"The researchers noted that with an observational study like this, no firm conclusions can be drawn about cause and effect. They added, however, that the findings could have important public health implications for a large sector of the population."

This little nugget tagged at the end of the article says it all. Not even the authors of this "study" understand all of the variables that contributed to the things they say they observed. So, they say, just to be safe, ignore this one risk and continue participating in all of the other risks. No guarantees, though. We've probably missed something.