A Study on Biological Reference Interval of Vitamin D in Western Indian Population

Background: Vitamin D plays a vital role in calcium-phosphorus metabolism and bone health. Its deficiency is a global health issue, with significant prevalence in India despite ample sunlight. This study aims to evaluate the Biological Reference Interval (BRI) of vitamin D levels in the Western Indian population and assess its adequacy using Chemiluminescence Immunoassay (CLIA). Methods: A cross-sectional study was conducted on 482 healthy participants (188 males, 294 females) aged 1?80 years at Sir Sayajirao Hospital, Gujarat, from April to September 2024. Serum 25-hydroxyvitamin D (25-OH vit D) levels were measured using the Abbott i-1000 SR analyzer. Data on diet, sunlight exposure, and lifestyle factors were collected via questionnaires. Statistical analysis included unpaired t-tests and percentile-based categorization. Results: Vitamin D deficiency (<20 ng/mL) was observed in 54.98% of participants, with 24.48% classified as insufficient (21?29 ng/mL) and 20.54% as sufficient (>30 ng/mL). Females had significantly lower mean levels (19.54 ? 9.25 ng/mL) compared to males (23.46 ? 11.16 ng/mL; p< 0.0001). The observed range (7.5?46 ng/mL) aligned with manufacturer-provided BRIs(6.6-49.9ng/ml). Hypovitaminosis D was prevalent across all age groups, with higher deficiency rates in females and older adults. Conclusions: Although the manufacturer's BRI was applicable, this study highlights the need to refine deficiency thresholds specific to the Western Indian population. The findings underscore the importance of tailored public health strategies to address the high prevalence of vitamin D deficiency and its associated health risks.