Large waist circumference and risk of hypertension

To examine the relationship between 24 h ambulatory blood pressure monitoring and three commonest anthropometric measurements for obesity--body mass index (BMI), waist-to-hip ratio (WHR) and waist circumference (W).

Cross-sectional survey among outpatients at the Obesity Research Center.

Four-hundred and sixty-one overweight or obese subjects, non-diabetic, otherwise healthy, aged 20-70 y, of either sex, were consecutively recruited. All subjects underwent 24 h ambulatory blood pressure monitoring. The population study was separated in normotensive and hypertensive males and females and the possible risk factors for hypertension (W, WHR, BMI and age) were subdivided into different classes of values.

Logistic regression shows that W is the most important anthropometric factor associated with the hypertensive risk. Among males with W> or =102 cm the odds ratio (OR) for hypertension is three times that of males with W<94 cm using casual BP measure (OR 3.04), nearly four times higher using 24 h BP mean (OR 3.97), and even five times higher using day-time BP mean (OR 5.19). Females with W> or =88 cm have a risk for hypertension twice that of females with W<80 cm, whatever BP measurement was take (casual, 24 h or day-time). Males with WHR> or =0.96 and females with WHR> or =0.86 show significant OR for hypertension only by 24 h BP measurement and by day-time BP measurement. BMI seems to have no significant relationship to hypertensive risk. Age shows a significant relationship to hypertensive risk only considering males aged > or =55 y and females aged > or =50 y.

The waist circumference seems to have a strong association with the risk of hypertension, principally by the ambulatory BP monitoring, when compared with casual BP measurement.