Environmental tobacco smoke and breast cancer incidence

Cumulative environmental quality is associated with breast cancer incidence differentially by summary stage and urbanicity

Individual environmental contaminants have been associated with breast cancer; however, evaluations of multiple exposures simultaneously are limited. Herein, we evaluated associations between breast cancer summary stages and the Environmental Quality Index (EQI), which includes a range of environmental factors across five domains. The EQI (2000-2005) was linked to county-level age-standardized incidence rates (SIRs) obtained from the North Carolina Central Cancer Registry (2010-2014). Incidence rates and SIRs of total, in situ, localized, regional, and distant breast cancers were evaluated stratified by rural-urban status. In counties with poor environmental quality compared to those with good environmental quality, total breast cancer incidence was higher by 10.82 cases per 100,000 persons (95% CI 2.04, 19.60, p = 0.02). This association was most pronounced for localized breast cancer (β = 5.59, 95% CI 0.59, 10.58, p = 0.03). Higher incidence of early-stage disease (carcinoma in situ β = 5.25, 95% CI 2.34, 8.16, p = 0.00 and localized breast cancer β = 6.98, 95% CI 2.24, 11.73, p = 0.00) and total breast cancer (β = 11.44, 95% CI 3.01, 19.87, p = 0.01) occurred in counties with poor land quality, especially urban counties. Our analyses indicate significant associations between environmental quality and breast cancer incidence, which differ by breast cancer stage and urbanicity, identifying a critical need to assess cumulative environmental exposures in the context of cancer stage.

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.

Exposure to Secondhand Smoke and Risk of Cancer in Never Smokers: A Meta-Analysis of Epidemiologic Studies

This is first meta-analysis to evaluate cancer risk associated with secondhand smoking across all cancers. A literature search was conducted for articles published before June 2014 on Pubmed, SCOPUS, Cochrane library, and CINAHL, and 40 articles on secondhand smoke and the prevalence of cancer among never smokers were selected for final analysis as per the inclusion criteria. Of the 40 articles, 27 were case-control studies and 13 were prospective cohort studies. With respect to overall cancer risk, odds ratio (OR) involving never smokers with significant exposure to secondhand smoke compared to never smokers without such exposure was 1.163 (95%CI 1.058–1.279). Subgroup meta-analyses by study design showed significant positive associations for both case-control studies and prospective cohort studies (OR 1.165, 95%CI 1.029–1.320; and OR 1.160, 95%CI 1.002–1.343, respectively). The association was stronger in the case of females (OR 1.253, 95%CI 1.142–1.374), lung cancer (OR 1.245, 95%CI 1.026–1.511), and breast cancer (OR 1.235, 95%CI 1.102–1.385). Secondhand smoking may increase the overall risk of cancer for never smokers, particularly lung and breast cancer, and especially in women. Strict implementation of smoking cessation programs should be encouraged, not only to reduce active smoking but also to limit exposure to secondhand smoke.

Evaluation of Prenatal Exposure to Bisphenol Analogues on Development and Long-Term Health of the Mammary Gland in Female Mice

BACKGROUND

Continued efforts to phase out bisphenol A (BPA) from consumer products have been met with the challenges of finding safer alternatives.

OBJECTIVES

This study aimed to determine whether early-life exposure to BPA and its related analogues, bisphenol AF (BPAF) and bisphenol S (BPS), could affect female pubertal mammary gland development and long-term mammary health in mice.

METHODS

Timed pregnant CD-1 mice were exposed to vehicle, BPA (0.5, 5, 50 mg/kg), BPAF (0.05, 0.5, 5 mg/kg), or BPS (0.05, 0.5, 5 mg/kg) via oral gavage between gestation days 10–17. Mammary glands were collected from resulting female offspring at postnatal day (PND) 20, 28, 35, and 56, and at 3, 8, and 14 months for whole mount, histopathological evaluation, and quantitative real-time polymerase chain reaction (qPCR); serum steroid concentrations were also measured at these time points.

RESULTS

In the bisphenol-exposed mice, accelerated mammary gland development was evident during early puberty and persisted into adulthood. By late adulthood, mammary glands from bisphenol-exposed female offspring exhibited adverse morphology in comparison with controls; most prominent were undifferentiated duct ends, significantly more lobuloalveolar hyperplasia and perivascular inflammation, and various tumors, including adenocarcinomas. Effects were especially prominent in the BPAF 5 mg/kg and BPS 0.5 mg/kg groups. Serum steroid concentrations and mammary mRNA levels of Esr1, Pgr, Ar, and Gper1 were similar to controls.

CONCLUSIONS

These data demonstrate that prenatal exposure of mice to BPAF or BPS induced precocious development of the mammary gland, and that siblings were significantly more susceptible to spontaneous preneoplastic epithelial lesions and inflammation, with an incidence greater than that observed in vehicle- and BPA-exposed animals. https://doi.org/10.1289/EHP3189.

Postdiagnosis Changes in Cigarette Smoking and Survival Following Breast Cancer

BACKGROUND

The purpose of this study was to examine whether at-diagnosis smoking and postdiagnosis changes in smoking within five years after breast cancer were associated with long-term all-cause and breast cancer-specific mortality.

METHODS

A population-based cohort of 1508 women diagnosed with first primary in situ or invasive breast cancer in 1996 to 1997 were interviewed shortly after diagnosis and again approximately five years later to assess smoking history. Participants were followed for vital status through December 31, 2014. After 18+ years of follow-up, 597 deaths were identified, 237 of which were breast cancer related. Multivariable Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Compared with never smokers, risk of all-cause mortality was elevated among the 19% of at-diagnosis smokers (HR=1.69, 95% CI=1.36 to 2.11), those who smoked 20 or more cigarettes per day (HR=1.85, 95% CI=1.42 to 2.40), women who had smoked for 30 or more years (HR=1.62, 95% CI=1.28 to 2.05), and women who had smoked 30 or more pack-years (HR=1.82, 95% CI=1.39 to 2.37). Risk of all-cause mortality was further increased among the 8% of women who were at-/post-diagnosis smokers (HR=2.30, 95% CI=1.56 to 3.39) but was attenuated among the 11% women who quit smoking after diagnosis (HR=1.83, 95% CI=1.32 to 2.52). Compared with never smokers, breast cancer-specific mortality risk was elevated 60% (HR=1.60, 95% CI=0.79 to 3.23) among at-/postdiagnosis current smokers, but the confidence interval included the null value and elevated 175% (HR=2.75, 95% CI=1.26 to 5.99) when we considered postdiagnosis cumulative pack-years. Conclusions: Smoking negatively impacts long-term survival after breast cancer. Postdiagnosis cessation of smoking may reduce the risk of all-cause mortality. Breast cancer survivors may benefit from aggressive smoking cessation programs starting as early as the time of diagnosis.

Polycyclic aromatic hydrocarbons and postmenopausal breast cancer: An evaluation of effect measure modification by body mass index and weight change

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) have been linked to breast cancer in many, but not all, previous studies. PAHs are lipophilic and stored in fat tissue, which we hypothesized may result in constant low-dose exposure to these carcinogens. No previous studies have evaluated whether obesity modifies associations between multiple measures of PAHs and breast cancer incidence.

METHODS

This population-based study included 1,006 postmenopausal women with first primary in situ or invasive breast cancer and 990 age-frequency matched controls. To evaluate effect modification by obesity (adult body mass index (BMI, kg/m²) and weight change) on multiple PAH measures (the biomarker PAH-DNA adducts, and long-term sources active cigarette smoking, living with a smoking spouse, grilled/smoked meat intake, residential synthetic log burning, and vehicular traffic), interaction contrast ratios (ICRs) for the additive scale, and ratio of odds ratios (RORs) with log-likelihood ratio tests (LRT) for the multiplicative scale, were determined using unconditional logistic regression.

RESULTS

BMI modified the PAH-DNA adduct and postmenopausal breast cancer association on the additive (ICR: 0.49; 95% CI: 0.01, 0.96) and multiplicative (ROR: 1.56; 95% CI: 0.91, 2.68) scales. The odds ratio for detectable vs. non-detectable adducts was increased among women with BMI ≥25 (OR=1.34; 95% CI: 0.94, 1.92), but not in those with BMI <25 (OR=0.86; 95% CI: 0.57, 1.28) (LRT p=0.1). For most other PAH measures, the pattern of modification by BMI/weight gain was similar, but estimates were imprecise.

