Can First Cigarette lead to Lifelong Smoking?

The smoking smell and its first effects can’t be forgotten so easy. Anyone who has ever tried smoking probably remembers that first cigarette. For some, it brought a wave of nausea or a nasty coughing fit. For others, those first puffs also came with a rush of pleasure.

Now, a new study links those first experiences with smoking, and the likelihood that a person is currently a smoker, to a particular genetic variation. Anti–smoking researchers can explain the path that leads from that first cigarette to lifelong smoking.

Other researchers have already linked variations in the same genetic region to smokers' level of dependence on nicotine, to the number of cigarettes smoked per day and to a far higher risk of lung cancer — the ultimate outcome of a lifetime of smoking.

Scientists took a smoking data from 435 volunteers. Among them were people who never smoked had, tried at least one cigarette but no more than 100 cigarettes in their lives, and never formed a smoking habit. And also there were regular smokers which had smoked at least five cigarettes a day for at least the past five years. The regular smokers in the study were far more likely than the never-smokers, in which just one base-pair in the gene sequence was different from the more common form. This kind of genetic variation is called a single nucleotide polymorphism or SNP.

Smokers were also eight times as likely to report that their first cigarettes gave them a pleasure.

Ovide Pomerleau, a professor of psychiatry at the University of Michigan Medical School and founder of the U-M Nicotine Research Laboratory, said: "It appears that for people who have a certain genetic makeup, the initial physical reaction to smoking can play a significant role in determining what happens next. If cigarette smoking is sustained, nicotine addiction can occur in a few days to a few months. The finding of a genetic association with pleasurable early smoking experiences may help explain how people get addicted — and, of course, once addicted, many will keep smoking for the rest of their lives."

The researchers said that the genetic variant explains only a portion of human smoking behavior. Mr. Promerleau added: "Taking into account its links to increased liking of initial smoking, stronger likelihood of getting addicted to nicotine, and greater probability of developing lung cancer, this genetic variant may well constitute a "triple whammy" for smoking-related disease."