Personality characteristics and the risk of breast cancer: a prospective cohort study

The impact of personality on the risk and survival of breast cancer: a Mendelian randomization analysis

BACKGROUND

It has long been hypothesized that personality plays a causative role in incidence and outcome of breast cancer (BC), but epidemiological evidence of association between personality and BC is inconsistent.

METHOD

We used two-sample Mendelian randomization analysis to estimate the impact of personality on the risk and survival of BC. In total, 109 single nucleotide polymorphisms (SNPs) were utilized as instruments of neuroticism from a large-scale Genome-Wide Association Studies (GWAS), and five SNPs were utilized as instruments of extraversion from Genetic of Personality Consortium and 23andMe. Genetic association with the risk and survival of overall and individual subtype BC were obtained from the Breast Cancer Association Consortium.

RESULT

Neuroticism is significantly associated with the risk of overall BC [odds ratio (OR) 1.06; 95% confidence interval (CI) 1.01-1.11; p = 0.015] and the risk of luminal A BC (OR 1.09; 95% CI 1.03-1.16; p = 0.004). Extraversion is not associated with the risk of BC. None of neuroticism or extraversion is associated with the survival of BC.

CONCLUSION

Neuroticism was associated with a modest increased risk of BC and particularly luminal A BC.

The influence of personality and perceived stress on the development of breast cancer: 20-year follow-up of 29,098 Japanese women

Breast cancer is the most common cancer in women. However, it remains unproven whether psychological factors have an influence on breast cancer incidence. In our earlier study, subjects possessing two personality traits, decisiveness and "ikigai" (a Japanese word meaning something that makes one's life worth living), showed a significantly lower risk of developing breast cancer, although no psychological factors have been convincingly demonstrated to have an influence on breast cancer development in other studies. Therefore, we conducted this follow-up analysis to confirm the association between breast cancer incidence and psychological traits, using the final dataset of a large-scale prospective cohort study in Japan. We identified 209 cases of incident breast cancer out of a maximum 21-year follow-up of 29,098 Japanese women. Cox proportional hazard regression analysis, adjusted for the same potential confounders used in our previous study, did not reveal any significant relationships between breast cancer incidence and four psychological traits: having "ikigai", decisiveness, ease of anger arousal, and perceived stress. Our finding is consistent with previous studies, and suggests that the psychological traits are unlikely to be an important risk factor for breast cancer.

Personality and breast cancer risk and survival: the Miyagi cohort study

It has long been hypothesized that personality is associated with breast cancer risk and survival. The present population-based prospective cohort study in Japan tested this hypothesis. To investigate the association of personality with breast cancer risk, a total of 15,107 women aged 40-64 years who completed the Eysenck Personality Questionnaire-Revised (EPQ-R) Short Form were followed from 1990 to 2007. To assess the association of personality with survival after breast cancer, 250 identified cases were further followed up from the date of diagnosis to 2008, and 45 all-cause deaths were documented. Study subjects were categorized into four groups based on the quartile points of scores ranging between 0 and 12 on each EPQ-R subscale (extraversion, neuroticism, psychoticism, and lie), and the hazard ratio (HR) for each category was computed using the lowest category as reference. Multivariate analysis revealed no association between any of the four personality subscales and the risk of breast cancer. In the analysis on survival, no significant association was found between any of these subscales and the risk of death, although breast cancer cases with a higher score of extraversion tended to have a lower risk of death (P for trend = 0.07; HR for highest score level = 0.38). Exclusion of 32 cases diagnosed in the first 3 years of follow-up did not largely change the results with regard to either breast cancer risk or survival. The present findings suggest that personality does not impact significantly on the development and progression of breast cancer.

Is personality associated with cancer incidence and mortality? An individual-participant meta-analysis of 2156 incident cancer cases among 42,843 men and women

Background:

The putative role of personality in cancer risk has been controversial, and the evidence remains inconclusive.

Methods:

We pooled data from six prospective cohort studies (British Household Panel Survey; Health and Retirement Study; Household, Income, and Labour Dynamics in Australia; Midlife in the United Survey; Wisconsin Longitudinal Study Graduate; and Sibling samples) for an individual-participant meta-analysis to examine whether personality traits of the Five Factor Model (extraversion, neuroticism, agreeableness, conscientiousness, and openness to experience) were associated with the incidence of cancer and cancer mortality in 42 843 cancer-free men and women at baseline (mean age 52.2 years, 55.6% women).

