The Pervasive High Rate of Deficiency
A comprehensive meta-analysis, which consolidated data from 40 studies involving over 111,000 participants, revealed widespread vitamin D inadequacy in Turkey. The estimated deficiency prevalence for the overall population was 63%, with even higher rates within specific demographics. The findings showed particularly alarming rates in certain at-risk groups:
- Infants: An extremely high prevalence of 86.6% was reported. While the national prophylaxis program has shown success, data indicates that the benefits often diminish after the first year.
- Pregnant Women: With a deficiency rate of 76%, this group represents a critical concern.
- Adults: The general adult population also suffers from a high deficiency rate of 63.5%.
- Gender Disparity: Women showed a higher deficiency rate of 64.7% compared to 39.5% in men.
Contributing Factors to Low Vitamin D Status
Geographic and Seasonal Effects
Turkey experiences significant regional and seasonal variations in vitamin D status, with lower levels typically observed during winter and spring. Studies indicate that regional factors beyond sun availability play a role.
Lifestyle and Social Determinants
Several factors contribute to deficiency risk, including cultural practices that limit skin exposure to sunlight, increased time spent indoors, and insufficient dietary intake. Air pollution may also play a role in reducing UVB radiation. Maternal vitamin D levels are crucial, as low stores in mothers contribute to deficiency in infants.
Impact on Public Health
Skeletal and Extraskeletal Consequences
Widespread deficiency contributes to long-term health issues. While infantile rickets has decreased due to national programs, adults face increased risk of osteoporosis, osteomalacia, muscle weakness, and higher fracture rates. Low vitamin D is also linked to a higher risk of chronic diseases like cardiovascular disease, diabetes, and autoimmune conditions.
Interventions and Remaining Challenges
Turkey's national vitamin D supplementation program for infants, providing free drops up to one year of age, has been effective in eradicating widespread rickets. However, the benefits often do not extend beyond infancy. Challenges include ensuring continued supplementation for older groups and addressing variations in healthcare provider practices and public awareness.
Comparative Vitamin D Status in Turkey
| Aspect | Alpdemir et al. Meta-analysis (2019) | JCRPE study (2011–2016 data) | |
|---|---|---|---|
| Study Population Size | 111,582 (40 studies) | 108,742 (nationwide laboratory data) | |
| Overall Deficiency Prevalence (<20ng/mL) | 63% (CI 58.9-66.6) | 51% (Using Endocrine Society's criteria) | |
| Prevalence in Infants (<1 yr, <12ng/mL) | 86.6% (Using <20ng/mL) | 7% | |
| Mean 25(OH)D Level (ng/mL) | Not reported for overall population | 21.6 ± 13.3 | |
| Key Finding | High overall deficiency rates, especially in women, infants, and pregnant women. | Confirmed high rates in adults; national infant program is effective but impact fades with age. |
Conclusion: The Continuing Need for Action
The meta-analysis confirms vitamin D deficiency as a serious public health concern in Turkey, affecting a significant portion of the population. Despite successful infant programs, high deficiency rates persist in older infants, pregnant women, and adults due to lifestyle, environmental, and regional factors. Continued efforts including monitoring, targeted supplementation, and education are crucial to improve vitamin D status and mitigate associated health risks. A multi-pronged approach is necessary to effectively address this challenge. For more information on vitamin D deficiency, consult authoritative health resources like the National Institutes of Health (NIH).
