It's no secret that cigarettes and heavy drinking are linked, people who engage in risky behaviors tend to do so in multiple ways, but a link to e-cigarettes, which have no tobacco, is new. A paper in Addictive Behaviors also found that more women than men use e-cigarettes socially, like when drinking, opposite to patterns seen in regular cigarette smoking.

Electronic cigarettes, or e-cigarettes, were developed to mimic real cigarettes, giving users the nicotine they are addicted to, along with the same feel and experience as smoking a cigarette, without the harmful chemicals in smoke. They are widely promoted as a smoking cessation tool, like gums and patches, or at least harm reduction because they don't have all of the smoke. The authors claim that more than 6 percent of the general population - and 17 percent of people with addictions - use e-cigarettes. The authors of the new study say it's crucial to consider the knock-on effects of e-cigarette use when evaluating their safety, not just their direct health effects.

Because of the rapid increase in their use, research has focused on their health effects. However, the new study looks at one of the secondary effects of e-cigarette use and suggests that people need to be aware of the link between e-cigarette use and problematic drinking.

"This area of research is extremely important and I don't want it to get pushed to the side," said graduate student Alexandra Hershberger, lead author of the paper from Purdue University. "Establishing the direct health effects of e-cigarette use is important but it's vital to look at the secondary effects too."

Previous studies have revealed a strong link between cigarette smoking and drinking, so the researchers hypothesized that a similar connection may be found with e-cigarette use and drinking. They surveyed two groups of people who drink alcohol using a modified version of the Nicotine and Other Substance Interaction Expectancy Questionnaire (NOSIE) to find out whether people expected to use e-cigarettes and alcohol together.

In both groups, of 692 and 714 people, the survey results were that drinking alcohol leads to e-cigarette use and vice versa. E-cigarette users were significantly more likely to drink problematically than non-users in both groups. What's more, people who expected to use e-cigarettes and alcohol together reported drinking more.

The results suggest to the the authors that using e-cigarettes to quit smoking could mean people miss out on one of the benefits of quitting; smoking cessation generally results in people drinking less alcohol, but using e-cigarettes means this decrease may not happen.

"If you quit smoking cold turkey, it affects other behaviors associated with smoking, such as drinking," said Alexandra. "By replacing smoking with e-cigarette use, it could be that you're at risk of continuing behaviors you don't want to continue. This is particularly serious for people with alcohol addiction - using e-cigarettes could make it harder to stop drinking."

The study also revealed that more women use e-cigarettes socially than men. In general, men report more risk-taking behaviors than women, including smoking, drinking and drug use. The findings suggest that women may not perceive e-cigarette use as risky.

"We were surprised to see higher e-cigarette use in women," said Alexandra. "Generally men tend to report more risk-taking across the board, but in our study, women outnumbered men in terms of e-cigarette use. This could be because women perceive the device differently to other risk-taking behavior; e-cigarettes tend to be viewed more positively than cigarettes. Those views could be driving more use in women than we'd expect."