Prevalence and Correlates of Vitamin D Deficiency among Adult Population in Urban and Rural Areas of the National Capital Region of Delhi, India.

High prevalence of Vitamin D deficiency has been reported among selective population, but its population prevalence from representative adult population is lacking in India. The aim of this study was to estimate the prevalence and identify the correlates of Vitamin D deficiency among urban and rural areas of the National Capital Region (NCR) of Delhi, India. Serum Vitamin D levels of 1403 adults (aged 30 years above), 702 from urban and 701 from rural NCR of Delhi, who participated in a representative cross-sectional survey were measured using the quantitative chemiluminescent immunoassay method. The prevalence of Vitamin D deficiency was classified as severe deficient, and insufficient at three serum levels of 25-hydroxyvitamin D-<10, 10-<20, and 20-<30 ng/mL, respectively. The median (interquartile range) 25-hydroxyvitamin D levels in urban and rural areas were 7.7 (5.2, 10.8) ng/mL and 16.2 (10.9, 22.3) ng/mL, respectively. The prevalence of Vitamin D severe deficiency, deficiency, and insufficiency in urban areas were 71%, 27%, and 2%, respectively. The corresponding prevalence in rural areas was 20%, 47%, and 25%. Urban location (odds ratio [OR] [95% confidence interval [CI]: 11.7 [8.6, 15.9]), female gender (OR [95% CI]: 1.5 [1.1, 2.2]), and abdominal obesity (OR [95% CI]:1.5 [1.1, 2.0]) were independently associated with severe deficiency. This study revealed a high prevalence of severe vitamin deficiency among the adult living in NCR, more so among urban areas, women, and obese.