Table 1

Reported parameters in all studies

Reported parametersAnand11Babineau12Barnett13
Porter18
Bunnell14
Cardenas15
Dutra16
Lee17
Wang19
Camenga2021Cho22Cooper23Czoli24Fotiou25Goniewicz26Hanewinkel27Hughes28Kinnunen29Kong30
Krishnan sarin31
Lee32Moore33Pentz34
Riggs35
Pepper41Suris36Tucker37Wang38White39Wills30
Level 1
 Ever e-cig (or never), regardless of CC
 Current e-cig, regardless of CC
 Ever CC (or never), regardless of e-cig
 Current CC, regardless of e-cig
Level 2
 Dual current use
 Dual lifetime use
 Never either
 Never CC and ever e-cig
 Never CC and current e-cig
 Ever CC and never e-cig
 Ever CC and current e-cig
 Current CC and never e-cig
 Current CC and ever e-cig
Level 3
 Proportion of never CC who are:
  Never e-cig
  Ever e-cig
  Current e-cig
 Proportion of ever CC who are:
  Never e-cig
  Ever e-cig
  Current e-cig
 Proportion of current CC who are:
  Never e-cig
  Ever e-cig
  Current e-cig
 Proportion of never e-cig who are:
  Never CC
  Ever CC
  Current CC
 Proportion of ever e-cig who are:
  Never CC*
  Ever CC*
  Current CC
 Proportion of current e-cig who are:
  Never CC*
  Ever CC
  Current CC*
  • *Data provided, but unclear if related to ever or current.

  • CC, conventional cigarettes; e-cig, e-cigarette.