Struggling to quit smoking? Now you can blame your genes

Smokers who find it hard to cut down or quit may be at the mercy of their genes.

Scientists identified three genetic mutations that increase the number of cigarettes people smoke a day.

Several also appear to be associated with taking up smoking, and one with being able to quit.

The findings could lead to more personalised - and ultimately more effective - treatments that help people stub out their cigarettes.

Three studies published online in Nature Genetics compared the DNA of a total of more than 140,000 people and discovered the desire to give up is down to your genes rather than willpower.

Two of them found regions associated to the number of cigarettes smoked per day that include two genes that have been linked with nicotine dependence and two others that regulate nicotine metabolism in the body.

Mutations in these genes are associated with a small increase in smoking quantity - about half a cigarette a day - but around 10 per cent increase in risk of lung cancer compared with non carriers.

Lead author Professor Kari Stefansson, a neurologist at deCODE genetics in Reykjavik, Iceland, said: 'Smoking is bad for anyone's health. It is even worse for some.

'To some degree these variants suggest those for whom nicotine is more addictive are driven to smoke more, increasing their exposure to environmental risk.

'But given the quite substantial corresponding increases in risk of lung cancer it may also be that they make people more susceptible to the noxious effects of tobacco smoke.

'What is clear is that these variants - which are all near genes that encode nicotine metabolizing enzymes and receptors - are giving us a solid starting point for finding answers to advance personal and public health.'

A third study by Dr Clyde Francks, of the University of Oxford, and colleagues found variants of three genes on chromosome 15 that make people more prone to nicotine addiction. Nicotine is the primary chemical responsible for smoking addiction.

He said: 'Smoking behavior and nicotine dependence are multifactorial traits with substantial genetic influences. There is an urgent need to better understand the molecular neurobiology of nicotine dependence in order to design targeted, more effective therapies.

'These findings have provided further new insights into the biology of smoking behaviour.'

E-cigarettes can help kick the butt

Nicotine delivered via an e-cigarette can help curb the urge to smoke, says new research.

E-cigarettes are electronic nicotine delivery devices that resemble cigarettes but do not use tobacco. They release a small dose of nicotine with each puff.

"The e-cigarettes that we tested appeared to be as effective as a standard nicotine replacement therapy inhalator in reducing the desire," says Chris Bullen, associate professor at the University of Auckland, who led the study.

"Our results indicate that e-cigarettes have potential as a method to help people stop smoking, in the same ways as a nicotine inhalator. However, our findings should be seen as preliminary and need to be confirmed for this and other e-cigarette brands."

"E-cigarettes are popular in the United States and Asia where people report buying them to reduce the cost of smoking, cut down on cigarette consumption, use in smokefree places, relieve tobacco withdrawal symptoms, or help quit smoking," says Bullen.

But this is the first reputable clinical study to actually examine their effect on smokers," says Bullen.

The study compared 40 adult smokers who on different days used a Ruyan V8 e-cigarette delivering either nicotine or placebo; a Nicorette nicotine inhalator; or their usual cigarette, says an Auckland release.

"We found that the device delivered nicotine to the bloodstream in a similar way as an inhalator, reduced the desire to smoke, and was acceptable to most users," says Bullen.

"However further studies are required to examine the potential and safety of long-term e-cigarette use, and a large clinical trial would be needed to determine their effectiveness in helping people stop smoking."

MLB asked to chew on tobacco ban

Major League Baseball and the players' union should "take action to end the use of smokeless tobacco by big-league players," Rep. Henry Waxman, D-Calif., chairman of the House Committee on Energy and Commerce, said Wednesday.

Executives from Major League Baseball and the players' association joined U.S. public-health officials to testify before the panel on the prevalence of smokeless tobacco and whether its use by professional athletes influences children.

"Like many generations of Major League Baseball players, I started using spit tobacco because I saw other players doing it, and I thought it was part of being a major-league player," said Joe Garagiola, a television announcer and former player. "This is a dangerous, deadly habit."

Tobacco of all kinds is banned in minor-league baseball, a policy Garagiola urged major-league players to adopt. While major-league players aren't allowed to smoke cigarettes in uniform in view of spectators, chewing tobacco is different, said David Prouty, chief labor counsel for the Major League Baseball Players Association.

"Cigarettes impact the ability to play the game, are banned from public use under a variety of state and municipal laws, and may endanger the health of those in the immediate area," Prouty said. "Baseball players should not be prohibited from using substances that are perfectly legal and available to the general public."

Tobacco companies led by Philip Morris and RJ Reynolds argue they should be allowed to market smokeless products as a safer alternative to cigarettes.

"Some adults who would otherwise continue smoking may be willing to move to a smokeless-tobacco alternative to cigarettes," said James Dillard, a senior vice president at Altria Group, which owns Philip Morris. "Smokeless-tobacco products are substantially lower on the risk continuum than cigarettes."

Health officials say they worry chewing tobacco will have the opposite effect: that it may act as a gateway to cigarettes, and that children could become addicted to tobacco by emulating its use by baseball players.

"We don't let baseball players go stand out in the field and drink beer," Waxman said during the hearing. "The MLB Association won't let them stand out there and smoke cigarettes," and chewing tobacco also should disappear from games, he said.

Waxman last year supported a bill giving the Food and Drug Administration (FDA) authority to regulate tobacco products. The law bans tobacco-brand sponsorships of sports and entertainment events among measures aimed at reducing underage smoking.

Nine of every 10 people who die from mouth and throat cancers used tobacco, according to the American Dental Association (ADA).

Tobacco products also are linked to higher rates of gum disease, one of the leading causes of adult tooth loss, the ADA said in an October letter to the FDA.

Terry Pechacek of the Centers for Disease Control and Prevention, and Deborah Winn of the National Cancer Institute testified about the links between smokeless tobacco and cancer, and the addictiveness of smokeless tobacco.

Pechacek said smokeless tobacco can cause oral cancer and pancreatic cancer, and has been linked to fatal heart attacks.

Banning use would require negotiations with the players union, said Robert Manfred, an executive vice president for Major League Baseball.

"Like drug testing, the regulation of player use of tobacco products is a mandatory subject of collective bargaining with the players association," he said. "But unlike performance-enhancing substances, smokeless-tobacco products are legal in all 50 states for sale to, and consumption by, adults."