Cigarette smoking can alter genes, making it possible for the health risks associated with smoking to be inherited, studies have found.
Researchers from Uppsala University and Uppsala Clinical Research Center in Sweden found that smoking alters several health genes that can be associated with health problems for smokers, such as increased risk for cancer and diabetes. These genes can be inherited by their offspring.
A smoker's genetic material can be altered by "epigenetic modifications, i.e. chemical alterations of the DNA the affect the activity of the genes," according to a press release. These alterations are normally cause by aging but they can also result from environmental factors and lifestyle.
In a study recently published in the journal Human Molecular Genetics, the researchers examined how genes are changed in smokers and users of non-smoke tobacco. They identified a large number of genes that were altered in smokers but found no effect on the genes of non-smoke tobacco.
"This means that the epigenetic modifications are likely not caused by substances in the tobacco, but by the hundreds of different elements that are formed when the tobacco is burnt," Åsa Johansson, researcher at the Department of Immunology, Genetics and Pathology at Uppsala University and Uppsala Clinical Research Center, said in a statement.
Although it has been previously known that smokers have an increased risk of developing many types of cancer and have a reduced immune defense, the results from the study also showed that genes that increase the risk for cancer and diabetes, or are important for the immune response or sperm quality, are affected by smoking.
"Our results therefore indicate that the increased disease risk associated with smoking is partly a caused by epigenetic changes. A better understanding of the molecular mechanism behind diseases and reduced body function might lead to improved drugs and therapies in the future," Johansson said.
A previous study by Mutagenesis Section of Health Canada's Environmental and Occupational Toxicology Division in Canada suggested that children could inherit genetic damage from a father who smokes.
They demonstrated in mice that smoking can cause changes in the DNA sequence of sperm cells that could potentially be inherited by offspring.
Researchers said the mutations caused by smoking in the DNA of sperm can persist as "irreversible changes in the genetic composition of off-spring."
"We have known that mothers who smoke can harm their fetuses, and here we show evidence that fathers can potentially damage offspring long before they may even meet their future mate," Carole Yauk, lead author of the study and research scientist in the Mutagenesis Section of Health Canada's Environmental and Occupational Toxicology Division, said in a statement.
