TABLE 4.

Longitudinal analyses of cannabis and tobacco exposure with spirometric lung function

	Subjects n	Cannabis			Tobacco
		Coefficient	95% CI	p-value	Coefficient	95% CI	p-value
FEV1 mL	779	4.4	−1.4–10.3	0.137	−4.3	−8.2– −0.4	0.031
FVC mL	779	10.7	3.9–17.5	0.002	0.2	−4.4–4.8	0.928
FEV1/FVC %	779	−0.07	−0.14–0.01	0.069	−0.09	−0.14– −0.04	0.001

FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity. Linear regression analyses of lung function at age 32 yrs using both cannabis and tobacco smoking as predictors, adjusted for lung function at age 15 yrs. Analyses also adjusted for sex, height, change in height between age 15 and 32 yrs, and current asthma at age 32 yrs. Coefficients represent the difference in lung function at age 32 yrs associated with each joint-year of cannabis or pack-year of tobacco up to age 32 yrs, adjusted for the use of the other substance.