Background: Obesity is a risk factor for the incidence of hypertension, but it is still unclear whether this risk can be better estimated by body mass index (BMI) or waist circumference (WC).
Methods: In the baseline evaluation of a population-based cohort, 1089 adults answered a pretested questionnaire and had their baseline blood pressure (BP) and anthropometric measurements assessed according to standardized recommendations. Excluding the individuals with hypertension at baseline, and those deceased or lost during the follow-up, 592 individuals (80.5% of those eligible) were visited again. Obesity was defined as BMI >/=30 kg/m(2) for both genders, and WC >/=102 cm for men and WC >/=88 cm for women. Incident cases of hypertension were characterized by BP >/=140/90 mm Hg or use of BP medication in the follow-up visit.
Results: After a mean follow-up of 5.6 +/- 1.1 years, 127 incident cases of hypertension were identified. The hazard ratios (Cox model), adjusted for age and baseline systolic BP (95% CI and P), for BMI higher than 30 kg/m(2) were 1.08 (0.52-2.24, P =.82) in men and 1.74 (0.93-3.26, P =.08) in women. The corresponding figures were 1.78 (0.76-4.09, P =.18) for men with WC >/=102, and 1.72 (1.09-2.73, P =.02) for women with WC >/=88 cm.
Conclusions: We conclude that the risk for hypertension may be better identified by obesity defined by higher WC than higher BMI.