No evidence that social stress is associated with breast cancer incidence

Mechanisms of stress-attributed breast cancer incidence and progression

Breast cancer is the most commonly diagnosed cancer and the second leading cause of cancer deaths in women, with psychosocial stress commonly cited by patients as one of its causes. While there is conflicting epidemiological evidence investigating the association between psychosocial stress and breast cancer incidence and progression, there is reason to believe that interventions aimed at reducing stress pharmacologically or psychologically may improve breast cancer outcomes. The aim of this review is to discuss the molecular and biological mechanisms of stress-attributed breast cancer incidence and progression, including the induction of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS), as well as decreased immune function and stress hormone-induced resistance to chemotherapy. Moreover, these mechanisms have been cited as potential therapeutic targets of pharmacologic and psychological interventions that may improve the care, well-being and survival of breast cancer patients. Further research is recommended to investigate whether interventions in the primary care setting for women with risk factors for breast cancer development may lead to a decreased incidence of invasive breast tumors.

Association between allostatic load and breast cancer risk: a cohort study

BACKGROUND

Allostatic load (AL) reflects the collective load of chronic stress during lifetime. Previous studies have shown that higher AL is associated with poor clinical outcomes among breast cancer patients. However, the relationship between AL and breast cancer risk is still unclear.

METHODS

To fill the gap, we analyzed the association between AL and the development of breast cancer in 181,455 women identified from the UK Biobank.

RESULTS

During the follow-up from 2006 to 2020, 5,701 women were diagnosed with incident breast cancer. Significantly higher AL was observed among incident breast cancer cases than all study participants (mean: 2.77 vs. 2.63, P < 0.01). Univariate Cox regression analysis indicated the risk of breast cancer was increased by 5% per one AL unit increase (hazard ratio (HR) = 1.05, 95% confidence interval (CI) 1.04, 1.07). In multivariate analyses, after adjusting demographics, family history of breast cancer, reproductive factors, socioeconomic status, lifestyle factors, and breast cancer polygenic risk score (PRS), the significant association remained (HR = 1.05, 95%CI 1.03, 1.07). The significant relationship was further confirmed in the categorical analysis. Compared with women in the low AL group (AL: 0 ~ 2), those in the high AL group (AL: 3 ~ 11) had a 1.17-fold increased risk of breast cancer (HR = 1.17, 95%CI 1.11, 1.24). Finally, in the stratified analysis, joint effects on the risk of breast cancer were observed between the AL and selected known breast cancer risk factors, including age, family history of breast cancer, PRS, income, physical activity, and alcohol consumption.

CONCLUSION

In summary, those findings have demonstrated that higher AL was associated with an increased breast cancer risk in women. This association is likely independent of known breast cancer risk factors. Thus, the AL could be a valuable biomarker to help breast cancer risk prediction and stratification.

Latent Class Models of Early-life Trauma and Incident Breast Cancer

BACKGROUND

Psychosocial trauma has been hypothesized to influence breast cancer risk, but little is known about how co-occurring traumas-particularly during early life-may impact incidence. We examine the relationship between multiple measures of early-life trauma and incident breast cancer.

METHODS

The Sister Study is a prospective cohort study of US women (n = 50,884; enrollment 2003-2009; ages 35-74). Of 45,961 eligible participants, 3,070 developed invasive breast cancer or ductal carcinoma in situ through 2017. We assessed trauma before age 18 using previously studied measures (cumulative score, individual trauma type, and substantive domain) and a six-class latent variable to evaluate co-occurring traumas. We accounted for missing data using multiple imputation and estimated hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional-hazards models.

RESULTS

Approximately 49% of participants reported early-life trauma. Using the latent class variable approach, breast cancer hazard was higher among participants who had sexual trauma or household dysfunction (HR = 1.1; CI = 0.93, 1.3) or moderate (HR = 1.2; CI = 0.99, 1.4) but not high trauma (HR = 0.66; CI = 0.44, 0.99) compared to low trauma. Breast cancer HRs associated with sexual early-life trauma or household dysfunction were elevated for pre- and postmenopausal breast cancer and by estrogen receptor status. We found no effect modification by race-ethnicity. Estimated effects were attenuated with report of constant childhood social support.

CONCLUSIONS

Breast cancer incidence varied by latent patterns of co-occurring early-life trauma. Models capturing childhood social support and trauma patterning, rather than cumulative or discrete indicators, may be more meaningful in breast cancer risk assessment.

