Evidence secondhand smoke causes breast cancer in 2005 stronger than for lung cancer in 1986

Indoor Household Exposures and Associated Morbidity and Mortality Outcomes in Children and Adults in South Africa

Human exposure to indoor pollution is one of the most well-established ways that housing affects health. We conducted a review to document evidence on the morbidity and mortality outcomes associated with indoor household exposures in children and adults in South Africa. The authors conducted a scientific review of the publicly available literature up to April 2022 using different search engines (PubMed, ProQuest, Science Direct, Scopus and Google Scholar) to identify the literature that assessed the link between indoor household exposures and morbidity and mortality outcomes in children and adults. A total of 16 studies with 16,920 participants were included. Bioaerosols, allergens, dampness, tobacco smoking, household cooking and heating fuels, particulate matter, gaseous pollutants and indoor spray residue play a significant role in different morbidity outcomes. These health outcomes include dental caries, asthma, tuberculosis, severe airway inflammation, airway blockage, wheeze, rhinitis, bronchial hyperresponsiveness, phlegm on the chest, current rhinoconjunctivitis, hay fever, poor early life immune function, hypertensive disorders of pregnancy, gestational hypertension, and increased incidence of nasopharyngeal bacteria, which may predispose people to lower respiratory tract infections. The findings of this research highlight the need for more initiatives, programs, strategies, and policies to better reduce the negative consequences of indoor household exposures.

The potential role of nicotine in breast cancer initiation, development, angiogenesis, invasion, metastasis, and resistance to therapy

A large body of research studying the relationship between tobacco and cancer has led to the knowledge that smoking cigarettes adversely affects cancer treatment while contributing to the development of various tobacco-related cancers. Nicotine is the main addictive component of tobacco smoke and promotes angiogenesis, proliferation, and epithelial-mesenchymal transition (EMT) while promoting growth and metastasis of tumors. Nicotine generally acts through the induction of the nicotinic acetylcholine receptors (nAChRs), although the contribution of other receptor subunits has also been reported. Nicotine contributes to the pathogenesis of a wide range of cancers including breast cancer through its carcinogens such as (4-methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N-nitrosonornicotine (NNN). Current study aims to review the mechanistic function of nicotine in the initiation, development, angiogenesis, invasion, metastasis, and apoptosis of breast cancer with the main focus on nicotine acetylcholine receptors (nAChRs) and nAChR-mediated signaling pathways as well as on its potential for the development of an effective treatment against breast cancer. Moreover, we will try to demonstrate how nicotine leads to poor treatment response in breast cancer by enhancing the population, proliferation, and self-renewal of cancer stem cells (CSCs) through the activation of α7-nAChR receptors.

Never-smokers and the fraction of breast cancer attributable to second-hand smoke from parents during childhood: the Norwegian Women and Cancer Study 1991-2018

BACKGROUND

Second-hand smoke (SHS) is not an established risk factor for breast cancer. We examined exposure to SHS from parents during childhood and breast-cancer risk overall and by oestrogen- and progesterone-receptor status in the Norwegian Women and Cancer Study. Furthermore, we utilized our nationally representative prospective cohort study to estimate the fraction of breast cancer attributable to parental SHS during childhood.

METHODS

We followed 45 923 never-smoking women, aged 34-70 years, who completed a baseline questionnaire between 1991 and 2007 through linkages to national registries through December 2018. We used Cox proportional-hazards models to estimate age-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). We estimated the attributable and the population attributable fraction of breast cancer with 95% CIs.

RESULTS

During a mean follow-up of 19.8 (6.8) years, 2185 women developed invasive breast cancer, confirmed by histology. Women exposed to SHS from parents during childhood had an 11% higher (95% CI: 1.02-1.22) risk of breast cancer compared with those who were not. No difference was found for oestrogen (Pheterogeneity = 0.31) and progesterone (Pheterogeneity = 0.95) receptor status. For women exposed, the attributable fraction was 10.3% (95% CI: 1.8-18.0), whereas the population attributable fraction of breast cancer was 7.0% (95% CI: 1.0-13.0).

