Popular Drink Increases Stroke Risk

A new study by University of Miami Miller School of Medicine researchers link diet soda to increased risk of vascular events, including stroke. The research was presented during the American Stroke Association’s International Stroke Conference, February 1-3, 2011 in Los Angeles.

In the study, the scientists found that if you drink diet soda – instead of the sugar variety – you could still have a much higher risk of vascular events compared to those who do not drink soda. In findings involving 2,564 people in the large, multi-ethnic Northern Manhattan Study, the researchers said people who drank diet soda every day had a 61 percent higher risk of vascular events than those who reported no soda drinking.

“If our results are confirmed with future studies, then it would suggest that diet soda may not be the optimal substitute for sugar-sweetened beverages for protection against vascular outcomes,” said Hannah Gardener, Sc.D., lead author and epidemiologist in the Department of Neurology at the Miller School.

The Northern Manhattan Study is a collaboration of investigators at the Miller School and Columbia University in New York launched in 1993 to examine stroke incidence and risk factors in a multi-ethnic urban population.

At the start of the study, researchers asked subjects to report how much and what kind of soda they drank. Based on the data, they grouped participants into seven consumption categories: no soda (meaning less than one soda of any kind per month); moderate regular soda only (between one per month and six per week); daily regular soda (at least one per day); moderate diet soda only; daily diet soda only; and two groups of people who drink both types: moderate diet and any regular, and daily diet with any regular.

During an average follow-up of 9.3 years, 559 vascular events occurred (including ischemic and hemorrhagic stroke, which is caused by rupture of a weakened blood vessel). Researchers accounted for participants’ age, sex, race or ethnicity, smoking status, exercise, alcohol consumption and daily caloric intake. And even after researchers also accounted for patients’ metabolic syndrome, peripheral vascular disease and heart disease history, the increased risk persisted at a rate 48 percent higher.

The fact that participants reported their dietary behavior is a key limitation of both studies, Gardener said.

In the soda study, investigators also lacked data on types of diet and regular drinks consumed, preventing analysis of whether variations among brands or changes over time in coloring and sweeteners might have played a role.

Miller School co-authors are Tatjana Rundek, Clinton Wright, and Ralph L. Sacco.

Source : Miller School of Medicine, University of Miami