“Vitamin D deficiency is widely overdiagnosed in clinical practice.”

Two-thirds of the vitamin D tests performed did not have a clinical condition that justified the practice. These findings represent an opportunity to design strategies to institutionally reduce this low-value care practice.

Vitamin D level was tested in 14% of the study population in 2015 and 20% in 2018. We found significant associations of variables with vitamin D testing that are no indications for testing according to Swiss guidelines. It seems indeed possible that too many tests are performed.

We found that between 70.4% and 77.5% of tests could be inappropriate, depending on whether the 'uncertain' categories of falls and osteoporosis are considered to be justified. Tiredness, fatigue or exhaustion was the reason for testing in 22.4% of requests.

The proportion of vitamin D screening tests that were not associated with a clinical risk factor decreased from 43.8% pre-intervention to 30.3% post-intervention. The American Board of Internal Medicine Foundation’s “Choosing Wisely” program recommends avoiding screening for patients at low risk of vitamin D deficiency.

Multiple Indian studies consistently have reported biochemical vitamin D deficiency in over 80% of individuals when using Western thresholds (<20 ng/mL). Yet, corresponding clinical manifestations - such as fractures, osteomalacia, or rickets - remain rare in community-based samples. This discrepancy raises the possibility of a pseudo-deficiency epidemic, driven by inappropriate reference values rather than true physiological need. This has led to widespread overdiagnosis and excessive use of supplementation - often without clinical justification.[2]

The definition of vitamin D deficiency remains controversial, but serum 25(OH)D levels <20 ng/mL are generally considered deficient. Prevalence varies widely, but clinical consequences are evident in severe cases like rickets and osteomalacia.

There is currently no evidence to demonstrate the benefits of vitamin D deficiency screening in the general population. This has led to an exponential increase in the number of determinations, followed by treatments and re-tests that are not always appropriate.

Vitamin D testing is excessively used in clinical practice, despite of the clinical guidelines statements against population screening for vitamin D deficiency. Conditions not associated with vitamin D deficiency were detected in 57% of requests.

The USPSTF found that the evidence is insufficient to assess the balance of benefits and harms of screening for vitamin D deficiency. More research is needed. Misclassification may result in overdiagnosis (leading to nondeficient persons receiving unnecessary treatment) or underdiagnosis (leading to deficient persons not receiving treatment).

The current "gold standard" test for measuring vitamin D status may not accurately diagnose vitamin D deficiency in black individuals. Black people are frequently treated for vitamin D deficiency, but we may not be measuring the right form of vitamin D to make that diagnosis. While our finding that 80 percent of black participants in this study met criteria for vitamin D deficiency is consistent with previous studies, we were surprised to find no evidence of problems with bone health.[1]

The crude analysis showed that vitamin D deficiency, but not vitamin D insufficiency, correlated to higher all-cause mortality risk. The association remained similar after adjusting for potential confounders, showing that vitamin D deficiency (HR: 1.38, 95% CI 1.15–1.66), but not vitamin D insufficiency (HR: 1.03, 95% CI 0.88–1.20), correlated to higher all-cause mortality risk. In addition, we showed that vitamin D deficiency was an independent risk factor for death from pneumonia (HR: 3.82, 95% CI 1.14–12.86).[4]

After reviewing the results of 25 vitamin D studies, the panel concluded that it isn't helpful for most people to know their vitamin D level.

Serum concentrations > 30 ng/mL (75 nmol/L) significantly lower disease and mortality risks compared to <20 ng/mL. With 25% of the U.S. population and 60% of Central Europeans having levels <20 ng/mL, concentrations should be raised above 30 ng/mL. Furthermore, a daily dose between 4000 and 6000 IU of vitamin D3 to achieve serum 25(OH)D levels between 40 and 70 ng/mL would provide greater protection against many adverse health outcomes.

