With secondhand smoke exposure (SHSe) in cancer patients known to lead to higher death rates, researchers sought to find the estimated percentage of nonsmoking adult cancer survivors in the U.S. who had signs of SHSe (Cancer Epidemiol Biomarkers Prev 2017; doi:10.1158/1055-9965.EPI-16-0777).
The study, led by Oladimeji Akinboro, MD, MPH, Chief Medical Resident in the Department of Medicine at Montefiore New Rochelle Hospital in New Rochelle, N.Y., found SHSe was in decline among nonsmoking cancer survivors. However, SHSe rates of nonsmoking cancer survivors were similar to those of the general population despite their higher risk of poor clinical outcomes, such as death.
"We were surprised to discover that rates of secondhand tobacco exposure among nonsmoking adult cancer survivors were similar to those reported for the general population of U.S. adults," noted Akinboro. "This is concerning because those who have had or have cancer represent a group of people whose health outcomes are adversely influenced by any form of tobacco exposure, whether direct smoking or secondhand exposure."
Research Methods
Utilizing interview and serum cotinine data from seven consecutive National Health and Nutrition Examination Surveys, stretching from 1999 to 2012, investigators analyzed cases of 686 nonsmoking adults.
Researchers utilized data from 82 participants in the 1999/2000 survey, 106 in the 2001/2002 survey, 118 in the 2003/2004 survey, 79 in the 2005/2006 survey, 145 in the 2007/2008 survey, 87 in the 2009/2010 survey, and 69 in the 2011/2012 survey.
The surveys collected data of those aged 20 and over, with a history of cancer and self-reported exposure to indoor secondhand smoke.
A serum cotinine level between 0.05 ng/mL and 10 ng/mL was defined as exposure to secondhand smoke. Additionally, participants were defined as a nonsmoker if they had a lifetime smoking history of under 100 cigarettes.
Study Results
Among all the adults studied, 28.26 percent had been exposed to secondhand smoke. The SHSe rates of the 2011/2012 study declined to 15.7 percent, down from the 1999/2000 study's rate of 39.6 percent.
However, percentages of SHSe were higher for minorities, those with less than a high school education, those living below the federal poverty line, and those with a history of a smoking-related cancer. Data showed that 55.64 percent of non-Hispanic blacks had been exposed to secondhand smoke compared with 26.14 percent of non-Hispanic whites. Of individuals with a history of smoking-related cancer, 35.54 percent suffered from SHSe compared to 26.33 percent of those with a type of cancer not linked to smoking.
Additionally, researchers reported that 53.25 percent of individuals below the federal poverty line were exposed to secondhand smoke, while cancer survivors with an income three or more times greater than the poverty level experienced SHSe.
The fact that certain subgroups remain disproportionately burdened indicates "potential opportunities for tobacco control and cessation interventions among underserved cancer survivors," noted Carolyn Heckman, PhD, Associate Professor, Fox Chase Cancer Center in Philadelphia.
"The difference in the rates of secondhand smoke exposure, as measured by blood levels of cotinine and self-reported rates of indoor household secondhand smoke exposure were striking," emphasized Akinboro. "It is very plausible that this difference may be related to inhalation of tobacco smoke from other households in multi-unit apartments, clubs, bars, and public spaces, which would have numerous policy implications, including encouraging widespread adoption of nonsmoking policies in multi-unit housings by housing managements and public housing authorities."
Public Health Implications
Due to the higher-than-expected rates of SHSe, researchers are calling for cancer patients and survivors to help themselves.
"[They] must be encouraged to be their own advocates regarding secondhand smoke exposure in adopting voluntary smoke-free home and vehicle rules, and avoiding settings outside the home where they are more likely than not to be involuntarily exposed to tobacco smoke," suggested Akinboro. "Smoking households and social contacts of cancer patients and survivors also need to be engaged and, as a society, we can reduce secondhand smoke exposure by intensifying local, state, and federal measures and policies that prohibit smoking in the workplace, in public places, and multi-unit housing."
While this study focused only on SHSe in the household, an important issue for future research, noted Heckman, should be the focus of SHSe outside of the home in places such as the workplace.
Evan Prince is a contributing writer.