Ethnic differences in adipose tissue dysfunction and insulin resistance: a scoping review

The objective of this scoping review is to synthesize ethnic comparison studies focused on characteristics of adipose tissue dysfunction including ectopic fat, adipokines and insulin resistance in populations of south Asian (SA), black (BA) and white (WE) ethnicity. A search of the literature was conducted on MEDLINE using keywords for adipose tissue dysfunction and ethnicity. Studies were included if they compared ectopic fat in adults (>18-years) of SA, BA or WE ethnicity, with data on insulin sensitivity and adipokines extracted where present. Thirty-one studies were included in this review. Trends showed most studies were conducted in USA (n = 22); BA were the focus of most ethnic comparison studies (n = 28). Most studies focused on intrahepatic lipids (n = 26), with fewer investigating intrapancreatic lipids (n = 3) and intramyocellular lipids (n = 8). Only 2 studies investigated leptin and adiponectin alongside ectopic fat deposition by ethnicity. Current trends indicate intrahepatic lipid is lower in BA but greater in SA compared to WE populations, indicting possible ethnic disparities in the role ATD in the development of T2D. Few ethnicity studies have investigated multiple characteristics of ATD between BA and SA groups in a single study which may be needed to elucidate ethnic-specific pathophysiology of T2D.