Objective: To determine recent prevalences of, and short-term trends in, characteristics of chronic pulmonary disease amongst adults in the Netherlands.
Design: Long-term cross-sectional study.
Method: An analysis was carried out on data collected from the 'Monitoring of risk factors and health in the Netherlands' study (Dutch acronym: MORGEN) in the period 1993-1997. The study involved 9791 men and 11,712 (non-pregnant) women aged 20-59 years from three Dutch cities, Amsterdam, Doetinchem and Maastricht. A written questionnaire was used to collect data on items such as respiratory symptoms, age, educational level and smoking habits. The presence of asthma symptoms was defined as: wheezing without a cold, nocturnal attacks of breathlessness or 'had ever suffered from asthma'. The presence of chronic obstructive pulmonary disease (COPD) symptoms was defined as: chronic cough, chronic phlegm or breathlessness when walking with people of the same age. Pulmonary function (FEV1) was measured only in 1994-1997 (n = 12,347). Bronchial obstruction was defined as FEV1 < 80% of predicted. Age standardisation was performed using the age distribution of the Dutch population in 1995 as standard. Changes over time were studied using linear regression analysis.
Results: The age-standardised prevalence of asthma symptoms (circa 14%), COPD symptoms (circa 14%) and obstruction (circa 8%) were comparable in men and women. The prevalence of respiratory symptoms and obstruction was clearly higher in subjects with a low versus a high educational level and this trend was also observed amongst those who had never smoked. After adjustment for age, education and city, the prevalence of respiratory symptoms increased during the study period in women (beta = 0.79% per year (95%-CI: 0.27-1.32)), but not in men. The strongest increase was observed in women aged 40-49 years and in those women with a low educational level. In both men and women no increase in the prevalence of bronchial obstruction was observed.