CONCLUSIONS

The association between PAH-DNA adducts and breast cancer incidence may be elevated among overweight/obese 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.

Polymorphisms in DNA repair genes, traffic-related polycyclic aromatic hydrocarbon exposure and breast cancer incidence

Vehicular traffic polycyclic aromatic hydrocarbons (PAHs) have been associated with breast cancer incidence in epidemiologic studies, including our own. Because PAHs damage DNA by forming adducts and oxidative lesions, genetic polymorphisms that alter DNA repair capacity may modify associations between PAH-related exposures and breast cancer risk. Our goal was to examine the association between vehicular traffic exposure and breast cancer incidence within strata of a panel of nine biologically plausible nucleotide excision repair (NER) and base excision repair (BER) genotypes. Residential histories of 1,508 cases and 1,556 controls were assessed in the Long Island Breast Cancer Study Project between 1996 and 1997 and used to reconstruct residential traffic exposures to benzo[a]pyrene, as a proxy for traffic-related PAHs. Likelihood ratio tests from adjusted unconditional logistic regression models were used to assess multiplicative interactions. A gene-traffic interaction was evident (p = 0.04) for ERCC2 (Lys751); when comparing the upper and lower tertiles of 1995 traffic exposure estimates, the odds ratio (95% confidence interval) was 2.09 (1.13, 3.90) among women with homozygous variant alleles. Corresponding odds ratios for 1960-1990 traffic were also elevated nearly 2-3-fold for XRCC1(Arg194Trp), XRCC1(Arg399Gln) and OGG1(Ser326Cys), but formal multiplicative interaction was not evident. When DNA repair variants for ERCC2, XRCC1 and OGG1 were combined, among women with 4-6 variants, the odds ratios were 2.32 (1.22, 4.49) for 1995 traffic and 2.96 (1.06, 8.21) for 1960-1990 traffic. Our study is first to report positive associations between traffic-related PAH exposure and breast cancer incidence among women with select biologically plausible DNA repair genotypes.

Exposure to multiple sources of polycyclic aromatic hydrocarbons and breast cancer incidence

BACKGROUND

Despite studies having consistently linked exposure to single-source polycyclic aromatic hydrocarbons (PAHs) to breast cancer, it is unclear whether single sources or specific groups of PAH sources should be targeted for breast cancer risk reduction.

OBJECTIVES

This study considers the impact on breast cancer incidence from multiple PAH exposure sources in a single model, which better reflects exposure to these complex mixtures.

METHODS

In a population-based case-control study conducted on Long Island, New York (N=1508 breast cancer cases/1556 controls), a Bayesian hierarchical regression approach was used to estimate adjusted posterior means and credible intervals (CrI) for the adjusted odds ratios (ORs) for PAH exposure sources, considered singly and as groups: active smoking; residential environmental tobacco smoke (ETS); indoor and outdoor air pollution; and grilled/smoked meat intake.

RESULTS

Most women were exposed to PAHs from multiple sources, and the most common included active/passive smoking and grilled/smoked food intake. In multiple-PAH source models, breast cancer incidence was associated with residential ETS from a spouse (OR=1.20, 95%CrI=1.03, 1.40) and synthetic firelog burning (OR=1.29, 95%CrI=1.06, 1.57); these estimates are similar, but slightly attenuated, to those from single-source models. Additionally when we considered PAH exposure groups, the most pronounced significant associations included total indoor sources (active smoking, ETS from spouse, grilled/smoked meat intake, stove/fireplace use, OR=1.45, 95%CrI=1.02, 2.04).

CONCLUSIONS

Groups of PAH sources, particularly indoor sources, were associated with a 30-50% increase in breast cancer incidence. PAH exposure is ubiquitous and a potentially modifiable breast cancer risk factor.

Sources of polycyclic aromatic hydrocarbons are associated with gene-specific promoter methylation in women with breast cancer

BACKGROUND

Tobacco smoke, diet and indoor/outdoor air pollution, all major sources of polycyclic aromatic hydrocarbons (PAHs), have been associated with breast cancer. Aberrant methylation may be an early event in carcinogenesis, but whether PAHs influence the epigenome is unclear, particularly in breast tissue where methylation may be most relevant. We aimed to evaluate the role of methylation in the association between PAHs and breast cancer.

METHODS

In a population-based case-control study, we measured promoter methylation of 13 breast cancer-related genes in breast tumor tissue (n=765-851 cases) and global methylation in peripheral blood (1055 cases/1101 controls). PAH sources (current active smoking, residential environmental tobacco smoke (ETS), vehicular traffic, synthetic log burning, and grilled/smoked meat intake) were evaluated separately. Logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

When comparing methylated versus unmethylated genes, synthetic log use was associated with increased ORs for CDH1 (OR=2.26, 95%CI=1.06-4.79), HIN1 (OR=2.14, 95%CI=1.34-3.42) and RARβ (OR=1.80, 95%CI=1.16-2.78) and decreased ORs for BRCA1 (OR=0.44, 95%CI=0.30-0.66). Residential ETS was associated with decreased ORs for ESR1 (OR=0.74, 95%CI=0.56-0.99) and CCND2 methylation (OR=0.65, 95%CI=0.44-0.96). Current smoking and vehicular traffic were associated with decreased ORs for DAPK (OR=0.53, 95%CI=0.28-0.99) and increased ORs for TWIST1 methylation (OR=2.79, 95%CI=1.24-6.30), respectively. In controls, synthetic log use was inversely associated with LINE-1 (OR=0.59, 95%CI=0.41-0.86).

DISCUSSION

PAH sources were associated with hypo- and hypermethylation at multiple promoter regions in breast tumors and LINE-1 hypomethylation in blood of controls. Methylation may be a potential biologic mechanism for the associations between PAHs and breast cancer incidence.

Vehicular Traffic-Related Polycyclic Aromatic Hydrocarbon Exposure and Breast Cancer Incidence: The Long Island Breast Cancer Study Project (LIBCSP)

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants, known human lung carcinogens, and potent mammary carcinogens in laboratory animals. However, the association between PAHs and breast cancer in women is unclear. Vehicular traffic is a major ambient source of PAH exposure.

OBJECTIVES

Our study aim was to evaluate the association between residential exposure to vehicular traffic and breast cancer incidence.

METHODS

Residential histories of 1,508 participants with breast cancer (case participants) and 1,556 particpants with no breast cancer (control participants) were assessed in a population-based investigation conducted in 1996-1997. Traffic exposure estimates of benzo[a]pyrene (B[a]P), as a proxy for traffic-related PAHs, for the years 1960-1995 were reconstructed using a model previously shown to generate estimates consistent with measured soil PAHs, PAH-DNA adducts, and CO readings. Associations between vehicular traffic exposure estimates and breast cancer incidence were evaluated using unconditional logistic regression.

RESULTS

The odds ratio (95% CI) was modestly elevated by 1.44 (0.78, 2.68) for the association between breast cancer and long-term 1960-1990 vehicular traffic estimates in the top 5%, compared with below the median. The association with recent 1995 traffic exposure was elevated by 1.14 (0.80, 1.64) for the top 5%, compared with below the median, which was stronger among women with low fruit/vegetable intake [1.46 (0.89, 2.40)], but not among those with high fruit/vegetable intake [0.92 (0.53, 1.60)]. Among the subset of women with information regarding traffic exposure and tumor hormone receptor subtype, the traffic-breast cancer association was higher for those with estrogen/progesterone-negative tumors [1.67 (0.91, 3.05) relative to control participants], but lower among all other tumor subtypes [0.80 (0.50, 1.27) compared with control participants].

CONCLUSIONS

In our population-based study, we observed positive associations between vehicular traffic-related B[a]P exposure and breast cancer incidence among women with comparatively high long-term traffic B[a]P exposures, although effect estimates were imprecise.

CITATION

Mordukhovich I, Beyea J, Herring AH, Hatch M, Stellman SD, Teitelbaum SL, Richardson DB, Millikan RC, Engel LS, Shantakumar S, Steck SE, Neugut AI, Rossner P Jr., Santella RM, Gammon MD. 2016. Vehicular traffic-related polycyclic aromatic hydrocarbon exposure and breast cancer incidence: the Long Island Breast Cancer Study Project (LIBCSP). Environ Health Perspect 124:30-38; http://dx.doi.org/10.1289/ehp.1307736.

