Maternal antenatal vitamin D status and offspring muscle development: findings from the Southampton Women's Survey.

CONTEXT

Maternal 25-hydroxyvitamin D [25(OH)D] status in pregnancy has been associated with offspring bone development and adiposity. Vitamin D has also been implicated in postnatal muscle function, but little is known about a role for antenatal 25(OH)D exposure in programming muscle development.

OBJECTIVE

We investigated the associations between maternal plasma 25(OH)D status at 34 weeks of gestation and offspring lean mass and muscle strength at 4 years of age.

DESIGN AND SETTING

We studied a prospective UK population-based mother-offspring cohort: the Southampton Women's Survey (SWS).

PARTICIPANTS

Initially, 12,583 nonpregnant women were recruited into the SWS, of whom 3159 had singleton pregnancies; 678 mother-child pairs were included in this analysis.

MAIN OUTCOMES MEASURED

At 4 years of age, offspring assessments included hand grip strength and whole-body dual-energy x-ray absorptiometry, yielding lean mass and percent lean mass. Physical activity was assessed by 7-day accelerometry in a subset of children (n=326).

RESULTS

The maternal serum 25(OH)D concentration in pregnancy was positively associated with offspring height-adjusted hand grip strength (β=0.10 SD/SD, P=.013), which persisted after adjustment for maternal confounding factors, duration of breastfeeding, and child's physical activity at 4 years (β=0.13 SD/SD, P=.014). Maternal 25(OH)D was also positively associated with offspring percent lean mass (β=0.11 SD/SD, P=.006), but not total lean mass (β=0.06 SD/SD, P=.15). However, this association did not persist after adjustment for confounding factors (β=0.09 SD/SD, P=.11).

CONCLUSIONS

This observational study suggests that intrauterine exposure to 25(OH)D during late pregnancy might influence offspring muscle development through an effect primarily on muscle strength rather than on muscle mass.