Dietary sodium is positively associated with blood pressure, and ecological and animal
studies both have suggested that high dietary sodium intake increases stroke mortality.
To examine the risk of cardiovascular disease associated with dietary sodium intake
in overweight and nonoverweight persons.
Prospective cohort study.
The first National Health and Nutrition Examination Survey Epidemiologic Follow-up
Study, conducted in 1982-1984, 1986, 1987, and 1992.
Of those aged 25 to 74 years when the survey was conducted in 1971 -1975 (14407 participants),
a total of 2688 overweight and 6797 nonoverweight persons were included in the analysis.
Dietary sodium and energy intake were estimated at baseline using a single 24-hour
dietary recall method. Incidence and mortality data for cardiovascular disease were
obtained from medical records and death certificates.
For overweight and nonoverweight persons, over an average of 19 years of follow-up,
the total number of documented cases were as follows: 680 stroke events (210 fatal),
1727 coronary heart disease events (614 fatal), 895 cardiovascular disease deaths,
and 2486 deaths from all causes. Among overweight persons with an average energy intake
of 7452 kJ, a 100 mmol higher sodium intake was associated with a 32% increase (relative
risk [RR], 1.32; 95% confidence interval [CI], 1.07-1.64; P = .01) in stroke incidence,
89% increase (RR, 1.89; 95% CI, 1.31-2.74; P<.001) in stroke mortality, 44% increase
(RR, 1.44; 95% CI, 1.14-1.81; P = .002) in coronary heart disease mortality, 61% increase
(RR, 1.61; 95% CI, 1.32-1.96; P<.001) in cardiovascular disease mortality, and 39%
increase (RR, 1.39; 95% CI, 1.23-1.58; P<.001) in mortality from all causes. Dietary
sodium intake was not significantly associated with cardiovascular disease risk in
nonoverweight persons.
Our analysis indicates that high sodium intake is strongly and independently associated
with an increased risk of cardiovascular disease and all-cause mortality in overweight
persons.