The Effects of Smokers Switching Behaviour on Health-Related Symptom Burden and Quality of Life: Analysis of US Prospective Longitudinal Cohort Study Data

Background Ecigarette (EC) use is rising, and evidence increasingly supports that ECs are helpful in smoking cessation. However, evidence concerning the longterm health effects of conventional cigarette smokers who switch to using ECs, and changes in healthrelated symptoms and quality of life (QoL), are lacking. Objective To examine the effects of switching from smoking to using ECs on healthrelated symptoms (fatigue, pain, and emotional problems) and general QoL. Methods We analysed data from 7,122 adult respondents in the U.S. Population Assessment of Tobacco and Health (PATH) study. These were exclusive cigarette smokers at Wave 1 and were followed up at any of Waves 2 to 5. At the followup waves, respondents were categorised into four groups based on their switching behaviours: (1) full switching (switching to exclusive EC use); (2) partial switching (switching to dual use of cigarettes and ECs); (3) quitting (not beginning EC use); and (4) nonswitching (exclusive cigarette smoking). Linear mixedeffects models controlling for age, sex, race, level of education and time were used to calculate adjusted mean differences (aMD) with 95% confidence intervals (CI) in general QoL and related factors between nonswitching and switching groups. Results Compared to nonswitching, full switching was significantly associated with less fatigue (aMD − 0.092; CI -0.167 to -0.017; P = 0.016), less emotional problems (aMD − 0.089; CI -0.175 to -0.002; P = 0.044), better QoL (aMD − 0.124; CI -0.193 to -0.056; P < 0.001), but similar pain (aMD − 0.156; CI -0.351 to 0.038; P = 0.108). No significant differences were observed between partial switching and nonswitching groups for fatigue, pain, emotional problems, or QoL ( P > 0.05 in all cases). Those who quitted smoking and did not begin EC use reported the lowest fatigue, pain, and emotional problems, and the best QoL, among the four groups (all P < 0.001). Conclusions Smokers who quitted smoking or fully switched to using ECs had less healthrelated symptoms and better QoL than those who continued smoking. This impact on QoL should be taken into account when assessing the harm reduction potential of ECs, and the development of practices to help smokers switch and improve their QoL also needs to be considered.