How Common Is Low Vitamin D Deficiency? Global Prevalence and Risk Factors

December 22, 2025 •

4 min read

Approximately one billion people worldwide are estimated to have low vitamin D deficiency, a widespread public health issue affecting populations across different ages and geographical locations. This global pandemic of low vitamin D deficiency persists even in sunny climates due to various lifestyle and cultural factors.

Quick Summary

Low vitamin D deficiency is a widespread global issue affecting diverse populations. Several factors, including age, skin pigmentation, lifestyle, and geography, influence prevalence rates across the world.

Key Points

Global Prevalence: Approximately one billion people worldwide are estimated to have low vitamin D deficiency, making it a widespread public health issue.
Regional Disparities: Prevalence is not uniform, with higher rates observed in certain regions like South Asia and the Eastern Mediterranean, influenced by cultural practices and diet.
High-Risk Groups: The elderly, obese individuals, and those with darker skin pigmentation are disproportionately affected due to physiological and lifestyle factors.
Beyond Sunlight: Deficiency is widespread even in sun-rich areas, as modern indoor lifestyles, clothing, and dietary patterns limit vitamin D synthesis and intake.
Skeletal and Extraskeletal Impact: While known for affecting bone health (rickets, osteoporosis), vitamin D deficiency is also associated with an increased risk of various non-skeletal diseases.
Management is Key: Effectively addressing this widespread deficiency requires a combination of public health initiatives, dietary changes, and targeted supplementation.

What Defines Low Vitamin D Status?

Before exploring prevalence, it is important to understand how vitamin D status is defined. The most common and reliable method for assessing vitamin D status is by measuring the serum 25-hydroxyvitamin D (25[OH]D) concentration in the blood. While exact cut-offs can be debated by different health bodies, a general consensus recognizes three key levels:

Deficiency: Serum 25(OH)D levels below 30 nmol/L (or 12 ng/mL). This severe level significantly increases the risk of bone health issues like rickets and osteomalacia.
Insufficiency: Serum 25(OH)D levels typically between 30-50 nmol/L (or 12-20 ng/mL).
Sufficiency: Serum 25(OH)D levels above 50 nmol/L (or 20 ng/mL).

A Global Public Health Problem

Based on a large meta-analysis of studies from 2000 to 2022 involving nearly 8 million participants, low vitamin D status is a persistent global problem. While the prevalence of severe deficiency (<30 nmol/L) slightly decreased over this period, it still affects a significant portion of the global population, particularly when considering insufficiency levels as well. Despite the assumption that sunnier climates would naturally prevent this issue, data shows that high prevalence is common even in regions with abundant sunshine. This underscores the complexity of the factors influencing vitamin D levels beyond just geographical location.

Regional Variations in Prevalence

Prevalence rates for low vitamin D status vary significantly across different regions of the world, highlighting the impact of local diets, cultural practices, and healthcare strategies.

Eastern Mediterranean Region: This area, including many countries in the Middle East, consistently shows some of the highest prevalence rates globally. Factors contributing to this include cultural practices involving extensive body covering and potentially low dietary intake.
South Asia: Meta-analysis in countries like Pakistan, India, and Bangladesh show very high prevalence, with up to 73% of adults affected in Pakistan. Factors include clothing, vegetarianism, and low food fortification.
Europe: Rates vary, but many studies show significant prevalence, with some reporting up to 60% of the population having deficient or insufficient levels in parts of Southern and Eastern Europe.
United States: Data indicates a notable portion of the population is affected. For example, a study using NHANES data from 2007-2016 found that over 50% of middle-aged and older adults had insufficient or deficient vitamin D levels.

Populations with Higher Risk

Certain demographics and conditions put individuals at a higher risk of developing low vitamin D levels. Identifying these groups is critical for targeted screening and intervention.

