ABSTRACT

Introduction:

Although pathogenesis of AMD is not fully understood it is well established that angiogenesis has a major role in the development and progression of AMD. Recently, inflammation has received attention as a potential risk factor for this disease. Additionally, immune cell involvement and oxidative stress have been associated with this disease. A number of in vitro and in vivo studies have suggested an anti-inflammatory role for 25-hydroxyvitamin D3 (25(OH)D3). Furthermore, it was recently shown that 25(OH)D3 was a potent inhibitor of angiogenesis by its effects on endothelial cells and by interrupting signaling pathways that are key to angiogenesis, specifically in tumorigenesis. Based on this association and the involvement of 25(OH)D3 in processes underlying several diseases with an inflammatory or immune component, we hypothesised that 25(OH)D3 might play a role in AMD pathophysiology and, in particular, neovascular AMD.

Material & Methods:

The study population consisted of 95 adults with exudative type AMD and 95 age and sex matched controls without AMD. Patients with AMD were selected from the retina department who had the neovascular form of AMD in at least one eye, defined by subretinal haemorrhage, submacular choroidal neovascular membrane, fibrosis or presence of neovascularization, a leakage from the vascularite of the membrane in any phase of fluorescein angiography. The diagnosis of macular degeneration was confirmed by optical coherence tomography. Patients whose only exudative finding was a retinal pigment epithelium (RPE) detachment were excluded. Patients with signs of pathological myopia, presumed ocular histoplasmosis syndrome, angioid streaks, choroidal rupture, any hereditary retinal diseases other than AMD and previous laser treatment due to retinal conditions were also excluded. Participants taking any supplement therapy including 25(OH)D3 were also excluded. Serum 25(OH)D3 levels were studied according to the standart protocol of the biochemistry department and then results were classified in 3 categories, based on serum 25(OH)D3 levels as: deficient (<20 ng/ml), insufficient (20.1–29.9 ng/ml), and sufficient (>30 ng/ml).19 Serum 25(OH)D3 levels were compared between patients and control subjects. Age-related macular degeneration ratio was also compared between patients whose serum 25(OH)D3 levels were in deficient range and patients whose 25(OH)D3 levels were in sufficient and insufficient range.

Results:

Mean age was 73.6 ± 7.8 and 73.3 ± 7.8 in patient and control group respectively (p=0.756). Median 25(OH)D3 level was 11.7 ng/ml ( range:4-34) in the patient group and was 17 ng/ml (4.2-37) in control group (p=0.042). The frequencies of the AMD (+) patients among vitamin D categories reached to a statistically significant level (p=0.043). The frequency of AMD (+) patients in subjects with deficient range of vitamin D level was significantly higher than subjects with sufficient and/or insufficient range of vitamin D levels (55% vs 36%, p : 0.021 respectively)

Discussion:

In our study, we investigated the association between serum levels of 25(OH)D3, with neovascular AMD. 25-hydroxyvitamin D3 levels were found to be reduced in AMD patients compared to healthy subjects. Besides the frequencies of the AMD (+) patients showed an association among 25(OH)D3 categories (p=0.043). The subgroup analysis of the present study showed that the frequency of AMD (+) patients in subjects who had deficient range of vitamin D level was significantly higher than found in subjects who had sufficient and/or insufficient range of vitamin D level. That’s why patients with 25(OH)D3 deficiency may be considered under higher risk of neovascular AMD and vice versa. We think that 25(OH)D3 levels may have an impact on the neovascular type of AMD, say, the more decrease in 25(OH)D3 levels the more increase in AMD frequency. Such studies may have important implications for the prevention or treatment of neovascular AMD by the regulation of modifiable lifestyle factors that in fluence levels of vitamin. That’s why more studies are needed to verify this association prospectively.


CONTACT DETAILS

Emrah Kan*, Konuralp Yakar, Elif Kiliç Kan, Nurullah Koak
Samsun Training and Educating Hospital
Samsun
Turkey
Email : dremrahkan@yahoo.com
Cell Phone: +905067189319
Work Phone: +903623111500