More Potassium, Less Risk of Stroke in Older Women

The higher a woman’s potassium intake, the lower her risk for all stroke and ischemic stroke, according to the results of a new study published in Stroke.

Looking at a cohort of more than 90,000 postmenopausal women, Arjun Seth, BS, from the department of epidemiology and population health, Albert Einstein College of Medicine, and colleagues found an inverse association between dietary potassium intake and the incidence of ischemic stroke as well as all-cause mortality.

“Because dietary intake of potassium in the United States is well below the recommended intake, these findings are important in suggesting preventive dietary measures to lower the risk of stroke,” the researchers wrote.

Multiple studies have previously reported an association between potassium intake and decreased risk for stroke. However, data were lacking on whether higher potassium intake reduced risk for all types of stroke and what subpopulations might receive the most benefit.

Seth and colleagues used data from the Women’s Health Initiative Observational Study, the largest prospective cohort study of postmenopausal women with long-term follow-up data. Looking at 90,137 women aged 50 to 79 years who had no history of stroke at baseline and were followed for a mean of 11 years, the researchers evaluated self-reported potassium intake and its association with total, ischemic, and hemorrhagic stroke, as well as all-cause mortality. Patients’ dietary potassium intake was divided into quartiles for the comparison.

The average dietary intake among the participants was 2,611 mg/d, with those who reported two or more episodes of physical activity a week having a higher intake.

“The US Department of Agriculture currently recommends that women eat ≥4,700 mg of potassium daily,” the researchers wrote. “In WHI, only 2.8% of women met or exceeded this level.”

The overall incidence of stroke per 1,000 person-years was 3.10 for all stroke, 2.24 for ischemic stroke, and 0.50 for hemorrhagic stroke. The overall incidence of all-cause mortality related to stroke was 11.60. When divided into quartiles, women in the lowest quartile of potassium intake had a higher risk for all stroke, ischemic stroke, and all-cause mortality compared with each of the other three quartiles in unadjusted, age-adjusted, race-adjusted, and hypertension-adjusted models.

In a fully adjusted model, women in the highest quartile of potassium intake had a lower risk for all-cause mortality (HR=0.90; 95% CI, 0.85-0.95), all stroke (HR=0.88; 95% CI, 0.79-0.98), and ischemic stroke (HR=0.84; 95% CI, 0.74-0.96) compared with women in the lowest quartile. No association between potassium intake and hemorrhagic stroke was found.

The researchers also isolated the data according to hypertension status. Women without hypertension had a lower risk for all-cause mortality, all stroke, and ischemic stroke across increasing potassium intake quartiles. However, women with hypertension and a higher potassium intake had a lower risk for all-cause mortality, but there was no association with stroke.

This finding underlines the importance of micronutrients in women, especially as they age. And while it may not be feasible as Ob/Gyns to discuss this fact in depth with your patients, a quick mention of this may help reiterate what other health care providers are telling them. Receiving this message from multiple health care providers may lend credibility to the advice and could lead to patients being more proactive about their health.