Symptoms and smoking habits in population
The
populations of Vlaardingen and Vlagtwedde can be subdivided
into various groups on the basis of chronic respiratory symptoms
(cough, phlegm, wheezing, asthmatic attacks, abnormal shortness
of breath for age) and smoking habits.
Our first interest is to form a reference group of subjects who have not had respiratory symptoms and are lifelong non-smokers. 35% of the males, and 29% of the females, do not comply with this requirement, as they had respiratory symptoms. The majority of asymptomatic males drop out on account of smoking habits; nearly half of asymptomatic females smoke. In the end the reference populations comprise 1 in about 10 men, and 1 in about 3 women.