We categorized serum 25(OH)D levels as <12, 12-20, 20-60 and >60 ng/mL. Among the 79 children (42 boys mean age 3.4 y), none had clinical features of rickets. The 25 (OH) D level was normally distributed on visual inspection of curve. The mean (range) Vitamin D level was 18.1 (3.7- 68.0) ng/mL. Majority of children (37.9%) had levels between 12-20 ng/mL. Twenty-two children (27.8%) had a vitamin D level less than 12 ng/mL, suggestive of significant vitamin D deficiency. None of these children had hypocalcemia, and only two of them had high PTH levels (PTH >55 pg/dL). The mean (range) level of PTH was 31.3 (6.5-53.6 pg/mL). Calcium, phosphorus and ALP level had mean (range) values of 9.0 (8.3-10.9) mg/dL, 6.2 (2.8-7.8) mg/dL and 201.7 (100-317) IU, respectively.

Vitamin D deficiency was initially considered rare in India, as the studies were based on serum calcium and alkaline phosphatase in our population [2]. Assessment of serum 25 (OH) D is increasingly being used to assess vitamin D status, resulting in common diagnosis of subclinical hypovitaminosis D. However, the optimal cut- off levels of 25 (OH) D for diagnosing vitamin D deficiency are not well described in children. In Kerala, there is a good antenatal care system assuming better maternal nutritional status [3]. The children in Central Kerala are adequately exposed to sunlight and have reasonably good health index. However, the mean value of 25 (OH) D in our study was 18.1 ng/dL, which is well below the accepted normal levels. Most of these children neither had clinical features of rickets nor had other laboratory evidence suggestive of Vitamin D deficiency. The present era is witnessing many diseases being etiologically attributed to vitamin D deficiency detected by low levels of 25 (OH) D. Hence, over prescribing Vitamin D, especially in pediatric age group, is quite common. Vitamin D is toxic in large doses and there are sporadic reports of vitamin D toxicity in literature [4]. Despite the concerns for over diagnosis and overtreatment of vitamin D deficiency, the practice, of testing for vitamin D deficiency using 25 (OH) D assay is on the rise. Few studies from Western countries have reported increased testing of 25 (OH) D levels leading to concerns related to quality of care, cost, and potential over-diagnosis [5].

Vitamin D measurement is often inaccurate and imprecise, and majority of tests performed currently fail to reveal vitamin D-deficiency [6]. IAP Guidelines on Vitamin D- and calcium-deficiency [7] do not recommend routine screening of healthy children; it should be performed only in those at risk of vitamin D deficiency. Moreover, there is a need for educating the practitioners as well as public about sun exposure for vitamin D synthesis [8], and dietary intake of vitamin D rich foods rather than promoting high market sales of calcium supplements, which could predispose to toxicity.

Contributors: AK, NT: conceptualized the study. AK collected the data and NT prepared the manuscript

Funding: Institutional Research Committee, Govt. Medical College, Thrissur; Competing Interest: None stated.

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