The above article, first published online in December 2008 in Journal of Endocrinology, and later in issue (J Endocrinol. 2009; 200: 259–271 (https://doi.org/10.1677/JOE-08-0477), has been retracted by agreement between the journal co-Editors-in-Chief, Professor Colin Farquharson and Professor Martin Haluzik, and Bioscientifica Ltd. Following a thorough re-evaluation of the article, our expert reviewers raised multiple concerns about the data and statistical interpretation presented. The authors were contacted with a request to provide the original data and offer explanations to address the concerns expressed by the reviewers; however, no response was received. Consequently, we can no longer verify the reliability of the results presented and therefore retract the article.