Adipocyte hypertrophy, fatty liver and metabolic risk factors in South Asians: the Molecular Study of Health and Risk in Ethnic Groups (mol-SHARE).
Level 4 - case-series / case-control
Cross-sectional comparative observational study
PubMed 21829446 · doi:10.1371/journal.pone.0022112
What was done
A cross-sectional comparative study evaluated 108 healthy South Asian (mean age 36.8 years) and white Caucasian (mean age 34.2 years) adults recruited across three BMI strata. Body composition, adipocyte size, abdominal fat area, and hepatic adiposity were measured and analyzed against fasting glucose, insulin, lipid profiles, and adiponectin.
What was found
After adjusting for age, sex, and BMI, South Asians compared to white Caucasians had higher ln fasting insulin (mean difference [MD]: 0.44; 95% CI: 0.20 to 0.69), lower HDL cholesterol (MD: -0.13; 95% CI: -0.26 to -0.01), lower adiponectin (MD: -2.38; 95% CI: -3.59 to -1.17), greater body fat (MD: 2.69; 95% CI: 0.70 to 4.69), lower lean muscle mass (MD: -3.25; 95% CI: -5.35 to -1.14), higher waist-to-hip ratio (MD: 0.03; 95% CI: 0.01 to 0.05), less superficial subcutaneous abdominal adipose tissue (MD: -2.94; 95% CI: -5.56 to -0.32), higher deep/visceral to superficial adipose tissue ratio (MD: 0.34; 95% CI: 0.02 to 0.65), more liver fat (MD: 7.43%; 95% CI: 2.30 to 12.55%), and increased adipocyte area (MD: 64.26 units²; 95% CI: 24.3 to 104.1). Adjustment for adipocyte area attenuated ethnic differences in insulin (MD: 0.22; 95% CI: -0.07 to 0.51), HDL (MD: -0.01; 95% CI: -0.16 to 0.13), and adiponectin (MD: -1.11; 95% CI: -2.61 to 0.39), while adjustment for adipocyte area and fat distribution attenuated differences in liver fat (MD: 5.19; 95% CI: 0.31 to 10.06).
Why it matters
These findings suggest that adipocyte hypertrophy and ectopic fat storage, rather than BMI alone, explain the elevated cardiometabolic risk seen in South Asian populations.
Limits
The study is cross-sectional, precluding causal inference. The sample size was modest (n = 108), limited to healthy younger adults, and did not measure longitudinal cardiovascular outcomes.
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- supports 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.