Evaluation of Female Breast Cancer Risk Among the Betel Quid Chewer: A Bio-Statistical Assessment in Assam, India

BACKGROUND

Breast cancer is the most commonly diagnosed cancer among the female population of Assam, India. Chewing of betel quid with or without tobacco is common practice among female population of this region. Moreoverthe method of preparing the betel quid is different from other parts of the country.So matched case control study is conducted to analyse whetherbetel quid chewing plays a significant role in the high incidence of breast cancer occurrences in Assam.

METHODS AND MATERIAL

Here, controls are matched to the cases by age at diagnosis (±5 years), family income and place of residence with matching ratio 1:1. Conditional logistic regression models and odd ratios (OR) was used to draw conclusions.

RESULTS

It is observed that cases are more habituated to chewing habits than the controls.Further the conditional logistic regression analysis reveals that betel quid chewer faces 2.353 times more risk having breast cancer than the non-chewer with p value 0.0003 (95% CI 1.334-4.150).

CONCLUSION

Though the female population in Assam usually does not smoke, the addictive habits typical to this region have equal effect on the occurrence of breast cancer.

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

BACKGROUND

The role of passive smoking on breast cancer risk was unclear. This study aimed to evaluate the association between passive smoking and breast cancer risk among Chinese women.

METHODS/PRINCIPAL FINDINGS

A hospital-based case-control study, including 877 breast cancer cases and 890 controls, frequency-matched by age and residence, was conducted. A structured questionnaire was used to collect information on passive smoking history through face-to-face interview by trained interviewers. Unconditional logistic regression models were used to estimate the association between passive smoking and breast cancer risk. A positive association between any passive smoking exposure and breast cancer risk was observed. Compared with women who were never exposed to passive smoking, women who were ever exposed had a higher breast cancer risk, with the adjusted odds ratio (OR) and 95% confidence interval (CI) of 1.35 (1.11-1.65). Similar result was found on home passive smoking exposure and breast cancer risk, but not on workplace passive smoking exposure. Women who were ever exposed to tobacco smoke at home had a higher risk of breast cancer compared with never exposed women, with the adjusted OR (95% CI) of 1.30 (1.05-1.61). Home passive smoking exposure showed significant dose-response relationships with breast cancer risk in smoker-years, cigarettes/day and total pack-years (Ptrend=0.003, 0.006 and 0.009, respectively). An increased total smoker-years of any passive exposure significantly elevated the risk of breast cancer (Ptrend<0.001). Positive associations and dose-response relationships were found among postmenopausal women and all subtypes of estrogen receptor (ER) and progesterone receptor (PR) status of breast cancer.

CONCLUSIONS

Passive smoking was associated with an increased risk of breast cancer among non-smoking Chinese women. A stronger positive association with breast cancer risk was seen mainly among postmenopausal women.

Husband's smoking status and breast cancer risk in Japan: From the Takayama study

The effects of smoking on breast cancer remain unclear. We assessed the associations of subjects' or husbands' smoking status with breast cancer incidence in a population-based prospective study in Japan. The subjects were 15 719 women aged 35 years or older. The follow up was conducted from September 1992 to March 2008. Cancer incidence was mainly confirmed through regional population-based cancer registries. Breast cancer was defined as code C50 according to the International Classification of Diseases and Health Related Problems, 10th Revision. Lifestyle, including smoking status, was assessed with a self-administered questionnaire. Alcohol consumption was assessed with a validated food-frequency questionnaire. After multivariate adjustments for age, body mass index, alcohol consumption, physical activity, education, age at menarche, age at first delivery, menopausal status, number of children and history of hormone replacement therapy, active smoking was not associated with the risk of breast cancer. Compared with never smokers whose husband had never smoked, the risks of breast cancer were 1.98 (95% CI: 1.03–3.84) among never smokers whose husband was a current smoker of 21 cigarettes per day or more. The increased risk of breast cancer among women having a smoking husband was pronounced among those who did not habitually consume alcohol. These results suggest that exposure to smoke from husbands is a potential risk factor for breast cancer. The impact of alcohol consumption on the increased breast cancer risk from passive smoking needs to be addressed in further studies.

Passive smoking exposure from partners as a risk factor for ER+/PR+ double positive breast cancer in never-smoking Chinese urban women: a hospital-based matched case control study

Background

The relationship between passive smoking exposure (PSE) and breast cancer risk is of major interest.

Objective

To evaluate the relationship between PSE from partners and breast cancer risk stratified by hormone-receptor (HR) status in Chinese urban women population.

Design

Hospital-based matched case control study.

Setting

Chinese urban breast cancer patients without current or previous active smoking history in China Medical University 1st Hospital, Liaoning Province, China between Jan 2009 and Nov 2009.

Patients

Each breast cancer patient was matched 1∶1 with healthy controls by gender and age (±2 years) from the same hospital.

Measurements

The authors used unconditional logistic regression analyses to estimate odds ratio for women with PSE from partners and breast cancer risk.

Results

312 pairs were included in the study. Women who endured PSE had significantly increased risk of breast cancer (adjusted OR: 1.46; 95% CI: 1.05–2.03; P = 0.027), comparing with unexposed women. Women who exposed to >5 cigarettes/day also had significant increased risk (adjusted OR: 1.99; 95% CI: 1.28–3.10; P = 0.002), as were women exposed to passive smoke for 16–25 years (adjusted OR: 1.87 95% CI: 1.22–2.86; P = 0.004), and those exposed to > 4 pack-years (adjusted OR: 1.71 95% CI: 1.17–2.50; P = 0.004). Similar trends were significant for estrogen receptor (ER)/progesterone receptor (PR) double positive subgroup(adjusted OR: 1.71; 2.20; 1.99; 1.92, respectively), but not for ER+/PR−, ER−/PR+, or ER−/PR− subgroups.

Limitations

limitations of the hospital-based retrospective study, lack of information on entire lifetime PSE and low statistical power.

Conclusions

Our findings provide further evidence that PSE from partners contributes to increased risk of breast cancer, especially for ER/PR double positive breast cancer, in Chinese urban women.

Cigarette smoking and breast cancer risk in relation to joint estrogen and progesterone receptor status: a case-control study in Japan

An association of cigarette smoking with breast cancer risk has been hypothesized. However, results from previous studies have been inconsistent. This case-control study investigated the association of cigarette smoking with breast cancer risk in terms of estrogen-receptor/progesterone-receptor (ER/PgR) status. From among female patients aged 30 years and over admitted to a single hospital in Japan between 1997 and 2011, 1,263 breast cancer cases (672 ER+/PgR+, 158 ER+/PgR-, 22 ER-/PgR+, 308 ER-/PgR- and 103 missing) and 3,160 controls were selected. History of smoking (ever, never), some smoking-related measures, and passive smoking from husbands (ever, never) were assessed using a self-administered questionnaire. Polytomous logistic regression and tests for heterogeneity across ER+/PgR + and ER-/PgR- were conducted. For any hormone receptor subtype, no significant association was observed between history of smoking (ever, never) and breast cancer risk. Analysis of smoking-related measures revealed that starting to smoke at an early age of ≤19 years was significantly associated with an increased risk of postmenopausal ER-/PgR- cancer (odds ratio = 7.01, 95% confidence interval: 2.07-23.73). Other measures of smoking such as the number of cigarettes per day, the duration of smoking, and start of smoking before the first birth were not associated with breast cancer risk for any receptor subtype. There was no association between passive smoking (ever, never) and breast cancer risk for any of the four subtypes. These results indicate that history of smoking and passive smoking from husbands may have no overall effect on breast cancer risk for any hormone receptor subtype. However, it is possible that women who start to smoke as teenagers may have a higher risk of developing postmenopausal ER-/PgR- cancer. Further studies are needed to clarify the association of smoking with breast cancer risk, especially the role of starting to smoke at an early age.

