Smoking, socioeconomic status, and chronic respiratory disease.

Prevalence rates of chronic bronchitis and asthma and mean levels of ventilatory lung function were related to age, smoking habits, occupation, education, and income in 4,699 men and women living in Tecumseh, Michigan. The prevalence of chronic bronchitis was higher and mean levels of 1-sec forced expiratory volume were lower in cigarette smokers than in other men and women, and heavy smokers were affected more than light smokers. The prevalence of chronic bronchitis was higher and mean 1-sec forced expiratory volume was lower in blue collar workers than in white collar workers. Men and women with some college education had higher mean values for 1-sec forced expiratory volume than did those with less formal education, and the prevalence of chronic bronchitis was least among men with most education. Mean levels of 1-sec forced expiratory volume were slightly lower in those with the smallest incomes. There were no significant associations between the prevalence of asthma and smoking habits, occupation, education, or income. Most of the differences in the prevalence of chronic bronchitis and mean 1-sec forced expiratory volume in men and women of different occupational, educational, or income classes were due to differences in smoking habits. In comparison with smoking, poor occupational, educational, or economic circumstances had only a weak deleterious effect.