Maternal vitamin D status: implications for the development of infantile nutritional rickets

The mother is the major source of circulating 25-OHD concentrations in the young infant. Thus maternal vitamin D status is an important factor in determining the vitamin D status of the infant and their risk of developing vitamin D deficiency and infantile nutritional rickets. As a result, breastfed infants of mothers with vitamin D deficiency who are unsupplemented and who receive little sunlight exposure are at high risk of developing vitamin D deficiency or rickets. Despite food fortification policies in many countries and recommendations for vitamin D supplementation of at-risk groups, vitamin D deficiency and infantile rickets remain major public health challenges in many developed and developing countries. There is evidence that the current supplementation recommendations, particularly for pregnant and lactating women, are inadequate to ensure vitamin D sufficiency in these groups. A widespread and concerted effort is needed to ensure daily supplementation of breastfed and other infants at high risk with vitamin D 400 IU from birth and pregnant women in high risk communities with at least 600 IU; awareness needs to be developed among the public and medical practitioners of the urgent need to improve the vitamin D status of pregnant and lactating mothers and their infants. Further studies are required to determine the optimal doses of vitamin D supplementation in pregnancy and during lactation, and for normalizing vitamin D stores in infancy to reduce the prevalence of infantile nutritional rickets. Operational research studies also need to be conducted to understand the best methods of implementing supplementation programs and the factors that are likely to impede their success.