Higher expression of circulating miR-182 as a novel biomarker for breast cancer

MicroRNAs (miRNAs), present in the serum in a stable and reproducible manner, may be used as biomarkers for various diseases. Few studies have previously investigated circulating miRNAs in the peripheral blood of breast cancer (BC) patients. To identify the role of serum miR-182 levels in BC, the present study detected miR-182 levels in the serum of 46 BC patients and 58 controls, by quantitative PCR. The results showed that the serum miR-182 levels in BC patients were significantly higher compared with the serum of healthy controls (P<0.01). The miR-182 was also overexpressed in the BC tissues compared with the para-carcinoma tissues. Furthermore, the serum levels of miR-182 in the estrogen receptor (ER)-positive patients were considerably lower compared with those in the ER-negative patients. The serum levels of miR-182 in the progesterone receptor (PR)-positive patients were also found to be lower compared with those in the PR-negative patients. The current study highlights results consistent with miR-182 as a novel and valuable biomarker for the diagnosis of BC.

Passive cigarette smoke exposure during various periods of life, genetic variants, and breast cancer risk among never smokers

The association between passive cigarette smoke exposure and breast cancer risk is inconclusive and may be modified by genotype. The authors investigated lifetime passive cigarette smoke exposures, 36 variants in 12 carcinogen-metabolizing genes, and breast cancer risk among Ontario, Canada, women who had never smoked (2003-2004). DNA (saliva) was available for 920 breast cancer cases and 960 controls. Detailed information about passive smoke exposure was collected for multiple age periods (childhood, teenage years, and adulthood) and environments (home, work, and social). Adjusted odds ratios and 95% confidence intervals were estimated by multivariable logistic regression, and statistical interactions were assessed using the likelihood ratio test. Among postmenopausal women, most associations between passive smoke and breast cancer risk were null, whereas among premenopausal women, nonsignificant positive associations were observed. Significant interactions were observed between certain types of passive smoke exposure and genetic variants in CYP2E1, NAT2, and UGT1A7. While these interactions were statistically significant, the magnitudes of the effect estimates were not consistent or easily interpretable, suggesting that they were perhaps due to chance. Although the results of this study were largely null, it is possible that premenopausal women exposed to passive smoke or carrying certain genetic variants may be at higher risk of breast cancer.

Smoking before the first pregnancy and the risk of breast cancer: a meta-analysis

The authors conducted a meta-analysis of the association between smoking before a first pregnancy, when undifferentiated breast tissue may be vulnerable to tobacco carcinogens, and the risk of breast cancer. A search of the published literature through August 2010 identified 23 papers reporting on associations between smoking before a first pregnancy and breast cancer. Odds ratios or hazard ratios and 95% confidence intervals, adjusted for known or suspected breast cancer risk factors, were abstracted from each study. Data were pooled using both fixed- and random-effects models. The fixed-effect summary risk ratio for breast cancer among the women who smoked before their first pregnancy versus women who had never smoked was 1.10 (95% confidence interval: 1.07, 1.14); the random-effects estimate was similar. The separate fixed-effect risk ratios for smoking only before the first pregnancy (5 studies) or only after the first pregnancy (16 studies) were both 1.07, providing no evidence that breast tissue is more susceptible to malignant transformation from smoking before the first pregnancy. While these small summary risk ratios may represent causal effects, residual confounding could readily produce estimates of this size in the absence of any causal effect.

Cigarette smoking and the incidence of breast cancer

BACKGROUND

Tobacco smoke contains carcinogens, which may increase the risk of breast cancer (BC). Conversely, cigarette smoking also has antiestrogenic effects, which may reduce the risk of BC. The association between smoking and BC remains controversial.

METHODS

Prospective cohort study of 111 140 participants of the Nurses' Health Study from 1976 to 2006 for active smoking and 36 017 women from 1982 to 2006 for passive smoking.

RESULTS

During 3 005 863 person-years of follow-up, 8772 incident cases of invasive BC were reported. After adjustment for potential confounders, the hazard ratio (HR) of BC was 1.06% (95% confidence interval [CI], 1.01%-1.10%) for ever smokers relative to never smokers. Breast cancer incidence was associated with a higher quantity of current (P for trend = .02) and past (P for trend = .003) smoking, younger age at smoking initiation (P for trend = .01), longer duration of smoking (P for trend = .01), and more pack-years of smoking (P for trend = .005). Premenopausal smoking was associated with a slightly higher incidence of BC (HR, 1.11; 95% CI, 1.07-1.15 for every increase of 20 pack-years), especially smoking before first birth (1.18; 1.10-1.27 for every increase of 20 pack-years). Conversely, the direction of the association between postmenopausal smoking and BC was inverse (0.93; 0.85-1.02 for every increase of 20 pack-years). Passive smoking in childhood or adulthood was not associated with BC risk.

CONCLUSION

Active smoking, especially smoking before the first birth, may be associated with a modest increase in the risk of BC.

Smoking and alcohol consumption in relation to risk of triple-negative breast cancer in a cohort of postmenopausal women

PURPOSE

Little is known about the risk factors for triple-negative breast cancer (TNBC), which has a worse prognosis compared to hormone receptor-positive breast cancer. We examined the association of smoking and alcohol intake with TNBC and estrogen receptor-positive (ER+) breast cancer.

METHODS

Among 148,030 women enrolled in the Women's Health Initiative, 300 TNBC cases and 2,479 ER+ cases were identified over a median of 8.0 years of follow-up. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI).

RESULTS

Cigarette smoking was not associated with TNBC, whereas drinkers had reduced risk compared to never drinkers. In contrast, both exposures showed slight positive associations with ER+ breast cancer: for women with ≥ 40 pack-years of smoking, the HR was 1.24, 95% CI 1.06-1.44; for women consuming ≥ 7 servings of alcohol per week, the HR was 1.26, 95% CI 1.06-1.50. Intakes of wine and hard liquor were also significantly positively associated with ER+ breast cancer.

CONCLUSIONS

These findings from a large cohort of postmenopausal women suggest that smoking and alcohol consumption are not associated with increased risk of TNBC, but may be modestly associated with increased risk of ER+ breast cancer.

Cigarette smoking in relation to risk of ductal carcinoma in situ of the breast in a cohort of postmenopausal women

In numerous studies, investigators have examined the association of active smoking with risk of invasive breast cancer, but to the authors' knowledge, no cohort study has assessed smoking in relation to the risk of in situ breast cancer, the postulated penultimate stage preceding invasive breast cancer. The authors examined the latter association using data collected at baseline from 63,393 women in the Women's Health Initiative Clinical Trial. A total of 486 cases of ductal carcinoma in situ (DCIS) of the breast were identified during 8 years of follow-up between 1993 and 2005. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals. For the primary analysis, invasive breast cancer was treated as a competing risk. After adjustment for covariates, associations with smoking status, smoking intensity, duration, pack-years, and age at quitting were all close to the null value and showed few meaningful trends. Sensitivity analyses performed to address different possibilities with respect to the natural history of breast cancer also did not provide consistent evidence of an association of smoking with DCIS. The results of this large cohort study provide little support for an association of cigarette smoking with risk of DCIS in postmenopausal women.

Associations between polycyclic aromatic hydrocarbon-related exposures and p53 mutations in breast tumors

BACKGROUND

Previous studies have suggested that polycyclic aromatic hydrocarbons (PAHs) may be associated with breast cancer. However, the carcinogenicity of PAHs on the human breast remains unclear. Certain carcinogens may be associated with specific mutation patterns in the p53 tumor suppressor gene, thereby contributing information about disease etiology.

OBJECTIVES

We hypothesized that associations of PAH-related exposures with breast cancer would differ according to tumor p53 mutation status, effect, type, and number.

METHODS

We examined this possibility in a population-based case-control study using polytomous logistic regression. As previously reported, 151 p53 mutations among 859 tumors were identified using Surveyor nuclease and confirmed by sequencing.

RESULTS

We found that participants with p53 mutations were less likely to be exposed to PAHs (assessed by smoking status in 859 cases and 1,556 controls, grilled/smoked meat intake in 822 cases and 1,475 controls, and PAH-DNA adducts in peripheral mononuclear cells in 487 cases and 941 controls) than participants without p53 mutations. For example, active and passive smoking was associated with p53 mutation-negative [odds ratio (OR) = 1.55; 95% confidence interval (CI), 1.11-2.15] but not p53 mutation-positive (OR = 0.77; 95% CI, 0.43-1.38) cancer (ratio of the ORs = 0.50, p < 0.05). However, frameshift mutations, mutation number, G:C-->A:T transitions at CpG sites, and insertions/deletions were consistently elevated among exposed subjects.

