New research suggests children with grandmothers who smoked have an increased risk of asthma even when mothers did not smoke.
An international team of researchers found that that if grandmothers had smoked whilst they were pregnant, there was an increased risk of asthma in grandchildren, even if their mothers had not smoked during pregnancy. The risk of asthma was increased by 10 to 22 percent.
"We found that smoking in previous generations can influence the risk of asthma in subsequent generations. This may also be important in the transmission of other exposures and diseases," Dr. Caroline Lodge, an author of the study and research fellow at the University of Melbourne, Australia, said in a statement.
There has been a rapid increase in asthma in the last 50 years. Changing environmental exposures are thought to be responsible for this and more recently researchers are looking at these exposures in previous generations. It is known that tobacco use can affect the activity of genes and the researchers in this new study hypothesized that these changes could then be passed to subsequent generations.
For the study, researchers investigated whether smoking in grandmothers, while they were pregnant with daughters, was linked with an increased risk of asthma in their grandchildren. They collected and analyzed data from more nearly 45,000 grandmothers from 1982 to 1986. Smoking exposure was recorded during pregnancy and use of asthma medication was recorded in 66,271 grandchildren.
"For us to understand more about the asthma epidemic, we require a greater understanding of how harmful exposures over your lifetime may influence the disease risks of generations to come," Lodge said. "Additionally, researchers in this area need to be aware, when interpreting the asthma risk from current exposures and genetic predisposition, that individuals may carry an inherited, non-genetic, risk from exposures in previous generation. This knowledge will help to clarify the findings concerning current risk factors in asthma research."
The findings were presented at the European Respiratory Society's International Congress.
