Sagittal Abdominal Diameter as a New Predictor for Incident Diabetes

OBJECTIVE: Obesity, particularly visceral adiposity, is a major risk factor for type 2 diabetes. The commonly used obesity indicators, BMI, waist girth, and waist-to-hip ratio (WHR), have limited ability to measure the visceral adipose tissue. Sagittal abdominal diameter (SAD) has been shown to predict the amount of visceral fat. So far no study has been published on its ability to predict diabetes occurrence. RESEARCH DESIGN AND METHODS: We assessed and compared the prediction of the four obesity indicators for diabetes incidence in a prospective study based on 5,168 participants from the nationally representative Health 2000 study. RESULTS: During a mean follow-up lasting 8.1 years, 222 incident diabetes cases occurred. In multivariate models adjusted for lifestyle factors, BMI, waist girth, WHR, and SAD were significant predictors of diabetes incidence. The relative risks (95% CI) between high and low levels were 15.0 (6.94–32.6), 11.4 (5.39–23.8), 12.5 (6.47–24.2), and 14.7 (6.89–31.2), respectively. Pairwise interaction analysis showed that the co-occurrence of high BMI and high SAD was associated with the highest diabetes incidence, with a relative risk of 37.0 (11.2–122). After adjustment for waist girth and the components of the metabolic syndrome, the relative risk was 9.88 (2.81–34.7). The corresponding population-attributable fraction estimate was 84% (49–95). CONCLUSIONS: The combination of SAD and BMI measurements yields a new predictor of diabetes incidence.