The prevalence of chronic obstructive pulmonary disease in Uppsala, Sweden – the Burden of Obstructive Lung Disease (BOLD) study: cross-sectional population-based study

Authors


  • Authorship and contributorship Christer Janson, Bryndis Benediktsdóttir and Thórarinn Gíslason designed the study. Inga Sif Ólafsdóttir and Christer Janson performed the study and collected data. Patrik Danielsson, Inga Sif Ólafsdóttir and Christer Janson analyzed the data. All the authors wrote the paper.

  • Ethics The study was approved by the ethics committee at the medical faculty at Uppsala University and fulfilled the Declaration of Helsinki. Informed consent was obtained from all participants.

  • Conflict of interest The authors have stated explicitly that there are no conflicts of interest in connection with this article.

Inga Sif Ólafsdóttir, MD, Department of Medical Sciences: Respiratory Medicine & Allergology, Uppsala University, Akademiska University Hospital, SE 751 85 Uppsala, Sweden. Tel: + 46 18 6110000/mobile: + 46 735856450, fax: + 46 18 6110228, email: inga_sif.olafsdottir@medsci.uu.se

Abstract

Objectives:  To estimate chronic obstructive pulmonary disease (COPD) prevalence in Uppsala and the impact of risk factors on disease prevalence using the standardised methods of the Burden of Obstructive Lung Disease (BOLD) study initiative.

Methods:  Randomly selected participants, aged 40 years or more (n = 548) responded to a questionnaire regarding smoking habits, respiratory symptoms, medical history, and exposure to airway irritants. Spirometry, with a post-bronchodilator test, was performed and COPD defined as post-bronchodilatory forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) < 0.70 or FEV1/FVC < lower limit of normality (LLN). Circulatory inflammatory markers were measured.

Results:  COPD prevalence was 16.2%, which was the fourth lowest prevalence of COPD, compared with 12 other BOLD centres. Main risk factors for COPD were increasing age [odds ratio (OR) = 2.08 per 10 years] and smoking (OR = 1.33 per 10 pack years). Higher education was protective (OR = 0.70 per 5 years). Previous tuberculosis was an almost significant risk factor for COPD (P = 0.08). Subjects with COPD reported more respiratory symptoms but only 29% had previous doctor diagnosed COPD, asthma, chronic bronchitis or emphysema. Participants with COPD had higher levels of C-reactive protein (P = 0.01), but no difference was observed in interleukin 6 (IL-6) levels. Using LLN instead of the fixed FEV1/FVC ratio reduced the prevalence of COPD to 10%.

Conclusion:  COPD prevalence in Uppsala was similar to other BOLD centres in high-income countries. Apart from known COPD risk factors (age, smoking, lower educational level), a history of tuberculosis may be associated with COPD even in high-income countries. COPD remains under-diagnosed, as only 29% of subjects with COPD had a previously diagnosed lung disorder.

Please cite this paper as: Danielsson P, Ólafsdóttir IS, Benediktsdóttir B, Gíslason T and Janson C. The prevalence of chronic obstructive pulmonary disease in Uppsala, Sweden – the Burden of Obstructive Lung Disease (BOLD) study: cross-sectional population-based study. Clin Respir J 2012; 6: 120–127.

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