Biobehavioral Pathways and Cancer Progression: Insights for Improving Well-Being and Cancer Outcomes

The relationship between psychosocial factors and cancer has intrigued people for centuries. In the last several decades there has been an expansion of mechanistic research that has revealed insights regarding how stress activates neuroendocrine stress-response systems to impact cancer progression. Here, we review emerging mechanistic findings on key pathways implicated in the effect of stress on cancer progression, including the cellular immune response, inflammation, angiogenesis, and metastasis, with a primary focus on the mediating role of the sympathetic nervous system. We discuss converging findings from preclinical and clinical cancer research that describe these pathways and research that reveals how these stress pathways may be targeted via pharmacological and mind-body based interventions. While further research is required, the body of work reviewed here highlights the need for and feasibility of an integrated approach to target stress pathways in cancer patients to achieve comprehensive cancer treatment.

Neighborhood disadvantage and individual-level life stressors in relation to breast cancer incidence in US Black women

BACKGROUND

Research on psychosocial stress and risk of breast cancer has produced conflicting results. Few studies have assessed this relation by breast cancer subtype or specifically among Black women, who experience unique chronic stressors.

METHODS

We used prospective data from the Black Women's Health Study, an ongoing cohort study of 59,000 US Black women, to assess neighborhood- and individual-level psychosocial factors in relation to risk of breast cancer. We used factor analysis to derive two neighborhood score variables after linking participant addresses to US Census data (2000 and 2010) on education, employment, income and poverty, female-headed households, and Black race for all households in each residential block group. We used Cox proportional hazards regression to estimate hazard ratios (HR) and 95% confidence intervals (CI) adjusted for established breast cancer risk factors.

RESULTS

During follow-up from 1995 to 2017, there were 2167 incident invasive breast cancer cases (1259 estrogen receptor positive (ER +); 687 ER negative (ER-)). For ER- breast cancer, HRs were 1.26 (95% CI 1.00-1.58) for women living in the highest quartile of neighborhood disadvantage relative to women in the lowest quartile, and 1.24 (95% CI 0.98-1.57) for lowest versus highest quartile of neighborhood socioeconomic status (SES). For ER+ breast cancer, living in the lowest quartile of neighborhood SES was associated with a reduced risk of ER+ breast cancer (HR = 0.83, 95% CI 0.70-0.98). With respect to individual-level factors, childhood sexual abuse (sexual assault ≥ 4 times vs. no abuse: HR = 1.35, 95% CI 1.01-1.79) and marital status (married/living together vs. single: HR = 1.29, 95% CI 1.08-1.53) were associated with higher risk of ER+, but not ER- breast cancer.

CONCLUSION

Neighborhood disadvantage and lower neighborhood SES were associated with an approximately 25% increased risk of ER- breast cancer in this large cohort of Black women, even after control for multiple behaviors and lifestyle factors. Further research is need to understand the underlying reasons for these associations. Possible contributing factors are biologic responses to the chronic stress/distress experienced by individuals who reside in neighborhoods characterized by high levels of noise, crime and unemployment or the direct effects of environmental toxins.

The Role of Psychologic Stress in Cancer Initiation: Clinical Relevance and Potential Molecular Mechanisms

The hypothesis that the physiologic response to psychologic stress influences the initiation of cancer is highly controversial. The link between initiating stressors, the psychologic stress response, and disease is plausible, considering that the stress response is associated with defined physiologic outcomes and molecular mechanisms. In light of this, we review the clinical relevance of psychologic stress on the risk of cancer, and we propose potential molecular pathways that may link the stress response to early stages of malignant cell transformation.

Genetic Variation and Immunohistochemical Localization of the Glucocorticoid Receptor in Breast Cancer Cases from the Breast Cancer Care in Chicago Cohort

BACKGROUND

Glucocorticoid, one of the primary mediators of stress, acts via its receptor, the glucocorticoid receptor (GCR/NR3C1), to regulate a myriad of physiological processes. We measured the genetic variation and protein expression of GCR, and the genes that regulate GCR function or response and examined whether these alterations were associated with breast cancer clinicopathological characteristics.

METHOD

We used samples from a multiracial cohort of breast cancer patients to assess the association between breast cancer characteristics and the genetic variants of single nucleotide polymorphisms (SNPs) in GCR/NR3C1, FKBP5, Sgk1, IL-6, ADIPOQ, LEPR, SOD2, CAT, and BCL2.

RESULTS

Several SNPs were associated with breast cancer characteristics, but statistical significance was lost after adjustment for multiple comparisons. GCR was detected in all normal breast tissues and was predominantly located in the nuclei of the myoepithelial cell layer, whereas the luminal layer was negative for GCR. GCR expression was significantly decreased in all breast cancer tissue types, compared to nontumor tissue, but was not associated with breast cancer characteristics. We found that high nuclear GCR expression was associated with basal cell marker cytokeratin 5/6 positivity.

CONCLUSION

GCR expression is reduced in breast cancer tissue and correlates with the basal cell marker CK5/6.

