Vitamin D Deficiency in African refugee families - implications for children

Vitamin D is re-emerging as an 'at risk' nutrient in the Australian community.  Most 'at risk' are those who get little sunlight; are dark skinned; who cover or veil themselves for cultural, religious, or medical reasons; and 'at risk' women who breast feed exclusively for longer than 6 months. A recent report (1) has shown that 'at risk' African refugee families in Sydney are deficient in vitamin D and seasonality affects their vitamin D status.

North African refugees living in south western Sydney were screened for markers of vitamin D deficiency (25(OH)D, parathyroid hormone, calcium phosphate and alkaline phosphatase) at the end of winter 2006 and at the end of summer 2007.  Of the 91 participants in the survey, all had some degree of vitamin D deficiency at the end of winter. By the end of summer (Feb-March) 2007, 79% were deficient with men and boys showing greatest improvement in Vitamin D status. Women and those over 16 years showed little improvement. This is a concern, as infants born to vitamin D deficient women are also likely to be vitamin D deficient risking rickets, developmental delay and seizures and continuing the cycle of vitamin D deficiency. As adults they are also likely to suffer osteoporosis and fracture.

The authors conclude that the study supports current recommendations that all dark skinned or veiled   women, children and infants be screened annually for vitamin D deficiency; be screened in the first trimester of pregnancy; be supplemented with vitamin D while breast feeding until the infant is 12 months and all 'at risk' groups receive a daily vitamin D supplement.

References.

1. Benitez-Aguirre PZ, Wood NJ et al. The natural history of vitamin D deficiency in African refugees living in Sydney. MJA 2009;190(8):426-428

Comments

[Lere]

Yes that sounds plausible - but it's wrong. The huge state of the art July 2010 study Common genetic determinants of vitamin D insufficiency: a genome-wide association study found that none of the genes they identified are linked with skin pigmentation.

Confirmation of that interpretation in an article Here :- ” the accompanying (Lancet) editorial points out, it is somewhat surprising that none of the genes identified are linked with skin pigmentation”
.

A systematic review of the association between common single nucleotide polymorphisms and 25-hydroxyvitamin D concentrations
"We speculate that recently identified U-shaped relationships between 25OHD concentrations and disease outcomes (i.e. increased risk at both high and low concentrations) may reflect a mixture of genotype-defined subgroups."

'Genetics to Blame for Vitamin D Deficiency?'
"Researchers conducted a genome-wide association study (Common genetic determinants of vitamin D insufficiency: a genome-wide association study) that involved almost 34,000 people of European descent from 15 different studies. They used radioimmunoassay and mass spectrometry to determine vitamin D concentrations and found that variants at three genetic sites, or "loci," were significantly associated with vitamin D concentrations. The presence of harmful alleles at three "loci" more than doubled the risk of Vitamin D insufficiency."

Maybe non-whites are the ones who benefit from doubling their vitamin D levels ? Nope - Vitamin D, Adiposity, and Calcified Atherosclerotic Plaque in African-Americans "positive associations exist between 25-hydroxyvitamin D and aorta and carotid artery CP in African-Americans"

Many people are naturally low in vitamin D, forcing vitamin D levels up by taking supplements can only do harm. If you think you can improve yor health by conforming to the advice of Holick or - God forbid - that of Hollis, Cannel & Co at the vitamin D 'Council' who recommend (>50ng/ml) then you are in for an unpleasant surprise.

Vitamin D and homeostasis

Mad dogs and ....