Anujuo K, Agyemang C, Snijder MB, et al. Contribution of short sleep duration to ethnic differences in cardiovascular disease: results from a cohort study in the Netherlands. BMJ Open 2017;7:e017645. doi: 10.1136/bmjopen-2017-017645

Following a review of published research by researchers of the HELIUS study, conducted at the Universitair Medische Centra UMC (formerly Academic Medical Center AMC), University of Amsterdam, the authors wish to bring to your notice, a slight change in the results of a study that was published in BMJ Open.

Researchers of the HELIUS study discovered unintended errors in the coding of the original ROSE questionnaire, which was used to calculate three variables of cardiovascular disease (CVD) used in the study referenced above. The affected variables include Angina, Intermittent claudication, and the derived prevalent CVD variable (which additionally includes the unaffected variable myocardial infarction). The error led to a slight over-estimation of CVD prevalence in the various ethnic groups studied (table 1), and by extension, affected the prevalence ratios (PR) (table 2), and results of contributions of sleep to CVD in the concerned ethnic groups investigated (table 3).

The error has now been corrected, and adjusted results are presented in the attached file (as shown above) while other results of the study remain unaffected.

However, it is worthy to note that the error does not change the overall results and conclusion of the study. Also, the pattern of the key findings remains unchanged. We regret any inconvenience this may/may have cause(d), but we are glad to report this error to maintain research integrity. This correction has been communicated to all authors of the published paper, and they gave their consent to effect these corrections.