I hate bullshit studies like this. Always biased, and you gotta pay attention to where the funding comes from. You give me a thesis you want to try to prove, I pretty much guarentee you I can set up a study, find a sampling, and create numbers that will do it. To me it's no different from doing a study to find a correlation between brown hair and obesity. What's the point if there is no logical explanation to start with unless its someone looking for a specific outcome funding researchers who are trying to justify their existence and get more grants to do more research that will turn out to be fruitless in another few years.