Abstract

Background: There is limited understanding of the effect of salt types on the progression of cardiovascular disease (CVD) and their longevity, due to previous evidence from cross-sectional studies. The purpose of this study was to evaluate the association of type of salt with CVD and all-cause mortality in the American population by using a prospective design. Methods: The National Health and Nutrition Examination Survey (NHANES) is a large, complex, public health survey of the US population. Weighted Cox proportional hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated to evaluate the association of type of salt with CVD and all-cause mortality, using data from NHANES 2006-2018 linked with mortality data obtained in December 31, 2019. Results: Among 29416 participants (aged ≥20 years, 47.53% male), 2562 deaths were recorded (717 from CVD) during a median follow-up of 7.6 years. In multivariable-adjusted models, ordinary salt decreased the risk of CVD and all-cause mortality by 25% and 10%, compared with no using salt. HRs (95% CIs) were 0.75 (0.64 - 0.89) and 0.90 (0.81, 0.99), respectively. Similarly, compared to no using salt, salt substitute was negatively associated with CVD and all-cause mortality, decreasing risk of CVD and all-cause mortality by 55% and 28%. HRs (95% CIs) were 0.45 (0.22 - 0.93) and 0.72 (0.52, 0.98), respectively. The stratification analyses showed association of ordinary salt and salt substitutes with CVD and all-cause mortality depend on irreversible age, unhealthy habits, and pre-existing chronic diseases. Conclusions: Moderate dietary salt intake was essential to alleviate CVD and all-cause mortality, and supported adding appropriate salt to food to meet human needs. Although salt is essential to an organism's survival, excessive salt intake significantly impacts individual and population health. Salt substitute should be promoted appropriately as a strategic healthcare program.