CONCLUSIONS

These findings suggest that PAHs may be associated with specific breast tumor p53 mutation subgroups rather than with overall p53 mutations and may also be related to breast cancer through mechanisms other than p53 mutation.

Multiple genetic variants in telomere pathway genes and breast cancer risk

PURPOSE

To explore the etiologic role of genetic variants in telomere pathway genes and breast cancer risk.

METHODS

A population-based case-control study, the Long Island Breast Cancer Study Project, was conducted, and 1,067 cases and 1,110 controls were included in the present study. Fifty-two genetic variants of nine telomere-related genes were genotyped.

RESULTS

Seven single nucleotide polymorphisms (SNP) showed significant case-control differences at the level of P < 0.05. The top three statistically significant SNPs under a dominant model were TERT-07 (rs2736109), TERT-54 (rs3816659), and POT1-03 (rs33964002). The odds ratios (OR) were 1.56 [95% confidence interval (95% CI), 1.22-1.99] for the TERT-07 G-allele, 1.27 (95% CI, 1.05-1.52) for the TERT-54 T-allele, and 0.79 (95% CI, 0.67-0.95) for the POT1-03 A-allele. TERT-67 (rs2853669) was statistically significant under a recessive model; the OR of the CC genotype was 0.69 (95% CI, 0.69-0.93) compared with the T-allele. However, none of the SNPs retained significance after Bonferroni adjustment for multiple testing at the level of P < 0.001 (0.05/52) except for TERT-07. When restricted to Caucasians (94% of the study subjects), a stronger association for the TERT-07 G-allele was observed with an OR of 1.60 (95% CI, 1.24-2.05; P = 0.0002). No effect modifications were found for variant alleles and menopausal status, telomere length, cigarette smoking, body mass index status, and family history of breast cancer risk.

CONCLUSIONS

Four SNPs in the TERT and POT1 genes were significantly related with overall breast cancer risk. This initial analysis provides valuable clues for further exploration of the biological role of telomere pathway genes in breast cancer.

Passive smoking and risk of breast cancer in the California teachers study

BACKGROUND

Although recent reviews have suggested active smoking to be a risk factor for breast cancer, the association with passive smoke exposure remains controversial. This risk association was explored in a large prospective study of women, the California Teachers Study.

METHODS

Detailed lifetime information on passive smoke exposure by setting (home, work, or social) and by age of exposure was collected in 1997 from 57,523 women who were lifetime nonsmokers and had no history of breast cancer. In the ensuing decade, a total of 1,754 women were diagnosed with invasive breast cancer. Cox proportional hazards models were fit to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) associated with several lifetime passive smoke exposure metrics.

RESULTS

For all breast cancer, measures of higher lifetime passive smoking intensity and duration were associated with nonstatistically significant HRs of 1.11 to 1.14. For postmenopausal women, HRs for lifetime low, medium, and high cumulative exposure were 1.17 (95% CI, 0.91-1.49), 1.19 (95% CI, 0.93-1.53), and 1.26 (95% CI, 0.99-1.60). For women exposed in adulthood (age > or =20 years), risk was elevated at the highest level of cumulative exposure (HR, 1.18; 95% CI, 1.00-1.40), primarily among postmenopausal women (HR, 1.25; 95% CI, 1.01-1.56). A statistically significant dose response was detected when analysis was restricted to women with moderate to high levels of passive smoke exposure.

CONCLUSION

These results suggest that cumulative exposures to high levels of sidestream smoke may increase breast cancer risk among postmenopausal women who themselves have never smoked tobacco products.

PAH-DNA adducts, cigarette smoking, GST polymorphisms, and breast cancer risk

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) may increase breast cancer risk, and the association may be modified by inherited differences in deactivation of PAH intermediates by glutathione S-transferases (GSTs). Few breast cancer studies have investigated the joint effects of multiple GSTs and a PAH biomarker.

OBJECTIVE

We estimated the breast cancer risk associated with multiple polymorphisms in the GST gene (GSTA1, GSTM1, GSTP1, and GSTT1) and the interaction with PAH-DNA adducts and cigarette smoking.

METHODS

We conducted unconditional logistic regression using data from a population-based sample of women (cases/controls, respectively): GST polymorphisms were genotyped using polymerase chain reaction and matrix-assisted laser desorption/ionization time-of-flight assays (n = 926 of 916), PAH-DNA adduct blood levels were measured by competitive enzyme-linked immunosorbent assay (n = 873 of 941), and smoking status was assessed by in-person questionnaires (n = 943 of 973).

RESULTS

Odds ratios for joint effects on breast cancer risk among women with at least three variant alleles were 1.56 [95% confidence interval (CI), 1.13-2.16] for detectable PAH-DNA adducts and 0.93 (95% CI, 0.56-1.56) for no detectable adducts; corresponding odds ratios for three or more variants were 1.18 (95% CI, 0.82-1.69) for ever smokers and 1.44 (95% CI, 0.97-2.14) for never smokers. Neither interaction was statistically significant (p = 0.43 and 0.62, respectively).

CONCLUSION

We found little statistical evidence that PAHs interacted with GSTT1, GSTM1, GSTP1, and GSTA1 polymorphisms to further increase breast cancer risk.

Second hand smoke exposure and excess heart disease and lung cancer mortality among hospital staff in Crete, Greece: a case study

Exposure to secondhand smoke (SHS) is a serious threat to public health, and a significant cause of lung cancer and heart disease among non-smokers. Even though Greek hospitals have been declared smoke free since 2002, smoking is still evident. Keeping the above into account, the aim of this study was to quantify the levels of exposure to environmental tobacco smoke and to estimate the attributed lifetime excess heart disease and lung cancer deaths per 1000 of the hospital staff, in a large Greek public hospital. Environmental airborne respirable suspended particles (RSP) of PM_2.5 were performed and the personnpel’s excess mortality risk was estimated using risk prediction formulas. Excluding the intensive care unit and the operating theatres, all wards and clinics were polluted with environmental tobacco smoke. Mean SHS-RSP measurements ranged from 11 to 1461 μg/m³ depending on the area. Open wards averaged 84 μg/m³ and the managing wards averaged 164 μg/m³ thus giving an excess lung cancer and heart disease of 1.12 (range 0.23–1.88) and 11.2 (range 2.3–18.8) personnel in wards and 2.35 (range 0.55–12.2) and 23.5 (range 5.5–122) of the managing staff per 1000 over a 40-year lifespan, respectively. Conclusively, SHS exposure in hospitals in Greece is prevalent and taking into account the excess heart disease and lung cancer mortality risk as also the immediate adverse health effects of SHS exposure, it is clear that proper implementation and enforcement of the legislation that bans smoking in hospitals is imperative to protect the health of patients and staff alike.

Age of smoking initiation and risk of breast cancer in a sample of Ontario women

Objectives

To examine the association between time of smoking initiation and both the independent and joint effects of active and passive tobacco smoke exposure and the risk of breast cancer in a sample of Ontario women.

Methods

Data from two large population-based case-control studies conducted among Ontario women aged 25–75 years were combined for analysis (n = 12,768).

Results

Women who had ever smoked and were exposed to passive smoke had a significant increased risk of breast cancer (OR 1.13, 95%CI 1.01–1.25). A significant increased risk was also observed among women who initiated smoking: at age 26 or older (OR 1.26, 95%CI 1.03–1.55); more than five years from menarche (OR 1.26, 95%CI 1.12–1.42); and, after their first live birth (OR 1.25, 95%CI 1.02–1.52).

Conclusion

The results suggest that women who initiate smoking at an older age are at an increased risk of breast cancer.

Validation of smoking history in cancer patients

OBJECTIVE

The aim of the study was to investigate the agreement between patient records and the information reported from relatives, and how the relationship and time since patient's death affected the response rate and the quality of the data.

METHODS

A questionnaire regarding smoking history was sent to next-of-kin of 270 deceased women diagnosed with breast cancer during 1958-2000 in the Stockholm County. Agreement between the reports of next-of-kin and patient records was calculated using a kappa statistics, along with its 95% confidence interval.

