001

Be physically active each day. How can we know?

For the first time in its five versions, Nutrition and Your Health: Dietary Guidelines for Americans contains an apparently nondietary guideline recommending physical activity. Although new as a separate guideline, physical activity has been included in the weight guideline of previous versions. The current version recognizes the importance of physical activity to health beyond its effect on weight maintenance. The purpose of this paper is to examine what data are available or required to evaluate the level of physical activity in the population, particularly in light of current recommendations. The physical activity sections of several national surveys that assess individual behavior or activity-related policies are described. Surveillance of physical activity as a risk factor for chronic disease is critical because physical inactivity is highly prevalent, strongly associated with increased morbidity and mortality, costly and preventable. Determinants of physical activity behavior are also considered. These determinants are potentially important factors for surveillance and are critical components for planning successful interventions.

Adult↗
PubMed2001

Population attributable risk: implications of physical activity dose.

PURPOSE: The purpose of this study is to describe the application of population attributable risk estimates in relation to the dose-related benefits or risks of physical activity. METHODS: Assumptions and limitations of population attributable risk calculations and interpretations are reviewed and evaluated in the context of physical activity dose. Theoretical estimates are developed for several hypothetical situations. RESULTS: National estimates of population attributable risk may be inaccurate because definitions and measurement techniques applied in physical activity research studies and physical activity prevalence surveys do not correspond. In addition, it is not established whether vigorous or moderate physical activity are independent contributors, sequential categories, or interactive variables in the process of disease reduction. This information is necessary to calculate population attributable risk most appropriately. CONCLUSION: Estimates of the disease burden of physical inactivity will be improved by two advances in empirical studies: first, the pairing of prevalence and relative risk estimates for nationally representative population-based samples; and second, refined relative risk estimates for various doses of physical activity.

Adult↗
PubMed2001

Limitations on the use of a single screening question to measure sedentary behavior.

OBJECTIVES: This study explored the limitations of identifying sedentary individuals via an existing screening question in a state-based surveillance system. METHODS: A national sample (n = 7529) of adults, selected by random-digit dialing between November 1999 and May 2000, responded about participation in leisure-time physical activity. RESULTS: Of those who initially reported no leisure-time physical activity (25%), 85% were engaging in at least some activity, and 20% were engaging in enough moderate- or vigorous-intensity activity to meet health-related recommendations. CONCLUSIONS: Public health programs that use only 1 screening question to identify sedentary behavior may not be able to target physical activity messages effectively, especially if physical activity is defined to include a broad range of activities beyond sports.

Adolescent↗
PubMed2000

Physical activity and self-reported, physician-diagnosed osteoarthritis: is physical activity a risk factor?

This prospective study evaluated regular physical activity and self-reported physician-diagnosed osteoarthritis of the knee and/or hip joints among 16,961 people, ages 20-87, examined at the Cooper Clinic between 1970 and 1995. Among those aged 50 years and older, osteoarthritis incidence was higher among women (7.0 per 1000 person-years) than among men (4.9 per 1000 person-years, P = 0.001), while among those under 50 years of age, osteoarthritis incidence was similar between men (2.6) and women (2.7). High levels of physical activity (running 20 or more miles per week) were associated with osteoarthritis among men under age 50 after controlling for body mass index, smoking, and use of alcohol or caffeine (hazard ratio = 2.4, 95% CI: 1.5, 3.9), while no relationship was suggested among women or older men. These findings support the conclusion that high levels of physical activity may be a risk factor for symptomatic osteoarthritis among men under age 50.

Adult↗
PubMed2000

Muscular strength and physical function.

