Don't read anything into the six month review time: it's perfectly normal. In fact, we've waited longer than that for a single set of reviews (ugh) and it's ra

Don't read anything into the six month review time: it's perfectly normal. In fact, we've waited longer than that for a single set of reviews (ugh) and it's rare for anything to be accepted straightaway. Most papers go through the review-revise cycle at least once, even at the journal where they're ultimately accepted. This also doesn't indicate much about the quality of the research. Reviewers can flag serious problems, but they may also just want improvements to the writing (more details/discussion) or complementary experiments. It's hard to check the numbers from the press release stuff. I swear I saw at <5mm somewhere too. I would bet the underlying studies are a morass of different definitions and methods, and I'd expect that a major contribution of the paper is to find some clever way to combine them.