Is serum vitamin D associated with diabetic retinopathy and its severity or with diabetes itself ?

CLINICAL RELEVANCE: Vitamin D (VitD) deficiency, which is found in approximately one-third of the population of the world, may play a role in the pathogenesis of diabetic retinopathy. Physicians following diabetes patients should be aware of this relationship and should refer patients to for ophthalmic care for control in a timely manner.

BACKGROUND

Diabetic retinopathy is one of the most common complications of diabetic microvascular disease. VitD deficiency has been implicated in the pathogenesis and progression of diabetes and may have a role in development and severity of diabetic retinopathy. The aim of this study was to examine the relationship of serum VitD and some laboratory parameters with the presence of diabetes and retinopathy.

METHODS

In this study, which has a retrospective epidemiological study design, comprehensive ophthalmologic examination data from the eye clinic, laboratory data from fasting blood tests, and internal medicine outpatient clinic examination data were reviewed. All participants were divided into four groups: 109 healthy controls, and 165 patients with type 2 diabetes of whom 54 did not have retinopathy, 64 had proliferative diabetic retinopathy, and 47 had non-proliferative diabetic retinopathy. Participants were also divided into four groups according to their serum VitD levels. Serum 25(OH)D, HbA1C, creatine, calcium, phosphate, triglyceride, low-density lipoprotein, and high-density lipoprotein levels were evaluated.

RESULTS

In the whole study cohort, 152 (55.5%) were female and 122 (44.5%) were male. A statistically significant difference was observed in VitD between the healthy group and the diabetic and proliferative diabetic retinopathy groups (p ≤ 0.001). However, no significant correlation was observed between the presence of diabetes and retinopathy and serum VitD in logistic regression analyses (p > 0.05).

CONCLUSION

Diabetic patients have lower 25(OH)D than non-diabetic patients and there is no direct relationship between 25(OH)D and the development of diabetic retinopathy.