Waist circumference,body mass index and glycated hemoglobin in Japanese men and women

AimsTo investigate the relationship of waist circumference and body mass index (BMI) with glycated hemoglobin (HbA_1c) concentrations and to define optimal cutoffs for these indices with respect to elevated HbA_1c (>5.8%).MethodsStudy subjects were 7731 Japanese men and women aged 50–74 years in Fukuoka City who participated in the baseline survey of a cohort study on lifestyle-related diseases. Linear regression analysis and logistic regression analysis were used with and without adjustment for age, smoking, alcohol use and physical activity. Receiver operating characteristic (ROC) curve analysis was performed to determine optimal cutoffs for the obesity indices.ResultsWaist circumference and BMI were linearly related to HbA_1c concentrations in men and women with almost the same magnitude in strength. With adjustment for the covariates, mean percent changes of HbA_1c per one standard deviation (S.D.) of waist circumference and BMI were 1.6% and 1.8% respectively in men, and 1.3% and 1.4% respectively in women. Adjusted odds ratios of elevated HbA_1c per one S.D. of waist circumference and BMI also showed statistically significant increases. Optimal cutoffs for waist circumference were 89 cm for men and 85 cm for women. The area under the ROC curve was much greater in women than in men.ConclusionsIn a population of middle-aged or elderly Japanese men and women, both waist circumference and BMI were strongly, positively associated with HbA_1c concentrations. The determined optimal cutoff points for waist circumference did not support the current Japanese criterion for abdominal adiposity.