Ethnic-specific Differences in Vitamin D Status is Associated with Adiposity

Background: Low circulating 25 hydroxyvitamin D [25(OH)D] concentrations are common in obesity (BMI ≥30 kg/m(2)) and a negative relationship with body fat distribution has recently been reported. Ethnic-specific differences in body fat distribution have been described with South Asians are reported to have greater visceral adipose tissue (VAT), which could influence circulating 25(OH)D concentrations. The objective of this study is to investigate the relationship between plasma 25(OH)D, adiposity, and body fat distribution in Europeans and South Asians.

Methods/principal Findings: 187 Europeans and 192 South Asians were assessed for demographics, anthropometrics, and plasma 25(OH)D concentrations. Subcutaneous adipose tissue (SAT) and VAT were quantified by CT scan, and percent body fat by DEXA. Data were assessed by general linear models. South Asians had lower (P<0.001) plasma 25(OH)D concentrations and higher VAT (P = 0.04) than Europeans. Plasma 25(OH)D concentrations were negatively (P<0.05) associated with BMI, waist circumference, percent body fat, total adipose tissue, VAT, and SAT in unadjusted models and negatively (P<0.05) associated with VAT, SAT, and percent body fat after adjusting for BMI, ethnicity, age, and season of blood collection in males and females. When percent body fat, VAT, and SAT were included in the same model, only VAT remained negatively (P<0.05) associated with plasma 25(OH)D concentrations. Ethnicity remained significant in all models (P<0.001).

Conclusion: Compared to other adipose tissue compartments, VAT may have a distinct role in determining plasma 25(OH)D concentrations, which may account for the lower levels in South Asians.