Stress et cancer : mythes et réalités

Les théories profanes émises par les patients et certains ouvrages destinés au grand public alimentent l’idée que le stress psychologique peut influencer le risque de survenue de cancer. Les études consultées sur cette question semblent donner des résultats contradictoires. D’un côté, ces théories peuvent sembler étayées par les résultats d’études expérimentales portant sur les corrélats physiologiques du stress sur des voies neuro-immunoendocrinologiques (perturbations immunitaires, altération de l’axe hypothalamohypophyso- surrénalien), métaboliques et cellulaires (stress oxydatif, dégénérescence cellulaire) pouvant être impliquées dans la tumorigenèse. De l’autre, les études épidémiologiques prospectives fondées sur une méthodologie robuste ne trouvent généralement pas d’association entre exposition au stress et développement ultérieur d’un cancer. Par ailleurs, les méta-analyses suggèrent l’existence de biais de publication pouvant surestimer le poids des études « positives ». Quand bien même une association est retrouvée, le caractère observationnel des études épidémiologiques et donc la possibilité de facteurs de confusion empêchent d’établir un lien de causalité entre l’exposition au stress et un risque majoré de cancer. En ce qui concerne les mécanismes d’une éventuelle relation causale directe, il faut souligner la difficulté d’extrapoler à l’être humain des résultats obtenus chez d’autres animaux, et s’assurer de bien prendre en compte la présence de facteurs comportementaux confondants ou médiateurs comme une mauvaise hygiène de vie alimentaire, la consommation de tabac et d’alcool, les expositions professionnelles, etc. Selon les recommandations du National Cancer Institute (NCI, 2012), les connaissances actuellement disponibles ne permettent pas d’établir un lien de causalité entre stress et augmentation du risque de cancer. Si le professionnel de soin psychique ne doit donc pas cautionner ce lien hypothétique au risque de culpabiliser le patient, il gardera à l’esprit, d’une part, que le cancer peut en revanche générer un stress bien réel au quotidien chez les patients atteints par cette maladie et, d’autre part, que ces théories « profanes » peuvent parfois témoigner d’un mécanisme de défense contre ce stress.

Does stress increase risk of breast cancer? A 15-year prospective study

OBJECTIVE

The possible impact of stress on cancer incidence remains controversial. We prospectively evaluated associations between life event stressors, social support, personality characteristics (optimism, anger control, antiemotionality), and risk of developing primary breast cancer (BCa), in women at increased familial risk of BCa.

METHODS

A prospective cohort, repeated measures design was used. Recruitment was through the Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer, which collects genetic, epidemiological, and clinical data from Australasian families with multiple BCa cases. Acute and chronic stressors for the prior 3 years and psychosocial, clinical, and epidemiological variables were measured at cohort entry and at 3-yearly intervals. Cox proportional hazard regression analysis controlling for BCa risk factors and familial clustering was undertaken. The primary outcome was histopathologically confirmed BCa (invasive or ductal carcinoma in situ, including occult cases diagnosed during risk-reducing mastectomy).

RESULTS

Of 3595 consecutive women invited to participate, 3054 (85.0%) consented. Of these, 2739 (89.7%) from 990 families (range 1-16 per family) completed at least 1 assessment point. During the study, 103 women were diagnosed with BCa. No stressor or psychosocial variable or interaction between them was significantly associated with BCa in unadjusted or adjusted models (total acute stressors HR = 1.03 [0.99-1.08], P = .19; total chronic stressors HR = 1.0 [0.90-1.11], P = .98).

CONCLUSIONS

This study did not demonstrate an association between acute and chronic stressors, social support, optimism, antiemotionality or anger control, and BCa risk. Women should focus on proven methods of BCa risk reduction.

Possible role of stress, coping strategies, and life style in the development of breast cancer

Objective The aim of the present study was to investigate the possibility of the effect of life long stressful events, along with coping method used, perception of social support, and life style on the development of breast cancer. Methods In this hospital-based case control study, the study group comprised 250 women with breast cancer who were followed by Florence Nightingale Breast Study Group. Control group included 250 women, who had similar sociodemographic characteristics to the study group. Data were collected with semi-structured interview form, Healthy Life Style Behavior Scale, Coping Strategy Indicator, and Stress Evaluation Form developed by us. Results In multivariate analysis, family history of cancer (OR: 1.55, 95% CI: 2.29-1.05), inadequate social support (OR: 1.83, 95% CI: 1.23-2.73), and loss of father during childhood (OR: 2.68, 95% CI: 5.52-1.30) and serious stressor within the last five years (OR: 4.72, 95% CI: 7.03-3.18) were found to be risk factors increasing the risk of breast cancer. When family history of cancer was excluded from the model, the presence of psychiatric disorder history (OR: 1.95, 95% CI: 3.26-1.17) and major life events (OR: 2.24, 95% CI: 4.07-1.24) were added to the model as risk factors. Conclusion The present study indicates that especially the stressful events experienced within the last five years plays an undeniable role in the risk of breast cancer. Social support may be as important in the period before the diagnosis as in the period after diagnosis.

