A controversial study about diet sodas makes a reckless assertion that these products might be associated with heart health issues such as stroke. But the study does not account for whether the people involved were overweight or obese.

Why is it a major problem to ignore this crucial piece of data? Because obesity and overweight are significant risk factors for heart disease and stroke – according to the American Heart Association, the National Heart, Lung and Blood Institute and WebMD, just to name a few sources.

So why would this study fail to account for such an obvious and high-profile risk factor?

Could it be that what really connects those in this study together is that they’re overweight or obese?

And because they’re overweight and obese, they’re drinking diet sodas in order to help control or reduce their weight. Diet soda likely is just a bystander in this study – a common dietary choice being made by people at risk of heart disease for other reasons such as their weight.

Medical experts are raising the same questions about what was ignored by the study:

Dr. Nehal N. Mehta, director of inflammatory risk cardiology at the University of Pennsylvania told MSNBC.com: “Soda may not be the villain. It may be the other things that people consume in association with diet soda.”

Phillip B. Gorelick, MD, MPH, head of neurology and stroke research at the University of Illinois in Chicago, says the study wasn’t a good way to gauge people’s overall dietary patterns. He told WebMD: “You have to look at what people eat in totality. People who are reducing calories by drinking diet soda may have an unhealthy dietary pattern, consuming a lot of fat and salt, for example.”

ABC News Chief Health and Medical Editor Dr. Richard Besser said: “This study has major flaws and should not change anyone’s diet soda consumption.”

It’s disheartening that a study about heart health issues would so easily dismiss such a prominent risk factor as obesity and overweight. And it’s reckless that the study’s authors attack the diet beverages people are choosing as one way to help control and reduce that risk factor.

Diet soda is safe. Certainly safer for public consumption than some of the science out there.