- Correspondence to Dr Ulrike Haug, Department of Clinical Epidemiology, Leibniz Institute for Prevention Research and Epidemiology—BIPS, Achterstr. 30, Bremen 28359, Germany;
- Received June 3, 2015
- Revised February 11, 2016
- Accepted February 23, 2016
- First published March 22, 2016.
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