Empirically derived dietary patterns and diabetes-related foot ulceration among adults with type 2 diabetes: a hospital-based case–control study

Evidence on the relationship between habitual dietary patterns and diabetes-related foot ulceration (DFU) remains limited. We examined associations between empirically derived dietary patterns and DFU among adults with type 2 diabetes. In this hospital-based case–control study, 115 patients with a first-ever DFU and 115 controls without current or previous DFU were recruited in Tehran, Iran. Dietary intake was assessed using a 147-item food-frequency questionnaire administered at enrollment. Cases retrospectively reported intake during the 12 months preceding DFU diagnosis, whereas controls reported intake during the 12 months preceding interview. Principal component analysis of 26 food groups was used to identify dietary patterns, and multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for DFU case status. Two retained dietary patterns explained 22.67% of the variance in the food-group data. A pattern characterized primarily by fish, olives and olive oil, vegetables, and fruits was inversely associated with DFU case status (upper versus lower median score: adjusted OR = 0.05, 95%CI 0.02–0.14). A second pattern characterized by sweets, snack foods, sugar-sweetened beverages, and refined grains was positively associated with DFU case status (adjusted OR = 5.74, 95%CI 2.33–14.12). These findings suggest an association between empirically derived dietary patterns and the odds of DFU in adults with type 2 diabetes. However, retrospective dietary reporting and the hospital-based case–control design limit causal interpretation, and differential recall, and reverse causation, cannot be excluded. Prospective studies are needed to clarify temporality and causality.