Passive Smoking and Breast Cancer Risk among Non-Smoking Women: A Case-Control Study in China

Health effects associated with exposure to secondhand smoke: a Burden of Proof study

Despite a gradual decline in smoking rates over time, exposure to secondhand smoke (SHS) continues to cause harm to nonsmokers, who are disproportionately children and women living in low- and middle-income countries. We comprehensively reviewed the literature published by July 2022 concerning the adverse impacts of SHS exposure on nine health outcomes. Following, we quantified each exposure-response association accounting for various sources of uncertainty and evaluated the strength of the evidence supporting our analyses using the Burden of Proof Risk Function methodology. We found all nine health outcomes to be associated with SHS exposure. We conservatively estimated that SHS increases the risk of ischemic heart disease, stroke, type 2 diabetes and lung cancer by at least around 8%, 5%, 1% and 1%, respectively, with the evidence supporting these harmful associations rated as weak (two stars). The evidence supporting the harmful associations between SHS and otitis media, asthma, lower respiratory infections, breast cancer and chronic obstructive pulmonary disease was weaker (one star). Despite the weak underlying evidence for these associations, our results reinforce the harmful effects of SHS on health and the need to prioritize advancing efforts to reduce active and passive smoking through a combination of public health policies and education initiatives.

The relationship between tobacco and breast cancer incidence: A systematic review and meta-analysis of observational studies

Background

The effect of tobacco on breast cancer (BC) is controversial. The purpose of this study was to investigate the relationship between tobacco and BC.

Methods

A search was conducted in PubMed, EBSCO, Web of Science and Cochrane Library databases before February 2022. The adjusted odd ratio (OR) and corresponding 95% confidence interval (CI) were used to examine the relationship between active or passive smoking and BC risk.

Results

A total of 77 articles composed of 2,326,987 participants were included for this meta-analysis. Active (OR=1.15, 95% CI=1.11-1.20, p<0.001) and passive (OR=1.17, 95% CI=1.09-1.24, p<0.001) smoking increased the risk of BC in the female population, especially premenopausal BC (active smoking: OR=1.24, p<0.001; passive smoking: OR=1.29, p<0.001), but had no effect on postmenopausal BC (active smoking: OR=1.03, p=0.314; passive smoking: OR=1.13, p=0.218). Active smoking increased the risk of estrogen receptor-positive (ER+) BC risk (OR=1.13, p<0.001), but had no effect on estrogen receptor-negative (ER-) BC (OR=1.08, p=0.155). The risk of BC was positively associated with the duration and intensity of smoking, negatively associated with the duration of smoking cessation. Active smoking increased the risk of BC in the multiparous population (OR=1.13, p<0.001), but had no effect on the nulliparous population (OR=1.05, p=0.432), and smoking before the first birth (OR=1.22, 95% CI=1.17-1.27) had a greater impact on the risk of BC than smoking after the first birth (OR=1.08, 95% CI=1.04-1.12).

Conclusion

Smoking (active and passive) increased the risk of BC in women. The effect of smoking on BC was influenced by smoking-related factors (duration, intensity, years of quitting), population-related factors (fertility status), and BC subtypes.

Systematic Review Registration

identifier CRD42022322699.

Impact of Smoking History on Pulmonary Metastasis-free Survival in Patients With Soft-tissue Sarcoma

Background/Aim

Although smoking history is predictive of poor pulmonary metastasis-free survival (PMFS) in patients with epithelial tumors, the impact of smoking history on PMFS in those with soft-tissue sarcoma (STS) is not known.

Patients and Methods

Patients undergoing treatment for STS at our institutes between 2008 and 2017 were enrolled. Patients were excluded if they had metastatic lesion, or had a histopathological classification demonstrating small round-cell sarcoma. The impact of smoking history on PMFS and overall survival was examined with multivariate analysis using a Cox proportional hazards model.

