Secondhand Suspicions: Breast Cancer and Passive Smoking

Four authoritative reviews of active smoking and breast cancer have been published since 2000, but only one considered data after 2002 and conclusions varied. Three reviews of secondhand smoke (SHS) and breast cancer (2004-2006) each came to different conclusions. With 30 new studies since 2002, further review was deemed desirable. An Expert Panel was convened by four Canadian agencies, the Ontario Tobacco Research Unit, the Public Health Agency of Canada, Physicians for a Smoke-Free Canada and the Canadian Partnership Against Cancer to comprehensively examine the weight of evidence from epidemiological and toxicological studies and understanding of biological mechanisms regarding the relationship between tobacco smoke and breast cancer. This article summarises the panel's full report (http://www.otru.org/pdf/special/expert_panel_tobacco_breast_cancer.pdf). There are 20 known or suspected mammary carcinogens in tobacco smoke, and recognised biological mechanisms that explain how exposure to these carcinogens could lead to breast cancer. Results from the nine cohort studies reporting exposure metrics more detailed than ever/never and ex/current smoker show that early age of smoking commencement, higher pack-years and longer duration of smoking increase breast cancer risk 15% to 40%. Three meta-analyses report 35% to 50% increases in breast cancer risk for long-term smokers with N-acetyltransferase 2 gene (NAT2) slow acetylation genotypes. The active smoking evidence bolsters support for three meta-analyses that each reported about a 65% increase in premenopausal breast cancer risk among never smokers exposed to SHS. The Panel concluded that: 1) the association between active smoking and breast cancer is consistent with causality and 2) the association between SHS and breast cancer among younger, primarily premenopausal women who have never smoked is consistent with causality.

Background: Active and passive tobacco smoke exposures are considered modifiable risk factors for female breast cancer (BC). According to a recent expert panel report, active smoking (AS) increases the risk of BC by 20%, while the association between passive smoking (PS) and BC in younger, primarily premenopausal women who have never smoked, is consistent with causality; however, the evidence for risk among post menopausal women is inconclusive [Canadian Expert Report, 2009]. Since 2006, BC has become the leading cause of female cancer in Mexico, followed by cervical malignant tumors, with highest incidence in Mexican northern states [Knaul, 2009]. According to the National Surveys of Addictions, 6.5 million Mexican women between 12 and 65 years who have never smoked are currently exposed to environmental tobacco smoke. The mean age of tobacco smoking onset decreased from 18.3 years in 2008 to 16.8 years in 2009 [ENA, 2008; GATS, 2009]. Objective: To estimate the risk of breast cancer due to lifetime tobacco passive smoking exposure among pre and postmenopausal women residing in Mexico-US border states; to estimate risk associated with active smoking; and to explore age windows of susceptibility for both passive and active exposures. Methods: The first 504 histologically confirmed incident BC cases and 504 age-matched controls from an ongoing population-based case-control study, are included in this analysis. Active (number of cigarettes/year) and passive (number of smokers/year) lifetime tobacco exposures, at home and the workplace, targeting periods of suspected susceptibility (i.e. puberty until first birth etc.) were estimated from direct interviews. Never active smokers without a history of passive smoking exposure were considered as the referent group and were compared with active smokers as well as passive smokers with no history of active smoking. Known reproductive BC risk factors were included as covariables in multivariate logistic regression models. Results: Passive smoking significantly increased BC risk (OR t3 vs. t1 =3.34,95% CI 2.38-4.68, p for trend<0.001) even after stratifying by menopausal status (OR premenopausal t3 vs. t1 =4.75,95% CI 2.58-7.35, p for trend<0.001, OR postmenopausal t3 vs. t1 = 2.83,95% CI 1.87-4.28) and by age windows of susceptibility (i.e. 20 to 39 years OR t3 vs. t1 =2.68,95% CI 1.87-3.83, p for trend<0.001). In the overall population, BC risk was also associated with active smoking (OR t3 vs. t1 =1.72,95%CI 1.11-2.69, p for trend<0.001) that remained significant only when the age of tobacco smoking onset was between menarche and first birth (OR t3 vs. t1 =1.93,95%CI 1.19-3.23, p for trend<0.001). Conclusions: Our results provide evidence that PS is a risk factor not only for premenopausal but also for postmenopausal Mexican women and confirm that active smoking is a risk factor for this tumor. Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):A99.

