Table 1 Characteristics of studies
From: Respiratory health effects of e-cigarette substitution for tobacco cigarettes: a systematic review
Study References Country | Design | Funder | Participants | Intervention | Duration |
|---|---|---|---|---|---|
Acute | |||||
Chaumont [23] Belgium | RCT | Private Non-profit | N = 9 randomly selected from a pool of Males 18, Females 7 Age: 23 (± 0.4) Very occasional smoking, less than 1 cigarette a week | 25 total puffs, one every 30 s [excessive exposure] non-nicotine | Tested 10 min after vaping |
Flouris [27] Greece | Quasi | No funding | Participants who smoke n = 15 Male 8, Female 7 Age: 23.5–54 years “Long-term smoking” | 3–14 puffs (average 10) on nicotine ENDS | Tested 1 h after vaping |
Kerr [29] UK | RCT | Non-profit | N = 20 male only Age: 31.6 (± 10.5) | 15 puffs of nicotine ENDS | Tested immediately after vaping |
Kotoulas [30] Greece | RCT | University Hospital | N = 50 n = 25 moderate asthma, smoking n = 25 “healthy” participants who smoke Asthma: Male 13, Females 12 Asthma age: 40.64 (± 10.81) | 10 puffs of nicotine ENDS | Tested 5 min after vaping |
Lappas [22] Greece | Quasi | Non-profit | N = 54 n = 27 mild asthma, dual use (> 1 cigarette past 30 days) (nicotine ENDS use ≥ 3 months) Age: 18–35 | 10 puffs on nicotine ENDS | Tested 30 min after vaping |
Palmidas [31] Greece | Quasi | Funding NR | N = 76 participants who smoke n = 16 COPD n = 11 asthma > 15 cigarettes/day | Nicotine or non-nicotine ENDS use for 10 min | Tested 0, 15, and 30 min after vaping |
Vardavas [35] Greece | Quasi | Non-profit | N = 30 Male 14, Females 16 Age: 19–56, Mean 34.8 | 5 min nicotine ENDS | Tested immediately after vaping |
Follow-up | |||||
Barna [24] Hungary | Quasi | Funding NR | N = 24 male only Age: 20–64 Former heavy smoking (not defined) Current use of ENDS Length of ENDS use: NR | ENDS users reverted to smoking 20–25 cigarettes daily | 7 days |
Cravo [25] UK | RCT | Industry | n = 286 ENDS n = 101 TC ~ 55% Male Age: 34.1 (± 10.6) TC use: 11–20/day (range 5–30) | Nicotine ENDS supplied TC abstinence requested | 12 weeks |
D’Ruiz [26] US | RCT | Industry | N = 105 65% Male Age: 37.8 (± 11.1) TC use 18.8 (± 6.5)/day | Clinical confinement Two groups: (1) exclusive nicotine ENDS (2) 50% of usual TC consumption plus nicotine ENDS | 5 days |
Hickling [28] UK | Quasi | Non-profit Government | N = 50 38 Male, 12 Female Mean age: 38.96 TC use: 17.9/day (mean) | Provided with nicotine ENDS used ad lib | 24 weeks |
Polosa asthma [33] Italy [39*] | Cohort | Funding NR | N = 16 mild to moderate asthma at follow-up n = 10 Exclusive ENDS use Male 7, Female 3 Age: 33.4 (± 11.6) n = 6 Dual users Age: 45.7 (± 9.9) | Participants continued to use ENDS or dual use | 24 months |
Polosa COPD [32] Italy | Cohort | University | N = 39 patients with COPD at F/U n = 20 COPD ENDS group (dual and exclusive use) Males 17, Females 3 Age: 66.9 (± 5.8) | Ad lib ENDS use | 60 months |
Pulvers [38]/ Arnold [34] US | RCT | Government | N = 186 at F/U ENDS n = 125 TC n = 61 Male 111, Female 75 Age: 43.3 (± 12.5) TC use: 12.1 (± 7.2)/day 92 African American 94 Latinx | Nicotine ENDS with education to reduce TC | 6 weeks |
Veldheer [36] US | RCT | Government | n = 191 participants using ENDS 56.5% female Age: 46.5 (± 11.4) TC use: 18.1 (± 6.5)/day | Nicotine and non-nicotine ENDS ad lib “Encouraged” to reduce TC | 3 months |
Walele [37] UK | RCT | Industry | N = 102 Males 57, Females 45 Age: 38.7 (± 10.2) | Nicotine ENDS supplied Requested TC abstinence and exclusive use of supplied ENDS | 24 months |