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Background: Sedentary behaviour (SB) may contribute to the development of several chronic diseases, such as hypertension, diabetes mellitus (DM) and all-cause mortality. The aim of this study is to investigate the association between different domains of SB with diabetes among adult users of the Brazilian National Health System (NHS)., Methods: Cross-sectional study from the primary care system of the Brazilian NHS in the city of Bauru, Brazil. SB, physical activity (PA), DM and other chronic diseases were assessed by face-to-face interviews and medical records. As potential confounders in the adjusted model, we used gender, age, economic status, smoking status, hypertension, hypercholesterolaemia and PA., Results: The study was composed of 147 men and 410 women. The fully adjusted model showed that Brazilian adults spending ≥3 h per day in television viewing (OR = 1.61 [95% CI: 1.11-2.33]) and overall SB (OR = 1.60 [95% CI: 1.09-2.36]) had increased prevalence of DM compared to those spending <3 h per day., Conclusions: TV viewing and overall SB was associated with higher prevalence of DM in Brazilian adults from the NHS, even after controlling for potential confounders including PA., (© The Author(s) 2019. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: While heavier weight is known to increase the incidence of dyslipidemia, limited data are available on the relationship between weight gain and its development., Methods: A total of 2647 males were categorized into the following four groups according to the difference between their self-reported weight at 20 years of age and their measured weight in 1994-95: a loss of ≥5% (decrease), loss of <5% or gain of <5% (no change), gain of ≥5 to <15% (increase) and gain of ≥15% (sizable increase). They were followed up until their 2002-03 health examination. Using the 'no change' group as reference, the multivariable-adjusted odds ratio (adjusted for age, body mass index at 20 years of age, physical activity, smoking and alcohol intake) and 95% confidence interval (95% CI) for the incidence of dyslipidemia were determined using logistic regression models., Results: A total of 1342 participants developed dyslipidemia during the follow-up period. The 'increase' and 'sizable increase' groups had odds ratios for the incidence of dyslipidemia of 1.97 (95% CI, 1.59-2.45) and 2.68 (2.15-3.34), respectively, demonstrating that there was a significant dose-response association between weight gain since 20 years of age and the incidence of dyslipidemia (P < 0.001 for trend)., Conclusion: These results suggest that dyslipidemia could be prevented by avoiding weight gain in adulthood., (© The Author 2015. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Being overweight or obese might be a risk factor for developing depression. It is also possible that low cardiorespiratory fitness, rather than overweight or obesity, is the better predictor of depressive symptom onset. Adults in the Aerobics Center Longitudinal Study (Dallas, Texas) underwent fitness and fatness assessments between 1979 and 1998 and later completed a questionnaire about depressive symptoms in 1990, 1995, or 1999. Separate logistic regression models were used to test the associations between 3 fatness measures (body mass index, waist circumference, and percentage of body fat) and the onset of depressive symptoms. Analyses were repeated using fitness as the predictor variable. Additional analyses were performed to study the joint association of fatness and fitness with the onset of depressive symptoms. After controlling for fitness, no measure of fatness was associated with the onset of depressive symptoms. In joint analyses, low fitness was more strongly associated with the onset of elevated depressive symptoms than was fatness, regardless of the measure of fatness used. Overall, results from the present study suggest that low fitness is more strongly associated with the onset of elevated depressive symptoms than is fatness. To reduce the risk of developing depression, individuals should be encouraged to improve their fitness regardless of body fatness., (© The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Aims: Current knowledge on the prognosis of metabolically healthy but obese phenotype is limited due to the exclusive use of the body mass index to define obesity and the lack of information on cardiorespiratory fitness. We aimed to test the following hypotheses: (i) metabolically healthy but obese individuals have a higher fitness level than their metabolically abnormal and obese peers; (ii) after accounting for fitness, metabolically healthy but obese phenotype is a benign condition, in terms of cardiovascular disease and mortality., Methods and Results: Fitness was assessed by a maximal exercise test on a treadmill and body fat per cent (BF%) by hydrostatic weighing or skinfolds (obesity = BF% ≥ 25 or ≥ 30%, men or women, respectively) in 43 265 adults (24.3% women). Metabolically healthy was considered if meeting 0 or 1 of the criteria for metabolic syndrome. Metabolically healthy but obese participants (46% of the obese subsample) had a better fitness than metabolically abnormal obese participants (P < 0.001). When adjusting for fitness and other confounders, metabolically healthy but obese individuals had lower risk (30-50%, estimated by hazard ratios) of all-cause mortality, non-fatal and fatal cardiovascular disease, and cancer mortality than their metabolically unhealthy obese peers; while no significant differences were observed between metabolically healthy but obese and metabolically healthy normal-fat participants., Conclusions: (i) Higher fitness should be considered a characteristic of metabolically healthy but obese phenotype. (ii) Once fitness is accounted for, the metabolically healthy but obese phenotype is a benign condition, with a better prognosis for mortality and morbidity than metabolically abnormal obese individuals.