RESULTS

When information about overall smoking history from patient records and next-of-kin was compared, the kappa value was 0.83 (95% confidence interval (CI): 0.73-0.92). Using two smoking categories (<or=15 cigarettes,>15 cigarettes), for quantitative smoking history the kappa value was 0.46. No evidence of a trend toward under-/over-reporting among next-of-kin was found. The overall smoking agreement between medical record and next-of-kin was similar for the two median recall periods (<or=10 years and >10 years), with kappa value 0.80 and 0.83, respectively.

CONCLUSION

Next-of-kin can provide reliable information with almost perfect agreement with patient records on lifetime smoking status, and should be considered in studies where information on smoking history is missing.

Passive smoking and breast cancer in never smokers: prospective study and meta-analysis

BACKGROUND

Active smoking has little or no effect on women's risk of developing breast cancer, but it has been suggested that passive exposure to tobacco smoke may increase this risk among women who have never smoked.

OBJECTIVE

To evaluate the possible relationship between passive smoking and breast cancer risk within the Million Women Study, a large UK prospective study, and to report a meta-analysis of published results.

METHODS

In the large prospective study, 224 917 never smokers who completed a questionnaire that asked women whether their parents had smoked and if their current partner smoked were followed up for an average of 3.5 years for incident breast cancer. In the meta-analysis, studies that had recorded exposure information prospectively and retrospectively were considered separately. Main outcome measures Adjusted relative risk of breast cancer in never smokers who were passively exposed to tobacco smoke at various ages compared with never smokers with no such exposure.

RESULTS

In the prospective study, 2518 incident invasive breast cancers occurred during follow-up and the adjusted relative risk of breast cancer for passive exposure either as a child or as an adult vs neither exposure was 0.98 (95% CI 0.88-1.09); results were similarly null for childhood exposure (0.98, 0.88-1.08) and adult exposure (1.02, 0.89-1.16) separately. We identified seven other studies with prospectively recorded exposure data; when results of all eight studies were combined (including 5743 never smokers with breast cancer), the aggregate relative risk was 0.99 (0.93-1.05) for any passive exposure. The aggregate findings differed substantially (P = 0.0002) between these 8 studies and 17 other studies with retrospectively recorded information (including 5696 never smokers with breast cancer).

CONCLUSIONS

Aggregate results from studies with prospectively reported information show that the incidence of breast cancer is similar in women who did and did not report passive exposure to tobacco smoke either as a child or as an adult. The aggregate findings from the retrospective studies may have been distorted by some women becoming more likely to report past exposures because they knew that they had breast cancer.

Case-control study of tobacco smoke exposure and breast cancer risk in Delaware

BACKGROUND

Tobacco smoke exposure may be associated with increased breast cancer risk, although the evidence supporting the association is inconclusive. We conducted a case-control study in Delaware, incorporating detailed exposure assessment for active and secondhand smoke at home and in the workplace.

METHODS

Primary invasive breast cancer cases diagnosed among female Delaware residents, ages 40-79, in 2000-2002 were identified through the Delaware cancer registry (n = 287). Delaware drivers license and Health Care Finance Administration records were used to select age frequency-matched controls for women <65 and > or = 65, respectively. Detailed information on tobacco smoke exposure was obtained through telephone interviews.

RESULTS

A statistically significant increased risk of breast cancer was observed for ever having smoked cigarettes (odds ratio = 1.43, 95% confidence interval = 1.03-1.99). However, there was no evidence of a dose-response relationship between breast cancer risk and total years smoked, cigarettes per day, or pack-years. Neither residential nor workplace secondhand smoke exposure was associated with breast cancer. Recalculations of active smoking risks using a purely unexposed reference group of women who were not exposed to active or secondhand smoking did not indicate increased risks of breast cancer.

CONCLUSION

These findings do not support an association between smoking and breast cancer.

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

OBJECTIVES

To compare the strength of evidence from epidemiologic studies of secondhand smoke of the US Surgeon General's 1986 conclusion that secondhand smoke caused lung cancer with the California Environmental Protection Agency's (CalEPA) similar 2005 conclusion on breast cancer in younger, primarily premenopausal women.

METHODS

We reviewed each report for criteria used to assess causality: numbers of studies, statistically significant increases in risk, and pooled summary risk estimates.

RESULTS

Both the Surgeon General and CalEPA used updated Bradford Hill criteria for assessing causality and found that the evidence met those criteria. Six of 13 lung cancer studies (46%) had statistically significant increases (one of three cohort studies). Pooled risk estimates for lung cancer for spousal exposure were 1.53 for 10 combined case-control studies and 1.88 for seven studies with dose-response results. The CalEPA reported 10 of 14 studies (71%) had statistically significant increases in breast cancer risk (two of four cohort studies). Pooled relative risk estimates for younger, primarily premenopausal women were 1.68 (95% CI: 1.33, 2.12) for all exposed women and 2.19 (1.68, 2.84) for five studies with better exposure assessment.

CONCLUSIONS

The evidence from epidemiologic studies of secondhand smoke in 2005 for breast cancer in younger, primarily premenopausal women was stronger than for lung cancer in 1986.

Plasma protein carbonyl levels and breast cancer risk

To study the role of oxidative stress in breast cancer risk, we analysed plasma levels of protein carbonyls in 1050 cases and 1107 controls. We found a statistically significant trend in breast cancer risk in relation to increasing quartiles of plasma protein carbonyl levels (OR = 1.2, 95% CI = 0.9–1.5; OR = 1.5, 95% CI = 1.2–2.0; OR = 1.6, 95% CI = 1.2–2.1, for the 2^nd, 3^rd and 4^th quartile relative to the lowest quartile, respectively, P for trend = 0.0001). The increase in risk was similar for younger (<50 years) and older women, more pronounced among women with higher physical activity levels (0.7 hrs/week for 4^th quartile versus lowest quartile OR = 2.0, 95% CI = 1.4–3.0), higher alcohol consumption (≥15 grams/day for 4^th quartile versus lowest quartile OR = 2.3, 95% CI = 1.1–4.7), and hormone replacement therapy use (HRT, OR = 2.6, 95% CI = 1.6–4.4 for 4^th quartile versus lowest quartile). The multiplicative interaction terms were statistically significant only for physical activity and HRT. The positive association between plasma protein carbonyl levels and breast cancer risk was also observed when the analysis was restricted to women who had not received chemotherapy or radiation therapy prior to blood collection. Among controls, oxidized protein levels significantly increased with cigarette smoking and higher fruit and vegetable consumption, and decreased with alcohol consumption >30 grams per day. Women with higher levels of plasma protein carbonyl and urinary 15F_2t-isoprostane had an 80% increase in breast cancer risk (OR = 1.8, 95% CI = 1.2–2.6) compared to women with levels below the median for both markers of oxidative stress. In summary, our results suggest that increased plasma protein carbonyl levels may be associated with breast cancer risk.

Environmental tobacco smoke: respiratory and other health effects

Involuntary exposure to environmental tobacco smoke (ETS) is a serious and entirely preventable public health hazard. It has become clear that ETS adversely affects the health of all who breathe its toxins. Independent of active smoking, ETS exposure is a modifiable risk factor for chronic obstructive pulmonary disease. The expanding body of research presented in this article provides evidence that the damaging consequences of ETS reach far beyond the lungs. Having been determined the third leading cause of preventable death in this country, this is a problem that must be addressed aggressively.

Xeroderma pigmentosum complementation group C genotypes/diplotypes play no independent or interaction role with polycyclic aromatic hydrocarbons-DNA adducts for breast cancer risk

Xeroderma pigmentosum complementation group C (XPC) is an important DNA nuclear excision repair (NER) gene that recognises the damage caused by a variety of bulky DNA adducts. We evaluated the association of two common non-synonymous polymorphisms in XPC (Ala499Val and Lys939Gln) with breast cancer risk in the Long Island Breast Cancer Study Project (LIBCSP), a population-based case-control study. Genotyping of 1067 cases and 1110 controls was performed by a high throughput assay with fluorescence polarisation. There were no overall associations between XPC polymorphisms and breast cancer risk. A diplotype CC-CC was significantly associated with increased breast cancer risk compared with diplotype CA-CA (OR=1.4, 95%CI: 1.0-1.9), but was not significant when compared with all other diplotypes combined (OR=1.22, 95%CI: 0.97-1.53). No modification effects were observed for XPC genotypes by cigarette smoking status, smoking pack-years or polycyclic aromatic hydrocarbons (PAH)-DNA adducts. The increase in breast cancer risk was slightly more pronounced among women with detectable PAH-DNA adducts and carrying the diplotype CC-CC (OR=1.6, 95%CI: 1.1-2.2) compared to women with non-detectable PAH-DNA adducts carrying other diplotypes combined, but no statistically significant interaction was observed (P(interaction)=0.69). These data suggest that XPCs have neither independent effects nor interactions with cigarette smoking and PAH-DNA adducts for breast cancer risk. Further studies with multiple genetic polymorphisms in NER pathway are warranted.

