A recent follow-up to the MAVIDOS trial has revealed that vitamin D supplementation during pregnancy can significantly enhance bone mineral density (BMD) in offspring, with benefits lasting until at least age seven.
Initially reported in the MAVIDOS trial, this study demonstrated a marked improvement in BMD in children at the age of four. The latest findings, published in The American Journal of Clinical Nutrition, explore whether these benefits extend into later childhood.
Overview of the MAVIDOS Study
The MAVIDOS study was a randomized controlled trial conducted in the United Kingdom, assessing the effects of vitamin D supplementation during pregnancy. Enrolled participants, all between 11 and 14 weeks of gestation, received a daily dose of 1,000 IU of vitamin D until delivery.
In total, 965 participants were included, with 723 children born at term. Among these, 477 children underwent dual-energy X-ray absorptiometry (DXA) scans to evaluate BMD at four years. At the subsequent assessment, when the children were aged six to seven, 447 underwent a second DXA scan.
Notably, children completing the second visit were more likely to be born to older, non-smoking mothers with higher educational attainment and had longer durations of breastfeeding. A slight increase in the number of children taking vitamin D supplements was also noted.
Enhanced Bone Health Outcomes
DXA scans were utilized to measure both whole-body bone mineral density (BMD) and bone mineral apparent density (BMAD). Results indicated that children in the vitamin D group exhibited higher BMD and BMAD compared to those in the placebo group at ages six to seven.
Adjusting for factors such as sex, height, weight, breastfeeding duration, and vitamin D supplementation, the findings remained significant. Children born to mothers who supplemented with 1,000 IU/day of vitamin D displayed notably higher bone mineral content (BMC) and BMAD, highlighting the long-term impact of prenatal vitamin D.
For a subset of children who had DXA scans at birth and both follow-up points, consistent increases in BMD were observed, with a trend towards increased lumbar spine BMAD noted at six to seven years.
While the primary objective of the MAVIDOS study was to assess BMC at birth—which showed no difference with supplementation—infants born in winter months did show higher BMC compared to the placebo group.
Comparison with Other Research
The MAVIDOS findings align with results from the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC2010), although a study conducted in Bangladesh did not observe similar benefits. This discrepancy may be attributed to differing baseline health conditions, such as malnutrition and infection prevalence, suggesting the need for further research to understand these variances.
An Australian observational study similarly reported positive outcomes in offspring at 20 years following maternal vitamin D supplementation during pregnancy.
Mechanisms Behind the Benefits
The study indicated that longer breastfeeding durations and childhood vitamin D use positively correlated with enhanced bone health outcomes, amplifying the advantages of prenatal supplementation.
Despite increased fetal vitamin D levels, supplementation during pregnancy does not boost calcium availability for the developing fetus. However, it may enhance calcium absorption, and higher anti-rachitic activity in breast milk could further support bone mineralization.
Epigenetic mechanisms may also play a role in the long-term impacts of vitamin D on bone health, influencing how bones respond to mechanical loading and promoting spinal growth during early childhood.
Conclusion
These findings reaffirm that the positive effects of vitamin D supplementation during pregnancy extend well beyond early childhood, necessitating further validation and research to establish comprehensive guidelines for pregnant women regarding daily vitamin D intake.
The observed increases in BMD are expected to contribute to reduced fracture risks later in life, as indicated by retrospective analyses from similar trials. Future research is crucial to determine whether these benefits persist into adulthood, potentially mitigating risks associated with fragile bones.
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