BMI, waist circumference, and clustering of cardiovascular risk factors in Japanese adults

Objective To examine whether the association between waist circumference (WC) and clustering of cardiovascular risk factors varies with obesity (BMI) status. Methods Using the 2008 health examination data of a Japanese health service association, eligible 57,141 adults aged 20–65 years without coronary heart disease or stroke, whose blood sample had been taken in the fasting state, were enrolled in the study. The participants were classified as being underweight (BMI\18.5), normal weight (BMI 18.5–24.9), and overweight (BMI C25.0). Multiple logistic regression analysis was performed to calculate adjusted odds ratios (OR) for clustering of cardiovascular risk factors. Receiver operating characteristic analysis was performed to assess the ability of WC to discriminate subjects with and without a clustering of cardiovascular risk factors. Results Clustering of cardiovascular risk factors was found in 16.0% of men and 3.4% of women. The adjusted OR [95% confidence intervals (CI)] per 5-cm increase in WC of the underweight, normal weight, and overweight groups was 1.57 (1.12–2.20), 1.55 (1.49–1.62), and 1.34 (1.30–1.38), respectively, for men and 1.50 (0.84–2.69), 1.53 (1.40–1.68), and 1.32 (1.23–1.41), respectively, for women. The area under curve (95% CI) of the underweight, normal weight, and overweight groups was 0.68 (0.59–0.77), 0.70 (0.69–0.71), and 0.62 (0.61–0.63), respectively, for men and 0.70 (0.53–0.86), 0.75 (0.73–0.78), and 0.64 (0.61–0.68), respectively, for women. Conclusion High WC was associated with increased risk of clustering of cardiovascular risk factors independent of BMI. As well as the magnitude of the association, the ability of WC to discriminate subjects with and without a clustering of cardiovascular risk factors varied with obesity (BMI) status.