How much second hand smoke is safe?

Posted on Mon, 22 Nov 10

Even at the lowest detectable levels of exposure there are significant changes in gene expression within the cells lining of your airways. Such genetic changes are thought to precede reparatory disease including lung cancer; no level of tobacco smoke exposure is safe.

To find out what level of second hand smoke exposure is linked to the development of lung disease and cancer researchers from Cornell University used a sensitive gene assay to detect changes in cells typically affected by lung disease and cancer (1). Compared to non-smokers, those with low level tobacco smoke exposure (second hand smoke or occasional smokers) exhibited genetic changes of a similar magnitude to regular smokers.

The group found there was no threshold for nicotine exposure and negative effects occurred even at the lowest level of measurable exposure. Is it safe to hang out with smokers or expose those around you to tobacco smoke? The answer is no, an answer that should better inform public behaviour and health policy.

References:

1. Strulovici-Barel Y, Omberg L, O'Mahony M, et al. Threshold of Biologic Responses of the Small Airway Epithelium to Low Levels of Tobacco Smoke. Am J Respir Crit Care Med. 2010 Aug 6. [Epub ahead of print]