Effect of salt substitution on fracture—a secondary analysis of the Salt Substitute and Stroke Study (SSaSS)

Abstract Background Associations of dietary sodium and potassium intake with fracture risk are inconsistent and the effects of salt substitute on fracture incidence are unknown. We assessed the effect of salt substitute compared to regular salt intake on fracture incidence using data from the Salt Substitute and Stroke Study (SSaSS). Methods SSaSS was a cluster-randomized controlled trial conducted in 600 villages in northern China. Villages were randomly allocated into intervention and control groups in a 1:1 ratio. Salt substitute was provided to intervention villages and control villages continued regular salt use for 5 years. The primary outcome for this secondary analysis was the incidence of all fractures. Secondary outcomes included incidence of vertebral fracture, non-vertebral fracture, and fracture of unknown or non-specific location. Results 20,995 participants were included in this study, and 821 fractures occurred during follow-up. Intention-to-treat analyses showed no differences between the salt substitute and regular salt groups in the incidence of all fractures (rate ratio (RR) 0.96; 95% CI 0.81 to 1.14), vertebral fracture (RR 0.82; 95% CI 0.53 to 1.26), non-vertebral fracture (RR 1.05; 95% CI 0.86 to 1.29), or fracture of unknown or non-specific location (RR 0.80; 95% CI 0.54 to 1.18). Conclusions Use of salt substitute compared to regular salt had no detectable effect on the incidence of fracture in a population at high risk of cardiovascular disease and fracture. Trial registration ClinicalTrials.gov, NCT02092090. Registered on March 12, 2014.