Purpose: Considerable variation in 25-hydroxyvitamin D (25(OH)D) in populations worldwide that seems to be independent of latitude has been reported. Therefore, we aimed to assess vitamin D status of a mid-aged German general population and to identify its dietary, lifestyle, anthropometric, and genetic determinants.
Methods: 25(OH)D concentrations were measured by LC-MS/MS in plasma samples of a random subcohort of the German arm of the European Prospective Investigation into Cancer and Nutrition (EPIC) comprising 2,100 subjects aged 35-65 years. Associations between potential predictors and 25(OH)D were assessed by linear regression models.
Results: 32.8% of the variance in 25(OH)D was explained by a multivariable regression model, with season being the by far strongest predictor (semi-partial R²: 14.6%). Sex, waist circumference, leisure time physical activity, smoking, polymorphisms in the GC, CYP2R1, and DHCR7 genes, supplement use, exogenous hormone use, alcohol consumption, egg consumption, and fish consumption were significantly associated with 25(OH)D concentrations as well. However, none of these factors explained >2.3% of the variance in 25(OH)D.
Conclusion: Even with a comprehensive set of genetic, anthropometric, dietary, and lifestyle correlates, not more than 32.8% of the variation in 25(OH)D could be explained in the EPIC-Germany study, implying that vitamin D prediction scores may not provide an appropriate proxy for measured 25(OH)D. Food intake was only a weak predictor of 25(OH)D concentrations, while a strong seasonal fluctuation in 25(OH)D was shown.