The authors examined the independent and combined associations of physical activity and obesity with incident type 2 diabetes among 675,496 Korean men from the database of the National Health Insurance Corporation. During an average follow-up of 7.5 years (1996-2005), 52,995 men developed type 2 diabetes. Men with overweight, obese I, and obese II classifications had 1.47, 2.05, and 3.69 times higher risk of type 2 diabetes, respectively, compared with normal weight men, and men with low, medium, and high activity had 5%, 10%, and 9% lower risk of type 2 diabetes, respectively, compared with inactive men after adjustment for confounders and physical activity or body mass index for each other. Overweight and obesity were detrimental within all activity categories, and meeting the activity recommendations (medium and high activity) was beneficial at all body mass index levels. Meeting the activity recommendations appeared to attenuate some negative effects of overweight or obesity, and the increased risk of type 2 diabetes due to inactivity was lower in normal weight men. Both preventing overweight or obesity and increasing physical activity are important to reduce the global epidemic of type 2 diabetes, regardless of body weight and activity levels.

Study Objectives: To evaluate the efficacy of a 12-week exercise training program for reducing obstructive sleep apnea (OSA) severity and improving sleep quality, and to explore possible mechanisms by which exercise may reduce OSA severity., Design: Randomized controlled trial., Setting: Clinical exercise physiology center, sleep laboratory., Participants: Forty-three sedentary and overweight/obese adults aged 18-55 years with at least moderate-severity untreated OSA (screening apnea-hypopnea index [AHI] ≥ 15)., Interventions: Participants randomized to exercise training (n = 27) met 4 times/week for 12 weeks and performed 150 min/week of moderate-intensity aerobic activity, followed by resistance training twice/week. Participants randomized to a stretching control (n = 16) met twice weekly for 12 weeks to perform low-intensity exercises designed to increase whole-body flexibility., Measurements and Results: OSA severity was assessed with one night of laboratory polysomnography (PSG) before and following the 12-week intervention. Measures of sleep quality included PSG, actigraphy (7-10 days), and the Pittsburgh Sleep Quality Index. Compared with stretching, exercise resulted in a significant AHI reduction (exercise: 32.2 ± 5.6 to 24.6 ± 4.4, stretching: 24.4 ± 5.6 to 28.9 ± 6.4; P < 0.01) as well as significant changes in oxygen desaturation index (ODI; P = 0.03) and stage N3 sleep (P = 0.03). Reductions in AHI and ODI were achieved without a significant decrease in body weight. Improvements in actigraphic sleep and subjective sleep quality were also noted following exercise compared with stretching., Conclusions: Exercise training had moderate treatment efficacy for the reduction of AHI in sedentary overweight/obese adults, which suggests that exercise may be beneficial for the management of OSA beyond simply facilitating weight loss., Trial Registration: Clinicaltrials.gov identification number NCT00956423.

The authors examined the prospective associations between marital status transitions and changes in fitness in men and women. Between 1987 and 2005, a total of 8,871 adults (6,900 men) aged 45.6 (standard deviation, 9.1) years were examined at the Cooper Clinic, Dallas, Texas; the median follow-up was ∼3 years. Marital transition categories (from single to married, married to divorced, divorced to remarried) were derived from self-reported marital status at baseline and follow-up. Fitness (maximal oxygen consumption) was assessed by a maximal treadmill test. Analyses were adjusted for baseline levels and changes in body mass index, physical activity, smoking, alcohol consumption, and major chronic diseases. Compared with the corresponding "control" groups (remaining single, married, or divorced), transitioning from being single to married was associated with a reduction in fitness in women (P = 0.03); divorce was associated with an increase in fitness in men (P = 0.04); and remarriage was associated with a reduction in fitness in men (P = 0.05). The authors conclude that the transitions to being married (from single to married or from divorced to remarried) are associated with a modest reduction, while divorce is associated with a modest increase in fitness levels in men. Study results suggest that these patterns may be different in women, but further research is required to confirm this.

