Routine daily vitamin D supplementation in infants is recommended by the Global consensus on rickets prevention, American Academy of Pediatrics and the Indian Academy of Pediatrics [1-3]. However parental adherence is key to its success, which has been shown to be sub-optional worldwide, resulting in poor outcome of the supplementation [4-8]. There is no relevant Indian data. We conducted this survey to estimate the proportion of infants adhering to prescription of routine vitamin D supplementation between birth and 9 months of age.

This cross-sectional study was conducted in the department of pediatrics of a public medical college-affiliated hospital in Delhi. An approval from the institutional ethics committee was obtained. Considering parental adherence of 68.9% [4], with alpha error of 5%, absolute precision of 5%, and confidence level of 95%, 330 mother-infant pairs were required to be enrolled. Healthy infants between 6 weeks to 9 months of age, who were prescribed vitamin D at birth, were recruited from the immunization clinic, after obtaining written informed consent from the mother. We included only those infants who were born in a health facility and having documents showing prescription of vitamin D at birth. The hospital policy is to prescribe routine vitamin D supplementation at the time of discharge from the health facility at birth. Term and preterm infants are prescribed 400 IU and 800 IU vitamin D, to be given daily till 12 months of age, irrespective of mode of feeding. No specific measures for reinforcement of supplementation are in place on follow-up.

Baseline socio-demographic information was recorded. Mothers were asked whether they are still providing routine vitamin D supplementation to their infant. If not, whether they administered vitamin D to their child at any time and if yes, for how long along with the dose. Compliance was the duration for which supplementation was given as a proportion of the duration of prescription till enrolment. We also ascertained the proportion of infants who had received oral vitamin D supplementation (400 IU) in last 7 days and in previous month, to minimize recall bias.

Parental understanding of the prescription was also assessed for their knowledge regarding total duration for which they needed to give the supplement. Parents were asked whether they were explained verbally by the healthcare worker about routine vitamin D supplementation, the reason for its requirement and method to give it; and whether they received reinforcement for same in their subsequent health visits, if any. They were asked whether they received vitamin D from the health facility, or it incurred out of pocket expenditure. In case of non-compliance of the prescription, the parents were asked for the reason. After the interview, mothers were advised to follow routine supplementation of vitamin D, if they were not giving it earlier. The practices of routine vitamin D supplementation were compared between groups using chi square test. Compliance was compared between groups using the independent samples Mann-Whitney U test. A P value of <0.05 was considered statistically significant.

We interviewed 330 mothers between March and August, 2019. The median (IQR) age of their infants was 3.5 (2.5, 6) months, 190 (57.6%) were <6 months of age, and 180 were boys. Majority of mothers were literate (288, 87.3%) and home-makers (307, 95.5%). Most families (233, 70.6%) belonged to lower socioeconomic strata; 85 (25.8%) were from middle socioeconomic group. Most (300, 91%) infants were born at term, 117 (35.5%) were low birthweight and 36 (10.9%) had required admission in neonatal intensive care unit (NICU) at birth. The study population did not have any infant with active rickets.

Overall, 137/330 (41.5%) infants received vitamin D supplementation at some point of time till enrolment; median (IQR) duration of vitamin D supplementation in 137 infants was 60 (30, 105) days. Only 52 (15.8%) children were receiving vitamin D continuously for 7 days in the last week. Thirty-six (26.3%) of those practicing routine supplementation (n=137) did not receive vitamin D in last 7 days, and 25 (18.3%) did not receive it anytime over last one month. Median (IQR) compliance to routine vitamin D supplementation in these 137 infants was 66.7% (50%, 83.3%). Only 29 (8.8%) infants were receiving appropriate routine vitamin D supplementation in terms of dose, frequency and duration. A significantly higher proportion of preterm infants and NICU graduates received vitamin D supplementation (ever, within 7 days and within 4 weeks) as compared to term and those not requiring NICU care, respectively (Table I). The compliance was also significantly higher in preterm and NICU graduates. There were no significant differences in supplementation practices or compliance according to gender or feeding status.