Vitamin D Deficiency: Regional Data, Risk Factors, and a Call to Action

Vitamin D deficiency remains a widespread global health issue and is a major cause of osteomalacia while contributing to a range of non-skeletal conditions. Global and regional data collected between 2000 and 2022 highlight the urgent need for public health action and increased awareness to address this largely preventable condition.

Background

Vitamin D deficiency is implicated in classical bone diseases such as rickets and osteomalacia, as well as non-skeletal disorders including immune-mediated and cardiovascular diseases. Vitamin D status is influenced by ultraviolet B (UVB) exposure, dietary intake, and food fortification practices. However, varying definitions of deficiency thresholds (<30, <50, and <75 nmol/L) complicate prevalence comparisons.

Regional and Global Patterns

Prevalence varies significantly by region:

• Eastern Mediterranean: Highest deficiency rates, with over 35% of populations below 30 nmol/L

• Europe: Moderate prevalence but substantial population burden

• Americas and Africa: Lower reported prevalence, though underdiagnosis may exist

Demographic Risk Factors

Key risk factors for vitamin D deficiency include:

• Age: Higher risk among young adults aged 19–44 years

• Seasonality: Winter–spring deficiency risk is approximately 1.7 times higher than summer–autumn

• Latitude: Higher prevalence in northern latitudes

• Gender: Higher prevalence in females compared with males

• Income level: Greater burden in lower- and middle-income countries

Global Prevalence Estimates

Globally, approximately:

• 15.7% of individuals have 25(OH)D levels below 30 nmol/L

• 47.9% are below 50 nmol/L

• 76.6% are below 75 nmol/L

Call to Action

Public health strategies should focus on:

• Raising awareness of both skeletal and non-classical effects of vitamin D deficiency

• Supporting food fortification and targeted supplementation programs

• Emphasizing the importance of seasonal and geographic context in vitamin D assessment

For clinicians and laboratories, priorities include identifying high-risk populations, interpreting vitamin D results with consideration of latitude, season, sex, and assay variability, and supporting evidence-based screening strategies.

Reference:
doi: 10.3389/fnut.2023.107080