Background: Improved understanding of the mediators of physical activity (PA) interventions could lead to improvements in theory and programs., Purpose: To examine the 24-month mediating effects of psychosocial variables on PA and cardiorespiratory fitness (CRF) outcomes in 878 initially sedentary adults aged 35-75 participating in the Activity Counseling Trial., Methods: Participants were assigned to one of three intervention arms: physician advice, assistance, or counseling. MacKinnon's product of coefficients was used to test for longitudinal and contemporaneous mediation., Results: Changes in behavioral processes of change from baseline to 24 months significantly mediated the relationship between the active intervention arms and improvements in PA and CRF from baseline to 24 months in both men and women. None of the other psychosocial variables tested met criteria for mediation., Conclusions: Results indicate that behavioral interventions should incorporate methods to encourage participants to use these behavioral strategies as they attempt to become more active.

Background: Few studies have examined the association between a combination of lifestyle factors and the incidence of hypertension, particularly among men. This is important as lifestyle factors are often interrelated, and may often occur in combination. Thus, we investigated the individual and combined effects of body mass index (BMI), smoking status, alcohol intake, physical activity (PA), and cardiorespiratory fitness (CRF) on the incidence of hypertension in men., Methods: A total of 14,568 men (mean age = 44.0 + or - 9.3 years) from the Aerobics Center Longitudinal Study (ACLS) initially free of hypertension completed an extensive baseline examination during 1974-2003, and were followed for the incidence of hypertension., Results: A total of 1,959 men reported having hypertension during a mean of 10.7 + or - 7.6 years of follow-up. Our data indicated that a combination of five protective health factors significantly reduced the risk of hypertension by 47% (95% confidence interval (CI): 36-56%). We also found that whether all participants in our sample had five protective health factors, the incidence of hypertension would be expected to decrease by 29% (95% CI: 26-31%). Additionally, having a normal BMI and being a nonsmoker and physically fit were significantly and independently associated with a lower risk of developing hypertension., Conclusions: Our results show that among men aged 20-82 years, a healthy lifestyle can significantly reduce the risk of developing hypertension, and should be considered for the prevention of this chronic condition.

Data from the 1999-2004 National Health and Nutrition Examination Survey were used to describe the distribution of cardiorespiratory fitness and its association with obesity and leisure-time physical activity (LTPA) for adults 20-49 years of age without physical limitations or indications of cardiovascular disease. A sample of 7,437 adults aged 20-49 years were examined at a mobile examination center. Of 4,860 eligible for a submaximal treadmill test, 3,250 completed the test and were included in the analysis. The mean maximal oxygen uptake ( max) was estimated as 44.5, 42.8, and 42.2 mL/kg/minute for men 20-29, 30-39, and 40-49 years of age, respectively. For women, it was 36.5, 35.4, and 34.4 mL/kg/minute for the corresponding age groups. Non-Hispanic black women had lower fitness levels than did non-Hispanic white and Mexican-American women. Regardless of gender or race/ethnicity, people who were obese had a significantly lower estimated maximal oxygen uptake than did nonobese adults. Furthermore, a positive association between fitness level and LTPA participation was observed for both men and women. These results can be used to track future population assessments and to evaluate interventions. The differences in fitness status among population subgroups and by obesity status or LTPA can also be used to develop health policies and targeted educational campaigns.

Background: While dietary patterns that are both predictive of chronic disease and mortality have been identified, the confounding effects of cardiorespiratory fitness have not been properly addressed. The primary objective was to assess the relation between dietary patterns with all-cause mortality, while controlling for the potentially confounding effects of fitness., Methods: This was a prospective cohort study. Participants consisted of 13 621 men and women from the Aerobics Center Longitudinal Study (ACLS). Participants completed a clinical exam and 3-day diet record between 1987 and 1999. Participants were followed for mortality until 2003. Reduced rank regression (RRR) was used to identify dietary patterns that predicted unfavourable total and high-density lipoprotein-cholesterol, triglyceride, glucose, blood pressure, uric acid, white blood cell and body mass index values., Results: One primary dietary pattern emerged and was labelled the Unhealthy Eating Index. This pattern was characterized by elevated consumption of processed and red meat, white potato products, non-whole grains, added fat and reduced consumption of non-citrus fruits. The hazard ratio for all-cause mortality in the fifth vs the first quintile of the Unhealthy Eating Index was 1.40 (1.02-1.91). This risk estimate was reduced by 13.5 and 55.0% after controlling for self-reported physical activity and fitness, respectively., Conclusion: In this study the association between diet and overall mortality was, in large part, confounded by fitness.

