About the Authors

Johanna Salonen

Roles Data curation, Formal analysis, Investigation, Visualization, Writing – original draft, Writing – review & editing

johanna.salonen@oulu.fi

Affiliations Respiratory Medicine, Research Unit of Internal Medicine, University of Oulu, Oulu, Finland, Medical Research Center (MRC) Oulu, Oulu University Hospital, Oulu, Finland

Hannu Vähänikkilä

Roles Formal analysis, Methodology, Supervision, Writing – review & editing

Affiliation Infrastructure for Population Studies, University of Oulu, Oulu, Finland

Minna Purokivi

Roles Supervision, Writing – review & editing

Affiliation The Center of Medicine and Clinical Research, Division of Respiratory Medicine, Kuopio University Hospital, Kuopio, Finland

Riitta Kaarteenaho

Roles Investigation, Project administration, Supervision, Writing – review & editing

Affiliations Respiratory Medicine, Research Unit of Internal Medicine, University of Oulu, Oulu, Finland, Medical Research Center (MRC) Oulu, Oulu University Hospital, Oulu, Finland

Competing Interests

JS reports congress fees and travel costs from Boehringer-Ingelheim, GlaxoSmithKline, Novartis, Orion Pharma and Roche, and lecture fees from Boehringer-Ingelheim, Chiesi, GlaxoSmithKline, Mundipharma, Orion Pharma and Roche outside the submitted work. HV has nothing to disclose. MP reports a lecture fee from Boehringer-Ingelheim Finland Ltd and a congress fee and travel costs from Roche, outside the submitted work. RK reports consultant fees from Boehringer-Ingelheim, lecture fees from Roche and Boehringer-Ingelheim, and a congress travel subsidy from Orion pharma outside the submitted work. This does not alter our adherence to PLOS ONE policies on sharing data and materials.