Longitudinal Change of Perceived Salt Intake and Stroke Risk in a Chinese Population

Background and Purpose Data for a relationship between salt intake and stroke have been inconsistent. This inconstancy could be because of the majority of studies evaluated salt intake at a single time point, which may be insufficient to accurately characterize salt intake throughout the observation period. Methods Included were 77605 participants from the Kailuan study. We assessed perceived salt intake via questionnaire in 2006, 2008, and 2010. Salt intake trajectories from 2006 to 2010 were identified using latent mixture models. Incident stroke cases were identified from 2010 to 2015 and confirmed by review of medical records. Cox proportional hazards model was used to examine the association between salt intake trajectories and stroke risk after adjusting for possible confounders, including age, sex, lifestyle, social economic status, body mass index, use of medicines, blood pressure, and lipoprotein profiles. Results Identified were 5 distinct salt intake trajectories: moderate-stable (n=59241), moderate-decreasing (n=9268), moderate-increasing (n=2975), low-increasing (n=2879), and high-decreasing (n=3242). During the 5-year follow-up period, there were 1564 incident strokes cases. Compared with individuals with the moderate-stable salt intake trajectory, individuals with moderate-decreasing salt intake trajectory had significantly lower cerebral infarction stroke risk (adjusted hazard ratio, 0.76; 95% confidence interval, 0.63-0.92) but not intracerebral hemorrhage risk (adjusted hazard ratio, 0.84; 95% confidence interval, 0.55-1.29). Further adjustment for 2006 or 2010 perceived salt intakes generated similar results. When baseline perceived salt intake only was used as the exposure, a significant dose-response relationship between higher perceived salt intake and higher stroke risk was observed (P trend=0.006). Conclusions Change in salt intake was associated with the stroke risk. These data support the dietary recommendation to the reduction of salt intake.