Purpose: Our objective was to prospectively examine active smoking and environmental tobacco smoke (ETS) in relation to breast cancer risk, with a focus on exposures during potential windows of susceptibility. Methods: Sister Study cohort participants (n = 50,884) were enrolled between 2003 and 2009 and were followed for a breast cancer diagnosis. Women ages 35–74 in the United States and Puerto Rico were eligible if they had a sister who had been diagnosed with breast cancer. Study participants completed extensive telephone and paper questionnaires including information on established breast cancer risk factors as well as active smoking history and exposure to ETS while in utero and during childhood and adult years. Cox regression analysis was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for invasive breast cancer incidence associated with active smoking and ETS exposure. Results: During follow-up (mean = 6.4 years), 1,843 invasive breast cancers were diagnosed in the study population. Exposure to ETS in adulthood was not associated with increased breast cancer risk. However, nonsmoking women who were exposed to ETS throughout their childhood (18 years) had an 18% higher risk of breast cancer (95% CI, 1.02–1.38) relative to those without any childhood ETS. In utero ETS exposure also was associated with a modest increase in breast cancer incidence (HR = 1.16, 95% CI, 1.01–1.32) among nonsmokers as was paternal smoking prior to the participant's mother's pregnancy (HR = 1.12, 95% CI, 0.98–1.29). Additionally, active smoking prior to first pregnancy for 10 or more pack-years (HR = 1.31, 95% CI, 1.02–1.67) was associated with an elevated risk of breast cancer. Conclusions: In this large, prospective study, we report evidence that both active smoking and ETS exposure during potential windows of susceptibility, including in utero exposure, childhood and prior to first pregnancy, are associated with higher risk of breast cancer.

ADMA and SDMA levels in healthy men exposed to tobacco smoke

Objective To examine the association between smoking and risk of invasive breast cancer using quantitative measures of lifetime passive and active smoking exposure among postmenopausal women.Design Prospective cohort study.Setting 40...

Three recent studies explored how smoking is related to certain breast and lung cancer risks. In the first study, postmenopausal women who were current or former smokers were found to have a 16% higher risk of developing breast cancer than never-smokers.1 The study also found that women who had extensive exposure to passive smoking, either as children or adults, had an excess risk of developing breast cancer. Although previous studies have indicated a link between smoking and breast cancer, passive smoking risk remains controversial. Researchers, led byJuhua Luo, MD, of West Virginia University in Morgantown, and Karen Margolis, MD, of Health-Partners Research Foundation in Minneapolis, Minnesota, used data from the 1993-1998 Women's Health Initiative Observational Study to determine links between smoking, passive smoking, and breast cancer They analyzed data from nearly 80,000 women between the ages of 50 and 79 years across 40 clinical centers nationwide, identifying a total of 3250 cases of invasive breast cancer diagnosed over 10 years. Participants were asked a variety of questions, including whether they had ever smoked, at what age they began smoking, how many cigarettes they smoked each day, and at what age they quit smoking. They also were asked if they had lived in smoking households as children or adults and whether they had worked in smoking environments. Researchers found that smokers had a 16% increased risk of developing breast cancer after menopause; former smokers had a 9% increased risk. Those women who had smoked for 50 years or more had the highest risk compared with lifetime nonsmokers. Women who started smoking as teenagers also had a particularly high risk. The increased risk continued for 20 years after a person had stopped smoking. Nonsmoking women who had been exposed to extensive passive smoking had a 32% excess risk of breast cancer “Extensive” was defined as more than 10 years' exposure in childhood, more than 20 years' exposure as an adult at home, and more than 10 years' exposure as an adult at work. However, because their analysis of secondhand smoke was limited to the most extensive passive smoking category, the authors say more research is needed to confirm these findings. In another study by Kenneth Piazza, MD, MPH, and Andrew Hyland, PhD, at Roswell Park Cancer Institute in Buffalo, New York, smoke free homes and workplaces were linked to reductions in breast cancer incidence and mortality rates.2 The study found a statistically significant decrease in breast cancer mortality, particularly among younger premenopausal women, as the number of smoke- free homes and workplaces increased. An estimated 20% of the change in breast cancer mortality rates was due to changes in smoke-free home and workplace policies. Similar to the first group of researchers, Drs. Piazza and Hyland cited the lack of definitive evidence regarding passive smoke and risk of breast cancer However, the study also found that states with higher percentages of women working and living in smoke-free environments had lower breast cancer rates. In a third study, researchers found that many longtime smokers quit spontaneously shortly before their lung cancer was diagnosed.3 As a result, they speculate that sudden smoking cessation may be a symptom of lung cancer The study found that most patients who quit did so before noticing any cancer symptoms. They also often quit with no difficulty, despite having tried to quit unsuccessfully in the past, notes lead author Barbara Campling, MD, a medical oncologist at Thomas Jefferson University in Philadelphia, Pennsylvania. Researchers interviewed 115 lung cancer patients from the Philadelphia Veterans Affairs Medical Center, all of whom had been smokers. Of these, 55 patients (48%) had quit smoking before diagnosis and only 6 (11%) of these patients had experienced symptoms before they quit. The patients who quit were as dependent on nicotine as those who continued to smoke, yet 31% said they quit without difficulty. Investigators compared these results with those found in patients with prostate cancer and heart attack survivors. In the patients with lung cancer, the median time elapsed between quitting smoking and lung cancer diagnosis was 2.7 years. The interval between quitting and the event was 24.3 years for patients with prostate cancer and 10 years for heart attack survivors. Dr. Campling and colleagues speculated that smoking cessation may be caused by tumor secretion of a substance that interferes with nicotine addiction. She cautions that these results should not be misinterpreted to suggest that heavy smokers should continue smoking; they still should be strongly encouraged to quit.

