Vitamin D supplementation unnecessary in healthy children
MedWire News: Study data do not support vitamin D supplementation to improve bone density in healthy children with normal vitamin D levels, show the findings of a new Cochrane Systematic Review.
However, the review does suggest that supplements given to vitamin D-deficient children may be clinically useful.
"It is well accepted that childhood factors are likely to have an impact on future risk for osteoporosis," say Tania Winzenberg (University of Tasmania, Australia) and colleagues.
However, results of trials using vitamin D supplementation to improve bone density in children are inconsistent, they add.
To address this, Winzenberg and team reviewed data from randomized controlled trials of vitamin D supplementation for at least three months in healthy children and adolescents (aged from one month to 19 years), which reported bone density outcomes.
They also looked at whether the effect varies by gender, age, pubertal stage, the type or dose of vitamin D given, or baseline vitamin D status, and whether effects persist after cessation of supplementation.
Of 1652 potential studies identified, six were included in the meta-analysis. The trials involved 343 participants receiving placebo and 541 receiving vitamin D.
The researchers report that, overall, vitamin D supplementation had no statistically significant effects on total body bone mineral content (BMC), hip bone mineral density (BMD), or forearm BMD.
There was a trend for a 3% change in lumbar spine BMD from baseline among participants that received supplementation.
The effect of supplementation with high (>200 IU daily) versus low (≤200 IU daily) dose vitamin D did not differ at any site, but there was a trend towards a larger effect on total body BMC with low dose vitamin D.
In studies among patients with low serum vitamin D levels (≤35 nmol/l) at baseline, total body BMC and lumbar spine BMD increased by approximately 2.6% and 1.7% more in the supplemented group compared with the control group. This effect was statistically significant.
Wizenberg et al note that overall, the data available for this review were not adequate to address important clinical factors that might influence the review results. For example, compliance data, and data in males and different ethnic groups were very limited.
Therefore "further randomized controlled trials in children with vitamin D deficiency are needed to determine definitively what benefits can be obtained," they conclude.
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By Laura Dean