Dietary Sodium a Risk Factor for Ischemic Stroke

Allison Gandey

February 09, 2011

February 9, 2011 (Los Angeles, California) — Sodium has already been linked to vascular disease, but a new study suggests that excessive intake may also heighten ischemic stroke risk.

"People who consumed more than 4000 mg per day of sodium had more than double the risk of stroke compared to those who consumed less than 1500 mg," lead investigator Hannah Gardener, ScD, an epidemiologist from the University of Miami Miller School of Medicine in Florida, told reporters attending a news conference here at the International Stroke Conference.

Dr. Hannah Gardener

"The data behind sodium consumption is pretty strong and persuasive," said American Stroke Association national spokesperson Larry Goldstein, MD.

The researchers looked at 2657 people from the multiethnic Northern Manhattan Study. Participants completed a food-frequency questionnaire, and investigators calculated total daily sodium intake by using DietSys software (National Cancer Institute).

During a mean follow-up of 9.7 years, 187 ischemic strokes occurred.

Investigators found that stroke risk, independent of hypertension, increased 16% for every 500 mg of sodium consumed a day.

Those numbers included adjustments for age, sex, race and ethnicity, education, alcohol use, exercise, daily caloric intake, smoking, diabetes, cholesterol, blood pressure, and previous heart disease.

Those consuming 4000 mg or more had a hazard ratio of 2.29 (95% confidence interval, 1.07 - 4.92).

The majority of the cohort, 88%, consumed more sodium than the American Heart Association recommendation of less than 1500 mg a day. US Dietary Guidelines allow for more sodium but still recommend that intake fall below 2300 mg, or about a teaspoon of salt per day.

The average intake was more than double that in the current study at 3031 mg, with a median of 2787 mg daily.

Previous work has suggested that salt consumption hasn't changed much in the United States over the past 50 years and remains too high.

"People need to read the labels of the food they are eating and see what the salt consumption is and at least try to reduce it toward the levels that are currently being recommended," said Dr. Goldstein, from the Duke Stroke Center, in Durham, North Carolina.

"It's clear that small changes in diet can make a huge difference in terms of stroke risk," Steven Greenberg, MD, vice chair of the International Stroke Conference Committee, said at the meeting.

"The evidence from our study may be used in campaigns aimed at reducing cardiovascular risk," Dr. Gardener said. "The new American Heart Association dietary goals will help promote cardiovascular and brain health."

This study was funded by the Javits award from the National Institute of Neurological Disorders and Stroke and the Evelyn McKnight Brain Institute. The researchers have disclosed no relevant financial relationships.

American Stroke Association International Stroke Conference. Abstract #25. News conference February 9, 2011.


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