To evaluate the association between grape intake and diabetic retinopathy.

A population-based cross-sectional study using a nation-wide, stratified, multistage, clustered sampling method included 1,555 subjects aged ≥30 years who participated in the Korean National Health and Nutritional Examination Survey 2008-2011. All participants performed standardized interviews, food frequency questionnaires (FFQ), and comprehensive ophthalmic examinations. Grape intake was evaluated by an FFQ using 10 intervals of average frequency of grape intake during the past year. Diabetic retinopathy (DR) was evaluated by 7 standard retinal fundus photographs after pharmacological pupil dilatation. DR was classified as any DR, proliferative DR, or vision-threatening DR by the modified Air House classification system.

The prevalence of diabetes was 16.9 ± 1.2%. As the grape intake frequency increases in FFQ, the odds ratio (OR) for any DR, proliferative DR, and vision-threatening DR were 0.86 (95% confidence interval [CI], 0.75-0.98), 0.65 (95% CI, 0.48-0.88), and 0.77 (95% CI, 0.60-0.99) respectively. Compared to the group with a grape intake of less than once per month, the OR for any DR, proliferative DR, and vision-threatening DR in the group with a grape intake of more than 2-3 times per month were 0.54 (95% CI 0.33-0.89), 0.25 (95% CI 0.07-0.81), 0.36 (95% CI 0.13-0.95), respectively.

The intake of grapes was inversely associated with the prevalence of DR.