Background: Whether higher cardiorespiratory fitness (CRF) attenuates the mortality risk associated with higher adiposity in adults with hypertension (HTN) is poorly understood., Methods: Participants were 13,155 men (mean age, 47.7 (s.d., 9.9) years) who completed a baseline health examination and maximal treadmill exercise test during 1974-2003. All men had HTN at baseline based on resting systolic blood pressure of > or =140 mm Hg or diastolic blood pressure > or =90 mm Hg. CRF was quantified as the duration of a symptom-limited maximal treadmill exercise test, and was grouped for analysis as low (lowest 20%), moderate (middle 40%), and high (upper 40%). Distributions of body mass index (BMI), waist circumference (WC), and percent body fat (%BF) were grouped according to standard clinical guidelines., Results: During a mean follow-up of 12 years, 883 deaths (355 cardiovascular disease (CVD)) were recorded. Multivariate hazard ratios (HRs) (95% confidence interval) for all-cause mortality, using low-fitness as the reference group, were 0.58 (0.48-0.69) and 0.43 (0.35-0.54) for moderate-fit and high-fit groups, respectively. We observed a similar pattern for CVD mortality. High-fit/obese men had no greater risk of all-cause (1.59 (0.95-2.67)) or CVD (1.23 (0.44-3.41)) death, high-fit/abdominal-obese men had no greater risk for all-cause (1.20 (0.80-1.78)) or CVD (0.62 (0.25-1.53)) death, and high-fit/percent body fat (%BF)-obese men had no greater risk for all-cause (1.19 (0.90-1.56)) or CVD (0.86 (0.52-1.43)) death compared with their high-fit/normal counterparts., Conclusions: Fitness is a powerful effect modifier in the association of adiposity to mortality in men with HTN, negating the all-cause and CVD mortality risk associated with obesity.

Evidence suggests that individuals have become more tolerant of higher body weights over time. To investigate this issue further, the authors examined cross-sectional associations among ideal weight, examination year, and obesity as well as the association of ideal weight and body weight satisfaction with health practices among 15,221 men and 4,126 women in the United States. Participants in 1987 reported higher ideal weights than participants in 2001, an effect particularly pronounced from 1987 to 2001 for younger and obese men (85.5 kg to 94.9 kg) and women (62.2 kg to 70.5 kg). For a given body mass index, higher ideal body weights were associated with greater weight satisfaction but lower intentions to lose weight. Body weight satisfaction was subsequently associated with greater walking/jogging, better diet, and lower lifetime weight loss but with less intention to change physical activity and diet or lose weight (P < 0.01). Conversely, body mass index was negatively associated with weight satisfaction (P < 0.01) and was associated with less walking/jogging, poorer diet, and greater lifetime weight loss but with greater intention to change physical activity and diet or lose weight. Although the health implications of these findings are somewhat unclear, increased weight satisfaction, in conjunction with increases in societal overweight/obesity, may result in decreased motivation to lose weight and/or adopt healthier lifestyle behaviors.

Substantial observational epidemiological evidence exists that physical activity and weight control are associated with decreased risk of postmenopausal breast cancer. Uncertainty remains regarding several aspects of these associations, including the effect of possible confounding factors on these associations. We present the rationale and design for two randomized controlled trials that can help resolve this uncertainty. In a 5-year prevention trial conducted among women at high risk of breast cancer, the primary endpoint would be breast cancer incidence. For a comparable survivorship trial, the primary endpoint would be the disease-free interval and secondary endpoints would be breast cancer recurrence-free interval, second primary breast cancer, and total invasive plus in situ breast cancer. A set of inclusion and exclusion criteria is proposed for both trials. Intervention goals are the same for both trials. Goals for the weight control intervention would be, for women whose body mass index (BMI) is greater than 25 kg/m(2), to lose 10% of body weight and, for women whose BMI is less than or equal to 25 kg/m(2), to avoid weight gain. The goal for the physical activity intervention would be to achieve and maintain regular participation in a moderate-intensity physical activity program for a total of 150-225 minutes over at least 5 days per week. Sample size calculations are based on alternative assumptions about hazard ratio, adherence, follow-up duration, and power and are presented for the primary prevention and survivorship trials. Although both studies could enhance our understanding of breast cancer etiology and benefit public health, practical considerations, including smaller sample size, ease of recruitment, and reduced likelihood of early termination, favor the survivorship trial at this time.

