Sodium intake, life expectancy, and all-cause mortality

Abstract

Aims: Since dietary sodium intake has been identified as a risk factor for cardiovascular disease and premature death, a high sodium intake can be expected to curtail life span. We tested this hypothesis by analysing the relationship between sodium intake and life expectancy as well as survival in 181 countries worldwide.

Methods and results: We correlated age-standardized estimates of country-specific average sodium consumption with healthy life expectancy at birth and at age of 60 years, death due to non-communicable diseases and all-cause mortality for the year of 2010, after adjusting for potential confounders such as gross domestic product per capita and body mass index. We considered global health estimates as provided by World Health Organization. Among the 181 countries included in this analysis, we found a positive correlation between sodium intake and healthy life expectancy at birth (β = 2.6 years/g of daily sodium intake, R2 = 0.66, P < 0.001), as well as healthy life expectancy at age 60 (β = 0.3 years/g of daily sodium intake, R2 = 0.60, P = 0.048) but not for death due to non-communicable diseases (β = 17 events/g of daily sodium intake, R2 = 0.43, P = 0.100). Conversely, all-cause mortality correlated inversely with sodium intake (β = -131 events/g of daily sodium intake, R2 = 0.60, P < 0.001). In a sensitivity analysis restricted to 46 countries in the highest income class, sodium intake continued to correlate positively with healthy life expectancy at birth (β = 3.4 years/g of daily sodium intake, R2 = 0.53, P < 0.001) and inversely with all-cause mortality (β = -168 events/g of daily sodium intake, R2 = 0.50, P < 0.001).

Conclusion: Our observation of sodium intake correlating positively with life expectancy and inversely with all-cause mortality worldwide and in high-income countries argues against dietary sodium intake being a culprit of curtailing life span or a risk factor for premature death. These data are observational and should not be used as a base for nutritional interventions.

Keywords: Sodium intake • Salt • Diet • Life expectancy • All-cause mortality • Cardiovascular disease • Hypertension • Blood Pressure.

Graphical abstract

Figure 1

Distribution of quintiles of sodium intake (g/day) (A) and healthy life expectancy at birth (B) for the year of 2010 in 181 countries worldwide.

Figure 2

Scatterplots of sodium intake (g/day) for the year of 2010 and healthy life expectancy at birth, healthy life expectancy at age 60, age-standardized death rates of death due to non-communicable diseases and all-cause mortality in 181 countries worldwide (A–D, respectively).

Figure 3

Scatterplots of sodium intake (g/day) for the year of 2010 and healthy life expectancy at birth, healthy life expectancy at age 60, age-standardized death rates of death due to non-communicable diseases and all-cause mortality in 46 high-income countries (A–D, respectively).

Figure 4

Quantile regression of sodium intake (g/day) in 181 countries worldwide for the year of 2010 and healthy life expectancy at birth (A), healthy life expectancy at age 60 (B), age-standardized death rates of death due to non-communicable diseases (C) and all-cause mortality (D) adjusted for gross domestic product per capita and age-standardized body mass index.

Figure 5

Quantile regression of sodium intake (g/day) in 46 high-income countries for the year of 2010 and healthy life expectancy at birth (A), healthy life expectancy at age 60 (B), age-standardized death rates of death due to non-communicable diseases (C), and all-cause mortality (D) adjusted for gross domestic product per capita and age-standardized body mass index.