To examine whether the association between waist circumference (WC) and clustering of cardiovascular risk factors varies with obesity (BMI) status.

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 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.

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.