Background: Few prospective studies have simultaneously investigated the relationship between physical activity, cardiorespiratory fitness (CRF), and the development of hypertension in initially normotensive individuals. In the Aerobics Center Longitudinal Study (ACLS), we examined this association among initially healthy normotensive men., Methods: Participants were 16,601 men aged 20-82 years who completed a baseline examination during 1970-2002 and were followed for hypertension incidence. Physical activity was self-reported and CRF was quantified from the duration of a maximal treadmill test., Results: A total of 2,346 men reported hypertension during a mean 18 years of follow-up. Event rates per 10,000 man-years adjusted for age and examination year were 86.2, 76.6, and 66.7 across physical activity groups of sedentary, walker/jogger/runner (WJR), and sport/fitness, respectively, and 89.8, 78.4, and 64.6 for low, middle, and high CRF, respectively (trend P < 0.0001). These associations persisted after further adjustment for body mass index (BMI), smoking, alcohol intake, resting systolic blood pressure, baseline health status, family history of diseases, and survey response patterns., Conclusion: Both physical activity and CRF are associated with lower risk of developing hypertension in a graded fashion. These findings provide a basis for health professionals to emphasize the importance of participating in regular physical activity to improve fitness for the primary prevention of hypertension in men.

Background: Few prospective studies have evaluated the risk for incident hypertension (HTN) across the normal range of body mass index (BMI). Even fewer studies included body composition and fat distribution measurements in their analyses. In the Aerobics Center Longitudinal Study, we examined HTN risk in women across a wide spectrum of baseline BMI (kg/m(2)) values and also studied waist circumference (WC, cm), percent body fat, fat mass (FM, kg), and fat-free mass (FFM, kg) on incident HTN in subgroup analyses., Methods: A total of 5,296 healthy normotensive women between 20 and 77 years of age completed a baseline examination during 1971-2004, and were followed for HTN incidence. Incident HTN was identified using mail-back surveys., Results: A total of 592 women reported HTN during a mean 16.7 years of follow-up. Higher BMI, even within the "normal" range, was associated with greater risk of HTN. Compared with women in the lowest fifth of BMI (18.5-20.0 kg/m(2)), the hazard ratios (HRs) (95% confidence interval (CI)) of developing HTN for women with a BMI of 20.1-21.2, 21.3-22.5, 22.6-24.7, and >24.7 were 1.19 (0.89-1.60), 1.33 (0.99-1.78), 1.36 (1.03-1.81), and 2.01 (1.52-2.66), respectively (P(trend) < 0.001). In a subgroup (n = 3,189) with complete data on all the five adiposity measures, significant positive associations with HTN were seen across incremental fifths of BMI, percent body fat, and FM (P(trend) < 0.05 each), but not WC and FFM., Conclusions: Clinicians should emphasize the importance of weight management for the primary prevention of HTN in women.

Prospective data relating cardiorespiratory fitness (CRF) with nonfatal cardiovascular disease (CVD) events are limited to studies in men or studies of combined fatal and nonfatal CVD endpoints. The authors examined the association between CRF and nonfatal CVD events in 20,728 men and 5,909 women without CVD at baseline. All participants performed a maximal treadmill exercise test and completed a follow-up health survey in the Aerobics Center Longitudinal Study (Dallas, Texas) between 1971 and 2004. There were 1,512 events in men and 159 events in women during an average follow-up of 10 years. Across incremental CRF groups, age- and examination year-adjusted event rates per 10,000 person-years were 107.9, 75.2, and 50.3 in men (p(trend) < 0.001) and 41.9, 27.7, and 20.8 in women (p(trend) = 0.002). After further adjustment for smoking, alcohol intake, family history of CVD, and abnormal exercise electrocardiogram responses, hazard ratios were 1.00 (referent), 0.82 (95% confidence interval (CI): 0.72, 0.94), and 0.61 (95% CI: 0.53, 0.71) in men, p(trend) < 0.001, and were 1.00 (referent), 0.74 (95% CI: 0.49, 1.13), and 0.63 (95% CI: 0.40, 0.98) in women, p(trend) = 0.05. After adjustment for other CVD predictors, the association remained significant in men but not in women.

Background: Whether the cardioprotective characteristic of higher cardiorespiratory fitness (CRF) extends to adults with manifest hypertension (HTN) is poorly understood., Methods: We examined the association between CRF and nonfatal cardiovascular disease (CVD) events in 8147 men and 1268 women, who, at baseline, were free of known CVD and had HTN based on a history of physician diagnosis or a measured resting blood pressure (BP) > or =140/90 mm Hg. The CVD events (myocardial infarction, stroke, coronary revascularization) were ascertained from mail-back surveys. The CRF was quantified as maximal treadmill exercise test duration and was grouped for analysis as low (lowest 20% of exercise duration), moderate (middle 40%), and high (upper 40%)., Results: A total of 71 CVD events occurred during 12,224 woman-years, and 837 CVD events occurred during 82,366 man-years of follow-up. Age and examination year adjusted CVD rates per 1000 person-years according to low, moderate, and high CRF groups were 10.8, 8.4, and 3.8 (trend P = .001) in women, and were 15.3, 10.9, and 7.2 (trend P < .001) in men. After further controlling for CVD risk factors, abnormal exercise electrocardiogram (ECG) responses, and family history of CVD, hazards ratios (95% CI) for CVD events across incremental CRF categories were 1.00 (referent), 0.88 (0.74 to 1.06), 0.70 (0.57 to 0.86), trend P < .001, in men, and were 1.00 (referent), 0.87 (0.48 to 1.58), 0.41 (0.20 to 0.84), trend P = .01, in women., Conclusions: In adults with HTN, higher CRF is associated with lower risk of nonfatal CVD events, independent of other clinical risk predictors.

