Vitamin D Deficiency Increases the Risk of Stunting and Other Adverse Pregnancy Outcomes: Results from a Perinatal Cohort Study in Kenya
Eunice Toko
Kenya Medical Research Institute, Kisumu, Kenya.
Odada Sumba *
Kenya Medical Research Institute, Kisumu, Kenya.
Fredrick Opinya
Kenya Medical Research Institute, Kisumu, Kenya.
Paul Baresel
SUNY Upstate Medical University, Syracuse, NY, USA.
Arlene Dent
Case Western Reserve University, Cleveland, OH, USA.
Julia Finkelstein
Cornell University, Ithaca, NY, USA.
Rosemary Rochford
SUNY Upstate Medical University, Syracuse, NY, USA.
Saurabh Mehta
Cornell University, Ithaca, NY, USA.
*Author to whom correspondence should be addressed.
Abstract
Objectives: Vitamin D may protect against adverse pregnancy outcomes. The prevalence of vitamin D deficiency in pregnant women in sub-Saharan Africa has not been extensively studied and no studies have examined vitamin D status at multiple time points during pregnancy and their association with birth outcomes.
Methods: We examined the prevalence of vitamin D deficiency (<50 nmol/L) and insufficiency (<75 nmol/L) in women during pregnancy, and their associations with adverse perinatal outcomes in Kenya. Serum 25-hydroxyvitamin D (25(OH)D) was measured at enrollment and at three additional time points during pregnancy, at delivery, and in cord blood. Binomial and linear regression was used to examine associations between maternal vitamin D status and adverse pregnancy outcomes.
Results: A total of 21% of women had vitamin D deficiency and 51% had insufficiency at enrollment. Vitamin D status improved during pregnancy; only 11% had vitamin D deficiency and 32% had insufficiency at delivery. However, 30% and 74% of the cord blood samples had vitamin D deficiency and insufficiency, respectively. Maternal vitamin D concentrations were also associated with significantly higher weight-for-age and weight-for-length Z-scores in the newborns with mean increases of 0.1 and 0.2 per 10 nmol/L serum 25-hydroxyvitamin D, respectively. Further, maternal vitamin D deficiency was associated with a 4-fold increase in the risk of stunting among the neonates (p=0.018).
Conclusions: Vitamin D insufficiency is common in pregnant women in Kenya and predicts neonatal birth size. Further research is needed on methods of improving vitamin D status during pregnancy in sub-Saharan Africa.