PURPOSE: The purpose of this study was to evaluate the potential association of muscular strength and endurance at baseline with the prevalence of functional limitations at follow-up. METHODS: Study participants were 3,069 men and 589 women (30-82 yr) who received a clinical examination including a strength evaluation at the Cooper Clinic between 1980 and 1989 and responded to a 1990 mail-back survey. Participants also had to achieve at least 85% of their age-predicted maximal heart rate on a maximal exercise treadmill test and have no history of heart attack, stroke, diabetes, high blood pressure, cancer, or arthritis at their first visit. A strength index composite score (0-6) was calculated using age- and sex-specific tertiles from bench press, leg press, and sit-up tests. Those scoring 5 or 6 were categorized in the high strength group. Functional health status was assessed by responses to questions about the participant's ability to perform light, moderate, and strenuous recreational, household, daily living, and personal care tasks. RESULTS: After an average follow-up of 5 yr, 7% of men and 12% of women reported at least one functional limitation. A logistic regression model including age, aerobic fitness, body mass index, and new health problems at follow-up found that, relative to those with lower levels of strength, the odds of reporting functional limitations at follow-up in men and women categorized as having higher levels of strength were 0.56 (95%CI = 0.34, 0.93) and 0.54 (95%CI = 0.21, 1.39), respectively. CONCLUSIONS: These findings, if replicated in other populations, suggest that maintenance of strength throughout the lifespan may reduce the prevalence of functional limitations.

Activities of Daily Living↗
PubMed2000

Comparison of three methods for measuring the time spent in physical activity.

PURPOSE: Three methods for measuring time spent in daily physical activity (PA) were compared during a 21-d period among 83 adults (38 men and 45 women). METHODS: Each day, participants wore a Computer Science and Applications, Inc. (CSA) monitor and completed a 1-page, 48-item PA log that reflected time spent in household, occupational, transportation, sport, conditioning, and leisure activities. Once a week, participants also completed a telephone survey to identify the number of minutes spent each week in nonoccupational walking and in moderate intensity and hard/very hard-intensity PA. Data were analyzed using descriptive statistics and Spearman rank-order correlations. Three equations developed to compute CSA cut points for moderate and hard/very hard PA were also compared with the PA logs and PA survey. RESULTS: There was modest to good agreement for the time spent in different PA intensity categories between the three CSA cut point methods (r = 0.43-0.94, P < 0.001). Correlations between the CSA and PA logs ranged from r = 0.22 to r = 0.36, depending on the comparisons. Correlations between the survey items and PA logs were r = 0.26-0.54 (P < 0.01) for moderate and walking activities and r < 0.09 (P > 0.05) for hard/very hard activities. Correlations between the survey items and the CSA min per day varied according to the method used to compute the CSA intensity cut points. CONCLUSIONS: The results were consistent with findings from other PA validation studies that show motion sensors, PA logs, and surveys reflect PA; however, these methods do not always provide similar estimates of the time spent in resting/light, moderate, or hard/very hard PA.

Activities of Daily Living↗
PubMed2000

Physical activity-related injuries in walkers and runners in the aerobics center longitudinal study.

OBJECTIVE: To examine the association between physical activity-related injuries and participation in walking versus running. DESIGN: Nested case-control study. SETTING: Cooper Clinic Preventive Medicine Center, Dallas. Texas. PARTICIPANTS: 5,327 men and women undergoing exams between 1987 and 1995 and completing follow-up health history questionnaires in 1990 or 1995. Participants were classified as those reporting regular participation in walking or jogging/running at baseline. Those reporting both or neither activity were excluded from the study (n = 1404). Cases (698 men, 169 women) were those reporting physical activity-related injuries requiring physician visits in the previous year on the follow-up questionnaire. Controls (2,358 men, 698 women) were randomly selected from the remaining population. MAIN OUTCOME MEASURES: Logistic regression was used to examine the risk of injury in walkers versus runners and risk of injury by exercise dose while considering age, body mass index, previous injury, and strength training. RESULTS: There was a significantly lower risk of injury for walkers compared with runners in young (<45 years old) (odds ratio [OR] = 0.75, 95% confidence interval [CI] = 0.58-0.97) and older (> or = 45 years) men (OR = 0.64, 95% CI = 0.49-0.82), and a nonsignificantly lower risk among young (OR = 0.73, 95% CI = 0.39-1.37) and older women (OR = 0.72, 95% CI = 0.38-1.35). There was no effect of greater amounts of walking on injuries for either gender; however, there was a higher injury risk associated with running 15-30 min/day (OR = 1.36, 95% CI = 1.07-1.73) and 30+ min/day (OR = 1.52, 95% CI = 1.14-2.04) compared with <15 min/day among men, but not among women. CONCLUSIONS: This low risk of musculoskeletal injury suggests that participation in walking can be safely recommended as a way to improve health and fitness.

Adult↗
PubMed2000

Does physical activity reduce the risk of developing peptic ulcers?

