Statistical Analysis of Vlagtwedde-Vlaardingen Data Set

To determine the effects in early adulthood of asthma, increased bronchial responsiveness, markers of allergy and smoking on pulmonary function level and the effects of these same risk factors on subsequent decline in pulmonary function, because these early adult factors presumably profoundly influence the risk for chronic obstructive pulmonary disease.

DESIGN NARRATIVE: The questions studied included whether the above named risk factors reduced the maximally attained level of pulmonary function in early adulthood, foreshortened the postulated stability of level of pulmonary function between age 18 and 35 and/or unfavorably affected subsequent decline in level of pulmonary function. FEV1/h2, VC/h2 and FEV1/IVC were studied, using graphic smooth techniques and regression analyses techniques on both cross-sectional and longitudinal datasets. In addition, the investigators tested the hypothesis stating that early adult symptoms of asthma, increased bronchial responsiveness, markers of allergy influenced who became a smoker, influenced the amount smoked and/or influenced who stopped smoking relatively early in adult life, using logistic regression analyses and survival analyses. The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.