Impact of body mass index on incident hypertension and diabetes in Chinese Asians, American Whites, and American Blacks: the People's Republic of China Study and the Atherosclerosis Risk in Communities Study

Abstract

Researchers have hypothesized that the impact of body mass index on chronic disease may be greater in Asians than in Whites; however, most studies are cross-sectional and have no White comparison group. The authors compared the associations with body mass index in Chinese Asians (n = 5,980), American Whites (n = 10,776), and American Blacks (n = 3,582) using prospective data from the People's Republic of China Study (1983-1994) and the Atherosclerosis Risk in Communities Study (1987-1998). Slopes of risk differences over body mass index levels were compared among the three ethnic groups in adjusted analyses. The authors found larger associations with body mass index in Chinese Asians compared with American Whites and Blacks for hypertension (p < 0.05). The increase in the incidence of hypertension associated with a one-unit increase in body mass index over approximately 8 years of follow-up was 2.5, 1.7, and 1.8 percentage points for Chinese Asians, American Whites, and American Blacks, respectively. For diabetes, the estimates were 1.7, 1.1, and 1.6 percentage points for the same groups- higher in Chinese Asians than in American Whites (p < 0.05) but similar between Chinese Asians and American Blacks. Given the ethnic differences in associations, the results support advocacy of public health and medical actions toward obesity prevention and treatment in China.

FIGURE 1

Adjusted cumulative incidence (and 95% confidence interval) for hypertension by body mass index categories and ethnicity, the Atherosclerosis Risk in Communities Study (1987–1998) and the People’s Republic of China Study (1983–1994). Point estimates for the same body mass index categories are shifted slightly in the horizontal plane so that confidence intervals are clearly visible.

FIGURE 2

Adjusted cumulative incidence (and 95% confidence interval) for diabetes by body mass index categories and ethnicity, the Atherosclerosis Risk in Communities Study (1987–1998) and the People’s Republic of China Study (1983–1994). Point estimates for the same body mass index categories are shifted slightly in the horizontal plane so that confidence intervals are clearly visible.

FIGURE 3

Percent increase per body mass index unit (and 95% confidence interval) from weighted least-squares regression of risk differences for hypertension and diabetes over full and restricted (18.5–<30.0 kg/m²) body mass index ranges by ethnicity, the Atherosclerosis Risk in Communities Study (1987–1998) and the People’s Republic of China Study (1983–1994).