Day-level associations of nicotine and cannabis vaping and co-vaping with sleep duration and quality among young adults: A smartphone-based daily diary study.

OBJECTIVE: Nicotine and cannabis vaping are increasingly prevalent among young adults, and aiding sleep is a common reason for cannabis use. This study examined relationships between daily nicotine/cannabis vaping patterns and sleep. METHODS: From 2023 to 2024, 111 California young adults (aged 18-29; mean age = 23.9±3.0; 64% female; 31.5% non-Hispanic White) who vaped nicotine/cannabis ≥20 days/month completed 30 consecutive days of smartphone-based surveys. Self-reported sleep outcomes included 1) sleep duration (inadequate <7 versus adequate ≥7 hours) and 2) sleep quality (0=terrible to 10=excellent). Daily vaping patterns were non-vaping, nicotine-only vaping, cannabis-only vaping, or same-day co-vaping. Generalized mixed-effects models examined day-level associations between vaping patterns and sleep that night, adjusting for other substance use and baseline covariates. RESULTS: Of 2147 daily assessments, 51.7% reported inadequate sleep; mean sleep quality was 6.1±2.1. Nicotine-only vaping was most frequently reported (42.5% of the days), followed by same-day co-vaping (32.1%), non-vaping (16.1%), and cannabis-only vaping (9.3%). Nicotine-only vaping days had greater odds of inadequate sleep versus non-vaping (OR=1.40, 95%CI: 1.01-1.94) and versus cannabis-only days (1.93 [1.31-2.85]). Days with same-day co-vaping had greater odds of inadequate sleep compared with cannabis-only vaping (1.50 [1.01-2.23]). Associations between sleep quality and daily vaping patterns were not statistically significant. CONCLUSIONS: Nicotine vaping was associated with inadequate sleep duration compared to non-vaping or cannabis-only vaping. Despite perceptions of cannabis as a sleep aid, cannabis vaping did not improve sleep quality compared to non-vaping. These findings highlight the need for educational efforts or interventions addressing sleep health among young adults who vape nicotine and/or cannabis.