Causal Attribution of Breast Cancer by Survivors in French West Indies

Patients frequently ask about the cause of their breast cancer. To answer, physicians refer to breast cancer risk factors based on medical reports. We aim to assess these risk factors for the point of view of survivors, a point of view which seems to differ from that of medical references. We ran a survey with open- and closed-ended questionnaires on patients' opinions about risks factors both for women in general and for their own case. We also collected data on their sources of information on this subject. Most patients had no opinion. The most frequently cited risk factors were stress, then genetic causes, and poor diet. Internet was the leading source of information for patients, followed by physicians and magazines. Our study highlights the mismatch between breast cancer risk factors as perceived by scientists and by survivors. Survivors tend to focus on non-controllable risk factors. Taking into account attribution theories of life events, an awareness of patient opinion may be valuable for psychological support of survivors, and it may be informative to record the way in which patients attribute causality for life events such as breast cancer and, more generally, all type of cancer.

Psychological stress and breast cancer incidence: a systematic review

OBJECTIVE

Breast cancer is the world's leading cause of cancer mortality in women. Stress is an imminent risk factor with a documented negative impact on neuro-endocrine and immune system. Numerous epidemiological studies have investigated the link between stress and cancer, reporting contradictory results from no association to a close causal link. The impact of the topic and the lack of conclusion compelled this systematic review.

METHODS

A systematic review was carried out, including all literature studies from 1966 to 2016, investigating the relationship between stress and the occurrence of breast cancer. Of the 1813 articles identified in the PubMed/Medline database, 52 were eligible and included in the analysis.

RESULTS

A number of 17 retrospective, 20 limited prospective and 15 prospective studies were analyzed. The number of patients exceeded 29,000, for a total number of more than 700.000 women recruited from hospital, screening cohorts or population registers. We identified 26 positive articles linking personal traits, stressful events and breast cancer, 18 negative articles that did not confirm their hypothesis and 8 articles that could not be classified. Facing heterogeneity, all possible misguiding factors such as: study design, information gathering, stress type, moment of exposure, individual susceptibility and personality, were discussed independently.

CONCLUSIONS

Qualitative analysis of articles has revealed a possible association between stress and cancer, especially regarding stressful life events. In the absence of a meta-analysis and taking into account the methodological heterogeneity of the studies, the results are difficult to interpret and the role of chance is difficult to exclude.

Association of striking life events with primary breast cancer in 265 Chinese women: a case-control study

The current case-control study investigated the relationship between striking life events and breast cancer in Chinese women. A total of 265 primary breast cancer patients and 265 controls were enrolled with matching for age and completed questionnaires. Logistic regression analysis was used. Thirty-nine breast cancer patients reported striking life events and twenty-four of the controls reported striking life events. The number of striking life events was significantly greater in patients (p = 0.04). It indicated a striking life event led to a 1.726-fold increased HR (95% CI 1.005-2.965, p < 0.05) for breast cancer with adjustment for age, and a 1.811-fold increased HR (95% CI 1.021 - 3.212, P < 0.05) with adjustment for age, BMI, and late age at menopause. High BMI (OR: 1.680, 95% CI: 1.258-2.196, p < 0.05) and a family history of breast cancer (OR: 2.244, 95% CI: 1.065-4.729, p < 0.05, respectively) increased the risk of breast cancer, and late age at menopause decreased the risk for breast cancer (OR: 0.513, 95% CI: 0.303-0.868, p < 0.05). Our findings indicate a significant association between striking life events and breast cancer in Chinese women, especially in the subpopulation with high BMI or family history of breast cancer.

Lifetime report of perceived stress at work and cancer among men: A case-control study in Montreal, Canada

BACKGROUND

The association between perceived workplace psychological stress, over the entire work career, and cancer among men has never been assessed. This was explored in the context of a population-based case-control study conducted in Montreal, Canada.

METHODS

3103 incident cancer cases (11 types) diagnosed in 1979-1985 and 512 population controls were interviewed. Subjects described in detail each job held during their lifetime, including the occurrence of stress, and its reason. Logistic regression estimated odds ratios (OR) and 95% confidence intervals (CI) for the association between perceived workplace stress and its duration, and each cancer site, adjusting for lifestyle and occupational factors.