Results:

During an average follow-up of 5.4 years, there were 2156 incident cancer cases. In random-effects meta-analysis adjusted for age, sex, and race/ethnicity, none of the personality traits were associated with the incidence of all cancers or any of the six site-specific cancers included in the analysis (lung, colon, breast, prostate, skin, and leukaemia/lymphoma). In the three cohorts with cause-specific mortality data (421 cancer deaths among 21 835 participants), none of the personality traits were associated with cancer mortality.

Conclusions:

These data suggest that personality is not associated with increased risk of incident cancer or cancer-related mortality.

Personality and the risk of cancer: a 16-year follow-up study of the GAZEL cohort

OBJECTIVE

Large-scale prospective studies do not support an association between neuroticism and extroversion with cancer incidence. However, research on other personality constructs is inconclusive. This longitudinal study examined the associations between four personality measures, Type 1, "suppressed emotional expression"; Type 5, "rational/antiemotional"; hostility; and Type A with cancer incidence.

METHODS

Personality measures were available for 13,768 members in the GAZEL cohort study (baseline assessment in 1993). Follow-up for diagnoses of primary cancers was obtained from January 1, 1994 to December 31, 2009. Associations between personality and cancer incidence were evaluated using Cox proportional hazards analyses and adjusted for potential confounders.

RESULTS

During a median follow-up of 16.0 years (range, 9 days-16 years), 1139 participants were diagnosed as having a primary cancer. The mean duration between baseline and cancer diagnosis was 9.3 years. Type 1 personality was associated with a decreased risk of breast cancer (hazard ratio per standard deviation = 0.81, 95% confidence interval = 0.68-0.97, p = .02). Type 5 personality was not associated with prostate, breast, colorectal, or smoking-related cancers, but was associated with other cancers (hazard ratio per standard deviation = 1.17, 95% confidence interval = 1.04-1.31, p = .01). Hostility was associated with an increased risk of smoking-related cancers, which was explained by smoking habits, and Type A was not associated with any of the cancer endpoints.

CONCLUSIONS

Several personality measures were prospectively associated with the incidence of selected cancers. These links may warrant further epidemiological studies and investigations about potential biobehavioral mechanisms.

Personality traits and life dissatisfaction as risk factors for disability pension due to low back diagnoses: a 30-year longitudinal cohort study of Finnish twins

OBJECTIVE

Little is known about the association of mild symptoms and mental well-being with risk of disability pension (DP) due to somatic diagnoses, even less for DP due to low back diagnoses (LBD). Moderate genetic influences on personality traits, life dissatisfaction and DP exist suggesting that shared genetic influences may underlie these associations. One can control for familial confounding (genetics and family environment) by examining twins. This twin study aimed to investigate personality traits and life dissatisfaction as predictors for DP due to LBD accounting for familial confounding.

METHODS

Data on 24043 twins aged 18-65year in a baseline survey in 1975 was followed up from national DP register data until 2004. Personality traits were assessed using the short version of the Eysenck Personality Inventory and life dissatisfaction was measured with a four item scale on levels of interest, happiness, easiness, and loneliness of life. Cox proportional hazards regression was used to calculate hazard ratios (HR) with 95% confidence intervals (CI).

RESULTS

DP due to LBD was granted to 537 individuals during the follow-up. Each one unit increase in life dissatisfaction (HR 1.06; 95%CI 1.03, 1.10) and neuroticism (1.07; 1.03, 1.10) but not extroversion was significantly associated with an elevated risk for DP due to LBD. These associations with life dissatisfaction and neuroticism remained when socioeconomic status, education, and marital status were taken into account, and demonstrated an independence from familial confounding.

CONCLUSION

Life dissatisfaction and neuroticism seems to be early, perhaps causal risk factors for DP due to LBD.

Characteristics and health consequences of intermittent smoking: long-term follow-up among Finnish adult twins

INTRODUCTION

The definition of a smoker as someone who smokes daily has been challenged. No consensus exists regarding whether intermittent smoking represents transition toward daily smoking or cessation or whether intermittent smokers consistently maintain their low tobacco use frequency. Although abundant evidence supports the adverse health consequences of daily smoking, less evidence is available on intermittent smoking.

METHODS

We examined characteristics and health consequences of intermittent cigarette smoking among Finnish adult twins. We used longitudinal data of 21,340 persons with smoking status from questionnaires in 1975 and 1981 and data on lung cancer incidence from 1982 to 2004 from the Finnish Cancer Registry.

