February 9, 2011 (Los Angeles, California) — Diet soda may not be the healthier alternative many had hoped. A new study suggests that the popular drinks may increase the risk for stroke, myocardial infarction, and vascular death.
“People who had diet soda every day experienced a 61% higher risk of vascular events than those who reported drinking no soda,” 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.
The risk persisted after controlling for metabolic syndrome, peripheral vascular disease, and cardiac disease history (relative risk, 1.48; 95% confidence interval, 1.03 – 2.12).
“This is the first report of this association,” said American Stroke Association national spokesperson Larry Goldstein, MD. “I think that it’s always good to do things in moderation. People should look at this information and consider it in the context of their other risk factors.”
The researchers looked at more than 2500 people from the multiethnic Northern Manhattan Study. Participants were asked to report how much and what kind of soda they drank.
During an average follow-up of 9.3 years, 559 vascular events occurred, including ischemic and hemorrhagic stroke.
The researchers also observed a marginally significant increased risk for vascular events among those who consumed diet soda daily and regular soda once or more a month (adjusted relative risk, 1.74; 95% confidence interval, 0.96 – 3.16).
As reported by Medscape Medical News, previous studies have suggested a link between diet soda consumption and the risk for metabolic syndrome and diabetes. But this is the first time diet drinks have been associated with vascular events.
“This is an observational study and not a prospective randomized trial,” Dr. Goldstein, from the Duke Stroke Center, in Durham, North Carolina, pointed out. “This is an association and not yet a proven causal relationship.”
The investigators acknowledge that additional studies are needed. The potential mechanisms for the association between diet soda and vascular events remain unknown.
What should clinicians advise patients on the basis of the information we have today? Steven Greenberg, MD, from Harvard Medical School in Boston, Massachusetts, suggests that patients start by concentrating on a healthy diet and regular exercise. “Once the metabolic syndrome is under control and any risk of diabetes, then we can consider cutting back on soda consumption.” Dr. Greenberg is the vice chair of the International Stroke Conference Committee, and during an interview he suggested that patients shouldn’t rush to eliminate diet drinks.
“I do think this is a wake-up call, though,” he said, “and we need to start paying closer attention.”
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 # P55. News conference February 9, 2011.