Ethnic variation in adiponectin and leptin levels and their association with adiposity and insulin resistance.

Description

This study sought to investigate ethnic differences in adipokine (adiponectin and leptin) concentrations and to determine whether these adipokines and a high glycemic index diet explained ethnic differences in insulin resistance. The study population included 1,176 Canadians of South Asian, Chinese, Aboriginal, or European origin who participated in the Study of Health Assessment and Risk in Ethnic Groups (SHARE). The analysis revealed that South Asians were characterized by lower adiponectin and higher leptin levels for the same level of adiposity as Europeans. Moreover, Aboriginal people had higher leptin levels than Europeans but similar adiponectin levels whereas Chinese also presented lower adiponectin levels than Europeans. The authors also found that South Asians and Aboriginal people showed a significantly greater increase in insulin resistance per unit decrease in adiponectin compared to Chinese and Europeans. In addition, a high glycemic index was associated with a larger decrease in adiponectin among South Asians (p=0.03) and Aboriginal people (p<0.001) as well as a greater increase in insulin resistance, particularly in South Asians. These findings indicate that South Asians have an unfavourable adipokine profile compared with other ethnic groups and also suggest that lowering intake of high glycemic foods could help to stabilize adipokine concentrations and improve insulin sensitivity in high-risk populations such as South Asians and Aboriginal people.