BACKGROUND: Although Helicobacter pylori has been identified as a major cause of chronic gastritis, not all infected patients develop ulcers, suggesting that other factors such as lifestyle may be critical to the development of ulcer disease. AIM: To investigate the role physical activity may play in the incidence of peptic ulcer disease. METHODS: The subjects were men (8529) and women (2884) who attended the Cooper Clinic in Dallas between 1970 and 1990. The presence of gastric or duodenal ulcer disease diagnosed by a doctor was determined from a mail survey in 1990. Subjects were classified into three physical activity groups according to information provided at the baseline clinic visit (before 1990): active, those who walked or ran 10 miles or more a week; moderately active, those who walked or ran less than 10 miles a week or did another regular activity; the referent group consisting of those who reported no regular physical activity. RESULTS: With the use of gender specific proportional hazards regression models that could be adjusted for age, smoking, alcohol use, body mass index, and self reported tension, active men were found to have a significant reduction in risk for duodenal ulcers (relative hazard (95% confidence interval) for the active group was 0.38 (0.15 to 0.94) and 0.54 (0.30 to 0.96) for the moderately active group). No association was found between physical activity and gastric ulcers for men or for either type of ulcer for women. CONCLUSIONS: Physical activity may provide a non-pharmacological method of reducing the incidence of duodenal ulcers among men.

Adult↗
PubMed2000

Physical activity and peptic ulcers. Does physical activity reduce the risk of developing peptic ulcers?

BACKGROUND: Although Helicobacter pylori has been identified as a major cause of chronic gastritis, not all infected patients develop ulcers, suggesting that other factors such as lifestyle may be critical to the development of ulcer disease. OBJECTIVE: To investigate the role physical activity may play in the incidence of peptic ulcer disease. METHODS: The participants were men (n = 8,529) and women (n = 2,884) who attended the Cooper Institute for Aerobics Research, Dallas, Texas, between 1970 and 1990. The presence of gastric or duodenal ulcer disease diagnosed by a physician was determined from a mail survey in 1990. Participants were classified into 3 physical activity groups according to information provided at the baseline clinic visit (before 1990): active, those who walked or ran 10 miles or more a week; moderately active, those who walked or ran less than 10 miles a week or did another regular activity; and the referent group consisting of those who reported no regular physical activity. RESULTS: With the use of gender-specific proportional hazards regression models that could be adjusted for age, smoking, alcohol use, body mass index, and self-reported tension, active men had a significantly reduced risk for duodenal ulcers (relative hazard [95% confidence interval] for the active group, 0.38 [0.15-0.94], and 0.54 [0.30-0.96] for the moderately active group). No association was found between physical activity and gastric ulcers for men or for either type of ulcer for women. CONCLUSION: Physical activity may provide a nonpharmacologic method of reducing the incidence of duodenal ulcers among men.

Adult↗
PubMed2000

Public health surveillance of physical activity.

There is a clear public health need to measure and track physical activity behavior. Surveillance systems should be flexible enough to keep up with scientific advances in identifying dose-response relationships and in developing new assessment techniques, and new ways to assess community indicators associated with physical activity. Having a strong public health surveillance system that produces data that can be used to plan, guide, and evaluate programs is essential for increasing the prevalence of an important health-related behavior: physical activity.

Adolescent↗
PubMed1999

Surveillance for five health risks among older adults--United States, 1993-1997.

PROBLEM/CONDITION: Overweight, drinking and driving, inadequate fruit and vegetable consumption, physical inactivity, and smoking are associated with the leading causes of morbidity and mortality among older adults (i.e., persons aged > or =65 years) in the United States. REPORTING PERIOD: This report presents data from the Behavioral Risk Factor Surveillance System (BRFSS) for 1994-1997 and from the National Health Interview Survey (NHIS) for 1993-1995. DESCRIPTION OF SYSTEMS: BRFSS and NHIS are maintained by CDC and have been used for surveillance purposes. Each survey is administered annually and includes questions about health risks and health behaviors from a representative sample of the U.S. civilian, noninstitutionalized population. The NHIS is designed to provide national estimates and the BRFSS, state estimates. RESULTS: Prevalences of overweight, drinking and driving, inadequate fruit and vegetable consumption, and smoking decreased with increasing age among older adults in the United States; physical inactivity was the only health risk that increased with increasing age. Sex and race were differentially associated with all five health risks. INTERPRETATION: Specific subgroups of older adults are at risk for being overweight, drinking and driving, inadequate fruit and vegetable consumption, physical inactivity, and smoking. These health risks varied by age, race, residential state, and socioeconomic status and highlight the heterogeneous nature of older adults. PUBLIC HEALTH ACTION: Surveillance for health risks among older adults provides information to help identify effective interventions for the growing population of older adults in the United States.