The authors examined the association between cardiorespiratory fitness and incident hypertension in women who were normotensive and free of cardiovascular disease at baseline in the Aerobics Center Longitudinal Study (Dallas, Texas), 1970-1998. A total of 4,884 women performed a maximal treadmill exercise test and completed a follow-up health survey. During an average follow-up of 5 years, 157 incident cases of self-reported, physician-diagnosed hypertension were identified from the health surveys. The cumulative incidence of hypertension was 3.2%. Compared with the rates of low-fit women, crude hypertension rates were 60% and 79% lower among women in the moderate and high fitness categories, respectively (p < 0.001). After adjustment for several potential confounders, the odds ratios for hypertension were 1.0, 0.61 (95% confidence interval (CI): 0.30, 1.21), and 0.35 (95% CI: 0.17, 0.73) in low-, moderately, and highly fit women, respectively (p(trend) < 0.01). Each 1-metabolic equivalent increment in treadmill performance was, on average, associated with a 19% (95% CI: 10, 27; p < 0.001) lower odds of incident hypertension. The pattern and strength of association between fitness and hypertension persisted in analyses stratified on body mass index, age, and the presence of prehypertension at baseline. An active lifestyle should be promoted for the primary prevention of hypertension in women.

Coronary artery calcium (CAC), a measure of subclinical coronary heart disease (CHD), may be useful in identifying asymptomatic persons at risk of CHD events. The current study included 10,746 adults who were 22-96 years of age, were free of known CHD, and had their CAC quantified by electron-beam tomography at baseline as part of a preventive medical examination at the Cooper Clinic (Dallas, Texas) during 1995-2000. During a mean follow-up of 3.5 years, 81 hard events (CHD death, nonfatal myocardial infarction) and 287 total events (hard events plus coronary revascularization) occurred. Age-adjusted rates (per 1,000 person-years) of hard events were computed according to four CAC categories: no detectable CAC and incremental sex-specific thirds of detectable CAC; these rates were, respectively, 0.4, 1.5, 4.8, and 8.7 (trend p<0.0001) for men and 0.7, 2.3, 3.1, and 6.3 (trend p=0.02) for women. CAC levels also were positively associated with rates of total CHD events for women and men (trend p<0.0001 each). The association between CAC and CHD events remained significant after adjustment for CHD risk factors. CAC was associated with CHD events in persons with no baseline CHD risk factors and in younger (aged <40 years) and older (aged >65 years) study participants. These findings show that CAC is associated with an increased risk of CHD events in asymptomatic women and men.

The purpose of this study was to determine the construct-related validity of self-reported historical walking, running, and jogging (WRJ) activity on the basis of data from the Aerobics Center Longitudinal Study (Dallas, Texas). A total of 4,100 men and 963 women underwent at least one medical examination between 1976 and 1985 and completed a follow-up questionnaire in 1986. Levels of glucose, cholesterol, and triglycerides, resting systolic blood pressure, body mass index (weight (kg)/height (m)(2)), and cardiorespiratory fitness were measured at the time of the medical examination. The follow-up questionnaire assessed WRJ and other strenuous activities for each year from 1976 through 1985. Data analysis included Spearman and partial correlations, analysis of variance, analysis of covariance, and t tests. Results indicated significant correlations between recalled WRJ and treadmill times for each year throughout the 10-year period (r = 0.40-0.61). Participants were classified as historically either sufficiently physically active to receive a health benefit or insufficiently active for a health benefit. Engaging in sufficient levels of historical WRJ was associated with higher treadmill times and lower body mass indices for men and women and lower triglyceride levels for men. Self-reported historical WRJ can be assessed with reasonable validity in comparison with measured treadmill performance, with no decay in accuracy of reporting for up to 10 years in the past.

