Nat. Rev. Dis. Primers article number: 15030; doi:10.1038/nrdp.2015.30; published online 24 September 2015

In the version of the article originally published, on page 7, it was incorrectly stated that individuals with a z-score of <1 are considered to have osteopenia, rather than a z-score of <−1. This has now been corrected.