Ethnicity modifies the relationships of insulin resistance, inflammation, and adiponectin with obesity in a multiethnic Asian population

Abstract

Objective: The development of obesity-related metabolic disorders varies with ethnicity. We examined whether ethnicity modifies the relationship between BMI and three metabolic pathways (insulin resistance, inflammation, and adiponectin) that are involved in the pathogenesis of diabetes and cardiovascular disease (CVD).

Research design and methods: We analyzed data from 4,804 Chinese, Malay, and Asian-Indian residents of Singapore with complete data on insulin resistance (IR), C-reactive protein (CRP), and total adiponectin levels. Linear regression models with an interaction term ethnicity*BMI were used to evaluate whether ethnicity modifies the association between BMI and IR, CRP, and adiponectin.

Results: In both uni- and multivariate analyses, BMI was directly associated with IR and CRP and inversely with adiponectin across all ethnic groups. When compared with Chinese and Malays, Asian-Indians had higher IR and CRP and lower adiponectin levels. The associations between BMI and its metabolic pathways were significantly stronger in Chinese than in other ethnic groups. The increase in IR and CRP and the decrease in adiponectin for each unit increase in BMI were greater in Chinese than in other ethnic groups. The findings were similar when waist circumference was used in the analyses instead of BMI.

Conclusions: The impact of BMI on IR, CRP, and adiponectin appears greater in Chinese as compared with other major Asian ethnic groups. This may partly explain the rapid increase in the prevalence of diabetes and CVD in Chinese populations and highlights the importance of weight management in Asian ethnic groups despite the apparently low levels of obesity.

Figure 1

Age-adjusted fitted regression plots showing relationships between BMI and IR, CRP, and adiponectin in Chinese (○), Malays (△), and Asian-Indians (□), stratified by sex. A: Relationship of IR to BMI in men (P interaction = 0.282). B: Relationship of IR to BMI in women (P interaction < 0.001). C: Relationship of CRP to BMI in men (P interaction = 0.304). D: Relationship of CRP to BMI in women (P interaction < 0.001). E: Relationship of adiponectin to BMI in men (P interaction < 0.001). F: Relationship of adiponectin to BMI in women (P interaction < 0.001).