Impact of marijuana smoking on lung function in older persons

The investigation by Tan et al. [1] addresses an important question regarding the impact of marijuana smoking in middle-aged and older individuals and the relative risk for developing COPD and an accelerated rate of decline in lung function. The importance of this question is underscored by the spreading legalisation of marijuana and the likely impact on its use in both older and younger persons. The authors approached this question using data from a Canadian cross-sectional population-based prevalence study of COPD carried out in subjects ≥40 years (the COLD cohort) and a selected subsample who were followed for up to 4 years and either had physiological evidence of COPD (forced expiratory volume in 1 s (FEV1) to forced vital capacity ratio <0.70) or served as age- and gender-matched control never and ever smokers with normal lung function (CanCOLD cohort). Since the vast majority (83%) of marijuana smokers in their study also smoked tobacco, the analysis was carried out by adjusting for the concomitant use of marijuana in the dual smokers. Dose–response was analysed by categorising the smokers using three levels of cumulative life-time exposure defined by the number of pack- or joint-years (mild, 1–5; moderate, >5–20; and heavy, >20), and the level of exposure, along with other influential covariates, was adjusted for in the analyses. In their cross-sectional study the authors found that heavy marijuana smoking (>20 joint-years) wa...
Source: European Respiratory Journal - Category: Respiratory Medicine Authors: Tags: Original Articles: Correspondence Source Type: research