stringent screening criteria of any odds ratio in the same direction than the effect observed in the meta-analysis. FINRISK 1997 is one of the population-based risk factor surveys carried out by the National Public Health Institute of Finland every five years37, and was approved by the Ethical Committee of the National Public Health Institute (decision number 38/96). The sample was drawn from the National Population Register for five geographical areas. The FUSION stage 2 study includes a series of cases and controls matched to take into account age, sex, and birth province within Finland13. The KORA S4 samples were recruited from Augsburg, Southern Germany, and do not overlap with the KORA S3 population. Prevalence, Prediction and Prevention of Diabetes (PPP) in the Botnia study is a population-based study started in 2004 to study the epidemiology of type 2 diabetes. More details can be found in the Supplementary Methods. These studies were approved by the appropriate ethical review boards.
