Reducing sodium, increasing potassium intake may cut CV risk
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Higher sodium intake, measured in multiple 24-hour urine samples, was associated with greater risk for CVD in a dose-response manner, researchers reported at the American Heart Association Scientific Sessions.
Moreover, lower intake of potassium and higher sodium-to-potassium ratio were also associated with greater risk.
“Our study offers new insights concerning current methodological challenges in sodium assessment. A single measurement is not sufficient to reflect a person’s usual sodium intake owing to large day-to-day variations in sodium consumption and excretion,” Yuan Ma, PhD, research scientist at Harvard T.H. Chan School of Public Health, and colleagues wrote in a simultaneous publication in The New England Journal of Medicine.
Ma said it is challenging to collect multiple 24-hour urine samples. Prior observational studies have assessed sodium intake using methods that are prone to measurement errors, including spot urine or single 24-hour hour samples that can be unreliable for estimating an individual’s usual sodium intake. These methodological limitations “have led to confusion about whether reducing current levels of sodium in the diet increases CVD risk,” Ma said in a press release issued by Harvard T.H. Chan School of Public Health.
The researchers analyzed individual sodium and potassium excretion data from 10,709 generally healthy individuals (mean age, 51.5 years; 54% women) with multiple 24-hour urine samples from six prospective cohorts. The median 24-hour sodium excretion in approximately 38,000 urine samples was 3,270 mg. Estimated daily intake of sodium was 3,516 mg and of potassium was 3,292 mg.
Over a median follow-up of nearly 9 years, 571 incident CV events occurred across the cohort studies (incidence rate, 5.9 per 1,000 person-years). The incident events included 445 CHD events (232 MIs, 213 coronary revascularizations), 136 stroke events and 12 additional deaths related to CV causes, according to the results.
Ma reported that higher 24-hour urinary sodium excretion was associated with elevated risk for CVD after adjustment for potential confounding factors. The HR for the highest quartile (median, 4,692 mg) vs. lowest quartile (median, 2,212 mg) of the urinary biomarker was 1.6 (95% CI, 95% CI, 1.19-2.14).
“Risk of CVD goes up gradually with higher sodium excretion, showing a clear dose-response association,” Ma said during the presentation.
Higher 24-hour urinary potassium excretion was associated with lower risk for CVD (aHR for highest quartile [median, 3,501 mg] vs. lowest quartile [median, 1,755 mg] = 0.69; 95% CI, 0.51-0.91), according to the results.
Each daily increase of 1,000 mg in sodium excretion was associated with an 18% increase in CVD risk, while each daily increase of 1,000 mg in potassium secretion was associated with an 18% decrease in risk, Ma said. Further, each unit increase in sodium-to-potassium ratio was associated with a 24% increase in CVD risk.
The associations remained consistent in subgroup analyses based on age, sex, weight, hypertension status and duration of follow-up.
“These findings support reducing sodium and increasing potassium intakes from current levels in most populations to lower CVD risk,” Ma said during the presentation.
The study combined data from the following six cohorts: Health Professionals Follow-up Study (HPFS), Nurses’ Health Study (NHS), Nurses’ Health Study II (NHS II), Prevention of Renal and Vascular End-Stage Disease (PREVEND) study and the Trials of Hypertension Prevention (TOHP I and TOHP II) Follow-up Studies.
“Although we acknowledge the challenges in collecting 24-hour urine samples, we do believe that to inform the policy on salt reduction and related strategies worldwide ... it is important to focus on the evidence that’s derived from studies with accurate sodium assessments,” Ma said.
Reference:
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Ma Y, et al. Salty Details on the Relationship Between Sodium and Heart Disease. Presented at: American Heart Association Scientific Sessions; Nov. 13-15, 2021 (virtual meeting).
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