Ethnic differences in the association between body mass index and hypertension

Interest in ethnicity-specific definitions of obesity has been hindered by a lack of data clarifying whether or not obesity-related comorbid conditions occur at different levels of body mass index (BMI) (weight (kg)/height (m)(2)) in different ethnic groups. The objective of this study was to examine ethnic differences in the strength of the association between BMI and hypertension. Cross-sectional data obtained from adults aged 30-65 years in China (1997, n = 3,423), the Philippines (1998, n = 1,929), and the United States (1988-1994, n = 7,957) were used. Higher BMI was associated with a higher prevalence of hypertension in all ethnic groups. However, at BMI levels less than 25, prevalence difference figures suggested a stronger association between BMI and hypertension in Chinese men and women but not in Filipino women, compared with non-Hispanic Whites, Non-Hispanic Blacks and Filipino women had a higher prevalence of hypertension at every level of BMI compared with non-Hispanic Whites and Mexican Americans. These ethnic differences in the strength of association between BMI and hypertension and in underlying prevalence warrant further investigation into the use of ethnicity-specific BMI cutoffs in clinical settings to more accurately identify individuals at risk from obesity.