THE RELATION BETWEEN MATERNAL VITAMIN D STATUS IN PREGNANCY AND INCIDENCE OF INFECTION IN INFANTS UP TO ONE YEAR OF AGE

Abstract

Research findings have suggested vitamin D enhances innate immunity in humans. Vitamin D deficiency among pregnant women is common, especially among women of darker skin. Studies have positively correlated newborn cord 25-hydroxyvitamin D (25(OH)D) with maternal serum 25(OH)D concentration during pregnancy. To our knowledge, no studies have addressed the associations between maternal serum 25(OH)D levels during pregnancy and incidence of infection in infants. The aim of this study was to assess the relationship between maternal vitamin D status during pregnancy and incidence of infections in infants during the first six and twelve months of life. The number and type of medically-diagnosed illnesses and infections of 220 infants were collected, and the associations between maternal 25(OH)D concentrations and incidence of illness, total infections, and specific infection types (respiratory; skin; eye, ear, nose and throat (EENT); and others) were examined. Significant negative correlations were found between maternal 25(OH)D concentrations and the incidence of illness (p= 0.022), infection(p=0.033), EENT (p=0.043), and skin infections (p=0.021) during the first six months, but not during the first 12 months. Ethnic differences in this relationship was also examined in infants of African-American (AA) mothers (n=69) and in those who were not African-American (n=151) because we were aware that AA mothers had a higher incidence of vitamin D deficiency (plasma 25(OH)D < 50 nmol/L; 84.1% vs. 37.1%) and lower mean plasma 25(OH)D (35.20 ± 22.74 vs. 63.30 ± 31.96 nmol/L). Infants of AA mothers were more likely than other women to have at least one incidence of any illness (p=0.013) and skin infection (p=0.007) during the first six months of life. In infants of non-AA mothers, significant negative correlations were found between maternal 25(OH)D concentrations and incidences of skin (p=0.025) and EENT (p=0.026) at six months in the first six months of life. The relative risk for being diagnosed with at least one EENT and one skin infection with increasing 25(OH) concentrations trended lower in the first twelve months, but did not reach statistical significance. Results suggest low maternal vitamin D status during pregnancy increases the risk of infection, in particular, the risk of skin and EENT infections in young infants. Few AA women had normal vitamin D status (4.3%), compared to women of other ethnic groups (26.5%), which could be one reason why their infants had more overall illnesses, infections, and skin infections during the first six month of life. Clinical trials to improve maternal vitamin D status during pregnancy could determine if there is a causal relationship between maternal vitamin D status and infant illness from infection, but caution should be taken since high concentrations of maternal 25(OH)D may be a risk factor for infant asthma.