Since Hippocrates first advised us more than 2000 years ago that exercise-though not too much of it--was good for health, the epidemiology of physical activity has developed apace with the epidemiological method itself. It was only in the mid-20th century that Professor Jeremy N Morris and his associates used quantitative analyses, which dealt with possible selection and confounding biases, to show that vigorous exercise protects against coronary heart disease (CHD). They began by demonstrating an apparent protection against CHD enjoyed by active conductors compared with sedentary drivers of London double-decker buses. In addition, postmen seemed to be protected against CHD like conductors, as opposed to less active government workers. The Morris group pursued the matter further, adapting classical infectious disease epidemiology to the new problems of chronic, non-communicable diseases. Realizing that if physical exercise were to be shown to contribute to the prevention of CHD, it would have to be accomplished through study of leisure-time activities, presumably because of a lack of variability in intensities of physical work. Accordingly, they chose typical sedentary middle-management grade men for study, obtained 5-minute logs of their activities over a 2-day period, and followed them for non-fatal and fatal diseases. In a subsequent study, Morris et al. queried such executive-grade civil servants by detailed mail-back questionnaires on their health habits and health status. They then followed these men for chronic disease occurrence, as in the earlier survey. By 1973 they had distinguished between 'moderately vigorous' and 'vigorous' exercise. In both of these civil service surveys, they demonstrated strong associations between moderately vigorous or vigorous exercise and CHD occurrence, independent of other associations, in age classes 35-64 years. In the last 30 years, with modern-day computers, a large number of epidemiological studies have been conducted in both sexes, in different ethnic groups, in broad age classes, in a variety of social groups, and on most continents of the world. These studies have extended and amplified those of the Morris group, thereby helping to solidify the cause-and-effect evidence that exercise protects against heart disease and averts premature mortality.

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.

Although erectile dysfunction is frequently seen in patients with manifestations of arteriosclerotic disease, the independent contribution of serum cholesterol in predicting erectile dysfunction is unclear. The aim of this study was to examine the relation between serum cholesterol and erectile dysfunction. Medical histories, physical examinations, and blood tests were obtained at Cooper Clinic, Dallas, Texas, from 3,250 men aged 26-83 years (mean, 51 years) without erectile dysfunction at their first visit, who had one more clinic visit, all between 1987 and 1991. These men were followed 6-48 months after the first clinic visit (mean, 22 months). Erectile dysfunction was reported in 71 men (2.2%) during follow-up. Every mmol/liter of increase in total cholesterol was associated with 1.32 times the risk of erectile dysfunction (95% confidence interval 1.04-1.68), while every mmol/liter of increase in high density lipoprotein cholesterol was associated with 0.38 times the risk (95% confidence interval 0.18-0.80). Men with a high density lipoprotein cholesterol measurement over 1.55 mmol/liter (60 mg/dl) had 0.30 times the risk (95% confidence interval 0.09-1.03) as did men with less than 0.78 mmol/liter (30 mg/dl). Men with total cholesterol over 6.21 mmol/liter (240 mg/dl) had 1.83 times the risk (95% confidence interval 1.00-3.37) as did men with less than 4.65 mmol/liter (180 mg/dl). Those differences remained essentially unchanged after adjustment for other potential confounders. The authors conclude that a high level of total cholesterol and a low level of high density lipoprotein cholesterol are important risk factors for erectile dysfunction.

The reliability of long-term recall of physical activity participation was examined in 322 women and 129 men in a worksite health study conducted at the Liberty Corporation, Greenville, South Carolina during 1976-1987. Leisure time physical activity was assessed at baseline; and energy expenditure in total, light, moderate, and vigorous activities was calculated. The long-term recall of baseline activities was determined 1-10 years after the examination. The relation between actual baseline and recalled activity was positive and in most cases the coefficients were statistically significant at p less than 0.05. The correlations were modest, most in the range of 0.20 to 0.50. Percent agreement between baseline and recalled activity generally ranged from 60 to 75%. Multiple regression analyses suggested that recalled activity was a significant predictor of baseline activity, but recall interval and age were not important contributors to the regression model. R2 values for the model were 0.10 for light activity and 0.26 for vigorous activity. Questionnaire assessment of long-term physical activity recall appeared to be reliable, length of recall interval up to 10 years was not an important factor, and recall of vigorous activity was more accurate than for less intensive activities.

