Prevalence and Determinants of Vitamin D Deficiency among under-5 Children Dwelling Slums of Mumbai, India

12 Oct, 21

Introduction

Considering the vital role of vitamin D in bone mineralization, remodelling, and immunological functions, it is critical to maintain optimum vitamin D levels among children aged <5 years. Children living in overcrowded slums are predisposed towards vitamin D deficiency (VDD) due to inadequate exposure to sunlight. Not many studies till date have ascertained various determinants of VDD in children aged <5 years.

Aim

To ascertain the prevalence and determinants of VDD among children aged 1-5 years

Profile of the Study Participants

Apparently healthy children aged 1-5 years from selected urban slums in Mumbai, India (N=426)

Method

Study Design

Community-based observational study

Assessments

Sociodemographic status
Diet (24-hour dietary recall)
Physical activity
Biochemical investigations [serum calcium, phosphorus, alkaline phosphatase, 25-Dihydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH)]
Direct sun exposure was calculated considering average duration and percentage of the exposed body surface area between 10 AM to 3 PM over last 6 months

Outcomes

Prevalence of VDD

Results

Mean age of the study population was 34.8 months, 53.8% were boys; 76% children belonged to middle socioeconomic group; 84% were in preschools and 7.5% were involved in outdoor activities at school.
Nearly three-fourth of the study population (76.8%) had VDD. VDD status was not associated with age and socioeconomic group, but was significantly associated with duration of sun-exposure of less than 10 minutes between 10 AM to 3 PM.
Despite 10-45 minutes of sun exposure, 68.8% children had VDD.
The PTH, alkaline phosphatase and calcium levels were in normal range for 83.9%, 92.2% and 87.5% children. 25(OH)D <20 ng/mL exhibited a significant negative correlation (r=-0.12; P=0.02) with PTH.
There was no significant association between VDD and adequate calcium intake (≥600mg/day) or consumption of vitamin D-rich food. Nevertheless, VDD was significantly less prevalent in children with adequate dietary calcium intake and supplemented with calcium and vitamin D during infancy (P=0.02).
As per a logistic regression analysis, male children were 43% less likely to have VDD. Children having frontal bossing or ≥6 episodes of upper respiratory tract infection (URTI) in the last one year had a 3-fold greater risk of having VDD compared with their counterparts. Moreover, children spending less than 10 minutes in outdoor activities between 10 AM to 3 PM were 75% more likely to have VDD compared with those who spent more than 10 minutes.

Conclusions

VDD was prevalent in under-5 children dwelling in urban slums in Mumbai, India.
Sun-exposure, male gender, and calcium and vitamin D supplementations during infancy may render protection against VDD among under-five children.

Indian Pediatr. 2021;58(9):888-889.