Narrow hips and broad waist circumferences independently contribute to increased risk of non-insulin-dependent diabetes mellitus

Objectives. Patients with non-insulin-dependent diabetes mellitus (NIDDM) have been shown to be more obese and have higher waist-to-hips circumference ratios compared to nondiabetics. In this study, we tried to dissociate obesity, waist and hip circumference from NIDDM. Design. A cross- sectional population-based case control study. Setting. General population. Subjects. Controls: 5887 men and 7018 women, aged 20-59 years, without known diabetes or hyperglycaemia. Cases: 93 men and 66 women were diagnosed with NIDDM. Main outcome measures. We predicted waist and hips' circumference from the body mass index, weight/height², (BMI) on the basis of linear regression. Differences between observed and expected values (residuals) of waist and hip circumference were categorized into tertiles. The relative odds of having NIDDM in tertiles of waist and hip residuals (middle tertile as reference) were calculated by multiple logistic regression analysis adjusted for each other and for age, smoking, physical activity, alcohol consumption and education. Results. NIDDM was most prevalent in men and women who had larger waists and in those who had smaller hip circumferences than expected from their BMI. Adjusted odds ratios (95% CI) for NIDDM were 2.9 (1.6-5.1) in men and 2.8 (1.5-5.1) in women who had a larger than expected waist, and were 3.7 (2.1-6.5) in men and 2.1 (1.1-3.8) in women who had smaller than expected hips. Conclusions. Our findings suggest that diabetics have larger waists and smaller hips compared to nondiabetics, irrespective of their degree of obesity, age and life-style factors. One possibility is that besides abdominal fatness, peripheral muscle atrophy is one of the factors associated with NIDDM.