New details of the long-term affects of secondhand smoke are detailed in two studies in the December 2009 issue of Cancer Epidemiology, Biomarkers & Prevention (CEBP), a journal of the American Association for Cancer Research.
The December issue features a special focus on tobacco studies, including lung cancer in minorities, risk for tobacco experimentation, the impact of popular culture and the effect of alternative products, such as herbal cigarettes.
In the special edition, one study found that adults have an increased risk of developing lung cancer when exposed to secondhand cigarette smoke as children, even if they never smoke themselves.
Curtis C. Harris, MD, chief of the laboratory of Human Carcinogenesis at the National Cancer Institute and one of the study's authors, said this year alone, more than 219,000 Americans will be diagnosed with lung cancer; of those, more than 72.6 percent (159,000+) will die because of it.
“Some of those will be people who have never smoked themselves. Studies to date have shown that exposure to secondhand smoke in adulthood has detrimental health effects, but data are limited on one's risk of developing lung cancer when exposure occurs in childhood,” he said.
Harris' research is different from previous studies in that it was conducted in two independent cohorts—The NCI Maryland Lung Cancer Study and a Mayo Clinic lung cancer study— and then combined data from a molecular analysis using DNA to genotype a protein encoding gene, known as MBL2. The MBL2 gene variants allow natural [innate] immunity to occur within the body. Deficiencies of this gene have been known to affect an individual's susceptibility to autoimmune, infectious and respiratory diseases.
Harris and colleagues not only found an association between childhood exposure to secondhand tobacco smoke and an increased incidents of lung cancer in adulthood, but also that MBL2 inactivity was associated with an heightened risk among those exposed to secondhand smoking in childhood.