CONCLUSIONS

Our results suggest that 1 in 14 breast-cancer cases could have been avoided in the absence of SHS exposure from parents during childhood in a population of never-smoking women. The cancer burden attributable to SHS may be underestimated.

Theory, methods, and operational results of the Young Women's Health History Study: a study of young-onset breast cancer incidence in Black and White women

Purpose

The etiology of young-onset breast cancer (BC) is poorly understood, despite its greater likelihood of being hormone receptor-negative with a worse prognosis and persistent racial and socioeconomic inequities. We conducted a population-based case–control study of BC among young Black and White women and here discuss the theory that informed our study, exposures collected, study methods, and operational results.

Methods

Cases were non-Hispanic Black (NHB) and White (NHW) women age 20–49 years with invasive BC in metropolitan Detroit and Los Angeles County SEER registries 2010–2015. Controls were identified through area-based sampling from the U.S. census and frequency matched to cases on study site, race, and age. An eco-social theory of health informed life-course exposures collected from in-person interviews, including socioeconomic, reproductive, and energy balance factors. Measured anthropometry, blood (or saliva), and among cases SEER tumor characteristics and tumor tissue (from a subset of cases) were also collected.

Results

Of 5,309 identified potentially eligible cases, 2,720 sampled participants were screened and 1,812 completed interviews (682 NHB, 1140 NHW; response rate (RR): 60%). Of 24,612 sampled control households 18,612 were rostered, 2,716 participants were sampled and screened, and 1,381 completed interviews (665 NHB, 716 NHW; RR: 53%). Ninety-nine% of participants completed the main interview, 82% provided blood or saliva (75% blood only), and SEER tumor characteristics (including ER, PR and HER2 status) were obtained from 96% of cases.

Conclusions

Results from the successfully established YWHHS should expand our understanding of young-onset BC etiology overall and by tumor type and identify sources of racial and socioeconomic inequities in BC.

Supplementary Information

The online version of this article contains supplementary material available (10.1007/s10552-021-01461-x).

Non-Smoker's Exposure to Second-Hand Smoke in South Africa during 2017

Current South African tobacco control law allows for 25% designated smoking areas in some indoor public places. This study investigates non-smokers’ exposure to second-hand smoke (SHS) in workplaces, homes, cafés/restaurants, and shebeens (local bars) using data from the 2017 South African Social Attitude Survey. Factors associated with any level of exposure were explored using multiple-variable-adjusted logistic regression analysis. The sample of 3063 participants (16+ years old), comprised 51.7% females and 78.5% Black Africans. The current smoking prevalence from this study was 21.5%. About 47% of non-smokers reported exposure to SHS in at least one location. Females were significantly less likely to be exposed to SHS in all locations except at home compared to males. Adjusted logistic regression analysis showed that females, adults aged 45–54 years, 55–64 years, and 65+ years were significantly less likely to be exposed to SHS (adjusted odds ratio (AOR) = 0.63, 0.60, 0.55, and 0.24, respectively) than males and those aged 16–24 years. Those who identified as Coloureds were significantly more likely to be exposed to SHS (AOR = 1.69) than Black Africans. This study found that nearly half of non-smokers reported exposure to SHS. A 100% smoke-free policy consistent with the World Health Organisation (WHO) Framework Convention on Tobacco Control would protect more people from exposure to SHS in South Africa.

Smoking and breast cancer risk by race/ethnicity and oestrogen and progesterone receptor status: the Multiethnic Cohort (MEC) study

BACKGROUND

The purpose of this study was to examine if the smoking-related higher breast cancer risk was similar for the five race/ethnicity groups in the Multiethnic Cohort (MEC) study and by oestrogen (ER) and progesterone (PR) receptor status.

