GLOSTRUP, Denmark – Electronic cigarettes are not as safe as researchers have claimed, especially researchers who have been found to have a conflict of interest when conducting their studies.
After examining 76 studies that often were inconsistent and contradicting, researchers in Denmark have concluded that about 34 percent of the studies with claims on the safety of e-cigarettes were authored under less-than-balanced circumstances.
The results of the survey were published online in the December 2014 edition of Preventive Medicine.
Studies pointing to potential health problems associated with e-cigarettes included fine/ultrafine particles, harmful metals, carcinogenic tobacco-specific nitrosamines, volatile organic compounds, carcinogenic carbonyls, cytotoxicity and changed gene expression.
Researchers are especially concerned about the compounds not found in conventional cigarettes but present in e-cigarettes such as propylene glycol. Some of the studies examined also found increased airway resistance after short-term exposure.
But, because of conflicts of interest, the reports on short-term adverse events were often flawed by selection bias.
The main conclusion to this survey is that non-biased, long-term studies need to be conducted to examine harmful effects of e-cigarette use.