January 17, 2011

Smoking Can Cause Genetic Damage Within Minutes

Researchers report in a new study released Saturday that the first few puffs on a cigarette can within minutes cause genetic damage linked to cancer.

"The effect is so fast that it's equivalent to injecting the substance directly into the bloodstream," according to findings described by researchers as a "stark warning" to those who smoke.

The study, which appears in the journal Chemical Research in Toxicology, issued by the American Chemical Society, is the first to track how substances in tobacco cause damage to human DNA.

Using 12 volunteer smokers, the scientists tracked pollutants -- polycyclic aromatic hydrocarbons (PAHs) -- that are carried in tobacco smoke and can also be found in coal-burning plants and in charred barbecue food.

They concentrated on one particular type of PAH -- phenanthrene, found in cigarette smoke -- and followed its journey through the blood and saw it form a toxic substance known to "trash DNA, causing mutations that can cause cancer," the study said.

"The smokers developed maximum levels of the substance in a time frame that surprised even the researchers: just 15-30 minutes after the volunteers finished smoking," said the researchers.

"These results are significant because PAH diol epoxides react readily with DNA, induce mutations, and are considered to be ultimate carcinogens of multiple PAH in cigarette smoke."

The research shows this process only took between 15 and 30 minutes to take place.

"This study is unique, it is the first to investigate human metabolism of a PAH specifically delivered by inhalation in cigarette smoke, without interference by other sources of exposure such as air pollution or the diet," Professor Stephen Hecht from the University of Minnesota and lead scientist on the study wrote in a statement.

"The results reported here should serve as a stark warning to those who are considering starting to smoke cigarettes," said Hecht.

Hecht and colleagues point out in the report that lung cancer claims a global toll of 3,000 lives each day, largely as a result of cigarette smoking.

Anti-smoking charity Ash described the findings as "chilling" and as a warning that it is never too early to quit smoking.

"Almost everybody knows that smoking can cause lung cancer," Martin Dockrell, director of policy and research at Ash (Action on Smoking and Health), told BBC News.

"The chilling thing about this research is that it shows just how early the very first stages of that process begin - not in 30 years but within 30 minutes of a single cigarette for every subject in the study," he said.

The research was funded by the National Cancer Institute. 


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