What Percent of the Population Has Low Vitamin D?

December 30, 2025 •

4 min read

According to the Cleveland Clinic, a staggering one billion people worldwide have a vitamin D deficiency, with 50% of the population experiencing vitamin D insufficiency. This widespread issue affects diverse populations across the globe, impacting bone health and various other bodily functions. The prevalence of this deficiency varies significantly based on geography, age, skin tone, and cultural practices.

Quick Summary

Vitamin D deficiency affects billions globally, with prevalence varying by region, age, gender, and skin tone. Studies highlight different rates worldwide, influenced by factors like sunlight exposure and lifestyle. The deficiency is linked to various health issues, underscoring its importance as a public health concern.

Key Points

Global Prevalence: About 1 billion people worldwide have vitamin D deficiency, with 50% also having insufficiency.
US Demographics: In the US, approximately 35% of adults have low vitamin D, with notably higher rates among Black and Hispanic individuals.
Risk Factors: Key contributors include darker skin pigmentation, limited sun exposure due to latitude or clothing, aging, and obesity.
Health Consequences: Deficiency impacts more than bone health, associating with immune dysfunction and chronic diseases like diabetes and cardiovascular issues.
Intervention Strategies: Solutions include food fortification, targeted supplementation for high-risk individuals, public health campaigns, and screening programs.
Regional Disparities: Prevalence varies significantly by region; for instance, some South Asian countries show much higher deficiency rates than some European or American regions due to lifestyle differences.
Gender Differences: Females are often more susceptible to vitamin D deficiency than males, a pattern observed in several studies.

Global and Regional Prevalence

Worldwide figures indicate that a substantial portion of the population is affected by low vitamin D levels, though the exact percentage can vary widely based on the criteria used to define deficiency. A comprehensive 2023 review in Frontiers in Nutrition analyzed data from millions of participants across 81 countries, revealing the significant scale of the problem. When defining low vitamin D as serum 25-hydroxyvitamin D levels below 50 nmol/L, approximately 47.9% of the global population is affected. Regional differences are notable, with the highest prevalence observed in the Eastern Mediterranean region. In contrast, some areas of the African region show lower rates.

Within specific regions, research highlights particular vulnerability. A meta-analysis focusing on South Asia found an average vitamin D deficiency prevalence of 68% among adults, with higher rates observed in Pakistan (73%) and among females across the region. Factors such as clothing practices and less outdoor activity are thought to contribute to this trend. In the United States, a 2011 study on US adults found an overall prevalence rate of 41.6% for vitamin D deficiency, with particularly high rates among Black (82.1%) and Hispanic (69.2%) populations. Another US study using earlier data (2001–2006) reported that 8% of the population was at risk of deficiency, while 25% were at risk of inadequacy.

Key Factors Influencing Vitamin D Levels

Several independent factors contribute to the risk of having low vitamin D. These range from personal characteristics to environmental influences. Understanding these variables is crucial for effective prevention and treatment strategies.

Skin pigmentation: Melanin in darker skin acts as a natural sunscreen, reducing the skin's capacity to produce vitamin D from sunlight. This biological difference is a major reason for higher deficiency rates in Black and Hispanic populations, even in sunny climates.
Sunlight exposure: The body's primary method for producing vitamin D is through exposure to UVB radiation from sunlight. Individuals living in high-latitude areas, those who cover their skin for cultural or religious reasons, and those with limited outdoor time are at higher risk.
Age: The skin's efficiency at synthesizing vitamin D decreases with age. This, combined with less time spent outdoors and potentially poorer nutrition, contributes to a high prevalence of deficiency in the elderly.
Diet and obesity: Insufficient dietary intake of vitamin D, as well as obesity, are significant risk factors. Vitamin D is a fat-soluble vitamin, and excess body fat can sequester it, limiting its availability in the bloodstream.

Comparison of Vitamin D Status Worldwide


Factor	Global Population (approximate prevalence of serum <50 nmol/L)	US Adults (approximate prevalence of serum ≤50 nmol/L)	South Asian Adults (pooled prevalence of deficiency)
Overall	~48%	~41.6%	~68%
Gender (overall)	Higher prevalence in females	Higher prevalence in females	Higher prevalence in females (76%) vs. males (51%)
Race/Ethnicity	Varies widely by region and genetic factors	Significantly higher in Black (82.1%) and Hispanic (69.2%) individuals	Higher deficiency observed in darker skin complexions
Season	Higher prevalence during winter/spring	Fluctuates, with lower levels in winter	Varies by climate and sunlight availability
Contributing Lifestyle	Dress codes and lack of sun exposure in some regions	Sedentary indoor lifestyle	Cultural dress and lower female outdoor participation

Addressing the High Prevalence

Public health initiatives are essential to combat the widespread issue of low vitamin D levels. These strategies can involve both large-scale population-level interventions and targeted approaches for at-risk groups.

Intervention Strategies:

Fortification of foods: In many developed countries, staple foods like milk, cereal, and orange juice are fortified with vitamin D. This has helped reduce deficiency rates, particularly in regions with long winters and limited sun exposure. However, many countries still lack comprehensive fortification policies.
Supplementation: For individuals with diagnosed deficiency or those at high risk, supplementation is a crucial tool. Recommended doses vary based on baseline vitamin D levels, but guidelines often suggest daily maintenance doses after initial correction. The Endocrine Society recommends supplementation during pregnancy due to its impact on fetal development.
Public education: Campaigns to raise awareness about vitamin D's importance, dietary sources, and safe sun exposure practices can empower individuals to manage their own health. Addressing cultural misconceptions about sun exposure is particularly important in some populations.
Screening: Targeted screening programs for at-risk groups, such as the elderly, individuals with dark skin, and those with certain medical conditions, can help identify and treat deficiency early. This can prevent more severe complications associated with long-term deficiency.

The Health Impact of Low Vitamin D

Beyond its well-known role in bone health, vitamin D has extraskeletal effects related to immune function, cell proliferation, and muscle function. Chronic deficiency has been linked to a wide range of diseases, underscoring its broad impact on public health.

Bone Health: The most recognized consequence of severe vitamin D deficiency is impaired bone mineralization, which can lead to rickets in children and osteomalacia in adults. Low levels also contribute to osteoporosis, increasing the risk of falls and fractures, especially in older adults.
Immune Function: Vitamin D plays a key role in modulating the immune system. Low levels have been associated with increased susceptibility to infections and autoimmune diseases.
Chronic Diseases: Research has observed connections between vitamin D deficiency and a variety of non-skeletal disorders, including cardiovascular disease, diabetes, and certain cancers. While supplementation studies have yielded mixed results, the association remains a subject of ongoing investigation.

Conclusion

Vitamin D deficiency is a major global public health concern, affecting a significant portion of the world's population, with an estimated one billion people suffering from it and many more experiencing insufficiency. The prevalence is not uniform and is influenced by a complex interplay of environmental, demographic, and behavioral factors, including geographic location, skin color, age, and cultural norms surrounding sun exposure. Addressing this issue requires a multifaceted approach involving food fortification, targeted supplementation, public health education, and consistent screening for at-risk individuals. By increasing awareness and implementing effective strategies, the adverse health effects of low vitamin D levels can be mitigated on a global scale. Learn more about the critical role of vitamin D here.

Frequently Asked Questions

While definitions vary, a common threshold for vitamin D deficiency is a serum 25-hydroxyvitamin D concentration below 50 nmol/L (or 20 ng/mL). Some authorities also categorize levels between 50 and 75 nmol/L (20-30 ng/mL) as insufficient.

Vitamin D levels are measured with a blood test that checks the concentration of 25-hydroxyvitamin D. This test can be ordered by a healthcare provider to assess your vitamin D status.

Yes, vitamin D deficiency can be a major issue even in sunny countries. Factors like cultural dress codes that limit skin exposure, spending most of the day indoors, and darker skin pigmentation can reduce the body's ability to produce vitamin D from sunlight.

Yes, individuals with darker skin pigmentation have higher levels of melanin, which reduces the skin's ability to produce vitamin D from sun exposure. This is a major reason for higher deficiency rates in darker-skinned populations.

Many people with low vitamin D are asymptomatic, but symptoms can include fatigue, bone pain, muscle weakness, and frequent infections. In severe, prolonged cases, it can lead to conditions like rickets in children or osteomalacia in adults.

Levels can be improved through moderate, safe sun exposure, dietary intake of vitamin D-rich foods (such as fatty fish and fortified products), and supplements, especially for those at high risk or with confirmed deficiency.

Food fortification is an effective public health strategy that has helped reduce vitamin D deficiency rates in many developed countries. However, its success depends on the widespread availability of fortified foods and local consumption patterns.

Yes, older adults are at a significantly higher risk. The skin's ability to synthesize vitamin D from sunlight diminishes with age, and many seniors also have limited sun exposure and dietary intake.