Prevalence and Risk Factors of Vitamin D Deficiency Among Children Aged 2–12 Years in Rural Tamil Nadu (Chengalpattu District): A Cross-Sectional Study
Dr. Nagajyothi Kammela
Abstract
Background: Vitamin D deficiency (VDD) constitutes a significant public health concern in India, paradoxically persisting despite abundant tropical sunlight. Community-level paediatric data from rural Chengalpattu district, Tamil Nadu, remain scarce, limiting evidence-based local intervention. Objectives: To estimate the prevalence of VDD and identify its associated risk factors among children aged 2–12 years residing in rural Chengalpattu district. Methods: A community-based cross-sectional study was conducted across three Primary Health Centre (PHC)-affiliated rural clusters of Chengalpattu district over six months. Using multi-stage cluster sampling, 420 children aged 2–12 years were enrolled. Serum 25-hydroxyvitamin D [25(OH)D] was measured by chemiluminescence immunoassay (CLIA) and categorised as deficient (<20 ng/mL), insufficient (20–29 ng/mL), or sufficient (≥30 ng/mL) per Endocrine Society guidelines. Anthropometry yielded height-for-age (HAZ), weight-for-age (WAZ), and BMI-for-age (BAZ) Z-scores. Determinants of deficiency were assessed by multivariable logistic regression. Results: VDD was present in 35.5% of children (149/420; 95% CI 30.9–40.2), with an additional 29.5% insufficient (124/420). Deficient children had significantly lower mean HAZ than sufficient children (−1.12 ± 1.08 vs −0.71 ± 1.15; p = 0.019). After multivariate adjustment, deficiency remained independently associated with lower HAZ (β −0.41, 95% CI −0.67 to −0.15; p = 0.003) and lower WAZ (β −0.27, 95% CI −0.52 to −0.01; p = 0.039). Greater daily sun exposure was independently protective against VDD (adjusted OR 0.74 per hour/day; 95% CI 0.57–0.97; p = 0.026), while low outdoor activity (vs high: aOR 1.68; 95% CI 1.03–2.74; p = 0.037) and older age group (8–12 years vs 2–4 years: aOR 1.52; 95% CI 0.98–2.38; p = 0.062) were associated with higher odds of deficiency. Conclusion: More than one-third of rural children in Chengalpattu were vitamin D deficient despite tropical latitude, with VDD independently linked to impaired linear and ponderal growth. Modifiable factors—particularly sun exposure and outdoor activity—represent actionable targets for primary prevention. Targeted supplementation through existing child health platforms and district-level policy advocacy are warranted.
