Analyses on effect on blood pressure
The primary analysis on the effect on blood pressure was assessed among participants who had at least one blood pressure measurement during follow-up (1219 participants). The model for analysis pre-specified in the statistical analysis plan (SAP) was a linear mixed model [Secondary analyses on the intervention effect on blood pressure were done with per-protocol analysis (1195 participants); multiple imputation for missing follow-up values (1612 participants); and adjustment for age, sex, and region (1219 participants), with exclusion of data from facilities in Xi’an (1019 participants), according to the pre-defined statistical analysis plan.Possible variation in intervention effect by season was explored using a linear mixed model that allows the effect of intervention to vary by season (see Additional file 