Recent cohort studies suggest that increased breast cancer risks were associated with longer smoking duration, higher pack-years and a dose-response relationship with increasing pack-years of smoking between menarche and first full-term pregnancy (FFTP). Studies with comprehensive quantitative life-time measures of passive smoking suggest an association between passive smoking dose and breast cancer risk. We conducted a study within the European Prospective Investigation into Cancer and Nutrition to examine the association between passive and active smoking and risk of invasive breast cancer and possible effect modification by known breast cancer risk factors. Among the 322,988 women eligible for the study, 9,822 developed breast cancer (183,608 women with passive smoking information including 6,264 cases). When compared to women who never smoked and were not being exposed to passive smoking at home or work at the time of study registration, current, former and currently exposed passive smokers were at increased risk of breast cancer (hazard ratios (HR) [95% confidence interval (CI)] 1.16 [1.05-1.28], 1.14 [1.04-1.25] and 1.10 [1.01-1.20], respectively). Analyses exploring associations in different periods of life showed the most important increase in risk with pack-years from menarche to FFTP (1.73 [1.29-2.32] for every increase of 20 pack-years) while pack-years smoked after menopause were associated with a significant decrease in breast cancer risk (HR = 0.53, 95% CI: 0.34-0.82 for every increase of 20 pack-years). Our results provide an important replication, in the largest cohort to date, that smoking (passively or actively) increases breast cancer risk and that smoking between menarche and FFTP is particularly deleterious.

BackgroundActive smoking and exposure to passive smoke are responsible for numerous adverse pregnancy outcomes for women and their infants. The aim of this study was to explore the perceptions, attitudes, patterns of personal tobacco use and exposure to environmental smoke among a sample of pregnant women in Greece.MethodA cross sectional survey was undertaken of 300 women identified from the perinatal care records of the Maternity Departments of two hospitals in Athens between February 2013 and May 2013. Data on active and passive maternal smoking status in the first, second, and third trimesters of pregnancy, fetal and neonatal tobacco related complications, exposure to environmental tobacco smoke during pregnancy, quit attempts, behaviors towards avoiding passive smoking and beliefs towards smoking cessation during pregnancy were collected using self-administered questionnaires on the 3rd postnatal day. Women also completed the Edinburgh Postnatal Depression Scale (EPDS).ResultsOf 300 women recruited to the study 48 % reported tobacco use during the first trimester of pregnancy. Amongst participants who were tobacco users, 83.3 % reported making an attempt to quit but less than half (45.1 %) were successful. Among women who continued to smoke during pregnancy the majority (55.8 %) reported that they felt unable to quit, and 9.3 % reported that they considered smoking cessation was not an important health issue for them. Participants who continued to smoke during pregnancy were more likely to report fetal (χ2 = 11.41; df = 5; p < 0.05) and newborn complications (χ2 = 6.41; df = 2; p < 0.05), including preterm birth and low birth weight. Participants who reported that their partners were smokers were more likely to smoke throughout their pregnancy (χ2 = 14.62; df = 1; p < 0.001). High rates of second-hand smoke exposure were reported among both smoking and non-smoking women. Pregnant smokers had significantly higher levels of postnatal depressive and anxiety symptomatology, as measured using the EPDS, than non-smokers.ConclusionOur data supports the importance of ensuring that pregnant women, their partners and close relatives are educated on the health risks of active and passive smoking and how these could have an adverse effect to their fetus and infants, as well as the pregnant women themselves.

