Results
Of the 226 subjects with CF who completed the one-time survey and met inclusion criteria, current use was reported by 29% (n=66) of subjects for marijuana, 22% (n=49) for CBD, 27% (n=60) for e-cigarettes, and 22% (n=49) for cigarettes. Only 0.9% (n=2) subjects used all four substances, 6.2% (n=14) used three substances, and 22.6% (n=51) used two of the substances currently (Figure 1).
The frequency of marijuana, CBD, e-cigarette, and cigarette usage varied among those who reported current use. Daily or near-daily use was highest in users of cigarette (45%, n=22) and e-cigarette (33%, n =20). Marijuana users were more likely to use daily or near-daily (23%, n=15) compared to CBD users (16%, n=8). A total of 39% (n=26) of marijuana users, 33% (n=16) CBD, and 35% (n=21) e-cigarette users had at least once a week usage compared to 22% (n=11) of cigarette users (Figure 2).
Overall, we found that current users of each of the four substances were more likely to be college-educated, between the ages of 26 and 39 years old, and Black when compared to non-users. Demographic and socioeconomic characteristics between current users and non-users differ depending on the substance used (Table 1). Compared to non-users, current users of CBD, e-cigarettes, and cigarettes were more likely to be male, which contrasts with current marijuana users, who were slightly more likely to identify as female and other gender identities. Black subjects were more likely to be current users of all substances than other races. Non-Hispanic white subjects were more likely to be current users of marijuana and cigarettes. Asian, Native American, other races, or multi-race subjects were more likely to be current users of e-cigarettes. Specific to marijuana, there was no significant association between current marijuana usage and state of residence in terms of legality (illegal, medically legal, legalized).
Significant patterns also emerged with respect to markers of CF disease severity and PHQ-4 scores between current users and non-users (Table 2). Current marijuana users were more likely to be on pancreatic enzymes, while current cigarette users were less likely to be on pancreatic enzymes. Subjects with self-reported FEV1 percent predicted of 60-80% were more likely to be current users of e-cigarettes and cigarettes as compared to non-users who were more likely to have a self-reported FEV1 less than 60% and greater than 80%. There were no differences in pulmonary function between current users and non-users of marijuana or CBD.
Current users of CBD, e-cigarettes, and cigarettes were more likely to have an abnormal mental health screen by PHQ-4 compared to non-users. CBD users were more likely than non-users to have a severe score on the PHQ-4, report depressive symptoms on the PHQ-4, but there was no difference in anxiety symptoms. E-cigarette and cigarette users were more likely to have a mild, moderate, and severe score on the PHQ-4 than non-users, as well as, more likely to report anxiety and depressive symptoms on the PHQ-4. There was no significant difference found in mental health between users and non-users of marijuana.
There were differences in CFTR modulator use between current-users and non-users of substances. Current marijuana users were 1.92 times more likely to report being on CFTR modulators in univariate logistic regression (95% CI 0.87-4.70, p=0.1) and 2.45 times more likely in the multivariate logistic model adjusted for age, gender, race, ethnicity, ppFEV1, and PHQ-4 (95% CI 0.97-7.17, p=0.08). Current users of e-cigarettes were 4.07 times more likely to report taking CFTR modulators (95% CI 1.54-14.07, p=0.01) in the univariate logistic regression, and 2.92 times more likely in the multivariate analysis adjusted for age, gender, race, ethnicity, ppFEV1, and PHQ-4 (95%CI 0.98-11.00, p=0.08). Although the differences for both marijuana and e-cigarettes did not reach statistical significance, the confidence intervals exclude any meaningful differences of lower CFTR modulator use in current substance users compared to non-users. There were no significant differences in current cigarette or CBD users by CFTR modulator use in logistic regressions (Table 3).