PHILADELPHIA - Children exposed to secondhand cigarette smoke have an increased risk of developing lung cancer in adulthood, even if they never smoked.
Results of this study are published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research, as part of a special tobacco focus in the December issue.
This year alone, more than 219,000 Americans will be diagnosed with lung cancer; more than 159,000 will die from it and some of those may be people who have never smoked. 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 exposed as a child.
What makes this study different from previous research is that it was conducted in two independent cohorts and included a molecular analysis of gene variants of innate immunity -- the mannose binding lection-2 gene, or MBL2 gene. The MBL2 gene is known to affect susceptibility to respiratory diseases.
Using the ongoing National Cancer Institute-Maryland Lung Cancer study (624 cases; 348 controls), Curtis C. Harris, M.D., chief of the Laboratory of Human Carcinogenesis at NCI, and colleagues collected information on secondhand smoke history among men and women. They used DNA for genotyping the MBL2 gene. Then, to compare, Harris, Ping Yang, M.D., Ph.D., professor of epidemiology at the Mayo Clinic in Rochester, Minn., and colleagues used results from a Mayo Clinic study (461 never smokers; 172 cases; 289 controls).
Harris and colleagues found an association between childhood exposure to secondhand tobacco smoke and increased risk of lung cancer in adulthood. Furthermore, MBL2 activity was associated with an even more increased risk among those who were exposed to secondhand smoke in childhood.
Based on the results of this study, Harris said "children should not be exposed to secondhand tobacco smoke due to the long-term health implications they can face in adulthood." He added that these results warrant further investigation in a larger study population.
The mission of the American Association for Cancer Research is to prevent and cure cancer. Founded in 1907, the AACR is the world's oldest and largest professional organization dedicated to advancing cancer research. The membership includes 30,000 basic, translational and clinical researchers; health care professionals; and cancer survivors and advocates in the United States and nearly 90 other countries. The AACR marshals the full spectrum of expertise from the cancer community to accelerate progress in the prevention, diagnosis and treatment of cancer through high-quality scientific and educational programs. It funds innovative, meritorious research grants, research fellowship and career development awards. The AACR Annual Meeting attracts more than 16,000 participants who share the latest discoveries and developments in the field. Special conferences throughout the year present novel data across a wide variety of topics in cancer research, treatment and patient care. The AACR publishes six major peer-reviewed journals: Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; Cancer Epidemiology, Biomarkers & Prevention; and Cancer Prevention Research. The AACR also publishes CR, a magazine for cancer survivors and their families, patient advocates, physicians and scientists. CR provides a forum for sharing essential, evidence-based information and perspectives on progress in cancer research, survivorship and advocacy.