Children with low levels of
vitamin D may be at increased risk for anaemia, according to a large new study.
Researchers analysed blood
samples from more than 10 400 children and found that vitamin D levels were
consistently lower in youngsters with anaemia, a condition involving
lower-than-normal levels of red blood cells.
Kids with vitamin D levels
below 30 nanograms per millilitre (ng/ml) were nearly twice as likely to have anaemia
as those with normal vitamin D levels.
Children with vitamin D
levels below 30 ng/ml have mild vitamin D deficiency while those with levels at
or below 20 ng/ml have severe deficiency, according to the study. Both require
treatment with vitamin D supplements.
The researchers also found
that 14% of black children had anaemia, much higher than the 2%
rate among white children. Black children also had lower vitamin D levels
overall, but their anaemia risk did not rise until their vitamin D levels were
far lower than those of white children.
These racial differences
suggest that current targets for preventing or treating these conditions may
require further research, according to the authors of the study, which was
published online in the Journal of Paediatrics.
"The clear racial
variance we saw in our study should serve as a reminder that what we may
consider a pathologically low level in some may be perfectly adequate in
others, which raises some interesting questions about our current one-size-fits-all
approach to treatment and supplementation," said study lead investigator Dr
Meredith Atkinson, a paediatric kidney specialist at the Johns Hopkins
The study does not,
however, prove a direct cause-and-effect link between vitamin D levels and anaemia
risk, the researchers said.
Dr Jeffrey Fadrowski, also a paediatric kidney specialist at
Johns Hopkins, said: "If our findings are confirmed through further research,
low vitamin D levels may turn out to be a readily modifiable risk factor for anaemia
that we can easily tackle with supplements."
The researchers explained
that several mechanisms could account for this association, including vitamin
D's effects on red blood cell production in the bone marrow or its ability to
regulate immune inflammation, a known trigger of anaemia.
The Nemours Foundation has
more about anaemia in children.