METHODS

From 1993 to 2013, we followed 67 313 women who were enrolled in the MEC study at 45-75 years of age. We identified breast cancer cases and tumour receptor status via linkage to the Hawaii and California Surveillance, Epidemiology and End Results Program cancer registries through December 2013. We used Cox proportional hazards regression to estimate multivariable-adjusted hazard ratios with 95% confidence intervals (CI).

RESULTS

During a mean follow-up of 16.7 years, we identified 4230 incident, invasive breast cancer cases. Compared with parous never smokers, parous ever smokers who had smoked more than 5 years before their first live childbirth had a higher risk of breast cancer overall of 31% (95% CI: 1.14-1.51). This higher risk was 51% (95% CI: 1.05-2.16) for African Americans, 66% (95% CI: 1.10-2.50) for Native Hawaiians, 42% (95% CI: 1.13-1.78) for Whites, 37% (95% CI: 1.17-1.61) for ER-positive (ER+) tumours and 33% (95% CI: 1.11-1.59) for PR+ tumours. No difference was suggested by racial/ethnic groups (Pheterogeneity = 0.15) or tumour receptor status (Pheterogeneity = 0.60 by ER status and 0.95 by PR status).

CONCLUSIONS

We find that the higher breast cancer risk related to smoking is similar across racial/ethnic groups and by ER and PR status, indicating that breast cancer should be considered as a smoking-related cancer.

The Role of Nitrosamine (NNK) in Breast Cancer Carcinogenesis

Smoking cigarettes is one of the most concerning issues that leads to tobacco-related cancers and can even result in death. Therefore, these issues should be addressed with a great sense of urgency with low-cost and simple approaches. Over the past several years, the scientific community has attempted to find solutions to overcome this issue. Thus, a large number of excellent studies have been reported in this field, and summarizing these results and providing important roadmaps for future studies is currently of great importance. Finding an outstanding solution to address aforementioned issue would be of great value to the community and to the social. Tobacco contains thousands of chemicals, and sixty-nine compounds have been established as human carcinogens; specifically, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is the strongest carcinogen among the tobacco-specific nitrosamines. Tobacco carcinogens are also linked to mammary gland pathogenesis and increased risk of developing many cancers, including breast cancer, the most common cancer in women worldwide. This mini-review summarizes the role of NNK and the mechanisms of its receptor, nicotine acetylcholine receptor (nAChR), signaling in breast cancer based on publications identified using the keywords "secondhand smoke (SHS)", "Nitrosamines" and "breast cancer". Furthermore, this review considers the risk of NNK to the public in an effort to reduce exposure to SHS in women and their chances of developing breast cancer.

Thirdhand smoke: when the danger is more than you can see or smell

Recent discussion has focused on another form of exposure to tobacco - thirdhand smoke (THS) - consisting of residual pollutants from cigarette smoke that remain in environments. The main concern with THS is based on the presence and persistence of many toxic compounds, some specific nitrosamines from tobacco that have carcinogenic activity. Little is known about THS, and few people are aware of its existence and potential health repercussions, thus highlighting the need to shed light on the subject and incorporate it into the public health debate, as was done with passive smoking several years ago. THS is a form of passive smoking, together with secondary or involuntary exposure to cigarette smoke. Recentemente, passou a ser discutida mais uma forma de exposição ao tabaco - thirdhand smoke (THS) - que consiste nos poluentes residuais da fumaça de cigarro que permanecem nos ambientes. A principal preocupação com o THS é embasada na presença e longa persistência de muitos compostos tóxicos, algumas nitrosaminas específicas do tabaco que têm atividade carcinogênica. Além de se saber pouco sobre o THS, poucos sabem de sua existência e preocupante repercussão na saúde. Coloca-se em destaque a necessidade de trazê-lo à luz e incluí-lo nas discussões, assim como foi feito com o tabagismo passivo alguns anos atrás, até mesmo porque o THS se caracteriza como uma forma de tabagismo passivo junto à exposição secundária ou involuntária da fumaça de cigarro.