Previous measures of physical activity for epidemiologic studies were considered inadequate to meet the needs of a community-based health education trial. Therefore, new methods of quantifying the physical activity habits of communities were developed which are practical for large health surveys, provide information on the distribution of activity habits in the population, can detect changes in activity over time, and can be compared with other epidemiologic studies of physical activity. Independent self-reports of vigorous activity (at least 6 metabolic equivalents (METs) ), moderate activity (3-5 METs), and total energy expenditure (kilocalories per day) are described, and the physical activity practices of samples of California cities are presented. Relationships between physical activity measures and age, education, occupation, ethnicity, marital status, and body mass index are analyzed, and the reliabilities of the three activity indices are reported. The new assessment procedure is contrasted with nine other measures of physical activity used in community surveys.

Assessment of habitual physical activity in epidemiologic and health education studies has been difficult. A seven-day physical activity recall interview was developed and administered in a community health survey, a randomized clinical trial, and two worksite health promotion programs during 1979-1982. These studies were conducted in several populations in California, Texas, Pennsylvania, and New Jersey. Energy expenditure estimates from the physical activity recall conformed to expected age- and sex-specific values in the cross-sectional community survey. Estimates of energy expenditure were also congruent with other questions on physical activity and job classification. In a randomized, one-year exercise trial, the physical activity recall detected increases in energy expenditure in the treated group and was positively associated with miles run during training (p less than 0.05). Changes in energy expenditure were associated with changes in maximal oxygen uptake (VO2max (r = 0.33, p less than 0.05) and body fatness (r = -0.50, p less than 0.01) at six months, and in high density lipoprotein-cholesterol (r = 0.31, p less than 0.05) and triglyceride (r = -0.41, p less than 0.01) at one year. The physical activity recall detected significant (p less than 0.01) increases in energy expenditure in treatment groups in two worksite health promotion projects. These data suggest that the physical activity recall provides useful estimates of habitual physical activity for research in epidemiologic and health education studies.

Associations between changes in treadmill time and changes in coronary heart disease risk factors were studied in 753 middle-aged men seen between 1978-1981 at the Cooper Clinic in Dallas, Texas. Men were free of known disease at baseline. Significant increases (p less than 0.01) in exercise habits and treadmill time were seen over the course of the study; average follow-up was 1.6 years. In bivariate analyses, increases in treadmill time and weight loss were associated with improvements (p less than 0.01) in risk factors. Multiple regression models were calculated for several risk factors with age, length of follow-up, change in weight, and change in treadmill time as independent variables. After controlling for confounding, increase in treadmill time was independently associated with decreases in the total cholesterol/high density lipoprotein-cholesterol ratio (p less than 0.01) and serum uric acid (p less than 0.05). High density lipoprotein-cholesterol rose with increase in treadmill time (p less than 0.05).

Studies on physical activity, physical fitness, and health have been hampered because of invalid, unreliable, or impractical measures of physical activity. This report examines the validity of sedentary traits (resting tachycardia, obesity, and low vital capacity) as predictors of physical fitness as assessed by a maximal treadmill exercise test. Study participants were women (n = 3,943) and men (n = 15,627) with at least one visit to the Cooper Clinic in Dallas, Texas. Association of the sedentary traits with physical fitness was examined by multiple regression analyses. Sedentary traits were associated with physical fitness in all age and sex groups, accounting for 12-40% of the variance in treadmill time. When smoking, a simple physical activity index, and sedentary traits were included in a model to predict physical fitness, R2 values ranged from 0.20 to 0.53 in women and 0.45 to 0.61 in men and were significant at p less than 0.0001. These models account for approximately twice as much variance in physical fitness as has been reported previously. The addition of sedentary traits measurements to a simple physical activity index provides a valid estimate of physical fitness in epidemiologic studies.

The associations of self-reported measures of physical activity from a mail survey with an objective measure of physical fitness were investigated. Respondents to a health status survey (n = 12,225), conducted in 1982 by the Institute for Aerobics Research in Dallas, TX, formed the population. From this group, males who also had a clinical examination within 60 days of the return of their questionnaire served as subjects. The study subjects (n = 375, mean age = 47.1 years) completed a maximal physical fitness assessment using a modified Balke protocol. The questionnaire included a section of inquiries concerning leisure time physical activity participation in which subjects were asked to quantitatively recall exercise participation for varying periods of time. Reported exercise participation values were converted to estimates of energy expenditure and combined into overall indices of physical activity participation. Multiple regression analyses were used to determine the individual contributions of the physical activity indices in predicting maximal treadmill performance (physical fitness). Significant predictors of physical fitness were age (beta = -0.34), an index of running, walking, and jogging participation (beta = 0.31), and the response to a question on frequency of sweating (beta = 0.35). The multiple correlation coefficient for these variables in predicting physical fitness was 0.65. These results indicate that exercise behavior can be accurately estimated in large populations by using simple questions in a mail survey.