The relation of BMI and skinfold thicknesses to risk factors among young and middle-aged adults: The Bogalusa Heart Study
Abstract
Objective : Although adverse levels of cardiovascular disease risk factors are related to skinfold thicknesses and BMI among adults, the relative strengths of these associations are unknown. We examine whether the triceps and subscapular skinfold thicknesses are more strongly related to adult levels of lipids, fasting insulin and blood pressure than BMI. Design and subjects : Cross-sectional ( n = 3318) and longitudinal ( n = 1593) analyses of 18- to 44-year-olds examined in the Bogalusa Heart Study from 1983 to 2002. Principal components analysis was used to derive a summary index of the six examined risk factors (triglycerides, low- and high-density lipoprotein cholesterol, insulin, and systolic and diastolic blood pressures). Results : The magnitudes of the differences were generally small, but all comparisons indicated that BMI was at least as strongly related to adverse risk factor levels as was the sum of subscapular and triceps skinfold thicknesses (SF sum). For example, adjusted cross-sectional associations with the risk factor summary were r = 0.55 (BMI) and r = 0.49 (SF sum), p < 0.001 for difference between correlations. Similar differences were seen in longitudinal analyses, with changes in the risk factor summary being more strongly associated with changes in BMI ( r = 0.50) than with changes in the SF sum ( r = 0.38). Conclusion : BMI appears to be at least as accurate as skinfold thicknesses in identifying metabolic risk among adults. The advantages of BMI should be considered in the design and interpretation of clinical and epidemiologic studies.