Daily fluctuations in drinking intensity: Links with vaping and combustible use of nicotine and marijuana

Background: Whether alcohol use intensity on a given day is linked with nicotine or marijuana use that same day is not well known, nor are links of drinking intensity with different modes of nicotine and marijuana use. This study examined these within-person links across 14 days in a national sample of young adults (YAs). Methods: Past 30-day drinkers participating in the U.S. nationally representative Monitoring the Future study of 12th graders in 2018, who also reported alcohol use during a 14-day data collection one year later in the Young Adult Daily Life Study in 2019, were included (N = 487). Weighted multilevel modeling estimated within- and between-person associations of drinking intensity with cigarette smoking, nicotine vaping, marijuana smoking, and marijuana vaping. Results: Within-person fluctuations in drinking intensity on a given day were associated with cigarette smoking, nicotine vaping, and marijuana smoking, but not marijuana vaping. There were significant between-person associations of means of drinking intensity and each outcome, except for cigarette smoking. Conclusion: Drinking intensity on a given day was associated with multiple modes of nicotine use and marijuana smoking that day. Nicotine and marijuana use remain critical areas of concern for public health, and future research and interventions should consider the comorbidity of drinking intensity and multiple modes of nicotine and marijuana use. Focusing on the same-day use of alcohol may provide a tailored avenue for preventing and reducing nicotine and marijuana emerging trends among YAs.