Blood pressure and body mass index: a comparison of the associations in the Caucasian and Asian populations.

A strong association between blood pressure (BP) and body mass index (BMI) has been observed in developed and developing countries. Whether there are differences in these associations between Caucasians and Asians remains unknown. Our objective was to compare the associations of BP with fatness measures in the Caucasian and Asian samples. The study used data from two population-based cross-sectional studies conducted using similar methodology: a survey in Australia in 1998-1999 (n = 832 adults aged 25-64 years; 47% male) and a survey in Vietnam in 2005 (n = 1978 adults aged 25-64 years; 46% male). Participants completed questionnaires and attended clinics for physical measurements including BP and anthropometry. Linear regression was used for analysis. Independent of age, there were strong associations between BP indices and BMI in each sample, but the patterns of associations were different. Among Caucasians, pulse pressure (PP) increased with increasing BMI because the slope of systolic pressure with BMI exceeded the slope of diastolic pressure with BMI (P<0.001 for both sexes). In contrast, among Asians, PP decreased with increasing BMI. Associations between BMI and BP are different between Caucasian and Asian populations. Among Asians, the stronger association of increasing BMI and diastolic BP, but not PP, suggests a different pathophysiology related to hypertension.