A new study into how e-cigarettes can help people quit smoking long-term suggests that the biggest effects are felt over the first month.

The paper, presented at the 2015 American Thoracic Society International Conference, finds that "e-cigarettes have been shown to significantly improve abstinence at 1 month" when compared to placebo electronic smokes.

Lead author Riyad al-Lehebi and his University of Toronto colleagues searched two medical databases' worth of previous studies -- 4,569 abstracts identified -- coming back with 297 articles and then whittling them down to 2 randomized trials and 2 uncontrolled before-and-after studies.

Their findings, published under the title "Efficacy and Safety of Electronic Cigarettes for Smoking Cessation: A Systematic Review," showed that e-cigarettes can make a significant difference for those seeking to abstain from traditional forms of smoking, at least over an initial month-long period.

But only one study went on to evaluate continuous abstinence at 6 months, with results from e-cigarettes equal to those obtained by subjects using open-label nicotine patches instead.

"Long-term studies of the efficacy and safety of e-cigarettes are needed to determine their possible role in smoking cessation," recommended the scholars, suggesting that open-label nicotine patches appear to be a better quitting aid for now in terms of other, more serious complications associated with the two methods' use.