Differences in subcutaneous abdominal adiposity regions in four ethnic groups

Objective: Previous studies have identified ethnic specific differences in visceral adipose tissue (VAT), which may account for ethnic differences in cardio-metabolic risk. However, two distinctive sub-compartments of abdominal subcutaneous adipose tissue (SAT) have been recently identified that may also differ among ethnic groups. Therefore, the relationship between SAT compartments and body fat mass (BFM) between Aboriginal, Chinese, and South Asian cohorts compared to Europeans was investigated.

Design and methods: Healthy Aboriginal, Chinese, European, and South Asian (n = 822) men and women (30-65 years) were assessed for BFM via dual energy X-ray absorptiometry, and SAT areas using computer tomography. SAT was subdivided into superficial SAT (SSAT) and deep SAT (DSAT) via the fascia-superficialis. Linear regression was performed using DSAT and SSAT as separate dependent variables and BFM and ethnicity as primary independent variables adjusting for confounders.

Results: Aboriginal (181.0 cm(2) ; p = 0.045) and South Asians (178.3 cm(2) ; p = 0.013) had significantly higher amounts of DSAT, whereas the Chinese cohort had significantly less when compared with Europeans (114.3 cm(2) ; p = <0.001). The Aboriginal cohort had a significantly higher amount of SSAT than Europeans (123.13 cm(2) vs. 108.7 cm(2) ; p = 0.04). Ethnicity modified the relationship between DSAT and BFM (p < 0.001 for interaction) such that Aboriginals and majority of South Asians had a significantly greater DSAT.

Conclusion: These data further demonstrate ethnic differences in body fat distribution such that Aboriginals and South Asians have greater amounts of DSAT. This may contribute to the increased cardio-metabolic risk in these groups.