Bone Health at Stake: Alarming Prevalence and Predictors of Vitamin D Deficiency in Karachi Children.

Background: Vitamin D insufficiency is a major public health problem for Pakistani children. The purpose of this cross-sectional research was to determine the prevalence and possible correlates of vitamin D insufficiency in young children under the age of five living in Karachi, Pakistan. Methods: We analysed data from 400 children aged 0 to 5 years who had vitamin D testing (serum 25-hydroxyvitamin D) at a diagnostic laboratory in Karachi between January and December 2022. Participants' vitamin D levels were classified as adequate (≥30 ng/ml) or insufficient (<30 ng/ml). Logistic regression with robust standard errors adjusted for clustering in the laboratory environment. Results: The prevalence of vitamin D insufficiency was disturbingly high at 71.8% (287/400), near national prevalence. Age emerged as a major risk factor, with older children being more likely to be deficient (OR: 1.20 per year increase in age, 95% CI: 1.11-1.30, p 0.001). Winter months increased the incidence of deficit compared to summer (OR: 1.80, 95% CI: 1.21-2.89, p = 0.010). Gender had no significant connection with deficit. Conclusions: Our data show that vitamin D insufficiency is a major problem among children in Karachi. To address this public health concern and protect children's health and development, targeted initiatives encouraging safe sun exposure, diversifying diets with vitamin D-rich foods, and investigating fortified staples or regular supplementation are urgently required.