Understanding the Problem Through Systematic Review and Meta-analysis
Systematic reviews and meta-analyses provide an evidence-based summary by combining results from multiple studies. This approach offers a clearer national picture of the prevalence of vitamin D deficiency in Iran than individual studies. It helps address inconsistencies from varying methods and diagnostic criteria.
Findings Across Different Demographics
Studies indicate that vitamin D deficiency is significantly prevalent across all age groups in Iran:
- Infants: A recent review estimated the prevalence in Iranian infants to be 51%. Earlier meta-analyses also found high rates in mothers and newborns.
- Children and Adolescents: One meta-analysis estimated the deficiency rate at around 30%, showing a gender disparity. Another review noted a prevalence of 47.35% for deficiency.
- Adults: Meta-analyses report high deficiency rates among adults, with one study finding a prevalence of 59.1%. More than half the adult population was deficient according to one review.
Stark Gender and Regional Differences
A notable finding is the significant gender difference in prevalence, particularly among younger people, linked to cultural and lifestyle factors.
| Demographic Group | Males with Vitamin D Deficiency | Females with Vitamin D Deficiency | Key Contributing Factors (Meta-analysis) |
|---|---|---|---|
| Children and Adolescents (meta-analysis up to 2016) | 35% (CI 95% 34–37) | 61% (CI 95% 60–63) | Dress code, lower sun exposure, higher obesity rates in girls |
| Adults (systematic review up to 2016) | 45.64% (95% CI: 29.63–61.65) | 61.90% (95% CI: 48.85–74.96) | Clothing practices, lifestyle shifts, urban vs rural trends |
Regional differences are also present, with factors like air pollution impacting urban populations by reducing UVB exposure, alongside urbanized lifestyles.
Why is Vitamin D Deficiency So Widespread in Iran?
Factors identified include cultural practices limiting sun exposure; urbanization and reduced outdoor time; air pollution; inadequate dietary intake; limited awareness; and economic factors affecting supplement access.
Health Consequences of Deficiency
Widespread deficiency increases the risk of non-communicable diseases. It is associated with rickets in children, and in adults, with osteoporosis, fractures, and increased risk of chronic conditions like cardiovascular disease and diabetes.
Public Health Policies and Interventions
The Iranian Ministry of Health has implemented policies including a supplementation program for infants, monthly mega-dose supplementation for older students and adults, pilot food fortification programs, and public nutrition education. Challenges like inconsistent implementation and low compliance persist. For more on health consequences, see {Link: PMC https://pmc.ncbi.nlm.nih.gov/articles/PMC5936844/}.
Conclusion
Systematic reviews and meta-analyses show that vitamin D deficiency is a major public health concern in Iran, affecting many people across all ages. Females are more affected, often due to cultural and lifestyle factors limiting sun exposure. Other issues like urbanization, air pollution, and diet also contribute. The Iranian government has started interventions, but inconsistent implementation and socioeconomic issues remain challenges. A continued, varied public health strategy is needed to address this deficiency and its health effects.