RESULTS

We identified 641 consistent intermittent smokers comprising 3% of the study population. Consistent intermittent smokers had higher education, less use of other tobacco products, healthier lifestyles, and partly more favorable mental health profiles compared with lifetime regular smokers. However, in terms of other lifestyle factors, intermittent smokers compared mostly unfavorably with never-smokers, despite being better educated. Intermittent smoking showed substantial heritability. There were 213 incident lung cancer cases among all study subjects; only one case was found among the intermittent smokers. The sex- and age-adjusted hazard ratios of lung cancer were not significantly elevated for the intermittent smokers, but they were increased more than 10-fold for all other smokers.

DISCUSSION

Although the present study did not find evidence of elevated lung cancer risk among intermittent smokers, compared with never-smokers, further studies should investigate other health consequences of intermittent smoking, such as cardiovascular and nonmalignant pulmonary outcomes.

Personality factors and breast cancer risk: a 13-year follow-up

Consistent scientific evidence on the possible relationship between psychologic variables and breast cancer development is lacking. In 1996, our group first reported on the present prospective, longitudinal study. We found a weak association between a high score on the antiemotionality scale (indicating an absence of emotional behavior or a lack of trust in one's own feelings) and the development of breast cancer. No associations were found between any of the other 10 studied personality traits and breast cancer development. However, the study had a relatively short follow-up and did not investigate interaction effects between various personality traits. Therefore, the current follow-up study was conducted with the same cohort, which included the 9705 women who attended a biennial population surveillance program for breast cancer and completed a self-report personality questionnaire between January 1, 1989, and December 31, 1990. Women who developed breast cancer during the period from May 17, 1995, through January 1, 2003, formed the case group (n = 217) and were compared with age-matched women without breast cancer who formed the control group (n = 868) with regard to personality traits and medical risk factors for breast cancer. None of the personality factors were statistically significantly associated with an increased risk of breast cancer, with or without adjusting for the medical risk factors. Also, the occurrence of a combination of various personality traits (eg, a so-called cancer-prone personality) was not related to breast cancer development.

Is cancer risk associated with anger control and negative affect? Findings from a prospective cohort study

OBJECTIVE

To examine the associations between anger control and negative affect and the risk of five common cancers and total cancers. Possible associations between emotional states and the risk of cancer have long been postulated.

METHODS

Prospective cohort study with average follow-up of 9 years. A total of 19,730 adults (99% aged between 40 and 69 years) answered questions on negative affect and anger control at baseline. A total of 1952 cancers were diagnosed, including 352 breast cancers, 318 prostate cancers, 88 lung cancers, 280 colorectal cancers, and 261 melanomas.

RESULTS

After adjustment for potential confounders, there was no significant association between anger control or negative affect and risk of breast cancer, melanoma, or total cancers. Weak associations were identified between anger control and prostate cancer, hazards ratio (HR) 1.17 (1.04-1.30) for a 1-unit increase in the standardized scale, negative affect, and lung cancer, HR 1.24 (1.01-1.52) and colorectal cancer, HR 1.14 (1.01-1.28). There was no evidence of an interaction effect between anger control and negative affect.

CONCLUSIONS

Results suggest that anger control and negative affect are not associated with breast cancer, melanoma, or total cancer risk, although they may have a small role in risk of prostate, colorectal, and lung cancer. Although more research is needed to confirm these latter associations, the results suggest that if affective states are associated with cancer development, the association may differ for different cancers and argue against the use of total cancer as an outcome measure for studies in this area.

A partnership in like-minded thinking-generating hopefulness in persons with cancer

A conceptual model of a partnership in 'like-minded thinking' consists of the following components: a relationship, a shared goal with mutual agreement to work toward that goal, and reciprocal encouragement between two people. A like-minded alliance is a relationship that offers support while at the same time encourages hope and establishes a reciprocating emotional attitude of hopefulness. The discussion focuses on the principles of such a model that is designed primarily as a lay intervention for anyone who has a close friend with cancer and who wants to assist the friend in maintaining a hopeful attitude in the face of illness. While this model is not directed at healthcare professionals it may be transferable into psychosocial interventions to assist persons toward sustaining hopefulness in the context of the cancer trajectory. Much has been written in the literature about how hopelessness spawns despair for individuals who have cancer and in those near the end of life; it may even create a desire for hastened death (Breitbart W., Heller K.S.: 2003, 'Reframing Hope: Meaning-Centered Care for Patients Near the End of Life'. Journal of Palliative Medicine 6, 979-988; Jones J.M., Huggins M.A., Rydall A.C., Rodin G.M.: 2003, 'Symptomatic distress, hopelessness, and the desire for hastened death in hospitalized cancer patients', Journal of Psychosomatic Research 55, 411-418). Therefore, the aim of this paper is to explore how like-minded thinking for a person with cancer and his or her support person provides a framework for a personal shared worldview that is hope-based, meaningful and coherent.

