Effect of Dietary Patterns on the Risk of Type 2 Diabetes Among Adults in Lagos State: A Case-Control Study

The incidence of type 2 diabetes mellitus is rising rapidly across Nigerian urban centres, with dietary transition identified as a critical modifiable risk factor. Despite growing evidence globally, empirical data linking specific dietary patterns to diabetes risk in Lagos State remain sparse. This study examined the effect of dietary patterns on the risk of type 2 diabetes among adults aged thirty to sixty years in Lagos State, South West Nigeria, using a case-control design. Two hundred adults with confirmed type 2 diabetes diagnosis were matched with 200 controls of comparable age and sex at four tertiary health facilities. Dietary patterns were derived using principal component analysis of food frequency questionnaire data. Multivariate logistic regression was employed to assess associations between dietary pattern scores and diabetes risk, controlling for physical activity, BMI, family history, and socioeconomic status. Three dominant dietary patterns were identified: a traditional plant-based pattern, a Western pattern characterised by high consumption of refined carbohydrates and processed meats, and a mixed pattern. Adherence to the Western dietary pattern was significantly associated with elevated diabetes odds after full covariate adjustment. The traditional plant-based pattern was inversely associated with risk. BMI mediated a substantial proportion of the effect. These findings underscore the need for population-level dietary guidance and targeted screening in Lagos State. Keywords: type 2 diabetes, dietary patterns, case-control, Lagos State, principal component analysis