Environmental tobacco smoke in hospitality venues in Greece

BACKGROUND

Exposure to environmental tobacco smoke is a major threat to public health. Greece, having the highest smoking prevalence in the European Union is seriously affected by passive smoking. The purpose of this study was to measure environmental tobacco smoke (ETS) exposure in the non smoking areas of hospitality venues and offices in Greece and to compare the levels of exposure to levels in the US, UK and Ireland before and after the implementation of a smoking ban.

METHODS

Experimental measurements of particulate matter 2.5 microm (PM2.5), performed during a cross sectional study of 49 hospitality venues and offices in Athens and Crete, Greece during February - March 2006.

RESULTS

Levels of ETS ranged from 19 microg/m3 to 612 microg/m3, differing according to the place of measurement. The average exposure in hospitality venues was 268 microg/m3 with ETS levels found to be highest in restaurants with a mean value of 298 microg/m3 followed by bars and cafes with 271 microg/m3. ETS levels were 76% lower in venues in which smoking was not observed compared to all other venues (p < 0.001). ETS levels in Greek designated non-smoking areas are similar to those found in the smoking sections of UK hospitality venues while levels in Ireland with a total smoking ban are 89% lower and smoke-free communities in the US are 91 - 96% lower than levels in Greece.

CONCLUSION

Designated non-smoking areas of hospitality venues in Greece are significantly more polluted with ETS than outdoor air and similar venues in Europe and the United States. The implementation of a total indoor smoking ban in hospitality venues has been shown to have a positive effect on workers and patrons' health. The necessity of such legislation in Greece is thus warranted.

Genetic variation of TP53, polycyclic aromatic hydrocarbon-related exposures, and breast cancer risk among women on Long Island, New York

BACKGROUND

p53 participates in cell cycle control, programmed cell death/apoptosis, and DNA repair, all pathways involved in carcinogenesis. TP53 variants may influence p53 function.

OBJECTIVES

We evaluated whether three well-characterized TP53 variants -- Ex4 + 119 C > G (rs#1042522, Arg72Pro), IVS6 + 62 A > G (rs#1625895), and an IVS3 16 bp insertion/ deletion (INDEL; rs#17878362) -- were associated with breast cancer risk in a population-based case-control study.

METHODS

Genotypes and haplotypes were determined using long-range PCR in a sample of 578 cases and 390 controls.

RESULTS

For the Ex4 + 19 C > G SNP (rs1042522), women with the heterozygous genotype (G/C) had a 32% increase in breast cancer risk. Other variants were not associated with risk. We further examined whether these associations were modified by cigarette smoking status and detection of PAH-DNA adducts in circulating lymphocytes. Among current smokers, each copy of the minor alleles for the IVS6 + 62 A > G SNP (rs1625895) and the IVS3 INDEL polymorphism (rs17878362) was associated with lower breast cancer risk (OR = 0.49, 95% CI 0.27-0.90; OR = 0.42, 95% CI 0.22-0.78, respectively). However, among former smokers, the homozygous variant genotype for these 2 SNPs was observed among cases (4.1 and 3.2%, respectively) and not controls. Genotype associations were not modified by the presence or absence of DNA adducts in circulating lymphocytes. Three-loci haplotypes were not significantly associated with breast cancer risk.

CONCLUSIONS

These results should be confirmed in larger studies, but suggest that cigarette smoking may influence breast cancer risk through interaction with p53.

Active and passive smoking and the risk of breast cancer in women aged 36-45 years: a population based case-control study in the UK

Active smoking has little or no effect on breast cancer risk but some investigators have suggested that passive smoking and its interaction with active smoking may be associated with an increased risk. In a population based case-control study of breast cancer in women aged 36-45 years at diagnosis, information on active smoking, passive smoking in the home, and other factors, was collected at interview from 639 cases and 640 controls. Women were categorised jointly by their active and passive smoking exposure. Among never smoking controls, women who also reported no passive smoking exposure were significantly more likely to be nulliparous and to be recent users of oral contraceptives. Among those never exposed to passive smoking, there was no significant association between active smoking and breast cancer, relative risk (RR) of 1.12 (95% confidence interval (CI) 0.72-1.73) for past smokers and RR of 1.19 (95% CI 0.72-1.95) for current smokers, nor was there an association with age started, duration or intensity of active smoking. Compared with women who were never active nor passive smokers, there was no significant association between passive smoking in the home and breast cancer risk in never smokers, RR of 0.89 (95% CI 0.64-1.25), in past smokers, RR of 1.09 (95% CI 0.75-1.56), or in current smokers, RR of 0.93 (95% CI 0.67-1.30). There was no trend with increasing duration of passive smoking and there was no heterogeneity among any of the subgroups examined. In this study, there was no evidence of an association between either active smoking or passive smoking in the home and risk of breast cancer.

Passive smoking and the use of noncigarette tobacco products in association with risk for pancreatic cancer: a case-control study

BACKGROUND

The associations between passive smoking and the use of noncigarette tobacco products with pancreatic cancer are not clear.

METHODS

In this case-control study, the authors collected information on passive smoking and the use of noncigarette tobacco products in 808 patients with pancreatic adenocarcinoma and 808 healthy controls by personal interview. Multivariable logistic regression was performed to estimate the adjusted odds ratio (AOR) and 95% confidence interval (95% CI).

RESULTS

The results confirmed the previously reported association between active smoking and increased risk for pancreatic cancer. The AOR was 1.7 (95% CI, 1.4-2.2) for regular smokers, 1.8 (95% CI, 1.4-2.4) for long-term smokers, and 3.1 (95% CI, 2.2-4.3) for former smokers. Although passive smoking showed a nonsignificantly elevated risk for pancreatic cancer in the entire study population (AOR, 1.3; 95% CI, 0.9-1.7), the association was present among ever smokers (AOR, 1.7; 95% CI, 1.03-2.6) but was absent among never smokers (AOR, 1.1; 95% CI, 0.8-1.6). Neither intensity nor duration of passive smoking modified the risk of pancreatic cancer among never smokers. The use of chewing tobacco, snuff, and pipes showed no significant risk elevation for pancreatic cancer after controlling for the confounding effects of demographics and other known risk factors. The use of cigars in never smokers showed a borderline significant increase of risk for pancreatic cancer (AOR, 2.2; 95% CI, 1.0-4.7; P = .05).

CONCLUSIONS

The current observations did not support a role for passive smoking or the use of noncigarette tobacco products in the etiology of pancreatic cancer. The association between cigar use and the risk of pancreatic cancer needs to be confirmed in other study populations.

Environmental tobacco smoke exposure and risk of breast cancer in nonsmoking women: a review with meta-analyses

Recent authoritative reviews consider smoking has no effect on breast cancer risk, but some studies report an increase from environmental tobacco smoke (ETS). We reviewed the overall evidence on ETS and breast cancer in nonsmoking women. We extracted details of available studies, derived relative risk (RR) estimates with confidence intervals (CIs) for various ETS exposure indices and conducted meta-analyses. Using an index for each study most closely equivalent to "spouse ever smoked," a weak, but significant, association was seen (random-effects RR = 1.12, 95% CI = 1.02-1.24, n = 22). However, the estimates were heterogeneous: close to 1.0 for prospective, North American and larger studies, and those adjusting for many potential confounders, but significantly (p < .05) elevated in case-control, European, and smaller studies, and those accounting for fewer potential confounders. Risk was increased in premenopausal women (RR = 1.54, 95% CI = 1.16-2.05, n = 10), but not postmenopausal women. Dose-response findings were similarly heterogeneous. No significant increase was seen for ETS in childhood or the workplace or from the spouse specifically, but an increase was seen for total exposure (RR = 1.54, 95% CI = 1.17-2.04, n = 6). Increases mainly derive from case-control studies asking detailed ETS histories, where RRs depend heavily on who is classified in the totally unexposed reference group, and may be prone to recall bias. Results from prospective studies using similar histories are needed. Study weaknesses and possible publication bias also limit interpretation. Because of the inherent implausibility that ETS exposure might cause breast cancer, given the similar risks of smokers and nonsmokers, one cannot confidently conclude ETS exposure increases risk in nonsmokers.

