Cooper Institute

High-volume physical activity (PA) is associated with a higher prevalence of subclinical coronary artery disease (CAD). However, the clinical significance of subclinical CAD among high-volume exercisers remains incompletely understood, and the dose-response relationship between high-volume PA and clinical CAD events remains uncertain. Individual participant data from the Cooper Center Longitudinal Study (1987-2018) were linked to Medicare claims files. PA volume was determined by self-report and categorized as <500, 500 to 1499, 1500 to 2999, and ≥3000 metabolic equivalent of task (MET)-minutes per week. Subclinical CAD (coronary artery calcium [CAC]) was measured by cardiac computed tomography. All other risk factors were measured in the standard fashion. Composite CAD events (acute myocardial infarction and revascularization) and all-cause mortality were determined from Medicare claims files. A multivariable-adjusted proportional hazards illness-death model with random shared frailty was used to estimate the association between PA volume, CAC, and both clinical CAD and death. Heterogeneity in the association between CAC and clinical CAD across levels of PA was determined with multiplicative interaction terms. We included 26 724 participants (54 years of age; 28% women). Mean exercise volume was 1130 MET-minutes per week, with 1997 (7.5%) reporting ≥3000 MET-minutes per week. After a mean follow-up of 20.5 years, we observed 811 acute myocardial infarction events, 1636 composite CAD events, and 2857 deaths without CAD. Compared with individuals exercising <500 MET-minutes per week, the lowest risk for acute myocardial infarction occurred among individuals with intermediate PA volumes (500-1499 MET-minutes per week: hazard ratio [HR], 0.77 [95% CI, 0.65-0.91]; 1500-2499 MET-minutes per week: HR, 0.78 [95% CI, 0.63-0.95]). There was no association between high-volume PA (>3000 MET-minutes per week) and risk for acute myocardial infarction (HR, 0.95 [95% CI, 0.72-1.25]). In contrast, the lowest risk for death was observed among the high-volume PA group (HR, 0.71 [95% CI, 0.60-0.83]). CAC (on log scale) was associated with a higher risk for composite CAD across all PA categories, including among the high-volume PA subgroup (HR, 1.29 [95% CI, 1.16-1.44]; P<0.001; Pinteraction= 0.969). Compared with low-volume PA, high-volume PA was associated with a lower risk for all-cause mortality but a similar risk for clinical CAD. CAC was associated with an increased risk for clinical CAD regardless of the volume of PA.

This study aimed to examine the longitudinal association between muscle strength, incident dementia, and dementia-related mortality among community-dwelling adults. This prospective cohort study included 7755 participants (20-90y) participating in the Cooper Center Longitudinal Study (1980-1990) and enrolled in Medicare between 1999 and 2019. Upper and lower body strength was measured with 1-repetition isotonic maximum bench and leg press. Relative muscle strength was computed relative to body weight and categorized into tertiles based on previously established age and sex normative data. Earliest indication of dementia and dementia-related mortality were determined with Medicare Administrative Claims Data and the National Death Index. The associations of muscle strength with incident dementia and dementia-related mortality were determined using an illness-death model with random frailty. Participants were predominantly White (97%) and male (86%), with an average age of 44years at baseline. The mean duration between baseline muscle strength assessment and Medicare surveillance was 23years. The incidence of all-cause dementia was 18.2 per 1000 person-years. Individuals in the medium tertile of lower body strength had reduced hazard of all-cause dementia (hazard ratio = 0.84; 95% CI, 0.72-0.98) relative to the low tertile, controlling for cardiovascular risk factors. Yet, the association was marginally significant (hazard ratio = 0.86; 95% CI, 0.73-1.0) when further controlled for cardiorespiratory fitness. There were no associations between body strength and dementia-related mortality. No associations of upper and lower body muscle strength with the risk of dementia and related mortality were observed after adjusting for cardiovascular risk factors and cardiorespiratory fitness.

