Comparison of Bladder Carcinogens in the Urine of E-cigarette Users Versus Non E-cigarette Using Controls

Sci Rep. 2018 Jan 11;8(1):507. doi: 10.1038/s41598-017-19030-1.


Electronic cigarette (EC) use is gaining popularity as a substitute for conventional smoking due to the perception and evidence it represents a safer alternative. In contrast to the common perception amongst users that ECs represent no risk initial studies have revealed a complex composition of e-cigarette liquids. Conventional cigarette smoking is a known risk factor for developing bladder cancer and prior reports raise concern some of those causative compounds may exist in EC liquids or vapor. Urine samples were collected from 13 e-cigarette using subjects and 10 non e-cigarette using controls. Five known bladder carcinogens that are either present in conventional cigarettes, products of combustion, or solvents believed to be used in some e-cigarette formulations were quantified by liquid chromatography - mass spectrometry (LC-MS). Analysis of e-cigarette user urine revealed the presence of two carcinogenic compounds, o-toluidine and 2-naphthylamine, at a mean 2.3 and 1.3 fold higher concentration (p-value of 0.0013 and 0.014 respectively). Many of these subjects (9/13) were long term nonsmokers (>12 months). Further study is needed to clarify the safety profile of e-cigarettes and their contribution to the development of bladder cancer given the greater concentration of carcinogenic aromatic amines in the urine of e-cigarette users.

Publication types

  • Comparative Study

MeSH terms

  • 2-Naphthylamine / analysis
  • Adult
  • Carcinogens / analysis*
  • Case-Control Studies
  • Chromatography, High Pressure Liquid
  • Electronic Nicotine Delivery Systems*
  • Female
  • Humans
  • Male
  • Mass Spectrometry
  • Middle Aged
  • Toluidines / urine
  • Young Adult


  • Carcinogens
  • Toluidines
  • 2-toluidine
  • 2-Naphthylamine