AbstractsMedical & Health Science

In the United States over 82 million Americans, or approximately 26% of the population, are aged 50 and older. The National Health and Nutrition Examination Survey estimate the prevalence of obesity in this group to be 32.6%. However, most healthcare providers rely upon Body Mass Index (BMI) and Waist Circumference (WC) as indicators of obesity-related health risks. The purpose of this study was to investigate the accuracy of BMI and WC as indicators of obesity status and risk for associated health concerns (e.g., cardiovascular disease, diabetes, hypertension, dyslipidemia). Subjects were 60 healthy males (n=22) and females (n=38) aged 50 and older (59.9±7.9 yrs.). Height and weight measurements were assessed via stadiometer and calibrated electronic scale; BMI was calculated as kg/m2 (M: 28.8±5.3 kg/m2; F:. 26.4±6.3 kg/m2). WC was measured using a Gulick tape at two anatomical points; narrowest waist (WCN)(M: 91.3±6.8cm ; F: 83.6±12.7cm ) and level with the umbilicus (WCU)(M: 102.0±7.5cm; F: 91.1±13.6cm). Each participant completed body composition analysis via air-displacement plethysmography (ADP)(M: 28.3±6.3%; F: 36.2±8.5%). Percent fat estimated by ADP (%fat) was used as the criterion measure of body composition in this investigation. All participants met pretesting requirements (e.g., no food, water, or exercise for 2 hours) to ensure accuracy. Based on NIH-accepted BMI and WC classifications, 26 (6M, 20F) participants were classified as normal weight, 13 (7M, 6F) as overweight and 21 (9M, 12F) as obese using BMI. WCN resulted in 40 (16M, 24F) participants classified as having healthy levels of abdominal fat and 20 (6M, 14F) classified as having unhealthy levels, while WCU resulted in 31 (13M, 18F) participants classified as having healthy levels and 29 (9M, 20F) as having unhealthy levels of abdominal fat. Using %fat via ADP, 29 (7M, 22F) participants were classified as normal weight, 9 (4M, 5F) as overweight, and 22 (11M, 11F) as obese using sex-specific cut-points (Gallagher et al., 2000). Sensitivity was calculated comparing BMI and WCN/WCU to %fat classification. Overall, the sensitivity of BMI in properly identifying men and women at risk for obesity-related health concerns was 0.90. Sensitivity values for WCN and WCU were inconsistent between sexes (WCN: 0.40M, 0.91F; WCU: 0.70M, 1.00F). Based on this investigation, using BMI to estimate obesity-related health risk in men and women over the age of 50 years provided accurate classifications. However, based on WC results, a potential sex difference was found. These findings indicate the need for further research to explore the use of WC at both anatomical points when identifying obesity-related health risk. In practice, this investigation found that BMI was the best indicator of obesity and obesity-related health risk in adults over the age of 50.