New Delhi, Jul 29 (IANS): Two in five eligible children in India are missing out on preventive vitamin A supplementation designed to ward off the health problems associated with deficiency of the vitamin, according to an analysis published in the open access journal BMJ Global Health on Friday.

Vitamin A is important for many cellular processes in the human body that are critical for eyesight, growth and development, wound healing, reproduction and immunity, among others.

The analysis based on representative survey data showed that there are a large number of 'cold spots' in provision across the country, and wide variations in coverage within and among states.

Out of 204,645 children, 123,836 -- that is 2 out of every 5 -- eligible Indian children hadn't been supplemented with vitamin A. Overall coverage was 60.5 per cent, which is low compared with that of most other South Asian countries.

It also varied widely, ranging from 29.5 per cent (Nagaland) to 89.5 per cent (Goa) across the various states/union territories.

Among districts, coverage ranged from just under 13 per cent (Longleng district, Nagaland) to 94.5 per cent (Kolar district, Karnataka).

The "low coverage was mostly in areas beset by infrastructure and logistical issues, high levels of disease, and inequitable health service provision, while high coverage was mostly seen in prosperous areas that generally rank high in health, demographic, socioeconomic and developmental indicators," said Kaustubh Bora Haematology Division, ICMR-Regional Medical Research Centre in Assam.

To find out levels of coverage, the researchers mapped provision by all 640 districts, encompassing each of the 29 states and 7 union territories, drawing on nationally representative cross-sectional data collected during wave 4 of the National Family and Health Survey 4 (NFHS-4) and the Comprehensive National Nutritional Survey (CNNS).

Of the 640 districts, 71 (11 per cent) achieved coverage above 80 per cent. But in 13 districts coverage was 20 per cent or below: 4 from Nagaland (Longleng, Mon, Phek, and Zunheboto); 3 from Manipur (Ukhrul, Chandel, and Senapati); 3 from Uttar Pradesh (Muzaffarnagar, Bareilly, and Bahraich); 2 from Rajasthan (Dungarpur and Rajsamand); and 1 from Arunachal Pradesh (East Kameng).

No significant association, however, was observed between supplement coverage and the prevalence of vitamin A deficiency, Bora said, adding that "this is an observational study, based on survey data, and as such, can't establish causality".

Adequate Vitamin A intake can only be obtained from the diet, but poor nutrition plus infections that are common in the under-5s in developing countries mean that an estimated 190 million young children -- 1 in 3 -- are Vitamin A deficient.

Childhood vitamin A deficiency has long been recognised as an important but controllable public health problem in India. And since 2006, the government has recommended high dose vitamin A supplements for all children aged 9 to 59 months.

And although regarded as an important public health intervention, the usefulness of universal vitamin A supplementation is increasingly being questioned, with calls for more nuanced and sustainable alternatives, the researchers noted.