The title is misleading. The abstract of the cited paper http://jme.bmj.com/content/early/2010/10/18/jme.2010.038125 says that retracted papers from the US published in PubMed had a higher ratio fraudulent to erroneous retractions than those of other nations. Given that the study targets English language publications only and that its results showed that groups of repeat offenders are responsible for the majority of fraudulent retractions, global statements about the likelihood of fake research originating from US scientists cannot be accurately drawn.