RESULTS

Employment in at least one stressful job was associated with increased odds of cancers of the lung (OR=1.33, 95% CI: 1.01-1.75), colon (OR=1.51, 95% CI: 1.15-1.98), bladder (OR=1.37, 95% CI: 1.03-1.81), rectal (OR=1.52, 95% CI: 1.10-2.10), and stomach (OR=1.53, 95% CI: 1.08-2.15). A duration-response trend was found for cancers of the lung, colon, rectum, stomach, and for NHL. Subjects reported changes in stress level over their career. Perceived stress was ascribed to several sources, including high demand and time pressure, financial issues, job insecurity, and hazardous conditions.

CONCLUSION

Prolonged exposure to perceived stress at work was associated with greater odds of cancer at 5 out of 11 sites. While over reporting of stress by cases cannot be fully ruled out, these associations, if substantiated, would bear important public health significance. Prospective studies building on detailed stress assessment protocols considering all sources and changes over the career are necessary.

Psychological stress, adverse life events and breast cancer incidence: a cohort investigation in 106,000 women in the United Kingdom

Background

Women diagnosed with breast cancer frequently attribute their cancer to psychological stress, but scientific evidence is inconclusive. We investigated whether experienced frequency of stress and adverse life events affect subsequent breast cancer risk.

Methods

Breast cancer incidence was analysed with respect to stress variables collected at enrolment in a prospective cohort study of 106,000 women in the United Kingdom, with 1783 incident breast cancer cases. Relative risks (RR) were obtained as hazard ratios using Cox proportional hazards models.

Results

There was no association of breast cancer risk overall with experienced frequency of stress. Risk was reduced for death of a close relative during the 5 years preceding study entry (RR = 0.87, 95 % confidence interval (CI): 0.78–0.97), but not for death of a spouse/partner or close friend, personal illness/injury, or divorce/separation. There was a positive association of divorce with oestrogen-receptor-negative (RR = 1.54, 95 % CI: 1.01–2.34), but not with oestrogen-receptor-positive breast cancer. Risk was raised in women who were under age 20 at the death of their mother (RR = 1.31, 95 % CI: 1.02–1.67), but not of their father, and the effect was attenuated after excluding mothers with breast or ovarian cancer (RR = 1.17, 95 % CI: 0.85–1.61).

Conclusions

This large prospective study did not show consistent evidence for an association of breast cancer risk with perceived stress levels or adverse life events in the preceding 5 years, or loss of parents during childhood and adolescence.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-016-0733-1) contains supplementary material, which is available to authorized users.

Breast Cancer Cause Beliefs: Chinese, Korean, and Mexican American Breast Cancer Survivors

This study examined causal attribution beliefs about breast cancer and the influence that these beliefs exert on health behavior change among breast cancer survivors (BCS). Focus groups with Chinese (n = 21), Korean (n = 11), and Mexican American (n = 9) BCS recruited through community- and hospital-based support groups were conducted. Interviews were audio-recorded, transcribed verbatim, and translated into English for thematic content analysis. Three themes concerning beliefs about breast cancer cause common to all three groups included (a) stress, (b) diet, and (c) fatalism. Causal beliefs corresponded to behavioral changes with women describing efforts to improve their diet and manage their stress. Ethnic minority BCS adhere to beliefs about what caused their cancer that influence their health behaviors. Providing quality health care to ethnically diverse cancer survivors requires cultural sensitivity to patients' beliefs about the causes of their cancer and awareness of how beliefs influence patients' health behaviors post diagnosis.

Mediation by peer violence victimization of sexual orientation disparities in cancer-related tobacco, alcohol, and sexual risk behaviors: pooled youth risk behavior surveys

OBJECTIVES

We examined the role of adolescent peer violence victimization (PVV) in sexual orientation disparities in cancer-related tobacco, alcohol, and sexual risk behaviors.

METHODS

We pooled data from the 2005 and 2007 Youth Risk Behavior Surveys. We classified youths with any same-sex sexual attraction, partners, or identity as sexual minority and the remainder as heterosexual. We had 4 indicators of tobacco and alcohol use and 4 of sexual risk and 2 PVV factors: victimization at school and carrying weapons. We stratified associations by gender and race/ethnicity.

RESULTS

PVV was related to disparities in cancer-related risk behaviors of substance use and sexual risk, with odds ratios (ORs) of 1.3 (95% confidence interval [CI] = 1.03, 1.6) to 11.3 (95% CI = 6.2, 20.8), and to being a sexual minority, with ORs of 1.4 (95% CI = 1.1, 1.9) to 5.6 (95% CI = 3.5, 8.9). PVV mediated sexual orientation disparities in substance use and sexual risk behaviors. Findings were pronounced for adolescent girls and Asian/Pacific Islanders.

CONCLUSIONS

Interventions are needed to reduce PVV in schools as a way to reduce sexual orientation disparities in cancer risk across the life span.