Results

A total of 250 patients were retrospectively reviewed. Patients with smoking history had worse PMFS on multivariate analysis (hazard ratio=2.00, 95% confidence interval=1.12-3.60). On the other hand, smoking history did not significantly affect overall survival (hazard ratio=1.26, 95% confidence interval=0.61-2.58).

Conclusion

Patients with STS need to be followed-up by frequent clinical assessments if they have a smoking history.

Gene-Environment Interaction between Arg72Pro SNP and Selected Environmental Exposures among Brazilian Women Diagnosed with Benign Breast Disease

Background:

Benign breast disease (BBD) is a factor strongly associated with breast cancer worldwide. Arg72Pro SNP association with breast cancer is controversial due to the suggestion that environmental factors are required to modulate such risk. There are no studies evaluating these environmental interactions of the aforementioned SNP within BBD.

Aim:

To determine the frequency of SNP Arg72Pro in a cohort of women diagnosed with BBD; and to investigate gene-environmental interactions with environmental factors.

Results:

The genotype frequency was 44.6% for Arg/Pro, 39.3% for Arg/Arg genotype, and 16.3% for Pro/Pro homozygote. Gene-environment interaction analysis shows that when Arg/Arg is considered as reference, there is an ORinteraction with Arg/Pro and fabric exposure (OR=1.90;95%CI:1.04,3.48), solvents (OR=2.21;95%CI:1.01,4.83) and chlorine, bleaches, disinfectants, and liquid wax exposure (OR=2.52;95%CI:1.07,5.91). Analysis with Pro/Pro genotype as the reference showed an interaction between alcohol consumption and recessive model (OR=1.58;95%CI:1.00,2.51). Gene-environmental interactions were observed too between exposure to hair dyes, straighteners or relaxers and Arg/Arg (OR=3.26;95%CI:1.21,8.82).

Conclusion:

The Arg/Pro genotype was the most frequent in the BBD cohort. When compared with the Arg/Arg genotype, the presence of Arg/Pro genotype and solvents, fabric and cleaning products exposure increased the risk of BBD. When compared with Pro/Pro genotype, there were interactions between recessive model with alcohol consumption and exposure to hair products on the risk of BBD.

Historical trends in breast Cancer among women in China from age-period-cohort modeling of the 1990-2015 breast Cancer mortality data

Background

Evidence on historical trends extracted embedded in recent data can advance our understanding of the epidemiology of breast cancer for Chinese women. China is a country with significant political, socioeconomic, and cultural events since the 1900s; however, no such studies are reported in the literature.

Methods

Age-specific mortality rates of breast cancer during 1990–2015 in China were analyzed using APC modeling (age-period-cohort modeling) method. Net effect from birth cohort was derived to measure cancer mortality risk during 1906–1990 when no mortality data were collected, and net effect from time period was derived to measure cancer mortality risk during 1990–2015 when data were collected. Model parameters were estimated using intrinsic estimator, a novel method to handle collinearity. The estimated effects were numerical differentiated to enhance presentations of time/age trend.

Results

Breast cancer mortality rate per 100,000 women increased from 6.83 in 1990 to 12.07 in 2015. After controlling for age and period, the risk of breast cancer mortality declined from 0.626 in 1906–10 to − 1.752 in 1991–95 (RR = 0.09). The decline consisted of 3 phases, a gradual phase during 1906–1940, a moderate phase with some fluctuations during 1941–1970, and a rapid phase with large fluctuations during 1971–1995. After controlling for age and cohort, the risk of breast cancer mortality increased from − 0.141 in 1990 to 0.258 in 2015 (RR = 1.49) with an acceleration after 2005. The time trends revealed by both the cohort effect and the period effect were in consistency with the significant political and socioeconomic events in China since the 1900s.

Conclusions

With recent mortality data in 1990–2015, we detected the risk of breast cancer mortality for Chinese women over a long period from 1906 to 2015. The risk declined more than 90% from the highest level in 1906–10 to the lowest in 1990–95, followed by an increase of 49% from 1990 to 2015. Findings of this study connected historical evidence with recent data, supporting further research to exam the relationship between development and risk of breast cancer for medical and health decision-making at the population level and prevention and treatment at the individual level.

