Differences and determinants of vitamin D deficiency among UK biobank participants: A cross-ethnic and socioeconomic study.
Level 4 - case-series / case-control
Cross-sectional analysis of observational cohort data
PubMed 33309415 · doi:10.1016/j.clnu.2020.11.019
What was done
The authors conducted cross-ethnic analyses using logistic regression to evaluate the prevalence and determinants of severe vitamin D deficiency (serum 25(OH)D ≤ 25 nmol/L) in 440,581 UK Biobank participants (415,903 White European, 7,880 Asian, 7,602 Black African, 1,383 Chinese, and 6,473 mixed ancestry).
What was found
Vitamin D deficiency prevalence was highest in Asian participants (57.2% in winter/spring, 50.8% in summer/autumn), followed by Black African (38.5% and 30.8%), mixed (36.5% and 22.5%), Chinese (33.1% and 20.7%), and White European participants (17.5% and 5.9%). Socioeconomic deprivation was strongly associated with deficiency (P < 1 × 10^-300), particularly among White Europeans and during summer (P interaction ≤ 6.4 × 10^-5). Regular oily fish consumption was associated with lower deficiency odds across all ethnicities. Outdoor time in summer was associated with substantially reduced odds of deficiency in White Europeans (OR 0.40, 95% CI 0.38 to 0.42), but this association was not statistically significant in Black Africans (OR 0.89, 95% CI 0.70 to 1.12).
Why it matters
These findings show severe cross-ethnic and socioeconomic disparities in vitamin D status across the UK, demonstrating that standard seasonal sunlight exposure provides inadequate protection against deficiency for darker-skinned individuals.
Limits
The study is cross-sectional and cannot prove causality. The UK Biobank cohort is subject to healthy-volunteer selection bias and underrepresents non-White ethnic groups relative to the general population. Unmeasured confounders, such as clothing habits or exact supplement dosages, were not captured in the abstract.
Cited by
- supports Individuals of African heritage traditionally have lower measured levels of vitamin D.