Cancer incidence and mortality following exposures to distal and proximal major stressors

PURPOSE

Severe psychological trauma has been shown to leave psychological and biological sequelae, including compromise of the neuro-hormonal and immunological systems. Despite much research, the putative effect of such stressor on cancer remains ambiguous. This study maximized the exploration of cancer incidence and mortality by combining a proximal (parental bereavement) with a distal major stressor (Holocaust exposure) on both risks.

METHODS

Subjects were bereaved Holocaust survivors (n = 904) and comparison individuals (n = 933) selected from the total cohort of 6,284 Jewish-Israeli parents who lost an adult son in war or from non-self-inflicted external causes. Cox regression was used to examine the differential risk for cancer between the two bereaved samples, adjusting for potential confounders.

RESULTS

No difference in cancer incidence or mortality was observed between both groups of bereaved parents. However, prior to bereavement, Holocaust survivors had an increased cancer risk compared with their counterparts in the general population.

CONCLUSIONS

Individuals who faced both a proximal (bereavement) and distal (Holocaust) major stressors had no additive risk for cancer incidence and mortality.

What causes breast cancer? A systematic review of causal attributions among breast cancer survivors and how these compare to expert-endorsed risk factors

PURPOSE

The aim of this paper was to review published research that analyzed causal attributions for breast cancer among women previously diagnosed with breast cancer. These attributions were compared with risk factors identified by published scientific evidence in order to determine the level of agreement between cancer survivors' attributions and expert opinion.

METHODS

A comprehensive search for articles, published between 1982 and 2012, reporting studies on causal attributions for breast cancer among patients and survivors was undertaken. Of 5,135 potentially relevant articles, 22 studies met the inclusion criteria. Two additional articles were sourced from reference lists of included studies.

RESULTS

Results indicated a consistent belief among survivors that their own breast cancer could be attributed to family history, environmental factors, stress, fate, or chance. Lifestyle factors were less frequently identified, despite expert health information highlighting the importance of these factors in controlling and modifying cancer risk. This review demonstrated that misperceptions about the contribution of modifiable lifestyle factors to the risk of breast cancer have remained largely unchanged over the past 30 years.

CONCLUSIONS

The findings of this review indicate that beliefs about the causes of breast cancer among affected women are not always consistent with the judgement of experts. Breast cancer survivors did not regularly identify causal factors supported by expert consensus such as age, physical inactivity, breast density, alcohol consumption, and reproductive history. Further research examining psychological predictors of attributions and the impact of cancer prevention messages on adjustment and well-being of cancer survivors is warranted.

Striking life events associated with primary breast cancer susceptibility in women: a meta-analysis study

Purpose

The association between striking life events, an important stress and acute anxiety disorder, and the occurrence of primary breast cancer is unclear. The current meta-analysis was designed to assess the relationship between striking life events and primary breast cancer incidence in women.

Methods

Systematic computerized searching of the PubMed, ScienceDirect, Embase, and BMJ databases with the combinations of controlled descriptors from Mesh, including breast cancer, breast tumor, cancer of breast, mammary carcinoma, life events, life change events, case–control studies, case-base studies, cohort study, and cohort analysis and identified a total of 307 papers published from January 1995 to April 2012. Following evaluation of methodological quality with the Downs & Black criteria, seven case–control or cohort studies were selected and the association between striking life events and primary breast cancer incidence in women was measured using random effect or fixed-effect odds ratios combined with 95% confidence interval.

Results

The seven studies included in the final meta-analysis included 99,807 women. A meta-analysis showed that the pooled OR for striking life events and breast cancer was 1.51 (95% CI 1.15 - 1.97, P = 0.003), indicating that women with striking life events were at 1.5-fold greater risk of developing breast cancer. The pooled OR for severe striking life events and breast cancer was 2.07 (95% CI 1.06 - 4.03), indicating that women with severe striking life events were at 2-fold greater risk of developing breast cancer.

Conclusions

The current meta-analysis showed significant evidence for a positive association between striking life events and primary breast cancer incidence in women.

Social adversity experience and blood pressure control following antihypertensive medication use in a community sample of older adults

BACKGROUND

Psychosocial stress is a risk factor for hypertension and has been shown to affect response to treatment for psychiatric illnesses.

PURPOSE

We investigate the relationship between a history of social adversity experience and blood pressure control following antihypertensive medication use.

METHODS

A total of 1,186 participants selected from the European Prospective Investigation into Cancer-Norfolk study (531 men and 655 women, aged 42 to 80 years) had attended two health checks at which blood pressure measurements were taken; were taking antihypertensive medication at the second, but not the first health check; and had completed a questionnaire assessment of their social and psychological circumstances which included details of traumatic experiences in childhood and of adverse life events, long-term difficulties, and perceived stress in adulthood.

