Gene stokes smoking addiction

Health researchers are investigating the idea of screening young Maori for a gene linked to nicotine addiction.

Research published overseas last year found two variants of a gene called CYP2A6 which reduce the level of nicotine-processing enzymes in the liver. People with those genes may process nicotine more slowly, exposing their brains to high concentrations of nicotine and the pleasurable feelings that are the key to addiction.

"DNA variants in the CYP2A6 gene differ significantly between ethnic groups around the world and we have shown that the Maori population has a much higher proportion of genetically slow nicotine metabolisers than Europeans," said Environmental Science and Research (ESR) genomics researcher Rod Lea.

"It's possible a slower nicotine metabolic rate may increase susceptibility to tobacco dependence," Dr Lea said in the ESR Briefing newsletter, published this week.

"Genetic tests based on this could enable personalised nicotine replacement therapy to be developed, making it more likely that it will be successful."

He said the gene could influence the likelihood of someone becoming addicted and their ability to give up, as well as their risk of developing smoking-related diseases like cancer.

Maori are twice as likely to smoke as non-Maori, and Maori women have one of the highest smoking rates in the world.

Dr Lea said ESR was comparing nicotine intake and metabolic rates between Maori and European smokers.

It was studying a sample of smokers from Te Iwi o Rakaipaaka - Nuhaka Maori from the northern Hawkes Bay - which would be examined alongside a comparative group of smokers of European descent, also from Hawkes Bay.

Dr Lea said the ESR work was part of the relatively new science of "envirogenomics", which aimed to understand how genetic make-up influenced the response of individual people to environmental agents such as drugs, toxins and microbes.

"Some smokers live a long and healthy life while others develop severe conditions such as cancer and heart disease," Dr Lea said.

"The differences are due to a complex interplay between an individual's genetic make-up and environmental agents they are exposed to".

He said that genetic susceptibility to nicotine addiction was only one research path. Stomach cancer, alcoholism and diabetes already showed evidence of having a genetic influence attributable to ethnic differences. 

- NZPA