I enjoyed this article. This part felt weird though when you go on to explain the pitfalls of correlation chains:<p>> Now, obesity causes diabetes. That much is indisputable.<p>The odds-ratios you quote still just means obesity is correlated with diabetes. They could both be caused by the same thing, for instance an inflammatory diet. Or diabetes could cause obesity (temporally this doesn't seem to make sense, obese people go on to develop type-2 diabetes. But there could be a pre-diabetic state that we don't currently understand/measure which, when entered, leads to obesity.)