Third-hand smoke may lead to a higher risk of developing lung cancer، especially among babies، according to a new study by a team of researchers from the Department of Energy's Lawrence Berkeley National Laboratory، as the Technical Times said.
Third-hand smoke is defined as the pollutants that remain in dust and on indoor surfaces even after the smoker has stopped. Other people are exposed to third-hand smoke through inhalation، ingestion، or dermal uptake of the residues. Making matters worse is that the timescale for third-hand smoke lasts much longer than second-hand smoke، stretching to days، months، and even years.
A 2017 study from the same team of researchers linked exposure to third-hand smoke to lower body weight and immune system changes in juvenile mice. The new study follows up on the previous findings، suggesting that early exposure to third-hand smoke may lead to greater risks to lung cancer، in terms of incidence and severity.
For the study، the researchers chose 24 juvenile mice with a strain known to carry a high risk of spontaneously developing lung cancer. The mice were placed in an environment that was the equivalent of what a human toddler will be exposed to if living in a home with smokers.
After 40 weeks، the mice were observed to have increased risk of developing lung cancer. They also carried a bigger risk of developing larger tumors at greater quantities.
In vitro studies with cultured lung cancer cells from humans also revealed to researchers that third-hand smoke results in further mutation of damaged cells، as well as larger tumors at greater quantities.
According to Bo Hang، a staff scientist from Berkeley Lab and a member of the team of researchers، young children were the most susceptible to the negative effects of third-hand smoke. This is because they crawl and place objects in their mouth، increasing the chances that they come in contact with surfaces that are contaminated with third-hand smoke.
The dangers of smoking have been well documented، with another study from January showing that smoking even just one cigarette per day may lead to higher risk for heart diseases and strokes. E-cigarettes، meanwhile، are falling from favor as a smoking alternative، with a recent study showing that teenagers using them are exposed to the same toxic chemicals that are found in tobacco-based cigarettes.
However، anti-smoking advocates have long argued that smoking also negatively affects the health of the people around smokers، as proven by the new study. Alarmingly، despite the warnings، one in 14 women in the United States continued smoking while pregnant.