Sept 21 : People who find it excessively difficult to quit smoking can now blame their genes for not being able to kick the butt, for a new study has found that a genetic variation affects smoking cessation treatment.

The study was conducted by a team of researchers led by Dr Anna M. Lee at the Centre for Addiction and Mental Health and the Department of Pharmacology at The University of Toronto in Ontario, Canada, and appears in the September 15 issue of the journal Biological Psychiatry.

According to the researchers, the genetic variation in a particular enzyme affects the success rates of treatment with bupropion, an anti-smoking drug.

This variant is present in 25-50pct of people, thus affecting a large portion of the population.

Dr Lee and her team performed CYP2B6 genotyping on smoking individuals. CYP2B6 is a gene that is known to be highly variable and whose enzyme metabolizes both bupropion and nicotine.

Participants were then provided with either placebo or bupropion treatment for ten weeks.

Following this, the researchers noted that participants with the CYP2B6*6 allele of the gene benefited from bupropion treatment and maintained abstinence longer while doing poorly on placebo, with a 32.5pct abstinent rate vs. 14.3pct, respectively.

In contrast, those in the CYP2B6*1 group did well on both bupropion and placebo, with similar abstinence rates at the end of treatment and after a six month follow-up.

“This first study, while requiring replication, identifies a very common genetic variant that appears to affect smoking cessation treatment outcome,” said Rachel Tyndale, M.Sc., Ph.D., one of the authors on this study. (ANI)