Research Article: Vitamin-D deficiency predicts infections in young north Indian children: A secondary data analysis

Date Published: March 8, 2017

Publisher: Public Library of Science

Author(s): Ranadip Chowdhury, Sunita Taneja, Nita Bhandari, Bireshwar Sinha, Ravi Prakash Upadhyay, Maharaj Kishan Bhan, Tor A. Strand, Jacobus P. van Wouwe.

http://doi.org/10.1371/journal.pone.0170509

Abstract

Recent studies have demonstrated a relationship between poor vitamin D status and respiratory infections and diarrhea among young children. Acute lower respiratory infections (ALRI) and diarrhea are among the two most important causes of death in under-5 children. In this paper, we examined the extent to which vitamin-D deficiency (<10 ng/ml) predicts ALRI, clinical pneumonia and diarrhea among 6 to 30 months old children. We used data from a randomized controlled trial (RCT) of daily folic acid and/or vitamin B12 supplementation for six months in 6 to 30 months old children conducted in Delhi, India. Generalized estimating equations (GEE) were used to examine the associations between vitamin-D deficiency and episodes of ALRI, clinical pneumonia and diarrhea. Of the 960 subjects who had vitamin-D concentrations measured, 331(34.5%) were vitamin-D deficient. We found, after controlling for relevant potential confounders (age, sex, breastfeeding status, wasting, stunting, underweight, anemia status and season), that the risk of ALRI was significantly higher among vitamin-D deficient (OR 1.26; 95% CI: 1.03 to 1.55) compared to vitamin-D-replete children in the six months follow-up period. Vitamin-D status was not associated with episodes of diarrhea or clinical pneumonia. Vitamin-D deficiency is common in young children in New Delhi and is associated with a higher risk of ALRI. The role of vitamin D in Indian children needs to be elucidated in further studies.

Partial Text

Vitamin D deficiency is considered to be the most common nutritional deficiency and often one of the most commonly undiagnosed medical conditions in the world [1]. The prevalence of vitamin D deficiency in young children is around 50–90% in the Indian subcontinent [2]. Vitamin D is primarily produced in the skin after exposure to ultraviolet radiation and less than 10% is derived from dietary sources [3].

A total of 1000 children were included in the main trial. Blood samples for vitamin D were collected at baseline for 960 (96%) children. Of these, 331 (34.5%) children were Vitamin D deficient (<10 ng/ml). The baseline characteristics of the population by deficiency status are presented in Table 1. Approximately half of the enrolled children were boys and almost all (98%) were ever breast fed. Over 36.4% of the children were stunted, 31% underweight, and 10.7% wasted. Approximately 70% of the children were anemic. We report the prevalence of vitamin D deficiency and its association with common infections in young children. We found a high prevalence of vitamin D deficiency which is consistent with other studies in India [2]. However, a recent study from Nepal found that only <5% of breastfed infants were vitamin-D deficient, even when a higher cut off (<20 ng/l) was used [26]. High prevalence of vitamin-D deficiency observed in our study setting, in spite of abundant sunlight may be because of relatively high solar zenith angle, in combination with atmospheric pollution, type- V skin types of the population and restricted outside activities [27, 28]. More Ultraviolet B (UVB) photons are absorbed by the stratospheric zone, and therefore fewer UVB photons penetrate to earth’s surface to produce cutaneous pre-vitamin D3 with a relatively high solar zenith angle. [29]. A recent study indicated that infants may get enough vitamin D from breast milk if their mothers take high-dose vitamin D supplements [30]. The complementary foods in the diets of Indian infants and children are primarily cereal based and low in vitamin D [31]. This is probably another contributing factor of the widespread vitamin-D deficiency among children in this setting. The present study demonstrates that vitamin D deficiency is common in New Delhi children aged 6–30 months and that it is associated with increased risk of ALRI. Randomized controlled trials measuring the effect of vitamin D supplementation in these setting should be prioritized.   Source: http://doi.org/10.1371/journal.pone.0170509