Large waist circumference and risk of hypertension.

OBJECTIVE: To examine the relationship between 24h ambulatory blood pressure monitoring and three commonest anthropometric measurements for obesity-body mass index (BMI), waist-to-hip ratio (WHR) and waist circumference (W). DESIGN: Cross-sectional survey among outpatients at the Obesity Research Center. SUBJECTS AND METHODS: Four-hundred and sixty-one overweight or obese subjects, non-diabetic, otherwise healthy, aged 20-70y, of either sex, were consecutively recruited. All subjects underwent 24h 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. RESULTS: Logistic regression shows that W is the most important anthropometric factor associated with the hypertensive risk. Among males with W greater than or equal to 102cm the odds ratio (OR) for hypertension is three times that of males with W < 94cm 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 greater than or equal to 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 greater than or equal to0.96 and females with WHR greater than or equal to0.86 show significant OR for hypertension only by 24 h SP 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 greater than or equal to 55 y and females aged greater than or equal to 50 y. CONCLUSION: 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.