Seasonal variation & determinants in vitamin D deficiency in healthy breastfed term infants & their mothers in India.

Sir,

There is alarmingly high incidence of vitamin D deficiency in healthy breast fed infants and their mothers at three months of age in India1. Our intention is to emphasize the immediate prerequisite of simple, point-of-care assay formats for quantification of 25-hydroxyvitamin D (25 OH D) in the individual health care centres in urban and rural areas.

Quantifications of the 25 OH D continue to be a privilege of the academic and research centers1–3 where trained personnel and sophisticated facilities to handle radioactive diagnostic kits are available. For example, Jain et al1 measured the vitamin D levels at the All India Institute of Medical Sciences, New Delhi, as 25 OH D levels using the radioimmunoassay with commercially available kits (DiaSorin Inc, USA).

In view of the global prevalence of vitamin D deficiency among women in childbearing age and infants1–3 it would be desirable to initiate simple and rapid point-of-care assays for quantification of vitamin D3, and 25 OH D , levels in general population, both in rural and urban areas. Lack of competent diagnostic laboratories in resource-poor countries has been alarming not only in rural and remote areas, but a large number of laboratories in big cities are also without high levels of diagnostic competence. Moreover, these are the only ones to serve vast population with different disorders4. Majority of diagnostic laboratories will not be able to measure 25-hydroxyvitamin D in their premises.

The future multi- component plans to address vitamin D deficiency in infants and their mothers in India1 or elsewhere should include, apart from vitamin D3 supplementations, a watch on the post-supplementation vitamin D3 levels. A daily supplementation of 1000 IU of vitamin D3 may fail to bring levels to a minimum of 75 nmol/l in 20-30 per cent cases5.

Last but not least, academic or research institutions and the regional or central laboratories with facilities for radioimmunoassay or enzyme linked immunosorbent assay should assist peripheral health care centres with their external quality assessment for 25-hydroxyvitamin D measurements. Recently, two state-of-art reference measurement procedures for serum 25 hydroxyvitamin D3 and D2 measurements have been standardized to enable calibration traceability and method validation.6