In this Research paper by Örtqvist and colleagues (BMJ 2014:349:g6979, doi:10.1136/bmj.g6979), a proof change by the author was taken in incorrectly. In the second paragraph under the statistical analysis section of the methods, the second sentence should have read: “For the controls we used all full siblings (excluding 9896 children for whom the father’s identity was unknown) who did not have the outcome of interest yet and who were still in the study at the age at which the index child developed asthma.” The word “age” is missing in the published article.
Cite this as: BMJ 2014;349:g7395