Alongside engaging in physical activity, previous Cooper Center Longitudinal Study (CCLS) research found that unhealthy weight status augments age-related declines in cardiorespiratory fitness (CRF). While body mass index (BMI) has been used as a measure of weight status, it has limitations; therefore, other measures of adiposity should be examined as determinants of CRF. PURPOSE: To examine the cross-sectional and longitudinal associations between adiposity measures (body fat percentage, waist circumference, BMI) and CRF over time among adults. METHODS: A total of 2,706 apparently healthy men and women aged ~47 years (on average) who presented at the Cooper Clinic (Dallas, TX) for preventive health at least 4 times participated in this study. The associations between the adiposity variables and CRF were estimated using mixed effects linear regression while adjusting for covariates. RESULTS: Multivariable analysis revealed that cross-sectionally a 1 kg/m2 higher BMI was related to a 0.28 MET (95%CI 0.26, 0.30; p < 0.001) lower CRF in a between-person comparison. Longitudinally, a 1 kg/m2 increase in BMI was associated with a 0.33 MET (95% CI 0.31, 0.34; p < 0.001) decrease in CRF during follow-up (median 9.1 years). In addition, 1 cm higher waist circumference was associated with a 0.10 MET (95%CI 0.09, 0.11; p < 0.001) lower CRF between individuals. Longitudinally, a 1 cm increase in waist circumference was related to a 0.07 (95%CI 0.06, 0.07; p < 0.001) decrease in METs within individuals during follow-up. With regard to body fat percentage, a 1 percentage point increase in body fat percentage was associated with a 0.21 (95%CI 0.20, 0.22; p < 0.001) lower MET level cross-sectionally. Similarly, a 1 percentage point increase in body fat percentage was associated with a 0.12 (95%CI 0.12, 0.13; p < 0.001) MET decrease in CRF longitudinally. When examining the variance explained in longitudinal models by adiposity measures, body fat percentage explained 21.8% of the within-person variance, followed by waist circumference (16.9%), and BMI (15.5%) compared to a model without body fat percentage, waist circumference, or BMI. CONCLUSION: Increases in adiposity measures were all related to decreases in CRF at baseline and over time. Additionally, body fat percentage appears as a strong explanatory measure of CRF.

PURPOSE: Studies have shown engaging in moderate to vigorous-intensity aerobic physical activity leads to maintenance of or increases in cardiorespiratory fitness (CRF). However, the contribution of strength training along with aerobic physical activity and CRF has rarely been explored in a large cohort of community-dwelling adults. PURPOSE: To investigate the associations between muscle strengthening, aerobic physical activity, and CRF at baseline and longitudinally among adults enrolled in the Cooper Center Longitudinal Study (CCLS). METHODS: Participants underwent cardiovascular fitness assessment, physical examination, and medical history including information regarding leisure-time aerobic and strength activities, after providing written informed consent that was approved by the Cooper Institute’s IRB. We included 3,579 apparently healthy men and women who had at least 4 visits to the Cooper Clinic (Dallas, TX). The association of the independent variables with CRF was examined using mixed effects regression while controlling for covariates (e.g., age, sex). RESULTS: Participants were primarily men (85.3%), their average age at baseline was 46.9 years (SD = 8.5), and the mean time between clinic visits was 2.1 years (SD = 1.8). At baseline, higher aerobic and muscle strengthening activities were each independently related to higher CRF levels. Specifically, an increase in aerobic physical activity of 1- metabolic equivalent of task (MET) hour per week was cross-sectionally related to a 0.029 (95% CI 0.026, 0.031) MET higher CRF. Similarly, 1-MET hour per week more muscle strengthening activity was associated with 0.046 (95%CI 0.035, 0.057) MET higher CRF at baseline. In longitudinal analysis controlling for baseline values and covariates, a 1-MET hour per week increase in aerobic activity was related to a 0.008 (95%CI 0.008, 0.009) MET increase in CRF during follow-up (median of 9.1 years). Additionally, a 1-MET hour per week increase in strength activities was associated with a 0.020 (95%CI 0.016, 0.023) increase in CRF during follow-up. CONCLUSIONS: Aerobic and muscle strengthening activities are each significantly associated with CRF levels among adults.

