[Relative importance of body mass index and waist circumference for hypertension in adults].

OBJECTIVE To assess the relative importance of Body Mass Index (BMI) and waist circumference for the determination of hypertension in adults. METHODS Cross sectional analysis of a sample of employees (N=1,584), aged 18 to 64 years, from a private general hospital in the city of São Paulo, Brazil. Data collection included the application of a structured questionnaire and blood pressure, weight, high, and waist circumference measurements. Hypertension was defined as blood pressure levels >or= 140/90 mmHg or reported use of anti-hypertensive medication. The relative importance of BMI and waist circumference was evaluated by calculating the attributable fraction of hypertension corresponding to each anthropometric indicator, employing both the usual cut-off points as well as cut-off points based on the observed distribution of the indicator in the population. In addition, an indicator combining simultaneously BMI and abdominal circumference values was also developed. RESULTS Prevalence of hypertension was 18.9% (26.9% in men and 12.5% in women). In men, the fraction of hypertension attributable to BMI exceeded the fraction attributable to waist circumference based on the usual cut-off points for the indicators (56% vs. 48%, respectively) and also considering the quartiles of the observed distribution for these indicators (73% vs. 69%, respectively). In women, the fraction of hypertension attributable to waist circumference was slightly higher than the fraction attributable to BMI based on the usual cut off points for both indicators (44% vs. 41%), but the reverse was true when quartiles of the observed distribution were used (41% vs. 57%, respectively). In women only, the fraction of hypertension attributable to the indicator combining BMI and waist circumference (64%) was higher that observed using each indicator alone. CONCLUSIONS Both BMI and abdominal circumference were positively and independently associated with the occurrence of arterial hypertension, the influence of BMI being higher among men.