I have to admit that I haven’t heard the term third hand smoke before but this study, published in the journal Clinical Science, caught my attention.

As health-freaks we obviously don’t smoke. When we smell smoke or see a person with a cigarette in a public place we raise our brows and utter an offensive comment about the smoker’s selfishness and lack of consideration.

But there is more to worry about when it comes to the negative health effects of this harmful habit. The residues of cigarette smoke deposit on furniture surfaces, floors and carpets, creating a toxic layer that is hard to get rid off. These residues is what is called third hand smoke and the new study by researchers from the University of California – Riverside has found that these residues can actually seriously harm people’s health.

As people touch the contaminated surfaces, the toxins penetrate into their bodies through the skin.

This particularly study didn’t involve people but mice. Still, the results are rather shocking. The researchers exposed the mice to levels of third hand smoke (THS) that mimicked human exposure in homes of smokers. They found that within a month of regular exposure, the mice started to show signs of liver and lung damage, type 2 diabetes, hyperactivity and slower wound healing.

“Our goal was to determine the minimum amount of time required to cause physiological changes in mice when they are exposed to THS,” said Manuela Martins-Green, professor and chair of the Department of Molecular, Cell and Systems Biology at the University of California – Riverside, who led the research. “We found that THS exposure as early as one month resulted in liver damage. THS exposure for two months resulted in further molecular damage, and at four to six months caused even more such damage. We also found that the mice showed insulin resistance after long-term THS exposure.”

What does all that mean? If you are regularly spending time somewhere where people smoke, even if they don’t smoke there in your presence, you are absorbing toxins that can seriously harm your health.

“THS is a stealth toxin, a silent killer,” Martins-Green said. “Contaminants can be absorbed through the skin and through breathing. Although our research was not done on humans, people should be aware that hotel rooms, cars, and homes that were occupied by smokers are very likely to be contaminated with THS.”

The mice also showed higher levels of stress hormones such as epinephrine within one month of continued exposure to THS. There is obviously nothing positive about having continuously elevated levels of stress hormones. In fact, stress is believed to be the cause of many complex health conditions (I have written about it in this article).

According to Martins-Green, THS toxins remain on surfaces for years and are resistant to even strong cleaning agents. Overtime, these toxins react with the surrounding air, giving rise to potent carcinogens.

“Exposure to tobacco smoke deposited on surfaces in homes and in house dust is an entirely newly recognized form of toxicity,” commented Stephen T. Holgate, Professor of Immunopharmacology at the Medical Research Council, who was not involved in the study.

“The fact that noxious chemicals in tobacco smoke once deposited change in chemistry to become even more toxic and carcinogenic is of considerable importance to the health of all of us, but our children in particular.”

Children not only absorb a disproportionate amount of THS through their skin as they crawl on the floors, they also ingest the toxins whenever they put their unwashed hands in their mouths, there searchers said.

Children living in the homes where smoking has occurred have been known to show tobacco metabolites in their urine as well as tobacco-derived carcinogens called tobacco specific nitrosamines.