Effects of long-term consumption of potassium-enriched and low-sodium salt on mortality in nursing home population in northern China - The China Salt Trial, 2021−2018

Objective  To explore the long-term effects of potassium-enriched and low-sodium salt on stroke, cardiovascular disease, and all-cause mortalities in nursing home population.

Methods From 2012 to 2018, a total of 29 nursing homes in counties (distrcts) in northern China were selected, and divided by cluster random sampling into a potassium-enriched low-sodium salt group (intervention group, with a sodium chloride to potassium chloride weight ratio of 1∶1) and a common salt group (control group). Causes of death were determined and recorded by collaborating clinical physicians. Changes in the study cohort and mortality were reported every 3 months, and the risk for death was calculated by using a Cox proportional hazards model.

Results A total of 3543 study subjects were enrolled, with 1887 in the potassium-enriched and low-sodium salt group and 1 656 in the control group. The average follow-up duration was (3.78±1.90) years and (3.48±1.83) years, respectively. During the follow-up period, there were 1065 cases of all-cause death (all-cause mortality rate of 83.06/1 000 person-years), with 588 in the control group (all-cause mortality rate of 89.66/1 000 person-years) and 477 in the potassium-enriched and low-sodium salt group (all-cause mortality rate of 76.16/1 000 person-years). After controlling for age and gender, the hazard ratios (HR) for all-cause mortality, cardiovascular disease mortality (including stroke), and stroke mortality in the study cohort were 0.88 95% confidence interval (CI): 078−1.00, 0.85 (95%CI: 0.71−1.02), and 0.88 (95%CI: 0.70−1.09), respectively. In the the age group 40−70 years, the potassium-enriched and low-sodium salt group showed more significant differences in all-cause mortality rate, cardiovascular disease mortality rate, and stroke mortality rate compared with the control group, with HRs of 0.78 (95%CI: 0.63−0.96), 0.66 (95%CI: 0.49−0.90), and 0.68 (95%CI: 0.47−0.98), respectively.

Conclusion Long-term consumption of potassium-enriched and low-sodium salt is safe and feasible, and in the age group 40−70 years, it can significantly reduce the risk for stroke, cardiovascular disease, and all-cause mortalities, thus reducing premature death.