Smokers who are trying to kick the habit may be able to turn to their cell phones to avoid temptation, a study published Tuesday suggests.

In a review of four clinical trials, researchers found that smoking-cessation programs that included text-messaged advice doubled the chances that smokers would be able to kick the habit for up to a year.

The programs, conducted in New Zealand, the UK and Norway, used text messages as a way to give smokers daily advice and encouragement. The programs also offered support when quitters needed it the most; if they found themselves craving nicotine, for example, they could text crave to the program and get immediate advice on what to do.

Two of the studies looked at programs that only involved text messages, finding that the service doubled the odds that smokers would quit over six weeks.

The other two studies focused on a program in Norway that used text messages, emails and a dedicated Web site; it found that smokers who used the program were twice as likely to report abstinence for up to one year.

The findings appear in the Cochrane Library, a publication of the international research organization the Cochrane Collaboration.

Kicking the smoking habit is notoriously difficult, and text messaging is no magic bullet. Most of the roughly 2,600 smokers across the studies did not succeed in quitting, regardless of whether they had text-message help.

But text messages could serve as one more tool in the smoking-cessation arsenal, according to lead researcher Dr. Robyn Whittaker, of the University of Auckland in New Zealand.

We know that stopping smoking can be really difficult and most people take several attempts to quit successfully, Whittaker told Reuters Health in an email. And so I think it is important to be able to offer lots of different options for extra support.

Text messaging may be effective for some people, in part, because they can get help right at the time when cravings strike, according to Whittaker.

The frequent messages can also act as a good reminder and motivation to keep going, Whittaker added.

One of the programs in the study, called Txt2Quit, is already up and running in New Zealand, with government funding. Smokers seeking to quit can sign up for the free 26-week program, which automatically sends users two to three text messages per day shortly before their designated quit date, and for one month afterward. After that, they receive three text messages a week.

A recent study of people who participated in the program's first year found that one-third were abstinent four weeks after their quit date. That figure dropped to 16 percent after 22 weeks.

It's estimated that only about 5 percent of smokers are able to kick the habit without any help.

SOURCE: The Cochrane Library, online October 7, 2009.