Study finds second-hand cigarette smoke can cause changes in children's genes

A new study found that This is similar to that in active smokers, thereby, making them more vulnerable to diseases as adults. The study was published in the journal Environment International. 

The findings of the highlight why children's exposure to second-hand smoke needs to be reduced. Marta Cosin-Tomàs, a researcher at the Barcelona Institute for Global Health (ISGlobal) and first author of the study said, "Our study shows that second-hand smoke during childhood leaves its mark at the molecular level and can alter the expression of genes that influence disease susceptibility in adulthood."

While genes in one's DNA act as an  instruction manual for the body, environmental factors such as tobacco smoke also affects 'gene expression'. 

Gene expression is how information in a gene translates into observable behaviour. 'DNA methylation' is one of the main processes involved that can turn a gene 'on' or 'off'. In certain cases, DNA methylation can silence specific genes which eventually leads to disease development. 

For the study,



the researchers analysed blood samples of nearly 2,700 children aged 7-10 years from across eight European countries, including Spain and France. The researchers found an increased DNA methylation in 11 regions on the genome, one's entire DNA, among children exposed to passive smoking.

The researchers said that most of these regions have been previously linked to direct or first-hand exposure to tobacco in active smokers or during pregnancy.

The team also said that six of these 11 regions were found to be associated with diseases such as asthma or cancer the risk of which is known to increase with smoking.

Mariona Bustamante, an ISGlobal researcher and senior author of the study said, "The results suggest that second-hand smoke in childhood leads to epigenetic changes (changes in gene expression) similar to those observed with intrauterine exposure to tobacco or active smoking."

Bustamante added, "This underlines the urgency of implementing comprehensive measures to reduce childhood exposure to tobacco smoke, both at home and indoors."