About the Authors

Mette Nørgaard

mn@dce.au.dk

Affiliation Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark

Vera Ehrenstein

Affiliation Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark

Rikke Beck Nielsen

Affiliation Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark

Leiv Sigmund Bakketeig

Affiliation Norwegian Institute of Public Health, Nydalen, Norway

Henrik Toft Sørensen

Affiliation Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: HTS MN VE. Analyzed the data: VE. Wrote the paper: MN VE LSB RBN HTS. Data Management: RBN VE.