Association between maternal vitamin D status during late pregnancy and acute lower respiratory tract infections and acute diarrheal disease during infancy - A cohort study.

BACKGROUND

Acute lower respiratory tract infection (ALRI) and acute diarrheal disease (ADD) are the leading causes of mortality in children globally. There is emerging evidence of an association between maternal hypovitaminosis D and ALRI/ADD during infancy.

OBJECTIVE

To determine whether maternal hypovitaminosis D (25(OH)D [<20 ng/ml] during late pregnancy is associated with increased risk of ALRI/ADD in their offspring during infancy.

METHODS

This South Indian hospital-based, ambispective cohort study included 140 mother-baby dyads with known maternal vitamin D status before delivery in late third trimester (72 mothers with hypovitaminosis D and 68 mothers with adequate vitamin D level). Babies with cord blood vitamin D deficiency were treated as per consensus guidelines and those with adequate levels were supplemented with 400 IU vitamin D daily for 1 year. All infants were followed up at 6,10,14 weeks and 6, 9, 12 months for the occurrence, frequency, and severity of ALRI (pneumonia, bronchiolitis, viral induced wheezing) and ADD.

RESULTS

Overall incidence of ALRI was 0.23 per child year during infancy. Incidence of ALRI was 0.12 per child year in adequate maternal vitamin D group versus 0.32 per child year in maternal hypovitaminosis D group (p value = 0.024) and that of bronchiolitis/viral wheeze was 0.07 per child year in adequate maternal vitamin D group versus 0.21 per child year in maternal hypovitaminosis D group (p value = 0.047). Cox regression analysis with maternal hypovitaminosis D level as predictor variable, adjusted for gestational age at birth and other covariates, revealed a hazard ratio of 3.18 (95 % CI: 1.17-8.65, p = 0.023) and 3.63 (95 % CI 1.36-9.65, p = 0.010) for ALRI and ADD respectively. No increased risk for occurrence of pneumonia was observed and none had severe pneumonia.

CONCLUSION

Maternal hypovitaminosis D is associated with increased risk of ALRI and ADD in their babies during infancy. Routine screening of pregnant women at risk for hypovitaminosis D and supplementation based on 25(OH)D level may decrease the burden of ALRI, for which further studies are needed.