This is a classic example of scare mongering statistics. The initial study showed no significant correlations, so they went looking for all sorts of pairwise subsets. This significantly reduces the effective sample size and also increases the number of statistical tests performed. The correct response should be to increase the required significance level but this is seldom done. What was found here is almost certainly a random sampling abnormality, which is why two journals rejected it. For a thorough debunking see the Respectful Insolence blog about two weeks ago. Negative results are hard to publish and don't generate headlines, so we get to see dubious science in the mainstream press.