There was a negative linear relationship between the level of vitamin D3 and the risk of diabetic retinopathy among adults in the United States.
Key Findings
Results
Higher serum vitamin D3 levels were significantly associated with lower odds of diabetic retinopathy after accounting for potential confounders.
OR: 0.995 (95% CI: 0.992–0.999; P = .0237) per unit increase in vitamin D3
Total sample size was 1,978 participants from the National Health and Nutrition Examination Survey (NHANES)
Multivariable logistic regression was the primary analytical method used
Vitamin D3 data were obtained from serum samples; DR data were obtained via physician-administered questionnaire
Results
Participants in the highest tertile of vitamin D3 had significantly lower odds of diabetic retinopathy compared to those in the lowest tertile.
T1 group (≤46.50 nmol/L or equivalent units) served as the reference group
T3 group (≥74.50) had a fully adjusted OR of 0.617 (95% CI: 0.455–0.837; P = .0019)
This represents approximately a 38% lower odds of DR in the highest versus lowest tertile
Adjustment for potential confounders was applied in the fully adjusted model
Results
The relationship between vitamin D3 and diabetic retinopathy was linear rather than nonlinear.
Restricted cubic splines (RCS) analysis was used to assess the shape of the dose-response relationship
Nonlinearity test P-value = .836, indicating no significant departure from linearity
The linear negative trend was consistent across the range of vitamin D3 values observed in the study population
Methods
The study used stratified analysis with interaction testing in addition to primary regression models.
Main analytical methods included multivariable logistic regression, stratified analysis with interaction, and restricted cubic splines (RCS)
Data were drawn from the National Health and Nutrition Examination Survey (NHANES), a nationally representative U.S. survey
The cross-sectional study design limits causal inference
DR status was ascertained via physician questionnaire rather than clinical examination or imaging
Background
Prior literature on the association between vitamin D3 and diabetic retinopathy has produced conflicting results.
Some prior studies reported a protective effect of vitamin D3 against DR
Other studies reported no significant effect
The authors positioned this NHANES-based analysis as addressing these conflicting findings in a U.S. adult population
The study specifically examined vitamin D3 (cholecalciferol) measured from serum samples
What This Means
This research suggests that higher levels of vitamin D3 in the blood are associated with a lower likelihood of having diabetic retinopathy (DR), a serious eye complication of diabetes that can lead to vision loss. Using data from nearly 2,000 American adults in a large national health survey (NHANES), the researchers found that people with the highest levels of vitamin D3 were about 38% less likely to have diabetic retinopathy compared to those with the lowest levels. This association followed a straight-line (linear) pattern, meaning the benefit appeared to increase steadily as vitamin D3 levels rose, rather than leveling off or changing direction at some threshold.
The study used several statistical methods to account for other factors that could influence the results, and the negative association between vitamin D3 and diabetic retinopathy held up after these adjustments. Importantly, this adds to a body of research that has produced mixed findings on whether vitamin D3 is protective against DR, with this study coming down on the side of a meaningful association.
Because this was a cross-sectional study — meaning it looked at one point in time rather than following people over years — it cannot prove that vitamin D3 directly causes a reduction in diabetic retinopathy risk. Additionally, DR was identified through patient questionnaires rather than formal eye examinations, which may affect accuracy. This research suggests a potentially meaningful link between vitamin D3 status and eye health in people with diabetes, warranting further investigation through longer-term studies.
Qin M, Zhang N, Zhang L, Zhao S, Feng N. (2026). Association of vitamin D3 and diabetic retinopathy in US adults: A cross-sectional study.. Medicine. https://doi.org/10.1097/MD.0000000000050563