Objectives: Serum 25(OH)-vitamin D (25(OH)D) concentration is known to influence muscle function in postnatal life. Maternal 25(OH)D status during pregnancy has been implicated in the fetal programming of bone and fat mass, but little is known about its role in determining offspring muscle development. We investigated the associations between maternal serum 25(OH)D concentration in pregnancy and offspring muscle mass and strength at 4 years.
Materials and methods: A prospective mother–offspring birth cohort, the Southampton Women’s Survey (Southampton, UK), was studied. Maternal serum 25(OH)D status was measured at 34 weeks gestation. At 4 years, offspring hand-grip strength (Jamar Dynamometer) and body composition by dual energy X-ray absorptiometry (Hologic Discovery) were assessed. Offspring physical activity (PA) was assessed over seven days using accelerometry (Cambridge Neurotechnology Actiheart).
Results: 326 mother–offspring pairs were included. Maternal serum 25(OH)D concentration in late pregnancy was positively associated with offspring height-adjusted hand grip strength (β=0.12 S.D./S.D., P=0.02), which persisted after adjustment for a number of maternal confounding factors (including maternal height, pre-pregnancy BMI, gestational weight gain, walking speed in late pregnancy and smoking status), duration of breastfeeding and child’s physical activity at 4 years (β=0.12 S.D./S.D., P=0.03). Maternal 25(OH)D was also positively associated with offspring percent lean mass (β=0.11 S.D./S.D., P=0.05), but not total lean mass (β=0.02 S.D./S.D., P=0.67). This however did not persist after adjustment for confounding factors (β=0.07 S.D., P=0.24).
Conclusions: Maternal 25(OH)D status during pregnancy is positively associated with offspring grip strength at four years. These results are consistent with a role for antenatal 25(OH)-vitamin D exposure in offspring muscle development.