Vitamin D Cutoff for Indian Population
For the Indian population, target a serum 25(OH)D level of 40-60 ng/mL (100-150 nmol/L) based on the most recent India-specific expert consensus, which differs substantially from Western thresholds. 1
India-Specific Thresholds vs. Western Guidelines
The 2025 Indian expert consensus (41 endocrinologists using DELPHI methodology with >90% agreement) established population-specific cutoffs that acknowledge the unique physiology of Indians, including darker skin pigmentation and different calcium homeostasis patterns 1:
Recommended Indian Cutoffs:
- Optimal range: 40-60 ng/mL (100-150 nmol/L) 1
- Insufficiency: Below 40 ng/mL 1
- Deficiency: Below 20 ng/mL 1
- Severe deficiency: Below 10 ng/mL 1
Why Indian Cutoffs Differ from Western Standards:
The traditional Western cutoff of 30 ng/mL may be too high for Indians. A 2023 study of 270 healthy Indians found that 97.8% had levels below 30 ng/mL, yet only 8.8% had elevated PTH and 1.85% had hypocalcemia 2. This suggests that Indians maintain adequate calcium homeostasis at lower vitamin D levels than Caucasians.
The lower physiological threshold for Indians appears to be approximately 13.5 ng/mL based on LOESS curve analysis showing the inflection point where PTH begins rising and bone health markers deteriorate 2. However, this represents the absolute minimum, not the optimal target.
Epidemiology of Vitamin D Deficiency in India
Vitamin D deficiency is paradoxically prevalent across India despite abundant sunshine:
- Using the 20 ng/mL cutoff, 65.4-78.3% of Indians are deficient 3, 4, 5
- Using the 30 ng/mL cutoff, prevalence reaches 66.3-97.8% 4, 2
- Severe deficiency (<5 ng/mL) affects 20.6% of urban Indians 4
- Mean levels range from 3.15 to 52.9 ng/mL across different Indian regions 6
High-Risk Groups Requiring Screening:
- Dark-skinned individuals (melanin reduces vitamin D synthesis) 3, 5
- Veiled/burkha-wearing individuals (limited sun exposure) 3, 5
- Urban populations (indoor lifestyle, pollution blocking UVB) 4, 5
- Younger age groups (paradoxically higher deficiency rates) 5
- Diabetic patients (independent predictor of deficiency) 5
Practical Recommendations for Indian Population
Who Should Be Tested:
Test serum 25(OH)D in individuals with musculoskeletal complaints, cardiovascular disease risk, autoimmune conditions, cancer risk, or the high-risk groups listed above 3
Who Can Be Supplemented Without Testing:
Dark-skinned or veiled individuals with limited sun exposure and institutionalized elderly can receive 800 IU/day without baseline measurement 3, 7
Treatment Targets:
Aim for 40-60 ng/mL in Indians rather than the Western target of 30-44 ng/mL 1, 3. This higher target accounts for measurement variability and ensures true sufficiency 3.
Supplementation Doses:
- Maintenance for at-risk Indians: 1,500-4,000 IU daily 7
- Deficiency correction (<20 ng/mL): 50,000 IU weekly for 8-12 weeks, then maintenance 8
- Severe deficiency (<10 ng/mL): 50,000 IU weekly for 12 weeks, then 2,000 IU daily maintenance 8
Safety Limits:
The upper safety limit remains 100 ng/mL regardless of ethnicity, with toxicity rare below this threshold 3, 9. Daily doses up to 4,000 IU are safe long-term 7, 9.
Critical Pitfalls to Avoid
Do not apply Western cutoffs blindly to Indians. The 30 ng/mL threshold used in Western guidelines 3 would classify nearly all healthy Indians as deficient, leading to overdiagnosis and unnecessary treatment 2.
However, do not use the 13.5 ng/mL threshold as a treatment target. This represents the minimum for preventing secondary hyperparathyroidism, not the optimal level for overall health 2. The Indian consensus target of 40-60 ng/mL provides a buffer for measurement uncertainty and seasonal variation 1.
Recognize that sun exposure alone is insufficient in India despite the country's latitude (8.4°N to 37.6°N) 4. Skin pigmentation, urban pollution, indoor lifestyles, and cultural clothing practices all contribute to widespread deficiency 6, 4, 5.
Measure 25(OH)D, not 1,25(OH)₂D. The active form (1,25-dihydroxyvitamin D) remains normal even in severe deficiency due to compensatory PTH elevation, making it an unreliable marker 4.
Wait at least 3 months after starting supplementation before rechecking levels to allow plateau 7, 8. For intermittent dosing (weekly/monthly), measure just before the next dose 8.