Patterns and clusters of diet in relation to metabolic syndrome among adults in Ubungo (urban) and Kilindi (rural) districts, Tanzania: a cross-sectional study

The prevalence of Metabolic Syndrome (MetS) is rising worldwide, with particularly high rates in regions undergoing rapid urbanization and dietary change, such as Sub-Saharan Africa (SSA). However, few studies have examined the relationship between dietary patterns, dietary clusters, and MetS in these transitioning communities. To examine the associations between dietary patterns, dietary clusters, and MetS in urban and rural Tanzania. A cross-sectional study was conducted among 379 adults in urban (Ubungo, Dar es Salaam) and rural (Kilindi, Tanga) districts. Data on demographics, medical history, and lifestyle factors were collected using validated tools. Anthropometric, blood pressure, and biochemical measurements followed the WHO STEPS survey protocols. Dietary habits were assessed using a food frequency questionnaire; dietary patterns were derived by principal component analysis (PCA) and dietary clusters by hierarchical clustering on the principal components (HCPC). Logistic regression models were used to assess associations between diet, lifestyle factors, and MetS/MetS components. Principal components analysis identified eight dietary patterns, including mixed, plant-rich, and processed diets. Hierarchical clustering on principal components classified participants into three dietary clusters: rural non-diverse, mixed unhealthy, and urban mixed diets. The prevalence of MetS was 47% (95% CI: 39—54) in urban areas and 38% (95%CI: 32 – 46) in rural areas (p = 0.11). High adherence (quartile 4) to the mixed diet—pattern 1 was associated with MetS. While dietary clusters were not significantly associated with MetS overall, the mixed unhealthy diet (cluster 2) was associated with two MetS components—central obesity and dyslipidemia. The prevalence of MetS is high in both urban and rural Tanzania, with no statistically significant difference between the two settings. Specific mixed unhealthy dietary patterns and clusters were associated with MetS, dyslipidemia and central obesity. Public health measures to address unhealthy dietary patterns and the burden of MetS are needed in both rural and urban Tanzania.