A feasibility study for a trial testing the effects of reduced-sodium salt on the rise in blood pressure with age

Background and aims: Excess sodium intake is associated with elevated blood pressure, a major risk factor for cardiovascular disease. Lowering sodium intake by switching regular salt for reduced-sodium salt may attenuate rises in blood pressure with age. We aimed to assess project feasibility in Nigeria before testing in a large-scale clinical trial. Methods and results: We conducted an unblinded, non-randomised feasibility study in two rural Nigerian communities between March and May 2024. Participants (≥6 years) were recruited at the household level and provided with reduced-sodium salt (66 % KCl, 34 % NaCl) to replace all regular salt for cooking and seasoning over two months. Outcomes included recruitment rate, adherence and acceptability of the reduced-sodium salt, adherence to study procedures, and willingness to participate in a longer-term study. 41 households (148 participants) were recruited over five days. The median age of children, adolescents, and adults were 7, 11, and 35 years respectively, and 55 % were female. Nine participants (6 %) were lost to follow-up at 2-months (including two households), but 98 % of the scheduled follow-up visits were completed. At 2-months, 83 % of participants reported replacing all regular salt with reduced-sodium salt and most participants reported it was similar or better than regular salt for taste (94 %) and overall acceptability (93 %). All participants indicated willingness to engage in a 4-year study. Conclusion: It is feasible to conduct a large-scale clinical trial in Nigeria testing the effects of reduced-sodium salt compared to regular salt on the rise in blood pressure with age. Trial registration: NCT05912426.