Psychological attitudes and risk of breast cancer in Japan: a prospective study

OBJECTIVE

To examine the association between psychological factors and the risk of breast cancer prospectively in a non-Western population.

METHODS

Data from the Japan Collaborative Cohort (JACC) study were analyzed. From 1988 to 1990, 34,497 women aged 40-79 years completed a questionnaire on medical, lifestyle and psychosocial factors. The rate ratios (RRs) of their responses were computed by fitting to proportional hazards models.

RESULTS

During the mean follow-up period of 7.5 years, 149 breast cancer cases were documented. Those individuals who possessed "ikigai" (Japanese term meaning something that made one's life worth living) showed a significantly lower risk of breast cancer (multivariate-adjusted RR=0.66; 95% confidence interval [CI]=0.47-0.94). Those who perceived themselves as able to make decisions quickly also had a lower risk of breast cancer (multivariate-adjusted RR=0.56; 95% CI=0.36-0.87). The other factors investigated, including ease of anger arousal and self-perceived stress of daily life were not associated with breast cancer risk.

CONCLUSIONS

Although further studies will be necessary to verify these findings, our results suggest that having "ikigai" and being decisive decrease an individual's subsequent risk of breast cancer.

Personality traits, health behavior, and risk for cancer: a prospective study of Swedish twin court

BACKGROUND

The authors conducted a prospective investigation into the relation between personality traits and the risk for cancer.

METHODS

The study cohort consisted of 29,595 Swedish twins from the national Swedish Twin Registry who were ages 15-48 years at time of entry. In 1973, the twins completed a questionnaire eliciting information on personality traits and health behavior. The Eysenck Personality Inventory was used to measure neuroticism and extroversion as two personality dimensions. A Cox proportional hazards model was used to estimate hazard ratios and 95% confidence intervals for extroversion and neuroticism separately as well as for their joint effect, and conditional logistic regression analyses were conducted to estimate the relation between personality traits and risks for cancer in twin pairs who were discordant for cancer. All analyses were conducted for six etiologically different groups of cancers: hormone-related organ cancers, virus-related and immune-related cancers, digestive organ cancers (excluding liver), respiratory organ cancers, cancers in other sites, and all cancer sites.

RESULTS

Follow-up in the Swedish Cancer Registry for 1974-1999 revealed 1898 incidents of primary cancer. The authors found no significant association between neuroticism, extroversion, their joint effects and the risk for any cancer group.

CONCLUSIONS

The current results did not support the hypothesis that certain personality traits are associated with cancer risk.

Relationship between depression and pancreatic cancer in the general population

OBJECTIVE

Prior research suggesting a relationship between pancreatic cancer and depression conducted on clinical populations has been subject to recall bias. We reexamined this association using longitudinal population-based data.

METHODS

This was a retrospective cohort study using longitudinal insurance claims data.

RESULTS

Men with mental disorders were more likely to develop pancreatic cancer than those without psychiatric claims (odds ratio 2.4, confidence interval 1.15-4.78). Depression more commonly preceded pancreatic cancer than it did other gastrointestinal malignancies (odds ratio 4.6, confidence interval 1.07-19.4) or all other cancers (odds ratio 4.1, confidence interval 1.05-16.0).

CONCLUSIONS

Depression and pancreatic cancer are associated in the general population.

Use of antidepressant medications and the possible association with breast cancer risk. A review

BACKGROUND

Antidepressant medication use has dramatically increased over the past decade, particularly for the newer classes such as selective serotonin reuptake inhibitors. While there is no question about the usefulness of these medications, it is important to review animal and epidemiologic studies that have evaluated the association between antidepressant medication use and the risk of breast cancer.

METHODS

This paper reviews the scientific literature pertaining to the prevalence of and indications for antidepressant medication use, and the possible association between antidepressant medication use and breast cancer risk.

RESULTS

Antidepressant medications are most commonly indicated for depressive disorders, and are also used for other conditions (e.g., anxiety disorders, personality disorders, and pain). In addition, antidepressants may be an effective alternative to estrogen therapy for the alleviation of hot flashes among peri-/postmenopausal women. Several epidemiologic studies have reported that certain antidepressants may be associated with a slightly increased breast cancer risk; however, the literature remains inconsistent.

CONCLUSIONS

The possibility of an association between certain antidepressant medications and breast cancer risk has not been excluded, although further studies are needed before the body of scientific evidence can be conclusive. Evidence to date does not support a change in the current use of antidepressant medications.