Showing papers by "Charles E. Matthews published in 2009"

Disparities in physical activity and sedentary behaviors among US children and adolescents: prevalence, correlates, and intervention implications.

Abstract: Regular physical activity is important for health benefits among youth, but disparities exist. This paper describes disparities in physical activity participation and sedentary behaviors among youth in the United States, provides intervention implications, and offers recommendations for future research focused on reducing disparities related to levels of physical activity. Secondary analysis of national accelerometer data showed that achievement of recommended levels of physical activity ranged across subgroups from 2% to 61%. Mean hours per day spent in sedentary behavior ranged from 5.5 to 8.5. The largest disparities were by gender and age. An improved understanding of correlates may inform the design of interventions to increase physical activity in targeted subgroups. Additional theoretically based research is needed to elucidate which factors contributing to physical activity disparities are amenable to change via intervention. To eliminate health disparities, changes in policies that have an impact on physical activity may be necessary to promote physical activity among high-risk youth.

Muscular Strength and Adiposity as Predictors of Adulthood Cancer Mortality in Men

Abstract: Background: We examined the associations between muscular strength, markers of overall and central adiposity, and cancer mortality in men. Methods: A prospective cohort study including 8,677 men ages 20 to 82 years followed from 1980 to 2003. Participants were enrolled in The Aerobics Centre Longitudinal Study, the Cooper Institute in Dallas, Texas. Muscular strength was quantified by combining 1-repetition maximal measures for leg and bench presses. Adiposity was assessed by body mass index (BMI), percent body fat, and waist circumference. Results: Cancer death rates per 10,000 person-years adjusted for age and examination year were 17.5, 11.0, and 10.3 across incremental thirds of muscular strength ( P = 0.001); 10.9, 13.4, and 20.1 across BMI groups of 18.5-24.9, 25.0-29.9, and ≥30 kg/m2, respectively ( P = 0.008); 11.6 and 17.5 for normal ( 102 cm), respectively ( P = 0.06). After adjusting for additional potential confounders, hazard ratios (95% confidence intervals) were 1.00 (reference), 0.65 (0.47-0.90), and 0.61 (0.44-0.85) across incremental thirds of muscular strength, respectively ( P = 0.003 for linear trend). Further adjustment for BMI, percent body fat, waist circumference, or cardiorespiratory fitness had little effect on the association. The associations of BMI, percent body fat, or waist circumference with cancer mortality did not persist after further adjusting for muscular strength (all P ≥ 0.1). Conclusions: Higher levels of muscular strength are associated with lower cancer mortality risk in men, independent of clinically established measures of overall and central adiposity, and other potential confounders. (Cancer Epidemiol Biomarkers Prev 2009;18(5):1468–76)

Seasonal changes in amount and patterns of physical activity in women.

Abstract: Background: Environmental factors including seasonal changes are important to guide physical activity (PA) programs to achieve or sustain weight loss. The goal was to determine seasonal variability in the amount and patterns of free-living PA in women. Methods: PA was measured in 57 healthy women from metropolitan Nashville, TN, and surrounding counties (age: 20 to 54 years, body mass index: 17 to 48 kg/m2) using an accelerometer for 7 consecutive days during 3 seasons within 1 year. PA counts and energy expenditure (EE) were measured in a whole-room indirect calorimeter and used to model accelerometer output and to calculate daily EE and intensity of PA expressed as metabolic equivalents (METs). Results: PA was lower in winter than in summer (131 ± 45 vs. 144 ± 54 × 103 counts/d; P = .025) and in spring/fall (143 ± 48 × 103 counts/d; P = .027). On weekends, PA was lower in winter than in summer by 22,652 counts/d (P = .008). In winter, women spent more time in sedentary activities than in summer (differe...

Cardiorespiratory Fitness and Digestive Cancer Mortality: Findings from the Aerobics Center Longitudinal Study

Abstract: Although higher levels of physical activity are inversely associated with risk of colon cancer, few prospective studies have evaluated overall digestive system cancer mortality in relation to cardiorespiratory fitness (CRF). The authors examined this association among 38,801 men ages 20 to 88 years who performed a maximal treadmill exercise test at baseline in the Aerobics Center Longitudinal Study (Dallas, TX) during 1974 to 2003. Mortality was assessed over 29 years of follow-up (1974-2003). Two hundred eighty-three digestive system cancer deaths occurred during a mean 17 years of observation. Age-adjusted mortality rates per 10,000 person-years according to low, moderate, and high CRF groups were 6.8, 4.0, and 3.3 for digestive system cancer (P(trend) < 0.001). After adjustment for age, examination year, body mass index, smoking, drinking, family history of cancer, personal history of diabetes, hazard ratios (95% confidence intervals) for overall digestive cancer deaths for those in the middle and upper 40% of the distribution of CRF relative to those in the lowest 20% were 0.66 (0.49-0.88) and 0.56 (0.40-0.80), respectively. Being fit (the upper 80% of CRF) was associated with a lower risk of mortality from colon [0.61 (0.37-1.00)], colorectal [0.58 (0.37-0.92)], and liver cancer [0.28 (0.11-0.72)] compared with being unfit (the lowest 20% of CRF). These findings support a protective role of CRF against total digestive tract, colorectal, and liver cancer deaths in men.

PSA and body composition by dual X-ray absorptiometry (DXA) in NHANES.

