Waist circumference vs body mass index in association with cardiorespiratory fitness in healthy men and women: a cross sectional analysis of 403 subjects
ABSTRACT OBJECTIVE: Body mass index (BMI) is more commonly used than waist circumference as a measure of adiposity in clinical and research settings. The purpose of this study was to compare the associations of BMI and waist circumference with cardiorespiratory fitness. METHODS: In a cross-sectional study of 403 healthy men and women aged 50 +/- 8.8 years, BMI and waist circumference were measured. Cardiorespiratory fitness was assessed from estimated maximal O2 uptake (VO2max), as calculated from a maximal fitness test. RESULTS: Mean BMI (kg/m2) was 27.8 +/- 3.7 and 25.5 +/- 4.6; and mean waist circumference (cm) 94.1 +/- 9.7 and 84.3 +/- 10.4 for men and women, respectively. Both men and women reported an average of 2.5 hours of weekly sports related physical activity, and 18% were current smokers. Correlation coefficients between both BMI and waist circumference, and VO2max were statistically significant in men (r = -0.280 and r = -0.377, respectively, p > 0.05 for both) and in women (r = -0.514 and r = -0.491, respectively, p > 0.05 for both). In women, the contribution of BMI to the level of VO2max in a regression model was greater, while in men waist circumference contributed more to the final model. In these models, age, hours of training per week, and weekly caloric expenditure in sport activity, significantly associated with VO2max, while smoking did not. CONCLUSION: The differences observed between the sexes in the associations of BMI and waist circumference with VO2max support the clinical use of both obesity measures for assessment of cardiorespiratory fitness.
SourceAvailable from: Emilson Colantonio06/2013; 18(3). DOI:10.12820/rbafs.v.18n3p354
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ABSTRACT: Major causative factor for major depression is inflammation, autoimmune tissue damage and prolonged psychological stress, which leads to oxidative stress. The aim of this study was to know the association of free radicals and antioxidant status in subjects suffering from major depression. Sixty patients diagnosed as a case of unipolar depression as per DSM IV, fulfilling the inclusion and exclusion criteria were compared with 40 healthy age and sex matched controls. The sera of both the groups were collected taking aseptic precautions and were evaluated for the markers of oxidative stress and for the antioxidants. The age group of the sample and the controls was between 18-60 y, both males and females were equally represented in the groups. A significantly high level of malondialdehyde (MDA) was found in the patients with major depression (1.95 ± 1.04 mmol/L) as compared to healthy controls (0.366 ± 0.175 mmol/L) (p < 0.0001). The serum level of nitrite was found to be lower in cases (23.18 ± 12.08 μmol/L) in comparison to controls (26.18 ± 8.68 μmol/L) (p = 0.1789). Similarly the serum level of ascorbic acid and superoxide dismutase (SOD) were significantly below as compared to healthy controls (all p < 0.0001). Ceruloplasmin levels were also depressed in cases (p = 0.3943). The study concluded that in the absence of known oxidative injury causative agents, the lowered levels of antioxidants and higher levels of MDA implicate the high degree of oxidative stress in unipolar depression.
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ABSTRACT: The objectives of this article are to demonstrate that the obesity paradox may be explained by collider stratification bias and to estimate the biasing effects of unmeasured common causes of cardiovascular disease (CVD) and mortality on the observed obesity-mortality relationship. We use directed acyclic graphs, regression modeling, and sensitivity analyses to explore whether the observed protective effect of obesity among individuals with CVD can be plausibly attributed to selection bias. Data from the third National Health and Examination Survey was used for the analyses. The adjusted total effect of obesity on mortality was a risk difference (RD) of 0.03 (95% confidence interval [CI]: 0.02, 0.05). However, the controlled direct effect of obesity on mortality among individuals without CVD was RD = 0.03 (95% CI: 0.01, 0.05) and RD = -0.12 (95% CI: -0.20, -0.04) among individuals with CVD. The adjusted total effect estimate demonstrates an increased number of deaths among obese individuals relative to nonobese counterparts, whereas the controlled direct effect shows a paradoxical decrease in morality among obese individuals with CVD. Sensitivity analysis demonstrates unmeasured confounding of the mediator-outcome relationship provides a sufficient explanation for the observed protective effect of obesity on mortality among individuals with CVD. Copyright © 2015 Elsevier Inc. All rights reserved.Annals of Epidemiology 02/2015; 25(5). DOI:10.1016/j.annepidem.2015.02.008 · 2.15 Impact Factor