It was presented at the American Stroke Association's International Stroke Conference 2011. The American Heart Association has a short summary on its website. And Rosie Mestel has an excellent account in The Los Angeles Times.
Here's what I can glean from the limited information available:
• The study started in 2003. It was designed to determine risk factors for heart disease and stroke in a multi-ethnic New York City population.
• It used a food frequency questionnaire to ask about 2,500 people how often they drank diet sodas (among many other questions).
• Nine years later, it assessed rates of stroke and heart disease.
• The result: People who said they habitually drank diet sodas had a 60 percent higher rate of stroke and heart attacks.
• They had a 48 percent higher rate when the data were controlled for contributing factors: age, sex, race, smoking, exercise, alcohol, daily calories, and metabolic syndrome.
That is all we know.
Does this study really mean that "diet soda may not be the optimal substitute for sugar-sweetened beverages for protection against vascular outcomes," as the lead author is quoted as saying?
As Rosie Mestel puts it:
It's worth noting, as some scientists did, that this is a link, not proof of cause and effect. After all, there are many things that people who slurp diet sodas every day are apt to do—like eat a lousy diet—and not all of these can be adjusted for, no matter how hard researchers try. Maybe those other factors are responsible for the stroke and heart attack risk, not the diet drinks. (Those who drink daily soda of any stripe, diet or otherwise, are probably not the most healthful among us.)