Abstract: BACKGROUND Obese men are at higher risk for advanced prostate cancer and have a poorer prognosis following treatment. Several studies also report that obese men have lower blood PSA levels, suggesting that obesity may be interfering with the ability to detect early-stage prostate cancer. METHODS Dual X-ray absorptiometry (DXA) is considered a gold-standard measurement of body composition. We investigated the association between PSA levels and body composition measured by DXA among 1,360 men participating in NHANES (2001–2004), a representative sample of the U.S. male population. RESULTS After controlling for age, race, and other factors, PSA concentration was ∼15% lower for men with the highest level of total mass, lean mass, fat mass, trunk lean mass, and trunk fat mass (all P for trend <0.05). We then multiplied PSA concentration by estimated plasma volume to calculate the amount of PSA in circulation (i.e., PSA mass). Total body fat mass and fat mass located in the body trunk were not significantly associated with PSA mass, however, PSA mass was ∼10–15% higher across low versus high categories of total body lean mass and bone mineral content (all P-trend <0.05). CONCLUSION Our results using DXA to measure body composition confirm that a greater body mass, not just fat mass, is associated with a lower PSA concentration. This is consistent with PSA hemodilution within men with a higher body mass index. The separate associations between measured lean and fat mass on calculated PSA mass require further investigation. Prostate 70: 120–125, 2010. ©2009 Wiley-Liss, Inc.

Joint effects of body size, energy intake, and physical activity on breast cancer risk

Abstract: To evaluate the joint effect of body size, energy intake, and physical activity on breast cancer risk, we analyzed information on body weight history, energy intake, anthropometric measurements, and physical activity patterns in a population based case–control study. Included in this analysis were 3,458 incidence breast cancer cases and 3,474 age-frequency matched controls from the Shanghai Breast Cancer Study. High weight, height, body mass index, waist-to-hip ratio, and weight gain showed stronger associations with breast cancer risk in postmenopausal women than premenopausal women. High total physical activity was inversely associated with postmenopausal breast cancer risk (p for trend = 0.026) and premenopausal breast cancer (p for trend = 0.059). The odds ratios for women with a high waist-to-hip ratio (≥0.84) and low total physical activity (≤10.9 MET-h/day) had the highest risk for breast cancer (OR = 2.7, 95% CI: 1.4–4.9 for postmenopausal women, OR = 2.1, 95% CI: 1.5–3.1 for premenopausal women) compared to their counterpart with low waist-to-hip ratio ( 20.5 MET-h/day). We did not find a statistically significant multiplicative interaction between body size, caloric intake and total physical activity on breast cancer risk.

Parity and breastfeeding in relation to obesity among black and white women in the southern community cohort study.

Abstract: Objective: This research sought to describe associations among parity, breastfeeding, and adult obesity in black and white women in the southeastern United States. Methods: Cross-sectional data from 7,986 white women and 23,198 black women (age 40–79 years) living in the southeastern United States and enrolled in the Southern Community Cohort Study during 2002–2006 were used to examine self-reported body mass index (BMI) and weight change since age 21 in association with parity and breastfeeding. Multiple linear regression and logistic regression with adjustment for demographic and lifestyle factors were used. Results: At all levels of parity and breastfeeding, black women had higher BMI and weight gain since age 21 than white women. Compared to nulliparity, five or more live births was associated with increased odds of obesity in white women (odds ratio [OR] = 1.37, 95% confidence interval [CI] = 1.08–1.74) and, to a lesser extent, in black women (OR = 1.22, 95% CI = 1.07–1.38). In white women, ...

Energy balance and type 2 diabetes: a report from the shanghai women’s health study

Abstract: Background and aims The combined effect of the components of energy balance (energy intake and physical activity) and the development of type 2 diabetes (T2D) has not been adequately investigated. The aim of this study was to examine the components of energy balance and the incidence of T2D in a cohort of middle-aged women. Methods and results A population-based prospective study of 64,227 middle-aged Chinese women who had no prior history of diabetes or chronic disease at study recruitment. Participants completed in-person interviews at baseline and follow-up surveys that collected information on diabetes risk factors including dietary and physical activity habits and disease occurrence. Anthropometric measurements were taken by trained interviewers at recruitment. Average follow-up time was 4.6 years. During 297,755 person-years of follow-up, 1608 new cases of T2D were documented. Body mass index (BMI) and weight gain (since age 20) were strongly associated with T2D incidence. Energy intake (EI) was associated with modestly increased risk, while physical activity (PA) was associated with decreased risk of T2D. Less active women with higher EI had higher risk of T2D (RR = 1.96; 95% CI: 1.44, 2.67) than active women with lower EI ( P interaction = 0.02). The EI to PA (EI:PA) ratio was positively associated with T2D risk; the association was more evident among overweight and obese women (BMI ≥ 23 kg/m 2 ). Conclusion These data suggest that energy balance plays an important role in the development of T2D, and this effect may be modified by BMI.

The Legacy of Dr. Ralph Seal Paffenbarger, Jr. - Past, Present, and Future Contributions to Physical Activity Research

Abstract: Ralph Seal Paffenbarger, Jr, M.D.; Dr.P.H.; D.Sc.,h.c. was born on October 21, 1922 in Columbus, Ohio; he died on July 9, 2007 from congestive heart failure in Sante Fe, New Mexico. Dr. Paffenbarger, together with Professor Jeremy Morris of the London School of Hygiene and Tropical Health, has been credited with pioneering the field of epidemiologic research on physical activity and health. Many, if not all, individuals conducting research in this area have been influenced by some aspect of Dr. Paffenbarger’s work. Below, we discuss some of Dr. Paffenbarger’s many contributions to the field – past, present, as well as future contributions.