Changes in respiratory symptoms related to smoking in a teenage population: the results of two linked surveys separated by one year.
Data on respiratory symptoms and smoking for 2749 white American high school students from two linked surveys, separated by a one year lapse, are presented. There was a significantly higher likelihood of smoking at second survey among those who had initial symptoms. (There had been no educational efforts linking smoking and respiratory symptoms in the interim.) This difference was almost entirely contributed by those who had been ex-smokers and light (less than or equal to four cigarettes/day) smokers at first survey. Initial ex-smokers and light smokers also had, overall, least fixed smoking habits. Whatever the initial smoking or symptom status, symptoms at second survey were far more likely with current smoking. Controlling for initial symptom and smoking status, the gradient of symptoms between current smokers and non-smokers was over two and a half fold, except among those who had had symptoms and had not been smoking, and whose initial symptoms presumably arose from causes other than current cigarette smoking. Even among that group, symptoms at second survey were half as likely again among those who reported having become smokers (p less than-001). There were also strong linear trends of increased likelihood of symptoms with increased numbers of cigarettes smoked. Symptom rates at second survey of those who had symptoms a year earlier, and who stopped smoking during the year, were not as low as for those who also stopped smoking, but who had not had initial symptoms, suggesting that symptoms associated with smoking were not completely reversible in the time interval of this study. The difference, however, was not significant.
D000293:Adolescent; D000367:Age Factors; D005260:Female; D006266:Health Education; D006801:Humans; D008297:Male; D009518:New York; D012140:Respiratory Tract Diseases / Q000453:epidemiology* / Q000209:etiology; D012737:Sex Factors; D012907:Smoking / Q000150:complications / Q000453:epidemiology*; D013997:Time Factors