Dietary sodium, potassium, saturated fat, alcohol, and stroke mortality

Although positive relationships between blood pressure, dietary sodium, and stroke risk have been reported, studies on the relationship between dietary sodium and stroke mortality are scarce. A significant relationship between dietary saturated fatty acids (SFA) and stroke risk has not been reported in epidemiological studies. The purpose of this study was to examine the relationship between dietary sodium and SFA together with dietary potassium, alcohol, and stroke risk.

The sex- and age-specific stroke mortality rates (log-transformed) for the age classes 45 to 54, 55 to 64, and 65 to 74 years for the period between 1986 and 1988 were obtained from World Health Organization statistics. The 24-hour urinary excretion levels of sodium (U-Na) and of potassium (U-K), dietary SFA intake levels, and alcohol consumption levels were obtained from dietary surveys performed in 17 countries. The relationships between stroke mortality and the dietary variables were examined by Pearson correlation and multiple regression analysis.

The highest degree of correlation, both in Pearson correlation and multiple regression analysis, was found between U-Na and log-stroke mortality (P < .01 to P < .001). In multiple regression analysis, U-Na (P < .01 to P < .001), SFA (P < .05 to P < .01), and alcohol (P < .05) independently, significantly, and positively correlated with log-stroke mortality rates, and U-K correlated negatively (P < .05). The exceptions were SFA in both sexes in the age class 45 to 54 years, alcohol in both sexes in the age class 45 to 54 years and in women in the age class 55 to 64 years, and U-K in women in the age class 65 to 74 years.

These results suggest that dietary factors, especially sodium and SFA, are of primary importance as determinants of stroke mortality at the population level.