Vlaardingen-Vlagtwedde study
In Vlaardingen and Vlagtwedde (an urban and a rural area of the Netherlands, respectively) van der Lende’s group on Epidemiology of chronic non-specific lung disease collected data in adults at three year intervals; the study was supported by the Netherlands Asthma Fund.
Not everybody showed up at each survey. People moving into the Vlagtwedde area after the start of the study were allowed to participate in subsequent studies. A group from the Department of Physiology, Leiden University, assessed maximum expiratory flow-volume curves and total lung capacity. Physiological data presented here derive from the Leiden group. After 12 years (i.e. 5 investigations at 3-year intervals) data on flow-volume curves, age, length, respiratory symptoms and smoking habits were available on about 4600 males and females.