The evolving landscape of tobacco use in the United States has witnessed a significant shift with the introduction and increasing prevalence of e-cigarettes. This study explores the relationship between the rise in e-cigarette use and the decline in traditional cigarette smoking among US adults, leveraging the latest data from the National Health Interview Survey (NHIS). 

Background 

E-cigarettes first appeared in the US market in 2007 and gained noticeable traction by 2010. This study aimed to assess whether the increasing use of e-cigarettes correlates with a decrease in smoking prevalence, particularly among sub-populations with the highest e-cigarette use. 

Methods 

The study updates previous analyses using NHIS data through 2022. It employs cross-sectional estimates to analyze the yearly prevalence of smoking and e-cigarette use among US adults, segmented by age, race/ethnicity, and sex. The analysis uses non-linear models to predict smoking prevalence based on pre-e-cigarette trends and compares these predictions with actual observed data in the e-cigarette era. 

Key Findings 

• Decline in Smoking Prevalence: The study found that observed smoking prevalence during the e-cigarette era was significantly lower than expected based on trends from the pre-e-cigarette era. This decline was more pronounced in sub-populations with higher e-cigarette use, particularly among younger adults aged 18-34. 

• Correlation Between E-Cigarette Use and Smoking Discrepancy: There was a statistically significant correlation between increased e-cigarette use and the discrepancy in smoking prevalence, suggesting that higher e-cigarette use is associated with a more substantial decline in smoking rates.  

• Demographic Variations: The impact of e-cigarette use on smoking prevalence varied across different demographic groups. For instance, young adults and non-Hispanic White adults showed the most significant discrepancies between expected and observed smoking rates, correlating with their higher e-cigarette use prevalence. 

Cigarette smoking and E-Cigarette use prevalence (All Adults) 

Discussion 

The introduction of e-cigarettes appears to have contributed to an accelerated decline in smoking prevalence among US adults. This effect is particularly evident in demographics with higher rates of e-cigarette use. These findings align with the hypothesis that e-cigarettes may help individuals switch from combustible cigarettes or prevent them from starting to smoke traditional cigarettes altogether. 

Implications 

These results suggest that e-cigarettes could play a role in public health strategies aimed at reducing smoking rates.  

Quotes from the Study 

“If e-cigarettes act as a ‘gateway’ to cigarette smoking, then at the population level, increased e-cigarette use prevalence would coincide with increased smoking prevalence [2, 3], or at the very least, a slowing of the rate of decline of smoking prevalence. While it is often observed that youth who use e-cigarettes are more likely to later initiate cigarette smoking, research has questioned whether this effect is causal, rather than due to shared risk factors or common liabilities between e-cigarette use and smoking [4,5,6,7,8]. Evidence for the ‘gateway’ effect has not been detected in population-level studies on prevalence of e-cigarette use and smoking among young people [9,10,11,12,13,14,15,16,17,18]; indeed, smoking prevalence remains at an all-time low among US adolescents [19, 20] and young adults [21], despite increases in e-cigarette use.” 

 

“This research examined whether observed trends in smoking prevalence among US adults during the e-cigarette era were consistent with empirically-derived projections based on trends before the e-cigarette era, and whether any discrepancy between observed and expected smoking prevalence was correlated with e-cigarette use prevalence, and thus might be explained by e-cigarette use. Significant discrepancies in smoking prevalence were identified, such that observed smoking prevalence in the e-cigarette era was lower than was to be expected based on pre-e-cigarette era trends, i.e., actual smoking prevalence was lower than it otherwise would have been if trends from before e-cigarettes were introduced or became prevalent had continued uninterrupted.” 

 

“If e-cigarettes help adults who smoke combustible cigarettes to switch away from cigarette smoking (i.e., ‘switching’), and/or if they divert individuals who otherwise would have started smoking away from taking up cigarettes in the first place (i.e., ‘diversion’), then at the population level, increased e-cigarette use prevalence would coincide with greater decreases in smoking prevalence than would otherwise be expected.” 

Conclusion 

The study provides robust evidence that the rise in e-cigarette use is associated with a significant decline in smoking prevalence among US adults. This relationship is particularly strong in younger adults and those with higher rates of e-cigarette use. As the landscape of tobacco use continues to evolve, these findings underscore the importance of considering e-cigarettes in the broader context of smoking cessation and public health policy.