Active and passive cigarette smoke and breast cancer survival

PURPOSE

The association between active and passive cigarette smoking before breast cancer diagnosis and survival was investigated among a cohort of invasive breast cancer cases (n = 1273) participating in a population-based case-control study.

METHODS

Participants diagnosed with a first primary breast cancer between August 1, 1996, and July 31, 1997, were followed-up until December 31, 2002, for all-cause mortality (n = 188 deaths), including breast cancer-specific mortality (n = 111), as reported to the National Death Index.

RESULTS

In Cox models, the adjusted hazards ratios (HRs) for all-cause mortality were slightly higher among current and former active smokers, compared with never smokers (HR, 1.23; 95% confidence interval [95% CI], 0.83-1.84) and 1.19 (95% CI, 0.85-1.66), respectively). No association was found between active or passive smoking and breast cancer-specific mortality. All-cause and breast cancer-specific mortality was higher among active smokers who were postmenopausal (HR, 1.64; 95% CI, 1.03-2.60 and HR, 1.45; 95% CI, 0.78-2.70, respectively) or obese at diagnosis (HR, 2.10; 95% CI, 1.03-4.27 and HR, 1.97; 95% CI, 0.89-4.36, respectively). Associations between smoking and all-cause and breast cancer-specific mortality did not differ by cancer treatment.

CONCLUSIONS

These data do not provide strong evidence for an association between smoking and all-cause or breast cancer-specific mortality, although smokers who are postmenopausal or obese at diagnosis may be at higher risk.

The association between exposure to environmental tobacco smoke and breast cancer: a review by the California Environmental Protection Agency

BACKGROUND

The California Environmental Protection Agency (Cal/EPA) recently completed a health effects assessment of exposure to environmental tobacco smoke (ETS) which resulted in California listing ETS as a Toxic Air Contaminant in January 2006. As part of the assessment, studies on the association between exposure to ETS and breast cancer were reviewed.

METHODS

Twenty-six published reports (including 3 meta-analyses) evaluating the association between ETS exposure and breast cancer were reviewed. A weight-of-evidence approach was applied to evaluate the data and draw conclusions about the association between breast cancer and ETS exposure.

RESULTS

The published data indicate an association between ETS and breast cancer in younger primarily premenopausal women. Thirteen of 14 studies (10 case-control and four cohort) that allowed analysis by menopausal status reported elevated risk estimates for breast cancer in premenopausal women, seven of which were statistically significant. Our meta-analyses indicated elevated summary relative risks ranging from OR 1.68 (95% C.I. 1.31, 2.15) for all 14 studies to 2.20 (95% C.I. 1.69, 2.87) for those with the best exposure assessment.

CONCLUSIONS

Cal/EPA concluded that regular ETS exposure is causally related to breast cancer diagnosed in younger, primarily premenopausal women and that the association is not likely explained by bias or confounding.

Relationship between urinary 15-F2t-isoprostane and 8-oxodeoxyguanosine levels and breast cancer risk

To evaluate the role of oxidative stress in breast cancer, we measured urinary levels of 15-F(2t)-isoprostane (15-F(2t)-IsoP) and 8-oxodeoxyguanosine (8-oxodG) in 400 cases and 401 controls, participants of the Long Island Breast Cancer Study Project. We also analyzed the effect of different factors that are associated with oxidative stress and might influence 15-F(2t)-IsoP and 8-oxodG levels. We observed a statistically significant trend in breast cancer risk with increasing quartiles of 15-F(2t)-IsoP levels [odds ratio (OR), 1.25; 95% confidence interval (95% CI), 0.81-1.94; OR, 1.53; 95% CI, 0.99-2.35; OR, 1.88; 95% CI, 1.23-2.88, for the 2nd, 3rd, and 4th quartile relative to the lowest quartile, respectively; P(trend) = 0.002]. Although it is possible that increased levels may reflect the stress associated with recent treatment, the positive association was also observed when the analyses were restricted to case women for whom chemotherapy and radiation therapy had not yet been initiated at the time of the urine collection. The association with the highest quartile compared with lowest quartile of 15-F(2t)-IsoP was similar across strata of age, physical activity, fruit and vegetable intake, alcohol intake, cigarette smoking, body mass index, and menopausal status. We did not observe any association of breast cancer risk with 8-oxodG levels, but when cases with radiation treatment were removed from the analysis, a significant inverse trend (P = 0.04) was observed. Among controls, levels of 15-F(2t)-IsoP were higher among current cigarette smokers but did not differ by the amount of physical activity, fruit and vegetable intake, alcohol intake, body mass index, and menopausal status. Among controls, levels of 8-oxodG were higher among postmenopausal women and current and former cigarette smokers but did not differ by the other factors. In summary, our results suggest that urinary markers of lipid peroxidation and oxidative DNA damage may be associated with breast cancer risk.

IGHMBP2 Thr671Ala polymorphism might be a modifier for the effects of cigarette smoking and PAH–DNA adducts to breast cancer risk

Laboratory and bioinformatics studies have suggested that immunoglobulin mu-binding protein 2 (IGHMBP2) is involved in DNA repair, replication and recombination. Using 1067 cases and 1110 controls from a population-based case-control study, we sought to clarify the potential role of the IGHMBP2 Thr671Ala polymorphism (A to G substitution) alone and as a modifier of the effects for cigarette smoking and PAH-DNA adducts on breast cancer risk. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). Overall, there was no significant association between the IGHMBP2 variant-G allele and breast cancer risk (OR = 1.1, 95% CI = 0.9-1.3). Increased risk was found among women who had detectable PAH-DNA adducts and carried at least one variant-G allele (OR = 1.4, 95% CI = 1.0-1.8, p for trend = 0.01) compared to women carrying the wild-type AA genotype and with non-detectable adducts. Smokers carrying the IGHMBP2 variant-G allele had no significant increased breast cancer risk compared with non-smoking women with the AA genotype. Heavy smokers (>31 pack years) had a statistically significant association with breast cancer risk (OR=2.0, 95% CI=1.2-3.3) relative to nonsmokers with the AA genotype though the magnitude of association was not different than heavy smokers (> 31 pack years) with the AA genotype (OR=1.6, 95% CI=0.9-2.6). Overall our study observes only modestly higher effect estimates for PAH-DNA adduct exposure and cigarette smoking among those with the high-risk genotype, but these differences are not statistically significant. Additional studies focused on the biological function of the variant-G allele and interactions with other genetic polymorphisms are necessary to confirm our findings.

Secondhand smoke exposure in early life and the risk of breast cancer among never smokers (United States)

Evidence is increasing that some early life exposures affect breast cancer risk. Exposure to secondhand smoke (SHS) during childhood may be one such exposure. As part of the WEB Study (Western New York Exposures and Breast Cancer Study), we conducted a population-based, case-control study with 1166 women aged 35 to 79 diagnosed with histologically confirmed, primary, incident breast cancer. Controls (n = 2105) were randomly selected from the Department of Motor Vehicles driver's license list (< or =age 65) and the Center for Medicare & Medicaid Services rolls (> age 65). Participants were queried regarding household and workplace SHS exposure. Person-years of lifetime cumulative SHS exposure were computed as well as cumulative exposure up to 21 years of age. Unconditional logistic regression adjusting for potential confounders was used to calculate odds ratios (OR) and 95% confidence intervals (95% CI). Lifetime cumulative exposure to household SHS was not associated with an increase in breast cancer risk for premenopausal (OR = 1.17, 95% CI = 0.54-2.56) or postmenopausal (OR = 1.29; 95% CI = 0.82-2.01) women. Neither was risk increased among women exposed to SHS before the age of 21 or at the time of birth, menarche, or a women's first birth. In this study, exposure to SHS either in adult or early life does not appear to be associated with the risk of breast cancer.