Vitamin D deficiency amongst minority ethnic groups in the UK: a cross sectional study.

BACKGROUND: Vitamin D deficiency is common amongst minority groups in Britain but its magnitude amongst South Asian (SA) and Black African-Caribbean (AC) groups is not well defined. The steroidal, endocrine nature of vitamin D provides it with a putative link with cardiovascular disease (CVD), and we hypothesised that aberrant levels of this hormone would reflect a heightened risk of CVD in these ethnic groups.
METHODS: SA (n=1105, 57% male) and AC (n=748, 51% male) were recruited as part of a community heart failure study from 20 primary care practices, Birmingham, UK. Vitamin D2/D3 levels were measured to determine rates of total vitamin D status, which were age/sex adjusted.
RESULTS: The majority of SAs had severe vitamin D deficiency (42.2%, 95% CI: 39.2-45.1), which was more frequent than in AC (12.5%, 10.2-14.9, p<0.001. Vitamin status in SA and AC was unrelated to the presence of osteoporosis, and on multivariate analysis of SA, vitamin D levels were independently associated with age (β=0.18, p<0.001), haemoglobin (β=0.12, p=0.002), and negatively with alkaline phosphatase (a marker of bone mineralisation, β=-0.11, p=0.022). Amongst AC, vitamin D was independently associated with having ever smoked (β=-0.13, p=0.006) and systolic blood pressure (β=0.10, p=0.038).
CONCLUSIONS: Vitamin D deficiency is a frequent biochemical observation amongst minority groups in Britain but the clinical significance is unclear, and ethnically specific. A proportionate susceptibility to bone disease is not apparent in either minority group.