Introduction: Overall and abdominal obesity are both well-established risk factors of vitamin D deficiency. However, it is unclear which fat depot is most strongly related to serum 25-hydroxyvitamin D (25(OH)D) concentrations.
Objective: This study aims to distinguish specific contributions of total body fat, abdominal subcutaneous adipose tissue (aSAT), visceral adipose tissue (VAT) and hepatic fat on 25(OH)D concentrations.
Methods: This study is a cross-sectional analysis of the baseline measurements of the Netherlands Epidemiology of Obesity study, a population-based cohort study in men and women aged between 45 and 65 years. We used linear regression analyses to examine associations of total body fat, aSAT, VAT (n=2441) and hepatic fat (n=1980) with serum 25(OH)D concentrations. In the analyses we adjusted for age, ethnicity, education, chronic diseases, smoking, alcohol consumption and physical activity. Standardized values were used to compare the different adiposity measures.
Results: Mean (S.D.) age and serum 25(OH)D concentrations of the study population was 56 (6) years and 70.8 (24.2) nmol/l, respectively. Total body fat was inversely associated with 25(OH)D concentrations in women, but not in men. One percent higher total body fat was associated with 0.40 nmol/l (95%CI: −0.67−0.13) lower 25(OH)D. VAT was inversely associated with serum 25(OH)D concentrations in both men and women. 1 cm2 higher VAT was associated with 0.05 nmol/l (−0.09−0.02) lower 25(OH)D in men, and 0.06 nmol/l (−0.10 −0.01) lower 25(OH)D in women. Hepatic fat was only associated with 25(OH)D in men. A tenfold increase in hepatic fat was associated with 6.21 nmol/l (−10.70−1.73) lower 25(OH)D. aSAT was not associated with 25(OH)D concentrations in both men and women. Regressions with standardized values showed VAT was most strongly related to serum 25(OH)D concentrations.
Conclusions: The relationship between different adiposity measures and 25(OH)D concentrations was different for men and women. In women, total body fat and VAT were inversely related to 25(OH)D concentrations. In men, VAT and hepatic fat were related to 25(OH)D concentrations. In both men and women, VAT was most strongly associated with 25(OH)D concentrations. This implies that specific attention for vitamin D deficiency should be given to individuals with a high amount of VAT.
19 May 2018 - 22 May 2018