An American highschool student can see that this study does not in any way suggest that diet drinks cause stroke. It only suggests that people who are more unhealthy (and likely to suffer a stroke) tend to switch to diet soda, perhaps as a step in the right direction.

The obviousness of the conclusion baffles me. Of course people who are overweight tend to drink diet soda more than others. That does not mean that diet soda is the cause of obesity. Was there any attempt to eliminate the major variable, weight? I doubt it, the study group was way to small and it sounds like they were biased.  

People actually do want to know if diet soda has negative health consequences. Bogus studies like this are good only for fanning preconceived prejudice. I'm disappointed to find that this website saw fit to print such unscientific rubbish.