Adequate vitamin D status is associated with the reduced odds of prevalent diabetic retinopathy in African Americans and Caucasians

Abstract

BackgroundVitamin D status has been hypothesized to protect against development of diabetic retinopathy via its anti-inflammatory and anti-angiogenic properties. Additionally, in vitro and in vivo studies suggest vitamin D favorably influences blood pressure and blood glucose control, strong risk factors for diabetic retinopathy. We examined the association between vitamin D status and prevalent diabetic retinopathy in participants with diabetes from a population-based cohort.MethodsAmong participants in the Atherosclerosis Risk in Communities (ARIC) study with diabetes at visit 3 (1993–1995), 1339 (906 Caucasians, 433 African Americans) had serum 25-hydroxyvitamin (25[OH]D) concentrations assessed at visit 2 (1989–1992) and nonmydriatic retinal photographs taken at visit 3. Dietary intake of vitamin D was assessed at visit 1 (1987–1989). Logistic regression was used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) for diabetic retinopathy by categories of season-adjusted 25(OH)D (<30 [referent], 30–<50, 50–<75 and ≥75 nmol/L), by quartile of vitamin D intake (IU/day), and use of vitamin D or fish oil supplements (yes/no). P for trend was estimated using continuous 25(OH)D or vitamin D intake. ORs were adjusted for race, and duration of diabetes. We further adjusted for HBA1c and hypertension to examine if 25(OH)D influenced diabetic retinopathy via its effects on either glycemic control or blood pressure.ResultsORs (95 % CIs) for retinopathy, adjusted for race and duration, were 0.77 (0.45–1.32), 0.64 (0.37–1.10), and 0.39 (0.20–0.75), p for trend = 0.001, for participants with 25(OH)D of 30–<50, 50–<75, and ≥75 nmol/L, respectively. Further adjustment for hypertension minimally influenced results (data not show), but adjustment for HBA1c attenuated the OR among those with 25(OH)D ≥75 (0.47 [0.23–0.96], p for trend = 0.030). No statistically significant association was observed between vitamin D intake from foods or supplements and retinopathy.Conclusions25(OH)D concentrations ≥75 nmol/L were associated with lower odds of any retinopathy assessed 3 years later. We speculate this may be due in part to vitamin D’s influence on blood glucose control.Electronic supplementary materialThe online version of this article (doi:10.1186/s12933-016-0434-1) contains supplementary material, which is available to authorized users.

Could Vitamin D be Associated with Proliferative Diabetic Retinopathy? Evidence from Pooling Studies

“…Some studies have opposite results. Millen et al [9] found that, after follow-up for 3 years, compared to patients with serum 25OHD < 30 nmol/l, patients with serum 25OHD ≥ 75 nmol/l had significant lower risk of DR after adjustment for covariates [OR 0.47 (95 % CI 0.23-0.96)], while no statistically significant association was observed between vitamin D and PDR. A prospective study of 936 type 2 diabetic patients also failed to yield a significant association between vitamin D status and the onset or progression of PDR after follow-up for 5 years [10].…”

“…Vitamin D is considered as a dichotomous variable (VDD vs. non-VDD). Data regarding effect of vitamin D deficiency on DR were available from twelve trials plus our study conducted [6,9,[17][18][19][20][21][22][23][24][25][26]. Risk of DR in VDD individuals might rise by 35 %, compared with non-VDD (OR = 1.35, 95 % CI 1.11-1.64) (▶ Fig.…”

“…In human studies, an inverse association between 25(OH)D levels and prevalence and severity of DR has been shown [6,9], but other researches conflict the results [10]. In addition, the effectiveness of individual studies could be reduced to evaluate the relationship due to the broad range of circulating 25(OH)D levels.…”

Association of Vitamin D and Diabetic Retinopathy in Patients with Type 2 Diabetes Mellitus

“…In addition to the classical role in skeleton and bone health, vitamin D (VD) has been identified to exert non-classical pleiotropic e f f e c t s s u c h a s a n t i -i n fl a m m a t o r y, a n t i a n g i o g e n i c , a n t i p r o l i f e r a t i v e , a n d immunomodulatory properties (5). It is also considered to positively regulate hypertension and blood glucose levels (6). Moreover, it has been established that maintaining VD at adequate levels can be a useful technique to prevent type 2 diabetes mellitus (T2DM) (7).…”

Vitamin D Deficiency Increases the Risk of Diabetic Retinopathy: A Meta-Analysis of Observational Studies

“…Accumulating evidence from some epidemiologic studies suggest that vitamin D status may be a novel modifiable risk factor for DR [6,7,[24][25][26]. There is some experimental evidence on the preventive effect of vitamin D in the development of DR in a rodent model, In vitro and in vivo studies suggested that vitamin D affects blood pressure and blood glucose control, which are the strong risk factors for DR [5].…”