Pre-conception vitamin D supplements don’t offer offspring protection against fractures, Danish research in over 30,000 families has suggested.
The results also suggested maternal vitamin D supplementation may be linked to an increased risk of fractures.
Researchers from the Centre for Fetal Programming at the Statens Serum Institute, the University of Copenhagen and the Aalborg University Hospital in Denmark paired up with the Harvard School of Public Health in the US to investigate the impact of maternal vitamin D status.
The paper used data from 30,132 mother-child pairs recruited through the Danish National Birth Cohort between 1996 and 2002.
The follow-up then ran from birth to first-time forearm fractures of the children.
They found that in mid-pregnancy, 91% of the women reported using vitamin D supplements.
Concluding in the British Journal of Nutrition, they wrote: “Our data indicated no protective effect of maternal vitamin D status with respect to offspring forearm fractures.”
They described osteoporosis – the disruption of ‘bone architecture’ and increased risk of bone fracture risk – as a “major public health issue” with a substantial cost.
The paper’s findings went against the expectations of the authors who wrote: “The disease may be prevented through increasing bone mass early in life to a degree that will have a biologically relevant effect in middle-aged and elderly people – for example, by the influence of diet, physical activity and endocrine status.
“A growing body of evidence also suggests that adult bone mass may be influenced by factors operating as early as in fetal life, and especially vitamin D status during pregnancy has been hypothesised to play a role.”
In fact they found the children of women who took more than ten micrograms of vitamin D a day in mid-pregnancy had a significantly increased risk for fractures compared with the reference level of zero, especially among girls.
“Further investigation into this field is highly needed to clarify whether dietary supplements with vitamin D during pregnancy may have a non-beneficial impact on offspring bone development and health.”
After certain circumstances like traffic accidents were excluded, 2216 forearm fractures were looked at in the final study. Overall 24,172 children were registered with at least one bone fracture.
Of the fractures caused by accidents (86%), the main fracture were of the elbow and forearm (41%), then the hand, wrist or fingers (18%), shoulder or upper arm (17%), lower leg or ankle (9%), feet or toes (10%), skull or face (4%), thigh and hip (1%) and other areas of the body (0.3%).
Source: British Journal of Nutrition
Published online ahead of print, doi:10.1017/S000711451500361X
“Predicted vitamin D status during pregnancy in relation to offspring forearm fractures in childhood: a study from the Danish National Birth Cohort”
Authors: S. B. Petersen, M. Strøm, E. Maslova, C. Granström, P. Vestergaard, C. Mølgaard and S. F. Olsen