{
  "abstract": "Background Chronic obstructive pulmonary disease (COPD) in never-smokers may have other clinical characteristics than tobacco smoking-related COPD.Research question What are the risk factors, biomarkers, respiratory symptoms and health status in never-smoking individuals with COPD?Study design and methods We investigated never-smokers with COPD (n=154, mean age 60 years) from the population-based Swedish CArdioPulmonary bioImage Study (SCAPIS), and compared them with four control groups: never-smokers with normal lung function (n=281), current smokers with normal lung function (n=97), ex-smokers with COPD (n=103) and current smokers with COPD (n=55). COPD was defined as forced expiratory volume in 1 s (FEV 1)/forced vital capacity (FVC) less than the lower limit of normal (LNN) after bronchodilation. We examined fractional exhaled nitric oxide (FeNO), blood biomarkers, respiratory symptoms, health status, medical history and living conditions.Results The never-smoker COPD group reported more respiratory symptoms and worse health status than never-smokers with normal lung function, but fewer symptoms, milder airflow limitation and better health status compared with ex-smokers and smokers with COPD. Never-smokers with COPD had more self-reported asthma. Moreover, never-smokers with COPD had higher Immunoglobulin E sensitisations to a mix of aeroallergens, higher geometrical mean FeNO levels and blood eosinophil counts than never-smokers with normal lung function. When participants with self-reported asthma were excluded, never-smokers with COPD still had more wheeze, cough and higher FeNO.Conclusion Never-smokers with COPD had more respiratory symptoms and elevated markers of type-2 inflammation, suggesting they might represent a distinct clinical phenotype which may differ from smoking-related COPD. They may therefore need to be treated and followed differently.Trial registration number NCT03049202.",
  "authors": [
    {
      "affiliations": [
        "Division of Immunology and Respiratory Medicine, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden",
        "Medical Unit Occupational Therapy and Physiotherapy, Women's Health and Allied Health Professionals Theme, Karolinska University Hospital, Stockholm, Sweden"
      ],
      "name": "Pernilla Sönnerfors"
    },
    {
      "affiliations": [
        "Department of Respiratory Medicine in Linköping, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden"
      ],
      "name": "Petra Kristina Jacobson"
    },
    {
      "affiliations": [
        "COPD Center, Department of Respiratory Medicine and Allergology, Sahlgrenska University Hospital, Gothenburg, Sweden",
        "COPD Center Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden"
      ],
      "name": "Anders Andersson"
    },
    {
      "affiliations": [
        "Department of Clinical Sciences, Respiratory Medicine, Allergology and Palliative Medicine, Lund University, Lund, Sweden"
      ],
      "name": "Leif Hilding Bjermer"
    },
    {
      "affiliations": [
        "Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden"
      ],
      "name": "Anders Blomberg"
    },
    {
      "affiliations": [
        "Division of Immunology and Respiratory Medicine, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden",
        "Department of Respiratory Medicine and Allergy, and Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden"
      ],
      "name": "Heléne Blomqvist"
    },
    {
      "affiliations": [
        "Unit of Airway Inflammation, Department of Experimental Medicine Sciences, Lund University, Lund, Sweden"
      ],
      "name": "Jonas S Erjefält"
    },
    {
      "affiliations": [
        "Division of Immunology and Respiratory Medicine, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden",
        "Department of Respiratory Medicine and Allergy, and Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden"
      ],
      "name": "Iryna Kolosenko"
    },
    {
      "affiliations": [
        "Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden"
      ],
      "name": "Andrei Malinovschi"
    },
    {
      "affiliations": [
        "Division of Immunology and Respiratory Medicine, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden",
        "Department of Respiratory Medicine and Allergy, and Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden",
        "Stockholm CF Center, Albatross, Karolinska University Hospital, Huddinge, Sweden"
      ],
      "name": "Terezia Pincikova"
    },
    {
      "affiliations": [
        "Department of Clinical Sciences, Respiratory Medicine, Allergology and Palliative Medicine, Lund University, Lund, Sweden"
      ],
      "name": "Ellen Tufvesson"
    },
    {
      "affiliations": [
        "Division of Immunology and Respiratory Medicine, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden",
        "Department of Respiratory Medicine and Allergy, and Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden"
      ],
      "name": "Åsa M Wheelock"
    },
    {
      "affiliations": [
        "Department of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden"
      ],
      "name": "Christer Janson"
    },
    {
      "affiliations": [
        "Department of Respiratory Medicine in Linköping, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden"
      ],
      "name": "Hans Lennart Persson"
    },
    {
      "affiliations": [
        "Division of Immunology and Respiratory Medicine, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden",
        "Department of Respiratory Medicine and Allergy, and Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden"
      ],
      "name": "Magnus Sköld"
    }
  ],
  "title": "Characterisation of chronic obstructive pulmonary disease (COPD) in never-smokers and ever-smokers from a population-based cohort",
  "uid": "fcd8108d-e34c-5f0b-94c0-434555e5014d"
}