Breast cancer in low-middle income countries: abnormality in splicing and lack of targeted treatment options

Breast cancer is a common malignancy among women worldwide. Regardless of the economic status of a country, breast cancer poses a burden in prevention, diagnosis and treatment. Developed countries such as the U.S. have high incidence and mortality rates of breast cancer. Although low incidence rates are observed in developing countries, the mortality rate is on the rise implying that low- to middle-income countries lack the resources for preventative screening for early detection and adequate treatment resources. The differences in incidence between countries can be attributed to changes in exposure to environmental risk factors, behaviour and lifestyle factors of the different population groups. Genomic modifications are an important factor that significantly alters the risk profile of breast tumourigenesis. The incidence of early-onset breast cancer is increasing and evidence shows that early onset of breast cancer is far more aggressive than late onset of the disease; possibly due to the difference in genetic alterations or tumour biology. Alternative splicing is a pivotal factor in the progressions of breast cancer. It plays a significant role in tumour prognosis, survival and drug resistance; hence, it offers a valuable option as a therapeutic target. In this review, the differences in breast cancer incidence and mortality rates in developed countries will be compared to low- to middle-income countries. The review will also discuss environmental and lifestyle risk factors, and the underlying molecular mechanisms, genetic variations or mutations and alternative splicing that may contribute to the development and novel drug targets for breast cancer.

GSTM1 and GSTT1 Genetic Polymorphisms and Breast Cancer Risk in Selected Filipino Cases

Background:

The association of genetic polymorphisms with cancer development has been shown to be race- and tumor site-specific. Thus, this study aimed to determine whether polymorphisms in the GSTM1 and GSTT1 genes are associated with breast cancer among selected Filipinos.

Methods:

A total of 136 histologically confirmed breast cancer cases were age- and sex-matched with 136 clinically healthy controls. Genomic DNA extracted from blood samples of participants were screened for GSTM1 and GSTT1 genetic polymorphisms by multiplex PCR.

Results:

The frequency of null genotypes among the cases (GSTM1: n=78; 57.4%; GSTT1: n=61; 44.9%) was not significantly different (p>0.05) from the controls (GSTM1: n=93; 68.4%; GSTT1: n=59; 43.4%). It was also demonstrated that risk for breast cancer was increased in passive smokers carrying the GSTM1 null (OR=2.56; 95% CI=1.38-4.75) or GSTT1 positive (OR=2.00; 95% CI=1.05-3.83) genotypes. Moreover, risk was decreased in alcohol users carrying the GSTT1 null (OR=0.39; 95% CI=0.16-0.97) genotype

. Conclusion:

This study suggests that variants of GSTM1 and GSTT1 may not be risk factors for breast cancer development among Filipinos. However, the risk may be increased when these genotypes were combined with lifestyle or environmental factors.

State of the evidence 2017: an update on the connection between breast cancer and the environment

BACKGROUND

In this review, we examine the continually expanding and increasingly compelling data linking radiation and various chemicals in our environment to the current high incidence of breast cancer. Singly and in combination, these toxicants may have contributed significantly to the increasing rates of breast cancer observed over the past several decades. Exposures early in development from gestation through adolescence and early adulthood are particularly of concern as they re-shape the program of genetic, epigenetic and physiological processes in the developing mammary system, leading to an increased risk for developing breast cancer. In the 8 years since we last published a comprehensive review of the relevant literature, hundreds of new papers have appeared supporting this link, and in this update, the evidence on this topic is more extensive and of better quality than that previously available.

CONCLUSION

Increasing evidence from epidemiological studies, as well as a better understanding of mechanisms linking toxicants with development of breast cancer, all reinforce the conclusion that exposures to these substances - many of which are found in common, everyday products and byproducts - may lead to increased risk of developing breast cancer. Moving forward, attention to methodological limitations, especially in relevant epidemiological and animal models, will need to be addressed to allow clearer and more direct connections to be evaluated.

