Last week, research out of the American Stroke Association’s International Stroke Conference pointed a potentially incriminating finger at diet sodas — suggesting that people who drink them daily may dramatically up their risk for vascular events like heart attack and stroke, compared to folks who don’t drink them at all.

But don’t set down the fizzy stuff just yet — while interesting, the findings don’t definitively prove cause an effect — only an association. We talked to cardiologist Dr. John Bisognano to learn what other factors might be at play behind the scenes.