Vitamin D status of adults in the North of the Netherlands: cross-sectional results from the Lifelines cohort study.

Abstract

Background/objectives: Maintaining an adequate vitamin D status is challenging for part of the Dutch adults; therefore, use of vitamin D supplements is advised for certain subgroups. Recent studies on vitamin D status in the general Dutch population are lacking. This study aimed to investigate vitamin D status in a Dutch adult population and how it compared to twelve years earlier.

Subjects/methods: Blood samples from participants of the Lifelines cohort collected in March 2023 were analysed for 25(OH)D₃ concentration (N = 1000). Log 25(OH)D₃ concentrations and proportion participants with a 25(OH)D₃ concentration <30 (18-69 yrs)/<50 nmol/L (≥70 yrs) were compared across gender and age groups (18-49, 50-69, and ≥70 yrs) using t-tests and ANOVA. Vitamin D status in March 2023 was compared to the status in March 2011 (N = 1221). Additionally, monthly variation in vitamin D status within 2011 was studied.

Results: Men had a significantly lower median 25(OH)D₃ concentration compared to women. 25(OH)D₃ concentration increased with age. Vitamin D deficiency was observed in 7% of women 50-69 yrs and in 26% of men and 13% of women ≥70 yrs. Compared to March 2011, 25(OH)D₃ concentration in March 2023 was significantly higher (median 45-49 vs. 54-75 nmol/L). Vitamin D status throughout 2011 showed highest deficiency levels in winter.

Conclusions: Vitamin D status improved between 2011 and 2023, but still up to a quarter of men and women in different age groups were vitamin D deficient at the end of the winter of 2023. Vitamin D status was highest in the subgroups with supplementation advice.