Mechanistic Pathways Linking Ultra-Processed Food Consumption and Hypertension in Nigerian Adults: A Mediation Analysis

Ultra-processed food consumption has been prospectively associated with hypertension in high-income country cohorts, but the biological mechanisms underlying this relationship, including adiposity, dietary sodium, added sugar, dietary inflammatory potential, and gut dysbiosis pathways, have not been mechanistically tested in a Nigerian adult population. This study examines mechanistic pathways linking ultra-processed food consumption and incident hypertension in a prospective cohort of adults in Enugu and Lagos States, South South and South West Nigeria. A cohort of 1,600 normotensive adults aged 25 to 55 years was enrolled and followed for three years with annual assessments. Ultra-processed food intake was quantified using the NOVA classification applied to a semi-quantitative food frequency questionnaire administered at each wave. Blood pressure was measured at each visit using a validated automated device following standardised protocol, with incident hypertension defined as systolic pressure above or equal to 140 or diastolic pressure above or equal to 90 millimetres of mercury at two consecutive visits. Proposed mediators measured at baseline and annual intervals included body mass index, waist circumference, 24-hour urinary sodium, dietary inflammatory index score, fasting triglycerides, homeostatic model assessment of insulin resistance, and gut microbiota alpha diversity. Causal mediation analysis using the counterfactual framework decomposed total effects into direct and indirect pathways through each mediator. This study provides the first mechanistic pathway analysis linking ultra-processed foods and hypertension in a Nigerian cohort, producing original evidence for both the causal diagram and intervention targeting in Nigerian cardiovascular nutrition. Keywords: ultra-processed foods, hypertension, mediation analysis, mechanistic pathways, Nigerian cohort.