Waist circumference as a determinant of hypertension and diabetes in Brazilian women: a population-based study.

OBJECTIVE: To evaluate the role of central adiposity, as evaluated by the measurement of waist circumference (WC), as an independent risk factor for hypertension and type 2 diabetes mellitus in the setting of a developing country. DESIGN: Population-based, cross-sectional study. SETTING: A medium-sized town in southern Brazil. PARTICIPANTS: One thousand and ninety-five non-pregnant women, 20 to 69 years old, recruited by cluster random sampling between 1999 and 2000. Their mean WC was 85.3 cm (standard deviation 13.9 cm) and 23.3% (n=255) were obese (body mass index >30 kg m(-2)). The prevalence of hypertension and diabetes was 25.6% (n=280) and 6.2% (n=68), respectively. RESULTS: The risks of hypertension and diabetes were directly related to WC measurement. Women with WC>80 cm had increased risk of hypertension (odds ratio (OR)=6.2, P<0.001). The association remained significant (OR=1.04 per cm increase in WC, P=0.02) after adjusting for confounders. The effect of WC on diabetes was modified by age. The effect was stronger in women younger than 40 years old (OR=12.7, P=0.016) than in those over 40 years old (OR=2.8, P=0.013). In the multivariate analysis, the odds ratio was 5.7 (P=0.12) in those under 40 years old and 2.8 (P=0.008) in older women. CONCLUSIONS: Waist circumference is an independent determinant for hypertension and diabetes in women in this population. The stronger association between WC and diabetes in younger women suggests that the validity of this indicator to assess abdominal adiposity is age-specific. Further studies should validate the usefulness of WC measurement in different age groups.