Endocrine Abstracts

Objectives: Examine the effect of maternal Index of Multiple Deprivation (IMD) on newborn 25-hydroxyvitaminD (25OHD) levels in a multi-ethnic newborn cohort.

Design: 3000 dried blood spots (DBS) were gathered from newborns at a regional newborn screening laboratory over two 1-week periods [February 2019 (winter) and August 2019 (summer)]. Data on birth weight, gestational age, maternal age, ethnicity, and post code were collected. Post code was replaced with lower layer super output area (LSOA). IMD quintiles for the corresponding LSOA was used to ascertain socio-economic status (SES) [quintile one (Q1) representing the most deprived 20% and quintile five (Q5) the least deprived 20% of the population]. Each of the seven domains of IMD were examined (income, employment, education, health, barriers to housing and services, crime and living environment). 25OHD was measured on 6mm sub-punch from DBS using quantitative liquid chromatography tandem mass spectrometry and equivalent plasma values derived.

Results: A total of 2999 (1500 summer-born, 1499 winter-born) newborn DBS (1580 males) were analysed. 35.7% were vitamin D deficient [25OHD<30 nmol/l] and 33.7% insufficient [25OHD 30-50 nmol/l]. Summer-born newborns had significantly higher 25OHD concentrations compared to winter-born [49.2 vs 29.1 nmol/l respectively, P<0.001]. 25OHD levels varied significantly between the IMD quintiles in the whole (P<0.001) and summer-born cohort (P<0.001), but not in the winter-born cohort (P=0.26), whereby the most deprived cohort had the lowest 25OHD concentrations. Among the seven independent domains of deprivation, living environment had a significant influence on 25OHD levels (β=0.07, P=0.002). In this subdomain, mean 25OHD levels varied significantly between quintiles in the whole (P<0.001) and in the summer-born cohort (Q1 46.45 nmol/l, Q5 54.54 nmol/l; P<0.001) but not in the winter-born cohort (mean Q1 31.57 nmol/l, Q5 31.72 nmol/l; P=0.16). In a regression model, living environment was still significant (P=0.018) and season of birth and ethnicity had a greater effect on 25OHD levels.

Conclusion: Maternal living environment has the greatest influence on newborn 25OHD levels among the seven domains of deprivation. Enhanced supplementation and food fortification have been shown to overcome the above non-modifiable risk factors and should be seriously considered.