Relationships among Smoking Habits, Airflow Limitations, and Metabolic Abnormalities in School Workers

BACKGROUND Chronic obstructive pulmonary disease is caused mainly by habitual smoking and is common among elderly individuals. It involves not only airflow limitation but also metabolic disorders, leading to increased cardiovascular morbidity and mortality. OBJECTIVE We evaluated relationships among smoking habits, airflow limitation, and metabolic abnormalities. METHODS Between 2001 and 2008, 15,324 school workers (9700 males, 5624 females; age: ≥ 30 years) underwent medical checkups, including blood tests and spirometry. They also responded to a questionnaire on smoking habits and medical history. RESULTS Airflow limitation was more prevalent in current smokers than in ex-smokers and never-smokers in men and women. The frequency of hypertriglyceridemia was higher in current smokers in all age groups, and those of low high-density-lipoprotein cholesterolemia and diabetes mellitus were higher in current smokers in age groups ≥ 40 s in men, but not in women. There were significant differences in the frequencies of metabolic abnormalities between subjects with airflow limitations and those without in women, but not in men. Smoking index was an independent factor associated with increased frequencies of hypertriglyceridemia (OR 1.015; 95% CI: 1.012-1.018; p<0.0001) and low high-density-lipoprotein cholesterolemia (1.013; 1.010-1.016; p<0.0001) in men. Length of smoking cessation was an independent factor associated with a decreased frequency of hypertriglyceridemia (0.984; 0.975-0.994; p = 0.007). CONCLUSIONS Habitual smoking causes high incidences of airflow limitation and metabolic abnormalities. Women, but not men, with airflow limitation had higher frequencies of metabolic abnormalities.