RESULTS

Experience of recent loss events in adulthood was associated with a smaller reduction in systolic blood pressure after starting hypertension treatment (β = 1.78, 95 % confidence interval 0.15-3.40, per life event), independently of age, sex, preexisting health conditions, cigarette smoking history, alcohol consumption, physical activity, and obesity.

CONCLUSION

Results from this study suggest that stress caused by recent losses may be associated with reduced effectiveness of treatment for hypertension. Subject to replication, these findings may help determine the specific physiological mechanisms by which medication treatment effectiveness is affected by stress.

The association between social stress and global cognitive function in a population-based study: the European Prospective Investigation into Cancer (EPIC)-Norfolk study

BACKGROUND

Stress is thought to exert both positive and negative effects on cognition, but the precise cognitive effects of social stress and individuals' response to stress remain unclear. We aimed to investigate the association between different measures of social stress and cognitive function in a middle- to older-aged population using data from the European Prospective Investigation into Cancer (EPIC)-Norfolk study.

METHOD

Participants completed a comprehensive assessment of lifetime social adversity between 1993 and 1997 and the short form of the Mini Mental State Examination (SF-MMSE), an assessment of global cognitive function, during the third health check between 2004 and 2011 (a median of 10.5 years later). A low MMSE score was defined as a score in the bottom quartile (20-26).

RESULTS

Completed MMSE scores and stress measures were available for 5129 participants aged 48-90 years. Participants who reported that their lives had been more stressful over the previous 10 years were significantly more likely to have low MMSE scores [odds ratio (OR) 1.14, 95% confidence interval (CI) 1.04-1.24 per unit increase in perceived stress], independently of sociodemographic factors, physical and emotional health. The effects were restricted to the highest level of stress and the association was stronger among participants with a lower educational level. Adaptation following life event experiences also seemed to be associated with MMSE scores after adjusting for sociodemographic factors, but the association was attenuated with further adjustment.

CONCLUSIONS

In this generally high-functioning population, individuals' interpretations and responses to stressful events, rather than the events themselves, were associated with cognitive function.

Educational attainment and mean leukocyte telomere length in women in the European Prospective Investigation into Cancer (EPIC)-Norfolk population study

BACKGROUND

Telomere length has been postulated as a marker of biological aging. Recent evidence has suggested that educational attainment but not social class is associated with telemore length.

METHODS

We investigated the associations between educational attainment, social class and relative mean telomere length in an ethnically homogeneous population of 4441 women, aged 41-80 years. Mean telomere length was measured using high-throughput quantitative Real Time PCR.

RESULTS

Educational attainment (p=0.015) but not social class (p=0.61) was associated with mean telomere length in these data. This association was independent of social class and of systolic blood pressure, high-density lipoprotein cholesterol, cigarette smoking, body mass index, glycated hemoglobin, plasma vitamin C and physical activity (p=0.014), and was not attenuated through additional adjustment for measures of social adversity, including those experienced during childhood (p=0.006).

CONCLUSIONS

Our results, at least for women, provide support for the findings previously reported in this journal that lower educational attainment, but not social class, is associated with shorter telomere length.

Changes over time in the effect of marital status on cancer survival

Background

Rates of all-cause and cause-specific mortality are higher among unmarried than married individuals. Cancer survival is also poorer in the unmarried population. Recently, some studies have found that the excess all-cause mortality of the unmarried has increased over time, and the same pattern has been shown for some specific causes of death. The objective of this study was to investigate whether there has been a similar change over time in marital status differences in cancer survival.

Methods

Discrete-time hazard regression models for cancer deaths among more than 440 000 women and men diagnosed with cancer 1970-2007 at age 30-89 were estimated, using register data encompassing the entire Norwegian population. More than 200 000 cancer deaths during over 2 million person-years of exposure were analyzed.

Results

The excess mortality of the never-married compared to the married has increased steadily for men, in particular the elderly. Among elderly women, the excess mortality of the never-married compared to the married has increased, and there are indications of an increasing excess mortality of the widowed. The excess mortality of divorced men and women, however, has been stable.

Conclusions

There is no obvious explanation for the increasing disadvantage among the never-married. It could be due to a relatively poorer general health at time of diagnosis, either because of a more protective effect of partnership in a society that may have become less cohesive or because of more positive selection into marriage. Alternatively, it could be related to increasing differentials with respect to treatment. Today's complex cancer therapy regimens may be more difficult for never-married to follow, and health care interventions directed and adapted more specifically to the broad subgroup of never-married patients might be warranted.

Life events, cortisol and levels of prostate specific antigen: a story of synergism

BACKGROUND

Previous studies have tested the relationship between stressful life events (LE) and cancer onset, but inconsistent results have been found. One possibility is that the LE-cancer relation may depend on other biological factors pertinent to stress and cancer.