Environmental Tobacco Smoke and Lung Cancer: A Reappraisal

Smoking during pregnancy has been shown to be detrimental for the developing fetus. The effects of active and passive maternal smoking on umbilical cord serum levels of vitamin A and vitamin E were examined. Secondary measures included anthropometric parameters in the newborn. Maternal and umbilical cord serum levels of vitamins A and E were measured at delivery. The mothers were assigned to three groups: non-smoking (n 12); passive smoking (n 13); active smoking (n 18). Based on multivariate linear regressions, active smoking during pregnancy was associated with increased umbilical cord serum levels of vitamin A and vitamin E. While enhanced circulating levels of vitamin A in cord blood were also found in non-smoking mothers exposed to tobacco smoke during pregnancy, those of vitamin E were not influenced. Further, an inverse association between smoking behaviour during pregnancy and birth length was observed, with shortest length in active smokers followed by passive smoking mothers. Active and passive maternal smoking behaviour during pregnancy increases the fetal demand for antioxidant compounds in order to counteract the oxidative burden by cigarette smoke. Against this background, the observed increase in umbilical cord serum levels of vitamins A and E may subserve antioxidative processes in response to tobacco smoke-induced oxidative stress. This would reduce the availability of vitamins A and E for fetal maturation, which is critical inasmuch as both compounds are indispensable for the developing fetus. However, due to the cross-sectional nature of our observation, this line of reasoning definitely requires validation in cause-effect experiments in the future.

Tobacco smoking and meningococcal disease in adolescents and young adults: a systematic review and meta-analysis

The Relationship of Active and Passive Smoking to Carotid Atherosclerosis 12-14 Years Later

Associations Between Family History of Allergy, Exposure to Tobacco Smoke, Active Smoking, Obesity, and Asthma in Adolescents

Tobacco smoke is a major health risk factor for smokers but also for non-smokers due to passive smoking. These risks come from conventional cigarette smoke but also from aerosol produced by electronic cigarettes and heated tobacco products (HTPs). The aim of this study was to investigate population knowledge about the adverse effects of passive smoking from traditional cigarettes, electronic cigarettes, and HTPs. Between February and October 2023, 504 subjects among the general population responded to a questionnaire with 8 questions in Italian, via a link to the Google Forms platform. The questions related to the oral health effects of active and passive smoking. Descriptive analyses of all variables in the questionnaire were performed, and statistical analyses between variables were carried out using the chi-squared test and Fisher's exact test. A large subset of individuals interviewed stated that active smoking is harmful to health and consider active smoking more damaging compared with passive smoking (86.3%). The majority believed that passive smoking of cigarettes is more harmful to oral health than passive smoking of HTPs (79.4%) or electronic cigarettes (e-cigarettes) (84.9%). Results suggest that most people in this study had good knowledge about the adverse effects of active or passive smoking on health; however, knowledge regarding e-cigarettes and HTPs was poor and confused. These results reveal the complexity of perceptions regarding different types of smoking and the need for further research to fully understand the risks associated with each type of passive smoking.

The present study investigated the associations of active, passive, and electronic cigarette (E-cigarette) smoking with asthma in Korean adolescents. We used the cross-sectional study of Korea Youth Risk Behavior Web-based Survey conducted in 2011, 2012 and 2013. Active smoking was classified into 4 groups (0 days, 1–5 days, 6–19 days, and ≥20 days a month). Passive smoking was also categorized into 4 groups (0 days, 1–2 days, 3–4 days, and ≥5 days a week). E-cigarette was defined as yes or no in the last 30 days. Age, sex, obesity, region of residence, economic level, and parental educational level were adjusted for as confounders. Smoking variables were adjusted for one another. Adjusted odd ratios (AORs) and 95% confidence intervals (CIs) were calculated using multiple logistic regression analysis with complex sampling. In total, 2.3% (4,890/216,056) of participants reported asthma in the past 12 months. Active smoking was significantly associated with asthma (AOR [95% CI] of smoking ≥20 days/month = 1.57 [1.38–1.77], P < 0.001). Passive smoking was also related with asthma (AOR [95% CI] of smoking ≥5 days/week = 1.40 [1.28–1.53], P < 0.001). E-cigarette showed positive relation with asthma, although the effects of past smoking history could not be excluded (AOR [95% CI] = 1.12 [1.01–1.26], P = 0.027).