High-risk groups include:

Older Adults: The skin's ability to synthesize vitamin D from sunlight decreases significantly with age. Furthermore, older adults may have less outdoor mobility and poorer nutritional intake, increasing their risk. A meta-analysis in 2024 found the global prevalence of deficiency (<20 ng/mL) in the elderly to be nearly 60%.
Darker-Skinned Individuals: Higher levels of melanin in darker skin act as a natural sunscreen, reducing the skin's capacity to produce vitamin D from sunlight. This explains the higher prevalence among African American and Hispanic populations in countries like the US.
Obese Individuals: Body fat can sequester vitamin D, making it less bioavailable for the body's needs. Studies show a higher prevalence of vitamin D deficiency in obese individuals compared to their non-obese counterparts.
Individuals with Limited Sun Exposure: Those who are homebound, institutionalized (e.g., in nursing homes), or wear extensive clothing for cultural or other reasons have significantly less sunlight exposure, impacting synthesis.
People with Malabsorption Disorders: Chronic conditions affecting nutrient absorption, such as celiac disease, inflammatory bowel disease, or bariatric surgery, can interfere with the body's ability to absorb vitamin D.
Infants: Breast milk often has low levels of vitamin D, putting exclusively breastfed infants at risk without supplementation. Some global studies show very high prevalence in infants in certain regions.

Prevalence Comparison by Demographic and Region


Population Group	Region	Example Prevalence Rate (approx.)	Primary Contributing Factors
Adults	Pakistan	73%	Clothing, diet, latitude
Adults	United States	35% deficient, 58% insufficient/deficient	Indoor lifestyle, low intake, skin color
Elderly	India	96% deficient	Aging, low sun exposure, diet
Elderly	United States	61% deficient	Aging, institutionalization
Women	South Asia (Meta-analysis)	76% deficient	Cultural clothing practices, indoor lifestyle
Urban Youth	India	18-24% deficient (5-19 years)	Diet, indoor lifestyle, season

Conclusion: A Persistent Public Health Concern

Low vitamin D deficiency is not a niche problem but a public health pandemic affecting a vast number of people worldwide across all age groups and geographies. The prevalence is influenced by a complex interplay of factors including latitude, sun exposure behaviors, dietary habits, and demographics. While global efforts have made progress, the consistently high rates, especially in vulnerable populations like the elderly, women in certain regions, and those with darker skin, show that significant work remains. Addressing this persistent issue requires a combination of public awareness campaigns, food fortification strategies, and, for high-risk individuals, targeted screening and supplementation strategies. For more detailed information on global and regional trends, please refer to authoritative meta-analyses and reports published in reputable journals, such as the comprehensive study on global vitamin D prevalence from 2000 to 2022.

Frequently Asked Questions

Low vitamin D status is typically divided into insufficiency and deficiency based on serum 25(OH)D levels. A level below 50 nmol/L (or 20 ng/mL) is often considered deficient, while levels between 50-75 nmol/L are insufficient.

Yes, it is a very common global public health problem. Estimates suggest that around one billion people worldwide have vitamin D deficiency, with a large portion of the global population also experiencing insufficiency.

Even in sunny countries, low vitamin D is common due to factors like cultural clothing practices that cover the skin, modern indoor lifestyles, fear of skin cancer leading to heavy sunscreen use, air pollution, and dietary habits.

High-risk groups include the elderly (as skin synthesis declines), individuals with darker skin (higher melanin levels), those who are obese, people with limited sun exposure (e.g., institutionalized), and those with malabsorption disorders.

While it's a factor, studies show that modern indoor lifestyles and other behaviors significantly mitigate the simple effect of latitude. However, seasonal variation is notable, with lower vitamin D levels reported in winter and spring, particularly at higher latitudes.

Symptoms can include fatigue, bone pain, muscle weakness, muscle aches, or muscle cramps. In severe cases, it can lead to bone hypomineralization disorders like rickets in children and osteomalacia in adults.

Strategies include recommended sun exposure, consuming dietary sources rich in vitamin D like fatty fish or fortified foods, and supplementation, especially for high-risk individuals or those with limited sun exposure.