Older women who drink more than two diet drinks a day may be more likely to have a heart attack, stroke or other cardiovascular problems, according to a recent study.

Research presented at the American College of Cardiology's 63rd Annual Scientific Session suggests that postmenopausal women who drink two or more diet drinks a day were 30 percent more likely to suffer a cardiovascular event and 50 percent more likely to die from related disease compared to women who never or rarely consume diet drinks, according to a press release.

"Our findings are in line with and extend data from previous studies showing an association between diet drinks and metabolic syndrome," Ankur Vyas, lead investigator of the study, said in a statement. "We were interested in this research because there was a relative lack of data about diet drinks and cardiovascular outcomes and mortality."

For the study, researchers analyzed diet drink intake and cardiovascular risk factors from more than 59,000 participants in the Women's Health Initiative Observational Study. Information on women's consumption of diet drinks was obtained through a questionnaire that asked them to report their diet drink consumption habits over the previous three months.

After following p with the study participants for 8.7 years, a composite of incident coronary heart disease, congestive heart failure, heart attack, coronary revascularization procedure, ischemic stroke, peripheral arterial disease and cardiovascular death -- occurred in 8.5 percent of the women consuming two or more diet drinks a day compared to 6.9 percent in the five-to-seven diet drinks per week group; 6.8 percent in the one-to-four drinks per week group; and 7.2 percent in the zero-to-three per month group, according to a press release.

The association between diet drinks and cardiovascular risks persisted even after researchers adjusted the data to account for demographic characteristics and other cardiovascular risk factors and comorbidities, including body mass index, smoking, hormone therapy use, salt intake and high cholesterol and sugar-sweetened beverage intake.

Vyas said although researchers found an association between diet drinks and cardiovascular problems, they did not prove a causal relationship.

"We only found an association, so we can't say that diet drinks cause these problems," Vyas said. "It's too soon to tell people to change their behavior based on this study; however, based on these and other findings we have a responsibility to do more research to see what is going on and further define the relationship, if one truly exists."