Environmental tobacco smoke exposure and risk of breast cancer in nonsmoking women. An updated review and meta-analysis

CONTEXT

In 2006, we reviewed the evidence on environmental tobacco smoke (ETS) and breast cancer in nonsmoking women. Since then various studies and reviews have been published but opinion remains divided.

OBJECTIVE

To provide an updated review.

METHODS

We extracted study details, derived relative risk (RR) estimates with confidence intervals (CIs) for various ETS exposure indices, and conducted meta-analyses.

RESULTS

The update increased the number of studies from 22 to 47. Using an index for each study most closely equivalent to "spouse ever smoked", a weak but significant association was seen (random-effects RR = 1.15, 95% CI = 1.07-1.23). However, the estimates were heterogeneous: higher for Asian studies than for North American or European studies, higher for studies adjusting for fewer potential confounding variables, and close to 1.0 for prospective studies, regardless of whether or not they asked detailed questions on ETS exposure. The RR for eight prospective studies asking detailed questions was 1.003, 95% CI = 0.96-1.05. Risk was increased in premenopausal women (RR = 1.36, 95% CI = 1.15-1.60), but not postmenopausal women. Dose-response findings were similarly heterogeneous. No significant increase was seen for childhood or workplace exposure, but an increase was seen for total exposure (RR = 1.22, 95% CI = 1.09-1.37).

CONCLUSIONS

Increases mainly derived from case-control studies are prone to recall bias. Study weaknesses and possible publication bias limit interpretation. Considering also the weak association of smoking with breast cancer, and the much lower exposures from ETS than from smoking, our analyses do not clearly demonstrate that ETS exposure increases risk of breast cancer in nonsmokers. More research is needed.

Environmental tobacco smoke exposure and lung cancer: A systematic review

AIM: To review evidence relating passive smoking to lung cancer risk in never smokers, considering various major sources of bias.

METHODS: Epidemiological prospective or case-control studies were identified which provide estimates of relative risk (RR) and 95%CI for never smokers for one or more of seven different indices of exposure to environmental tobacco smoke (ETS): The spouse; household; workplace; childhood; travel; social and other; and total. A wide range of study details were entered into a database, and the RRs for each study, including descriptions of the comparisons made, were entered into a linked database. RRs were derived where necessary. Results were entered, where available, for all lung cancer, and for squamous cell cancer and adenocarcinoma. “Most adjusted” results were entered based on results available, adjusted for the greatest number of potential confounding variables. “Least adjusted” results were also entered, with a preference for results adjusted at least for age for prospective studies. A pre-planned series of fixed-effects and random-effects meta-analyses were conducted. Overall analyses and analyses by continent were run for each exposure index, with results for spousal smoking given by sex, and results for childhood exposure given by source of ETS exposure. For spousal exposure, more extensive analyses provide results by various aspects of study design and definition of the RR. For smoking by the husband (or nearest equivalent), additional analyses were carried out both for overall risk, and for risk per 10 cigarettes per day smoked by the husband. These adjusted for uncontrolled confounding by four factors (fruit, vegetable and dietary fat consumption, and education), and corrected for misclassification of smoking status of the wife. For the confounding adjustment, estimates for never smoking women were derived from publications on the relationship of the four factors to both lung cancer risk and at home ETS exposure, and on the correlations between the factors. The bias due to misclassification was calculated on the basis that the proportion of ever smokers denying smoking is 10% in Asian studies and 2.5% elsewhere, and that those who deny smoking have the same risk as those who admit it. This approach, justified in previous work, balances higher true denial rates and lower risk in deniers compared to non-deniers.

