Association of Time to First Morning Cigarette and Chronic Obstructive Pulmonary Disease Measured by Spirometry in Current Smokers.

Compared to current smokers with a late time to first cigarette, those with an early time to first cigarette had a higher risk of obstructive pulmonary impairment, especially chronic obstructive pulmonary disease. Classifying smoking-related behaviors, especially time to first cigarette, may help target clinical screening for chronic obstructive pulmonary disease.