*For medical professionals only
I remember when I was in my early 10s, every year I had to make up for calcium for a period of time due to leg pain and midnight cramps, and saved a lot of small blue bottles to make wind chimes.
In our simple common sense, vitamin D and calcium absorption are deeply bound, and most of the calcium-containing health products purchased nowadays are also correspondingly added with vitamin D.
Recently, the results of a clinical study published in the journal Lancet Diabetes and Endocrinology may have some impact on our naïve cognition.
A multicenter, double-blind, randomized, placebo-controlled study conducted in Ulaanbaatar, Mongolia, found that long-term vitamin D supplementation in school-age children aged 6 to 13 years did not reduce the risk of fractures.
Diagram of the title of the dissertation
About one-third of children and adolescents have had at least one fracture before the age of 18 and are at highest risk during the period of growth during puberty. Improving bone strength in children through supplementation is a preventive idea, and vitamin D is naturally attracting attention due to its role in promoting calcium absorption.
However, the results of randomized trials are not always as we expected. Meta-analyses have shown that vitamin D supplementation can have a positive effect on hip bone mineral density in healthy children, but no significant changes have been found in the femoral neck, lumbar spine and forearm bone mineral content and bone mineral density of children after 1 year of supplementation.
Ulaanbaatar, where the study was conducted, had a higher risk of fractures and vitamin D deficiency was prevalent in children. Of the 8348 children included in the final analysis, 95.5% had a baseline serum 25(OH)D concentration of less than 50 nmol/L and 31.9% had a baseline serum 25(OH)D concentration of less than 25 nmol/L.
In general, a serum concentration of 25(OH)D at 75-125 nmol/L is ideal, less than 75 nmol/L can be considered vitamin D insufficiency, and less than 50 nmol/L is considered vitamin D deficiency.
The median age of these children was 9.2 years, of whom 49.4 per cent were girls. They were assigned 1:1 to vitamin D or placebo, with vitamin D supplementing with 14,000 IU of vitamin D per week and a median follow-up of three years.
But vitamin D supplementation for a long time doesn't seem to bring benefits to children.
There was no statistically significant difference between 6.4% and 6.1% of participants in the vitamin D and placebo groups, respectively, who had fractured at least once. Subgroup analyses showed that sex, baseline 25(OH)D concentration, and calcium intake levels did not affect this outcome.
In other words, vitamin D supplementation does not reduce the risk of fractures in children, regardless of whether boys and girls are deficient in vitamin D, or how much calcium they consume each day.
VD supplementation was concluded to be no reduction in fracture risk in all subgroup analyses
Measuring the participants' bone mineral density showed that the bone density of the children in the vitamin D group was not different from that of the control group.
But can you say that it makes up for loneliness?
In fact, at the end of the trial, the average serum 25(OH)D concentration in the vitamin D group had been raised to 72.1 nmol/L, compared to 26.1 nmol/L in the placebo group, which was actually quite effective.
The investigators believe that the absence of concomitant calcium supplementation may have had an effect, as 62.2% of participants had a daily calcium intake of less than 500 mg/day, which is the minimum recommended intake for children and adolescents. However, vitamin D supplementation also did not reduce the risk of fracture in the subgroup with relatively adequate calcium intake.
This is the largest randomized controlled trial of vitamin D supplementation in children to date, and the results may prompt a reconsideration of the effects of vitamin D supplementation on bone health.
Ganmaa Davaasambuu, corresponding author of the study and associate professor at the Harvard T.H. Chan School of Public Health, said in an interview: "It is surprising that continuous, substantial vitamin D supplementation has no effect on fracture risk and bone strength in vitamin D-deficient children. In adults, calcium and vitamin D supplementation were most effective in preventing fractures, so the failure of this study may be due to the lack of calcium supplementation. ”
Resources:
[1]https://www.thelancet.com/journals/landia/article/PIIS2213-8587(23)00317-0/fulltext
[2]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9920487/
[3]https://www.sciencedaily.com/releases/2023/12/231201194255.htm
The author of this article丨 Dai Siyu