Featured Research

from universities, journals, and other organizations

Genetic Defect Protects Against Smoking

Date:
June 25, 1998
Source:
University Of Toronto
Summary:
People with a common genetic defect that reduces their ability to metabolize nicotine are less likely to become smokers and, if they do smoke, will smoke fewer cigarettes, according to a University of Toronto study published in the June 25 issue of Nature.

People with a common genetic defect that reduces their ability to metabolize nicotine are less likely to become smokers and, if they do smoke, will smoke fewer cigarettes, according to a University of Toronto study published in the June 25 issue of Nature.

Related Articles


"People with a defective gene are twice as likely to avoid smoking altogether," said Rachel Tyndale, an assistant professor in U of T's department of pharmacology and member of the biobehavioural research department at the Centre for Addiction and Mental Health. "In North America, where 30 per cent of the adult population smokes, this translates into about 7.5 million people who are protected against smoking by carrying a single copy of this gene defect."

Building on a study published last year in which they identified the gene CYP2A6 as responsible for most nicotine metabolism, Tyndale, along with co-investigator Edward Sellers and graduate student Michael Pianezza, found that 20 per cent of non-smokers carry a defective version of the gene, compared to only 10 per cent of smokers.

As well, since dependent smokers must adjust their smoking to maintain constant blood and brain nicotine levels, those with a defective gene resulting in impaired nicotine metabolism smoked an average of 129 cigarettes a week compared to the 159 cigarettes a week smoked by people without the defect -- a decrease of 20 per cent.

There are three types of the CYP2A6 gene: wild type (functioning) and two null alleles (defective). Individuals inherit two copies of this gene, one from their maternal and one from their paternal side. People who inherit two wild type genes have a fully functioning nicotine metabolism, while those carrying a wild type plus one of the null alleles have the defect. Less than one per cent of the population has two CYP2A6 null alleles.

The researchers studied two groups of people to determine if they had one or two copies of the defective gene: 184 people who had never smoked and 244 people who smoked regularly and had become tobacco dependent.

"With these findings comes the possibility of developing a method to chemically inhibit the function of the enzyme produced from the gene -- a prevention and treatment for tobacco smoking, in other words. That is the next step," said Sellers, a professor of pharmacology and medicine at U of T and director of the psychopharmacology and dependence research group at Women's College Hospital.

The researchers say there may also be implications for nicotine replacement therapies such as gum, patches and spray as some smokers will metabolize the nicotine in these therapies faster than others, altering their effectiveness. They also note that smokers who carry the defective gene will be less efficient at turning the procarcinogens in tobacco smoke into carcinogens, and may therefore, in addition to decreased smoking, be less likely to develop lung and other tobacco-related cancers.

Funding for the study was provided in part by the National Institutes on Drug Abuse (USA), Nicogen Research Inc., the University of Toronto and the Centre for Addiction and Mental Health.

CONTACT:
Christina Marshall
U of T Public Affairs
(416) 978-5949
E-mail: christina.marshall@utoronto.ca


Story Source:

The above story is based on materials provided by University Of Toronto. Note: Materials may be edited for content and length.


Cite This Page:

University Of Toronto. "Genetic Defect Protects Against Smoking." ScienceDaily. ScienceDaily, 25 June 1998. <www.sciencedaily.com/releases/1998/06/980625083840.htm>.
University Of Toronto. (1998, June 25). Genetic Defect Protects Against Smoking. ScienceDaily. Retrieved March 31, 2015 from www.sciencedaily.com/releases/1998/06/980625083840.htm
University Of Toronto. "Genetic Defect Protects Against Smoking." ScienceDaily. www.sciencedaily.com/releases/1998/06/980625083840.htm (accessed March 31, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Tuesday, March 31, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Solitair Device Aims to Takes Guesswork out of Sun Safety

Solitair Device Aims to Takes Guesswork out of Sun Safety

Reuters - Innovations Video Online (Mar. 31, 2015) — The Solitair device aims to take the confusion out of how much sunlight we should expose our skin to. Small enough to be worn as a tie or hair clip, it monitors the user&apos;s sun exposure by taking into account their skin pigment, location and schedule. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Soda, Salt and Sugar: The Next Generation of Taxes

Soda, Salt and Sugar: The Next Generation of Taxes

Washington Post (Mar. 30, 2015) — Denisa Livingston, a health advocate for the Dinι Community Advocacy Alliance, and the Post&apos;s Abby Phillip discuss efforts around the country to make unhealthy food choices hurt your wallet as much as your waistline. Video provided by Washington Post
Powered by NewsLook.com
UnitedHealth Buys Catamaran

UnitedHealth Buys Catamaran

Reuters - Business Video Online (Mar. 30, 2015) — The $12.8 billion merger will combine the U.S.&apos; third and fourth largest pharmacy benefit managers. Analysts say smaller PBMs could also merge. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
S. Leone in New Anti-Ebola Lockdown

S. Leone in New Anti-Ebola Lockdown

AFP (Mar. 28, 2015) — Sierra Leone imposed a three-day nationwide lockdown Friday for the second time in six months in a bid to prevent a resurgence of the deadly Ebola virus. Duration: 01:17 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins