The same was true for prior 30-day e-cigarette use after accounting for baseline intent to quit, cigarette consumption, and dependence (OR 0.76, P=0.46), the group reported in a research letter online in JAMA Internal Medicine.
Electronic cigarettes didn't help smokers quit or even smoke less, according to a longitudinal study that may quash some public health hopes for the nicotine-delivery devices.
Note that while the U.S. Supreme court struck down FDA attempts to regulate e-cigarettes as drugs or devices in 2010, the agency has pending regulations that are expected to generally bring the same kind of restrictions to e-cigarettes as to other tobacco products.
Among people who didn't quit, "vaping" wasn't associated with smoking fewer cigarettes over time either (P=0.25).
These findings from analysis of 949 smokers in a nationally representative panel followed from 2011 through 2012 by web-based market research firm Knowledge Networks (now GfK) add to similar findings from population-based and Quitline studies.
"Although electronic cigarettes are aggressively promoted as smoking cessation aids, studies of their effectiveness for cessation have been unconvincing," Ling's group wrote.
"As a harm reduction proponent, I would be willing to put aside the fact that any product with the name 'cigarette' (e- or otherwise) causes me reflex tachycardia and support electronic cigarettes ... if there were good data indicating that they helped smokers to stop," JAMA Internal Medicine editorMitchell Katz, MD, wrote in a note accompanying Ling's letter.
However, he agreed with their conclusion and further advocated FDA regulation as drug-delivery devices.
"The bottom line is e-cigarettes are not a good way to quit," commented Brian Tiep, MD, director of smoking cessation at City of Hope in Duarte, Calif.
The devices may not have all the carcinogenic compounds found in burning tobacco, but that doesn't mean they're entirely safe, he told MedPage Today, pointing to FDA analyses finding carcinogenic nitrosamines and the antifreeze component diethylene glycol in e-cigarette nicotine solutions.
However, he noted that Ling's study population wasn't actively trying to quit and that an adequately-powered study is still needed to assess e-cigarettes' performance in a smoking cessation program.
Ling's group also cautioned about limited statistical power, as smoking cessation was self-reported and included only nine of the 88 e-cigarette users.
Their study lacked data on how frequently the population used e-cigarettes and motivation for use as well.
The data came from a study funded by the National Cancer Institute.
The researchers disclosed no relevant financial relationships with industry.
Tiep disclosed no relevant financial relationships with industry.