METHODS

This study examined the relationship between LE and prostate specific antigen (PSA) levels, a tumor marker, and whether cortisol mediates or moderates a LE-PSA relationship. During a voluntary screening for prostate cancer risk, 139 men (mean age=57.3 years) were assessed with the Holmes and Rahe questionnaire about their LE during the past 1-5 years, and their PSA and serum cortisol levels were measured.

RESULTS

LE and cortisol alone were unrelated to PSA. However, statistically controlling for age, body mass index and the ratio of triglycerides to HDL cholesterol, we found evidence for a synergistic interaction between LE and cortisol. Among men with low cortisol, number of LE were inversely and significantly correlated with PSA (r=-0.265, p<0.05), while in men with high cortisol, number of LE were positively and significantly correlated with PSA (r=0.344, p<0.01). These results more consistently stemmed from the effects of uncontrollable LE. Similar results were found, using a clinically significant PSA cut-off.

CONCLUSIONS

These results suggest considering the joint effects of psychosocial and biological factors in relation to possible cancer risk, where the hypothalamic pituitary adrenal axis may moderate stress-cancer risk associations.

Stress and breast cancer: from epidemiology to molecular biology

Stress exposure has been proposed to contribute to the etiology of breast cancer. However, the validity of this assertion and the possible mechanisms involved are not well established. Epidemiologic studies differ in their assessment of the relative contribution of stress to breast cancer risk, while physiological studies propose a clear connection but lack the knowledge of intracellular pathways involved. The present review aims to consolidate the findings from different fields of research (including epidemiology, physiology, and molecular biology) in order to present a comprehensive picture of what we know to date about the role of stress in breast cancer development.

Abuse victimization and risk of breast cancer in the Black Women's Health Study [corrected]

Few studies have examined the relation between abuse victimization and breast cancer, and results have been inconclusive. Using data from 35,728 participants in the Black Women's Health Study, we conducted multivariable Cox regression to estimate incidence rate ratios (IRRs) and 95% confidence intervals (CI) for the association of abuse across the life span (childhood, adolescence, and adulthood) with breast cancer. Incident breast cancer diagnoses were reported during 1995-2009, and abuse histories were reported in 2005. No associations were found between abuse victimization in either childhood or adolescence and breast cancer. We found a weak positive association between abuse in adulthood and breast cancer (IRR = 1.18, 95% CI = 1.03-1.34). IRRs for physical abuse only, sexual abuse only, and both physical and sexual abuse in adulthood, relative to no abuse, were 1.28 (95% CI = 1.09-1.49), 0.96 (95% CI = 0.76-1.20), and 1.22 (95% CI = 1.00-1.49), respectively. IRRs for low, intermediate, and high frequencies of physical abuse in adulthood, relative to no abuse, were 1.28 (95% CI = 1.07-1.52), 1.37 (95% CI = 1.04-1.79), and 1.24 (95% CI = 0.95-1.62), respectively. Our data suggest an increased risk of breast cancer among African-American women who reported physical abuse in adulthood, but there was little evidence of a dose-response relation. These results require confirmation in other studies.

Breast cancer survivors' beliefs about the causes of breast cancer

OBJECTIVE

To explore the beliefs held by breast cancer (BC) survivors about the factors that contribute to the development of their BC.  

METHODS

The BUPA Health Foundation Health and Well-being after Breast Cancer Study is a prospective cohort study of 1684 women recruited within 12 months of their first diagnosis with invasive BC. Participants completed an enrollment questionnaire (EQ), first follow-up questionnaire (FQ1) and a second follow-up questionnaire (FQ2), 12 months and 24 months post-EQ, respectively. In the FQ2, women were asked whether they believed anything contributed to the development of their BC and whether they had made lifestyle changes since the FQ1. Well-being was assessed at the FQ2 using the psychological general well-being index (PGWB).  

RESULTS

In total, 1496/1684 women completed the FQ2 and 43.5% reported belief in a factor that may have contributed to their developing BC. These women were more likely to be younger (p<0.0001) and educated beyond high school (p<0.0001). Stress (58.1%) was the most common reason given, followed by previous use of hormone therapy (17.0%) and a family history of any cancer (9.8%). Women who believed stress contributed to their BC had lower PGWB scores than other study participants (70.9 ± 16.1, n = 361 versus 77.3 ± 14.9, n = 1071, mean difference = 6.4, 95% CI: 4.6-8.2 p<0.0001) and were more likely to have made lifestyle changes since their BC diagnosis.  

CONCLUSIONS

Many women with BC believe that stress has contributed to their condition. Women who held this belief were more likely to adopt strategies to reduce stress than those who did not.