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.

Association between lifetime exposure to passive smoking and risk of breast cancer subtypes defined by hormone receptor status among non-smoking Caucasian women

Tobacco smoking is inconsistently associated with breast cancer. Although some studies suggest that breast cancer risk is related to passive smoking, little is known about the association with breast cancer by tumor hormone receptor status. We aimed to explore the association between lifetime passive smoking and risk of breast cancer subtypes defined by estrogen receptor and progesterone receptor status among non-smoking Caucasian women. A hospital-based case-control study was performed in 585 cases and 1170 controls aged 28-90 years. Information on lifetime passive smoking and other factors was collected via a self-administered questionnaire. Logistic regression was used for analyses restricted to the 449 cases and 930 controls who had never smoked actively. All statistical tests were two-sided. Adjusted odds ratio of breast cancer was 1.01 (95% confidence interval (CI): 0.72-1.41) in women who experienced exposure to passive smoking at work, 1.88 (95% CI: 1.38-2.55) in women who had exposure at home, and 2.80 (95% CI: 1.84-4.25) in women who were exposed at home and at work, all compared with never exposed regularly. Increased risk was associated with longer exposure: women exposed ≤ 20 years and > 20 years had 1.27 (95% CI: 0.97-1.66) and 2.64 (95% CI: 1.87-3.74) times higher risk of breast cancer compared with never exposed (Ptrend < 0.001). The association of passive smoking with hormone receptor-positive breast cancer did not differ from that with hormone receptor-negative breast cancer (Pheterogeneity > 0.05). There was evidence of interaction between passive smoking intensity and menopausal status in both overall group (P = 0.02) and hormone receptor-positive breast cancer group (P < 0.05). In Caucasian women, lifetime exposure to passive smoking is associated with the risk of breast cancer independent of tumor hormone receptor status with the strongest association in postmenopausal women.

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.

Cadmium exposure and the risk of breast cancer in Chaoshan population of southeast China

Recently, there is increasing evidence indicating a link between cadmium exposure and human breast cancer. This study was aimed to explore the relationship between blood cadmium burden and the risk of breast cancer in Chaoshan women with no occupational exposure. Blood cadmium levels (BCLs) were determined in whole blood of 186 breast cancer cases and 139 controls. Basic clinical data and information of age, occupation, blood types, family cancer history, and disease history, as well as other demographic characteristics were collected from medical records. BCLs were detected by graphite-furnace atomizer absorption spectrophotometer (GFAAS). BCLs and proportions of BCLs over 3 μg/L between cases and controls were compared. The relationships between BCLs and breast cancer were explored by comparing BCL differences between/among different characteristics of investigated factors. In addition, BCLs within cases were also compared in relation to the disease clinical stages, tumor-node-metastasis (TNM) stages, and estrogen receptor (ER), progesterone receptor (PR), and Cerb-B2 expressions. The breast cancer patients had a higher median concentration of blood cadmium (2.28, interquartile range 1.57-3.15 μg/L) than the controls (1.77, 1.34-2.57 μg/L; P = 0.001). The proportion of BCLs over 3 μg/L was 2.35 times higher in the breast cancer cases than that of the controls after adjusting for age. Cadmium tends to accumulate in the human body with age and body mass index (BMI) but not associates with type of job, family history, disease history, and other investigated characters. With the increase of clinical stages and T and M stages, the BCLs in the breast cancer cases also increased. BCLs were positively associated with Cerb-B2 expression (r = 0.152, P = 0.038) but not significantly associated with ER and PR expressions. The data obtained show that cadmium concentration is significantly higher in blood of breast cancer patients in comparison to healthy controls. Cadmium seems to be a risk factor of breast cancer, and high cadmium exposure was observed in advanced stages of this disease, which indicates that it may promote the development of breast cancer.