For all those of you throwing around those studies to prove your point: You can NEVER assume any given study is accurate. You don't have access to the full information, or the expertise, that you'd need to determine that. Many studies are designed to deliberately come to a particular conclusion, to the advantage of the party funding the study. I've seen too many of those examples to ever put any my faith in any study again.
Back in 2005, Dr. John Ioannidis, an epidemiologist at Ioannina School of Medicine, Greece, showed
that there is less than a 50 percent chance that the results of any randomly chosen scientific paper will be true. See his published report here:
PLoS Medicine: Why Most Published Research Findings Are False.
Prestigious journals boast that they are very selective, and turn down the vast majority of papers that are submitted to them. The assumption is that they therefore publish only the best scientific work.
But Dr. Ioannidis' study of 49 papers in leading journals, which had been cited by more than 1,000 other scientists — in other words, well-regarded research — showed that within only a few years, almost a third of the papers had been refuted by other studies.
Making matters worse, the "hotter" the field, the greater the competition, and the more likely that published research in top journals will be proven wrong.