Aged↗
PubMed1999

Association between exercise and HIV disease progression in a cohort of homosexual men.

PURPOSE: To study the relationship between exercise and human immunodeficiency virus (HIV) disease progression. METHODS: 415 individuals (156 HIV positive, 259 HIV negative), from a cohort study of 851 homosexual men from New York City, 1985-1991. By 1991, 68 of the 156 persons developed Acquired Immune Deficiency Syndrome (AIDS) and 49 died with AIDS. Exercise was defined as self-report of exercising 3-4 times/week or daily at entry; less was considered nonexercise. CD4 lymphocyte decline was constructed for each subject by modeling log CD4 count against time in days. The association between exercise and progression to AIDS and death with AIDS, adjusting for baseline CD4 count, was determined using Cox model. Linear regression was used to model CD4 decline with exercise for HIV positive and HIV negative groups separately, adjusting for initial CD4 count. RESULTS: Having exercised was associated with slower progression to AIDS at 1 year (HR = 0.68, 90% confidence interval (CI): 0.4-1.17); hazard ratios (HR) at 2, 3, and 4 years were 0.96, 1.18, and 1.36, respectively. Having exercised was also associated with slower progression to death with AIDS at 1 year (HR = 0.37, 90% CI: 0.14-0.94) with hazard ratios at 2, 3, and 4 years of 0.68, 0.98, and 1.27, respectively, suggesting a protective effect close to the time exercise was assessed, but an increased risk after 2 years. Exercising 3-4 times/week had a more protective effect than daily exercise. Exercisers in the HIV positive group showed an increase in CD4 count during a year by a factor of 1.07. CONCLUSION: Moderate physical activity may slow HIV disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed1999

The value of strength training for older adults.

Health in older adults can best be measured in terms of functional status. Skeletal muscle strength has been reported to be a determinant of functional status in older individuals. Two major contributors to the decline in muscle function as a person ages are disuse and physical inactivity. Declining muscle function through a loss of muscular strength may decrease functional independence and mobility and increase the risk for falls and injuries, physical frailty, and disability. Older individuals lacking an appropriate amount of muscular strength may not be able to perform various activities of daily living, which are important indicators of independence.

Activities of Daily Living↗
PubMed1999

Levels of physical activity and inactivity in children and adults in the United States: current evidence and research issues.

PURPOSE: The purpose was to describe current levels of physical activity and inactivity among adults and young people in the United States. METHODS: Estimates of participation in regular physical activity were derived from three national surveys for adults (National Health Interview Survey, National Health and Nutrition Examination Survey, and the Behavioral Risk Factor Surveillance System) and from the Youth Risk Behavior Survey for high school students. RESULTS: Overall, 63.8% of high school students surveyed on the 1997 YRBS reported participating in vigorous physical activity for at least 20 min on 3 or more days per week. Participation in vigorous activity was higher for boys (72.3%) than girls (53.5%), whites (66.8%) compared with blacks (53.9%) and Hispanics (60.4%), and decreased with advancing grade. Among adults, 27.7% meet recommended levels of either moderate or vigorous physical activity, whereas 29.2% report no regular physical activity outside of their work. Gender differences in participation in physical activity are less pronounced than in youth, and age-related patterns were complex. Whites are more active than blacks and Hispanics, and persons with higher family incomes and more education report being more physically active. There have been only minor changes in reported participation in leisure time physical activity over the past 15 yr. CONCLUSION: National estimates of physical activity appear to be reliable and valid for adults but may be less so for adolescents and are poor measures for children. Research is needed to determine the role that objective monitoring with accelerometers may play in surveillance. Reliable and valid measures of occupational, household, and transportation-related physical activity and sedentary behaviors are needed to better characterize the range of activity that is associated with health.

Adult↗