Ann-Christin Jonsson

Prevalence of Chronic Obstructive Pulmonary Disease according to BTS, ERS, GOLD and ATS Criteria in Relation to Doctor’s Diagnosis, Symptoms, Age, Gender, and Smoking Habits

Background: Guidelines and standards for diagnosis and management of chronic obstructive pulmonary disease (COPD) have been presented by different national and international societies, but the spirometric criteria for COPD differ between guidelines. Objectives: To estimate prevalence of COPD using the guidelines of the British Thoracic Society (BTS), the European Respiratory Society (ERS), the Global Initiative for Chronic Obstructive Lung Disease (GOLD), and the American Thoracic Society (ATS). Further, to evaluate reported airway symptoms, contacts with health care providers, and physician diagnosis of COPD in relation to the respective criteria, and gender differences. Method: In 1992 a postal questionnaire was sent to a random sample of adults aged 20–69 years, 4,851 (85%) out of 5,681 subjects responded. In 1994–1995 a random sample of the responders, 970 subjects, were invited to a structured interview and a lung function test; 666 (69%) participated. Results: The prevalence of COPD was 7.6, 14.0, 14.1, 12.2 and 34.1% according to BTS, ERS, GOLD, clinical ATS (with symptoms or physician diagnosis), and spirometric ATS criteria, respectively. Prevalent COPD was related to age, smoking habits and family history of obstructive airway disease but not to gender. Physician diagnosis of chronic bronchitis or emphysema was only reported by 16.3, 12.2, 11.0, 23.4 and 8.2% of subjects fulfilling the respective criteria, though a majority reported airway symptoms. Conclusion: The main determinants for prevalent COPD were age, smoking habits and spirometric criteria of COPD. Though a majority reported airway symptoms and contact with health care providers due to respiratory complaints, only a minority was diagnosed as having COPD, indicating a large underdiagnosis.

Incidence of asthma in adults : report from the Obstructive Lung Disease in Northern Sweden Study

Incidence studies offer a better opportunity to study risk factors for asthma than do prevalence studies. However, regular prospective follow‐ups of large cohorts are difficult to perform, and that is why direct measurement of the incidence rate of asthma is almost impossible. Thus, cross‐sectional follow‐up studies of defined cohorts can be used to provide data on incidence. In 1986, a postal questionnaire survey on respiratory symptoms and diseases was performed in the northernmost province of Sweden. The population sample comprised all subjects born in 1919—20, 1934—5, and 1949—50 in eight representative areas of the province, which comprises 25% of the total area of Sweden. Completed answers were given by 5698 subjects (86%) of the 6610 subjects invited to the study. In 1992, the cohort was invited to a follow‐up survey during the same season as in 1986, and 6215 subjects were traced. Of the 5393 subjects who answered the questionnaire, 4932 had participated in the 1986 survey, or 87% of those who participated in 1986. For the period 1986—92, the cumulative incidences of asthma were 4.9 and 5.0%, respectively, as assessed by the questions, “Have you ever had asthma?” and “Have you been diagnosed as having asthma by a physician?” Thus, the results indicate a mean annual cumulative incidence of asthma of 0.8%. After correction of the results for subjects who were diagnosed as having asthma in the clinical part later in the 1986 study, the mean annual cumulative incidence of asthma was found to be 0.5%. Risk factors were family history of asthma (OR 3.46) and current and former smoking, while female sex was a strong trend.

Decline in FEV1 in relation to incident chronic obstructive pulmonary disease in a cohort with respiratory symptoms.

Data on the relationship between decline in lung function and development of COPD are sparse. We assessed the decline in FEV1 during 10 years among subjects with respiratory symptoms by two different methods and evaluated risk factors for decline and its relation to incident Chronic Obstructive Pulmonary Disease, COPD. A cross-sectional postal questionnaire was in 1986 sent to 6610 subjects of three age strata. All subjects reporting respiratory symptoms were invited to a structured interview and spirometry. A follow-up survey was performed 10 years later, and totally 1109 subjects performed spirometry in both 1986 and 1996. COPD was defined according to the ATS/ERS standards (FEV1/FVC ≤0.70). The decline in FEV1 was 39 ml/year in men vs. 28 ml/year in women, p = < 0.001 (−1.53 vs. −0.12 change in percent of predicted normal value over 10 years (pp), p = 0.023), among smokers 39 vs. non-smokers 28 ml/year, p < 0.001 (−3.30 vs. 0.69 pp, p < 0.001), in subjects with chronic productive cough 36 vs. not 32 ml/year, p = 0.044 (−2.00 vs. −0.02 pp, p = 0.002). Incident cases of moderate COPD (n = 83) had a decline of 62 ml/year (−12.6 pp) and 22.9% of them had a decline > 90 ml/year (−27.8 pp over 10 years). Gender-specific analysis revealed that smoking was a stronger risk factor in women than in men, while higher age was a significant risk factor in men only. In conclusion, decline in FEV1 was associated with age, smoking, and chronic productive cough, but the risk factor pattern was gender-dependent. Among incident cases of COPD the decline was steeper and close to a quarter had a rapid decline.