Associations of body mass index and insulin resistance with leptin, adiponectin, and the leptin-to-adiponectin ratio across ethnic groups: The Multi-Ethnic Study of Atherosclerosis (MESA)

Purpose: Associations of adiponectin and leptin and their ratio with body mass index (BMI) and homeostasis model assessment of insulin resistance (HOMA-IR) have been investigated in different ethnic groups but variability in both assays and statistical methods have made cross-study comparisons difficult. We examined associations among these variables across four ethnic groups in a single study. Methods: Adiponectin and leptin were measured in a subset of participants from the Multi-Ethnic Study of Atherosclerosis study. We calculated associations (using both partial correlations and adjusted linear regression) in each ethnic group and then compared the magnitude of these associations across groups. Results: After we excluded individuals with type 2 diabetes, there were 714 white, 219 Chinese, 332 African-American, and 405 Hispanic subjects in the study sample. Associations of BMI with adiponectin and leptin differed significantly (P < .05) across the ethnic groups in regression analyses, whereas associations of HOMA-IR with adiponectin and leptin did not differ across ethnic groups. The leptin-to-adiponectin ratio was not associated with a greater amount of adiposity or HOMA-IR variance than leptin or adiponectin in any ethnic group. Conclusions: Given the consistency of HOMA-IR and adipokine associations, the differing means of adiponectin and leptin across ethnic groups may help to explain ethnic differences in mean insulin resistance.