RESULTS: One hundred and two studies were identified for inclusion, published in 1981 onwards, 45 in Asia, 31 in North America, 21 in Europe, and five elsewhere. Eighty-five were of case-control design and 17 were prospective. Significant (P < 0.05) associations were noted, with random-effects of (RR = 1.22, 95%CI: 1.14-1.31, n = 93) for smoking by the husband (RR = 1.14, 95%CI: 1.01-1.29, n = 45) for smoking by the wife (RR = 1.22, 95%CI: 1.15-1.30, n = 47) for workplace exposure (RR = 1.15, 95%CI: 1.02-1.29, n = 41) for childhood exposure, and (RR = 1.31, 95%CI: 1.19-1.45, n = 48) for total exposure. No significant association was seen for ETS exposure in travel (RR = 1.34, 95%CI: 0.94-1.93, n = 8) or in social situations (RR = 1.01, 95%CI: 0.82-1.24, n = 15). A significant negative association (RR = 0.78, 95%CI: 0.64-0.94, n = 8) was seen for ETS exposure in childhood, specifically from the parents. Significant associations were also seen for spousal smoking for both squamous cell carcinoma (RR = 1.44, 95%CI: 1.15-1.80, n = 24) and adenocarcinoma (RR = 1.33, 95%CI: 1.17-1.51, n = 30). Results generally showed marked heterogeneity between studies. For smoking by either the husband or wife, where 119 RR estimates gave an overall estimate of (RR = 1.21, 95%CI: 1.14-1.29), the heterogeneity was highly significant (P < 0.001), with evidence that the largest RRs were seen in studies published in 1981-89, in small studies (1-49 cases), and for estimates unadjusted by age. For smoking by the husband, the additional analyses showed that adjustment for the four factors reduced the overall (RR = 1.22, 95%CI: 1.14-1.31) based on 93 estimates to (RR = 1.14, 95%CI: 1.06-1.22), implying bias due to uncontrolled confounding of 7%. Further correction for misclassification reduced the estimate to a marginally non-significant (RR = 1.08, 95%CI: 0.999-1.16). In the fully adjusted and corrected analyses, there was evidence of an increase in Asia (RR = 1.18, 95%CI: 1.07-1.30, n = 44), but not in other regions (RR = 0.96, 95%CI: 0.86-1.07, n = 49). Studies published in the 1980’s, studies providing dose-response data, and studies only providing results unadjusted for age showed elevated RRs, but later published studies, studies not providing dose-response data, and studies adjusting for age did not. The pattern of results for RRs per 10 cigs/d was similar, with no significant association in the adjusted and corrected results (RR = 1.03, 95%CI: 0.994-1.07).

CONCLUSION: Most, if not all, of the ETS/lung cancer association can be explained by confounding adjustment and misclassification correction. Any causal relationship is not convincingly demonstrated.

Tobacco smoke exposure and breast cancer risk in Thai urban females

The incidence of urban female breast cancer has been continuously increasing over the past decade with unknown etiology. One hypothesis for this increase is carcinogen exposure from tobacco. Therefore, the objective of this study was to investigate the risk of urban female breast cancer from tobacco smoke exposure. The matched case control study was conducted among Thai females, aged 17-76 years and living in Bangkok or its surrounding areas. A total of 444 pairs of cases and controls were recruited from the Thai National Cancer Institute. Cases were newly diagnosed and histologically confirmed as breast cancer while controls were selected from healthy women who visited a patient, matched by age ± 5 years. After obtaining informed consent, tobacco smoke exposure data and information on other potential risk factors were collected by interview. The analysis was performed by conditional logistic regression, and presented with odds ratio (ORs) and 95% confidence intervals(CI). From all subjects, 3.8% of cases and 3.4% of controls were active smokers while 11.0% of cases and 6.1% of controls were passive smokers. The highest to lowest sources of passive tobacco smoke were from spouses (40.8%), the workplace (36.8%) and public areas (26.3%), respectively. After adjusting for other potential risk factors or confounders, females with frequent low-dose passive smoke exposure (≤ 7 hours per week) from a spouse or workplace had adjusted odds ratio 3.77 (95%CI=1.11-12.82) and 4.02 (95%CI=1.04-15.50) higher risk of breast cancer compared with non-smokers, respectively. However, this study did not find any association of breast cancer risk in high dose passive tobacco smoke exposure, or a dose response relationship in cumulative passive tobacco smoke exposure per week, or in the active smoker group. In conclusion, passive smoke exposure may be one important risk factor of urban female breast cancer, particularly, from a spouse or workplace. This risk factor highlights the importance of avoiding tobacco smoke exposure as a key measure for breast cancer prevention and control.

