AbstractBackground: Sun exposure has been the main source of vitamin D for Indians with vitamin D synthesis occurring in the skin due to action of UVB light. Also, racial or ethnic groups with darker skin have been reported to have lower serum 25-hydroxyvitamin D levels than lighter skin colour groups living in same geographic area. Thus, lack of sun exposure and darker skin colour are identified as risk factors for poor vitamin D status. Objective: To study correlation of vitamin D deficiency with sun exposure and skin pigmentation in the paediatric population. Methods: The present hospital-based cross-sectional study was carried out from May 2012 to May 2013. 150 participants were recruited from population of young children aged 6 months to 15 years attending outpatient department of Dr. Babasaheb Ambedkar Central Railway Hospital at Byculla, Mumbai. Vitamin D levels were measured by electrochemiluminescent immunoassay. Vitamin D deficiency was defined as levels <50 nmol/L. Sun exposure was described as inadequate i.e. <3.5 hours per week or adequate i.e. ≥3.5 hours per week. Fitzpatrick skin grading system was used to grade the skin colour into 6 types. Assessment of vitamin D deficiency in relation to sun exposure and skin pigmentation was done. Results: Proportion of Vitamin D deficient children was found to be higher (89%) in subjects with < 3.5 hours per week sun exposure as compared to 59 % vitamin D deficient children among subjects with ≥3.5 hours per week of sun exposure time. Fitzpatrick grade 3 (lighter shade) were found to have lower prevalence of vitamin D deficiency as compared to grades 4, 5 and 6. Statistically significant correlation of vitamin D deficiency was noticed with sun exposure (p<0.001) and skin pigmentation grade (p = 0.009). Conclusion: In our study subjects, vitamin D deficiency was found to be significantly higher in subjects with < 3.5 hours per week sun exposure and dark grades (4, 5, and 6) of Fitzpatrick skin pigmentation.

Keywords: Hypovitaminosis D, Sun exposure, Fitzpatrick skin pigmentation grades.