Objective: A higher waist-to-hip ratio, which can be due to a higher waist circumference, a lower hip circumference, or both, is associated with higher glucose levels and incident diabetes. A lower hip circumference could reflect either lower fat mass or lower muscle mass. Muscle mass might be better reflected by thigh circumference. The aim of this study was to investigate the contributions of thigh and hip circumferences, independent of waist circumference, to measures of glucose metabolism.
Research methods and procedures: For this cross-sectional study we used baseline data from the Hoorn Study, a population-based cohort study of glucose tolerance among 2484 men and women aged 50 to 75. Glucose tolerance was assessed by a 75-g oral glucose tolerance test; hemoglobin A(1c) and fasting insulin were also measured. Anthropometric measurements included body mass index (BMI) and waist, hip, and thigh circumferences.
Results: Stratified analyses and multiple linear regression showed that after adjustment for age, BMI, and waist circumference, thigh circumference was negatively associated with markers of glucose metabolism in women, but not in men. Standardized beta values in women were -0.164 for fasting, -0.206 for post-load glucose, -0.190 for hemoglobin A(1c) (all p < 0.001), and -0.065 for natural log insulin levels (p = 0.061). Hip circumference was negatively associated with markers of glucose metabolism in both sexes (standardized betas ranging from -0.093 to -0.296, p < 0.05) except for insulin in men. Waist circumference was positively associated with glucose metabolism.
Discussion: Thigh circumference in women and hip circumference in both sexes are negatively associated with markers of glucose metabolism independently of the waist circumference, BMI, and age. Both fat and muscle tissues may contribute to these associations.