Cardiorespiratory fitness (CRF) declines with age, and greater declines increase the risk for adverse health outcomes. Understanding factors that attenuate age-related decreases in CRF can help extend healthy life. We sought to determine the longitudinal associations of aerobic physical activity, muscle-strengthening activity (MSA), and adiposity with CRF. Study participants were enrolled in the Cooper Center Longitudinal Study and had three or more preventive medical examinations at the Cooper Clinic (Dallas, Texas) during 1987-2019. Aerobic activity and MSA were self-reported, and three measures of adiposity were clinically assessed: body mass index (BMI), body fat percentage, and waist circumference. CRF, expressed as metabolic equivalents (METs), was estimated by a maximal treadmill test. The longitudinal associations of aerobic activity, MSA, and adiposity with CRF were estimated using multivariable mixed linear regression models. The study included 6105 participants who were followed for a median of 7.1 yr. Most participants were men (83.6%), and their average age at baseline was 47.0 (SD = 8.7) yr. Mean CRF at baseline was 12.2 (SD = 2.3) METs. Increasing aerobic activity (per 500 MET·min·wk -1 , β = 0.069, 95% confidence interval = 0.064-0.074 METs) or MSA (per days per week, β = 0.066, 95% confidence interval = 0.058-0.073 METs) was associated with increased CRF over time. Increasing BMI, body fat percentage, or waist circumference were each associated with decreased CRF over time. These data offer longitudinal evidence on how changes in aerobic activity, MSA, and various measures of adiposity (beyond BMI) independently correlate with CRF over time. Healthy lifestyle behaviors that include increasing aerobic and MSA and limiting adiposity may positively influence the retention of fitness with age and improve downstream health outcomes.

Background: Although physical inactivity, obesity, and low serum vitamin D [25-hydroxyvitamin D, 25(OH)D] are common among women, joint associations among these biomarkers are not well-described. Materials and Methods: A total of 7553 healthy women received a comprehensive examination (2006-2018), including self-reported physical activity (PA), body mass index (BMI), waist circumference (WC), waist:height ratio (W:HT), percent body fat (%Fat), and 25(OH)D. Participants were divided into four categories of PA based on current guidelines: <500 (not meeting guidelines), 500-1000 (meeting guidelines), 1001-2500 (>1-2.5 times guidelines), and >2500 (>2.5 times guidelines) metabolic equivalent-minutes/week (MET-Min/wk), and were also classified by clinical cut points for adiposity measures and 25(OH)D. We examined trends of 25(OH)D and adiposity exposures across PA categories and calculated odds ratios (ORs) of vitamin D deficiency across categories of each adiposity exposure. We examined joint associations among PA and adiposity with 25(OH)D. Results: A positive trend was observed for 25(OH)D across PA categories (p < 0.001). Compared with normal weight status, the odds for 25(OH)D deficiency were significantly higher for overweight women within adiposity exposures (p for all <0.001). When examining joint associations, 25(OH)D was higher across PA categories within each stratum of BMI, WC, W:HT, and %Fat (p trend <0.007 for all). When examining PA and BMI as continuous variables, OR for vitamin D deficiency were 0.95 (95% confidence interval [CI]: 0.93-0.96) per 250 MET-minutes/week increment in PA, and 1.20 (95% CI: 1.17-1.23) per 2 kg/m2 increment in BMI. Conclusions: 25(OH)D levels are positively associated with PA and negatively associated with different measures of adiposity. Higher levels of PA attenuate the association between adiposity and 25(OH)D.

Background: The association between long-chain omega-3 polyunsaturated fatty acids (n-3 PUFA) and prostate cancer (PC) remains unclear. Methods: We compared incident PC rates as a function of the Omega-3 Index [O3I, erythrocyte eicosapentaenoic and docosahexaenoic acids (EPA + DHA)] in 5607 men (40–80 years of age) seen at the Cooper Clinic who were free of PC at baseline. The average follow-up was 5.1 ± 2.8 years until censoring or reporting a new PC diagnosis. Proportional hazards regression was used to model the linear association between baseline O3I and the age-adjusted time to diagnosis. A meta-analysis of n-3 PUFA biomarker-based studies and incident PC was updated with the present findings. Results: A total of 116 cases of incident PC were identified. When O3I was examined as a continuous variable, the age-adjusted hazard ratio (HR) (95% CI) was 0.98 (0.89, 1.07; p = 0.25) for each 1% increment in the O3I. The updated meta-analysis with 10 biomarker-based studies found no significant relationship between EPA or DHA levels and risk for PC. Conclusions: We find no evidence in this study nor in a meta-analysis of similar studies that consuming n-3 PUFA-rich fish or using fish oil supplements affects the risk of PC.