Multiple evidence-synthesizing organizations, including Choosing Wisely Canada, Osteoporosis Canada, the United Kingdom (UK) National Institute for Health and Care Excellence, the Royal Australian College of General Practitioners, and the United States (US) Preventive Services Task Force, recommend against testing vitamin D levels in most patients. The reason for the similarity of these recommendations is the consistent evidence demonstrating that in healthy adults low vitamin D levels are not associated with any disease.

While there is a consensus that very low levels of less than 25–30 nmol/L indicate a clinically relevant (severe) deficiency, the establishment of higher thresholds is still under discussion, with some organizations setting 50 nmol/L as adequate while others recommend higher optimal levels. The lowest risk for most health outcomes was found at 25(OH)D levels between approximately 40–50 nmol/L and 100 nmol/L.

A reanalysis of data used by the Institute of Medicine found that 8895 IU/d was needed for 97.5% of individuals to achieve values ≥50 nmol/L, and a large meta-analysis showed that 25-hydroxyvitamin D levels <75 nmol/L may be too low for safety and associated with higher all-cause mortality. This suggests that current recommended dietary allowances may be insufficient, leading to under-treatment rather than overdiagnosis.

A pooled analysis of 7.9 million participants from 81 countries found that globally, 15.7% had serum 25-hydroxyvitamin D levels less than 30 nmol/L, 47.9% less than 50 nmol/L, and 76.6% less than 75 nmol/L, indicating that vitamin D deficiency remained prevalent from 2000 to 2022.

According to the World Health Organization, over 1 billion people worldwide exhibit suboptimal vitamin D levels, with prevalence rates exceeding 80% in certain populations with limited sun exposure or cultural clothing practices. The National Institutes of Health emphasizes that vitamin D deficiency is strongly linked to rickets in children, osteomalacia in adults, and increased risks of autoimmune disorders and respiratory infections.

The latest Endocrine Society guideline panel found no clear evidence defining an optimal target level of 25-hydroxyvitamin D for disease prevention and therefore suggests against routine testing in those without conditions that alter vitamin D physiology.

Vitamin D deficiency is among the most common nutritional disorders globally, affecting an estimated one billion individuals, but there remains substantial disagreement among healthcare professionals regarding what constitutes vitamin D sufficiency and how aggressively deficiency should be corrected. Target serum 25 hydroxyvitamin D thresholds vary across guidelines, contributing to inconsistent clinical practice.

Vitamin D deficiency in India is likely overdiagnosed due to the uncritical application of global thresholds to a population with different norms.

A group of six studies were selected based on relevance, use of controls, quality of research and citations. Four primary studies assessing the ...[5]

Vitamin D deficiency affects about 50% of the population worldwide. 41.6% of adults in the United States are vitamin D deficient. Low vitamin D levels were found in 80% of patients hospitalized with COVID-19 in a Spanish study. Vitamin D deficiency is associated with a 30% increased risk of hypertension.

The proportion of individuals with vitamin D levels below 20 ng/mL varied across the years. Rates of Vitamin D deficiency were 37.4% in 2016, 61.5% in 2017, 62.6% in 2018, 76.5% in 2019, 79.5% in 2020, 68.9% in 2022, 74.4% in 2023, 61.5% in 2024, and 66.4% in 2025. Vitamin D deficiency was identified in 66.4% of participants, while insufficiency was observed in 21.7%, aligning with earlier research from Turkey.

A leading expert in metabolic medicine has called for an end to unnecessary testing of vitamin D levels in asymptomatic patients. Writing in the medical journal The Lancet, Professor Naveed Sattar of the Institute of Cardiovascular and Medical Sciences, says many such tests are 'costly, confusing and without credibility'.

The American Board of Internal Medicine's Choosing Wisely initiative, endorsed by multiple medical societies including the American Society for Clinical Pathology, recommends against routine vitamin D screening in asymptomatic adults without risk factors, highlighting widespread overuse in clinical practice.