Anthropometric Markers of Health Risk
Obesity , Epidemiology , Measurement , Body composition , Risk factors , Diabetes , Mortality , Population
The objective of this thesis was to investigate the relationships between simple anthropometric measures and health risk towards a better characterization of the high-risk obesity phenotype. To this end, four studies were undertaken. The first study assessed the comparability of waist circumference (WC) data collected according to four commonly used measurement protocols in a sample of 520 community-dwelling men and women. This investigation quantified the influence of measurement site on the magnitude and reliability of WC and highlighted the impact of measurement site on prevalence estimates of abdominal obesity. To extend these findings, the second study examined the influence of WC measurement site on its association with cardiometabolic risk. Despite similar associations with risk factors including blood pressure, HDL-cholesterol, triglycerides, and blood glucose, prevalence estimates of metabolic syndrome differed depending on the anatomical site of WC measurement, particularly in women. In order to better understand the heterogeneity in human obesity and its sequelae, the third and fourth studies focused on the separate and combined influences of central and peripheral circumferences on health outcomes. Specifically, the third study used data from the Physical Activity Longitudinal Study (PALS) to demonstrate that after adjusting for BMI and WC, larger arm, calf, and thigh circumferences offer a protective effect against incident diabetes. The fourth study confirmed the opposing influences of central and peripheral circumferences on risk of all-cause mortality in a sample of 10,638 participants from the 1981 Canada Fitness Survey (CFS) with more than 12 y of follow-up. After adjustment for age, smoking status, alcohol consumption, leisure-time physical activity and BMI, WC was positively associated with mortality whereas arm, thigh, and calf circumferences were significantly protective in men and arm and thigh circumferences were protective in women. Collectively, the results from these studies contribute to a better understanding of the role of body dimensions in determining health risk and have implications for the use of anthropometric measures in clinical and research settings.