Insulin resistance and body fat distribution in South Asian men compared to Caucasian men.
Level 4 - case-series / case-control
Cross-sectional comparative physiological study
PubMed 17726542 · doi:10.1371/journal.pone.0000812
What was done
Researchers compared 29 non-diabetic South Asian men and 18 Caucasian men (both groups mean age 27 ± 3 years) with similar body mass index. Insulin sensitivity was assessed using euglycemic-hyperinsulinemic clamps, total body fat via underwater weighing, subcutaneous abdominal (SA) and intraperitoneal (IP) fat volume by abdominal MRI, and SA adipocyte cell size via fat biopsy.
What was found
Despite similar BMI, South Asian men had significantly higher total body fat (22 ± 6% vs. 15 ± 4%, p < 0.0001) and higher SA fat (3.5 ± 1.9 vs. 2.2 ± 1.3 kg, p = 0.004) compared to Caucasians, with no difference in IP fat (1.0 ± 0.5 vs. 1.0 ± 0.7 kg, p = 0.4). South Asian SA adipocyte size was significantly larger (3491 ± 1393 vs. 1648 ± 864 µm², p = 0.0001) and remained higher when matched for SA mass. SA adipocyte size was inversely correlated with glucose disposal rate (r = -0.57, p = 0.0008) and plasma adiponectin (r = -0.71, p < 0.0001).
Why it matters
The findings indicate that ethnic susceptibility to insulin resistance in young South Asian men is tied to subcutaneous adipose dysfunction and cell hypertrophy rather than excess visceral fat mass.
Limits
The study was cross-sectional with a small sample size (n = 47) and included only young, healthy men, precluding generalization to women, older adults, or individuals with established type 2 diabetes.
Cited by
- context A study found that South Asian men have subcutaneous adipocytes that are approximately four times larger volumetrically than Caucasian men matched for body size and body fat percentage.