Many of us are familiar with first-hand smoke and second-hand smoke, but what about third-hand smoke?

 

Well, you better get familiar with it because according to a new study conducted by researchers at the University of California, Riverside, the effects of third-hand smoke may be just as deadly as first-hand smoke.

 

First-hand smoke refers to the smoke inhaled by a smoker. Second-hand smoke refers to exhaled smoke and other substances emanating from a burning cigarette that can get inhaled by others. Third-hand smoke is the second-hand smoke that gets left on the surfaces of objects. Over time, these left over chemicals can age and becomes progressively more toxic.

 

The results of the study provide a basis for studies on the toxic effects of third-hand smoke in humans and serve to inform potential regulatory policies aimed at preventing involuntary exposure to third-hand smoke.

 

Third-hand smoke is a potential health threat to children, spouses of smokers and workers in environments where smoking is, or has been, allowed. Contamination of the homes of smokers by third-hand smoke is high, both on surfaces and in dust, including children’s bedrooms. Re-emission of nicotine from contaminated indoor surfaces in these households can lead to nicotine exposure levels similar to that of smoking.

 

The team found that the mice exposed to third-hand smoke in the lab showed alterations in multiple organ systems and excreted levels of a tobacco-specific carcinogen similar to those found in children exposed to second-hand smoke (and consequently to third-hand smoke):

 

- In the liver, third-hand smoke was found to increase lipid levels and non-alcoholic fatty liver disease, a precursor to cirrhosis and cancer and a potential contributor to cardiovascular disease.

- In the lungs, third-hand smoke was found to simulate excess collagen production and high levels of inflammatory cytokines (small proteins involved in cell signaling), suggesting propensity for fibrosis with implications for inflammation-induced diseases such as chronic obstructive pulmonary disease and asthma.

- In wounded skin, healing in mice exposed to third-hand smoke showed many characteristics of the kind of poor healing observed in human smokers who have gone through surgery.

- Finally, in behavioral tests the mice exposed to third-hand smoke showed hyperactivity.