Lack of an association between passive smoking and incidence of female breast cancer in non-smokers: evidence from 10 prospective cohort studies

BACKGROUND

Several case-control studies have suggested that passive smoking may increase the incidence of female breast cancer. However, the results of cohort studies have been inconsistent in establishing an association. The present study evaluated the association between passive smoking and incidence of female breast cancer through a meta-analysis of prospective cohort studies.

METHODS

Relevant articles published before August 2012 were identified by searching the electronic databases PubMed, Embase, and Web of Science. Pooled relative risks (RRs) were determined with either a fixed or random effects model and were used to assess the strength of the association. Sensitivity and subgroup analyses according to ethnicity, menopausal status, and the period and place of exposure to passive smoking were also performed.

RESULTS

Ten prospective cohort studies involving 782 534 female non-smokers were included in the meta-analysis and 14 831 breast cancer cases were detected. Compared with the women without exposure to passive smoking, the overall combined RR of breast cancer was 1.01 (95% confidence interval: 0.96 to 1.06, P = 0.73) among women with exposure to passive smoking. Similar results were achieved through the subgroup analyses. No evidence of publication bias was observed.

CONCLUSION

The results suggest that passive smoking may not be associated with increased incidence of breast cancer. However, the present conclusion should be considered carefully and confirmed with further studies.

Women and smoking: risks, impacts, and challenges

Smoking among women has drawn increasing attention because of the increase (or less pronounced decrease) in its prevalence when compared with that observed for men, as well as because of the specific effects that smoking has on women's health. For the 2010 "World No Tobacco Day", the World Health Organization chose the theme "Gender and tobacco with an emphasis on marketing to women", with the aim of encouraging policies to combat marketing strategies employed by the tobacco industry and to curb the epidemic of smoking among women. In this article, we discuss the characteristics of smoking among women, addressing factors such as smoking prevalence, nicotine dependence, the role of the tobacco industry, health risks, approaches to smoking cessation, treatment strategies, and prevention measures.

The nature, scope, and development of the global tobacco control epistemic community

Over the past 50 years, tobacco control has been transformed from a national to a global issue, becoming institutionalized in the World Health Organization (WHO) Framework Convention on Tobacco Control, the first international public health treaty negotiated under the auspices of the WHO. The global tobacco control epistemic community, a worldwide network of professionals with a common interpretation of the science in tobacco use and control, has contributed to this transformation. We investigated the development, structure, and function of this community through interviews and archival documents. Professionals in the community are bound by values and consensual knowledge developed after years of contentious debates undergirded their activities. Although these professionals play multiple roles, they recognize that scientific evidence should inform advocacy and policy activities. Public health professionals should continue to strengthen the links between science and advocacy for policy while being vigilant against industry efforts to undermine the scientific evidence on tobacco use and control.

From smoking to cancers: novel targets to neuronal nicotinic acetylcholine receptors

Cigarette smoking bears a strong etiological association with many neovascularization-related diseases, including cancer, cardiovascular disease, and age-related macular degeneration. Cigarette smoke is a complex mixture of many compounds, including nicotine, which is the major active and addictive component of tobacco. Nicotine and its specific metabolized carcinogens directly bind to nicotinic acetylcholine receptors (nAChRs) on cell membranes and trigger the nAChR signal cascade. The nAChRs were originally thought to be ligand-gated ion channels that modulate physiological processes ranging from neurotransmission to cancer signaling. For several decades, the nAChRs served as a prototypic molecule for neurotransmitter receptors; however, they are now important therapeutic targets for various diseases, including Alzheimer's and Parkinson's diseases, schizophrenia, and even cancer. This paper describes recent advances in our understanding of the assembly, activity, and biological functions of nicotinic receptors, as well as developments in the therapeutic application of nicotinic receptor ligands.