Cigarettes, ENDS Use, and Chronic Obstructive Pulmonary Disease Incidence: A Prospective Longitudinal Study.

INTRODUCTION: Understanding the relationship between ENDS use and chronic obstructive pulmonary disease (COPD) and other respiratory conditions is critical. However, most previous studies have not fully adjusted for cigarette smoking history. METHODS: Using Waves 1-5 of the U.S. Population Assessment of Tobacco and Health study, the association between ENDS use and self-reported incident COPD was examined among adults aged 40+ years using discrete-time survival models. Current ENDS use was measured as a time-varying covariate, lagged by 1 wave, defined as established daily or some days of use. Multivariable models were adjusted for baseline demographics (age, sex, race/ethnicity, education), health characteristics (asthma, obesity, exposure to second-hand smoke), and smoking history (smoking status and cigarette pack years). Data were collected between 2013 and 2019, and the analysis was conducted in 2021-2022. RESULTS: Incident COPD was self-reported by 925 respondents during the 5-year follow-up. Before adjusting for other covariates, time-varying ENDS use appeared to double COPD incidence risk (hazard ratio=1.98, 95% CI=1.44, 2.74). However, ENDS use was no longer associated with COPD (adjusted hazard ratio=1.10, 95% CI=0.78, 1.57) after adjusting for current cigarette smoking and cigarette pack years. CONCLUSIONS: ENDS use did not significantly increase the risk of self-reported incident COPD over a 5-year period once current smoking status and cigarette pack years were included. Cigarette pack years, by contrast, remained associated with a net increase in COPD incidence risk. These findings highlight the importance of using prospective longitudinal data and adequately controlling for cigarette smoking history to assess the independent health effects of ENDS.

ENDS, Cigarettes, and Respiratory Illness: Longitudinal Associations Among U.S. Youth.

INTRODUCTION: ENDS use is highly prevalent among U.S. youth, and there is concern about its respiratory health effects. However, evidence from nationally representative longitudinal data is limited. METHODS: Using youth (aged 12-17 years) data from Waves 1-5 (2013-2019) of the Population Assessment of Tobacco and Health Study, multilevel Poisson regression models were estimated to examine the association between ENDS use; cigarettes; and diagnosed bronchitis, pneumonia, or chronic cough. Current product use was lagged by 1 wave and categorized as (1) never/noncurrent use, (2) exclusive cigarette use, (3) exclusive ENDS use, and (4) dual ENDS/cigarette use. Multivariable models adjusted for age, sex, race and ethnicity; parental education; asthma; BMI; cannabis use; secondhand smoke exposure; and household use of combustible products. Data analysis was conducted in 2022-2023. RESULTS: A total of 7.4% of respondents were diagnosed with bronchitis, pneumonia, or chronic cough at follow-up. In the multivariable model, exclusive cigarette use (incident rate ratio=1.85, 95% CI=1.29, 2.65), exclusive ENDS use (incident rate ratio=1.49, 95% CI=1.06, 2.08), and dual use (incident rate ratio=2.70, 95% CI=1.61, 3.50) were associated with a higher risk of diagnosed bronchitis, pneumonia, or chronic cough than never/noncurrent use. CONCLUSIONS: These results suggest that ENDS and cigarettes, used exclusively or jointly, increased the risk of diagnosed bronchitis, pneumonia, or chronic cough among U.S. youth. However, dual use was associated with the highest risk. Targeted policies aimed at continuing to reduce cigarette smoking and ENDS use among youth, especially among those with dual use, are needed.

The Impact of Menthol Cigarette Flavor in the U.S.: Cigarette and ENDS Transitions by Sociodemographic Group.

INTRODUCTION: A better understanding of how menthol cigarette flavoring and ENDS impact smoking initiation, cessation, and transitions between tobacco products could help elucidate the potential impact of a U.S. menthol ban on combustible tobacco products. METHODS: A multistate transition model was applied to data on 23,232 adults from Waves 1-4 (2013-2017) of the Population Assessment of Tobacco and Health Study (analysis was conducted in 2020-2021). Transition rates among never, noncurrent, nonmenthol versus menthol cigarette, ENDS, and dual everyday/someday use were estimated, as were transition-specific hazard ratios for age, sex, race/ethnicity, education, and income. RESULTS: Non-Hispanic Blacks who smoked menthol discontinued smoking at a much lower rate than those who smoked nonmenthol (hazard ratio=0.43, 95% CI=0.29, 0.64), but there was no statistically significant difference in the discontinuation rates among non-Hispanic Whites (hazard ratio=0.97, 95% CI=0.80, 1.16) or Hispanics (hazard ratio=0.81, 95% CI=0.56, 1.16). Non-Hispanic Whites who smoked menthol were more likely to become dual users than those who smoked nonmenthol (hazard ratio=1.43, 95% CI=1.14, 1.80). Young adults initiated menthol smoking at a higher rate than older adults (age 18-24 years versus ≥55 years: hazard ratio=2.45, 95% CI=1.44, 4.15) but not nonmenthol smoking (hazard ratio=1.02, 95% CI=0.62, 1.69). There were differences by sex in the impact of menthol flavor on smoking initiation and discontinuation but little difference by education or income. CONCLUSIONS: Sociodemographic differences in product transitions should be accounted for when estimating the potential impact of a menthol ban.