Rajeev Jayadevana
a. American Board certification in Medicine, American Board certification in Gastroenterology; Convener, Research Cell, Kerala State IMA*
Vitamin D deficiency is widely diagnosed based on serum 25-hydroxyvitamin D levels, yet the thresholds defining deficiency and sufficiency remain inconsistent across guidelines. While the 2011 Endocrine Society guidelines defined vitamin D sufficiency as serum levels of ≥30 ng/mL, recent evidence — and the 2024 update — have moved away from such fixed numerical cut-offs. In recent years, there has also been growing criticism of certain experts who continue to advocate higher target levels despite limited evidence of clinical benefit. This change reflects growing recognition that vitamin D levels vary widely among individuals, and that modestly lower levels are not consistently associated with adverse clinical outcomes. Studies from India and elsewhere demonstrate that populations with levels far below 30 ng/mL often remain healthy, suggesting that applying previously established Western thresholds may label large numbers of individuals as “deficient” without clinical justification. Overdiagnosis leads to unnecessary supplementation and puts people at risk for toxicity. Establishing region-specific reference ranges that consider local sunlight exposure, diet, and ethnicity is essential. A one-size-fits-all approach risks medicalising normal biological variation rather than addressing true deficiency.