Daily quaffing of diet soda heightens vascular-event risk in cohort study

Allison Gandey

February 10, 2011

Los Angeles, CA - Artificially sweetened "diet" soda may not be the healthier alternative many had hoped: an observational study suggests the popular drinks may increase the risk of stroke, MI, and vascular death [1].

Dr Hannah Gardener

"People who had diet soda every day experienced a 61% higher risk of vascular events than those who reported drinking no soda," lead investigator Dr Hannah Gardener (University of Miami, FL) told reporters attending a news conference here at the International Stroke Conference 2011 sponsored by the American Stroke Associati on (ASA).

Previous studies have suggested a link between diet-soda consumption and the risk of metabolic syndrome and diabetes. But the current analysis from the Northern Manhattan Study is the first study to show such an association between diet soft drink consumption and hard vascular-disease end points, according to ASA national spokesperson Dr Larry Goldstein (Duke University Stroke Center, Durham, NC).

"This is an observational study and not a prospective randomized trial," he pointed out. "This is an association and not yet a proven causal relationship."

Still, Goldstein said, "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."

More than 2500 people from the multiethnic cohort study were asked to report how much and what kind of soda they drank. Over an average follow-up of 9.3 years, there were 559 vascular events, including both ischemic and hemorrhagic strokes.

The researchers also observed a marginally significant increased risk of vascular events among those who consumed diet soda daily and regular soda once or more a month (adjusted relative risk 1.74; 95% CI 0.96-3.16).

After researchers controlled for metabolic syndrome, peripheral vascular disease, and cardiac disease history, daily consumption of diet soda posed a 1.48 (95% CI 1.03-2.12) relative risk of vascular events compared with no soda intake.

The potential mechanisms for any association between diet soda and vascular events remain unknown, according to the investigators, who acknowledge that additional studies are needed.

What should clinicians advise patients based on the information that is known today? Dr Steven M Greenberg (Massachusetts General Hospital, Boston), vice chair of the meeting's program committee, proposes that patients start by concentrating on a healthy diet and regular exercise. "Once the metabolic syndrome is under control [along with] any risk of diabetes, then we can consider cutting back on soda consumption."

In an interview, Greenberg proposed also that people shouldn't rush to stop consuming diet soft drinks. "I do think this is a wake-up call, though, 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 declared they have no relevant financial relationships.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.