Alcohol consumption and breast cancer risk among women under age 45 years

Lifetime alcohol consumption patterns and young-onset breast cancer by subtype among Non-Hispanic Black and White women in the Young Women's Health History Study

PURPOSE

The role of alcohol in young-onset breast cancer (YOBC) is unclear. We examined associations between lifetime alcohol consumption and YOBC in the Young Women's Health History Study, a population-based case-control study of breast cancer among Non-Hispanic Black and White women < 50 years of age.

METHODS

Breast cancer cases (n = 1,812) were diagnosed in the Metropolitan Detroit and Los Angeles County SEER registry areas, 2010-2015. Controls (n = 1,381) were identified through area-based sampling and were frequency-matched to cases by age, site, and race. Alcohol consumption and covariates were collected from in-person interviews. Weighted multivariable logistic regression was conducted to calculate adjusted odds ratios (aOR) and 95% confidence intervals (CI) for associations between alcohol consumption and YOBC overall and by subtype (Luminal A, Luminal B, HER2, or triple negative).

RESULTS

Lifetime alcohol consumption was not associated with YOBC overall or with subtypes (all ptrend ≥ 0.13). Similarly, alcohol consumption in adolescence, young and middle adulthood was not associated with YOBC (all ptrend ≥ 0.09). An inverse association with triple-negative YOBC, however, was observed for younger age at alcohol use initiation (< 18 years vs. no consumption), aOR (95% CI) = 0.62 (0.42, 0.93). No evidence of statistical interaction by race or household poverty was observed.

CONCLUSIONS

Our findings suggest alcohol consumption has a different association with YOBC than postmenopausal breast cancer-lifetime consumption was not linked to increased risk and younger age at alcohol use initiation was associated with a decreased risk of triple-negative YOBC. Future studies on alcohol consumption in YOBC subtypes are warranted.

Association between wine consumption and cancer: a systematic review and meta-analysis

Background

Alcohol consumption is related to the risk of developing different types of cancer. However, unlike other alcoholic beverages, moderate wine drinking has demonstrated a protective effect on the risk of developing several types of cancer.

Objective

To analyze the association between wine consumption and the risk of developing cancer.

Methods

We searched the MEDLINE (through PubMed), Scopus, Cochrane, and Web of Science databases to conduct this systematic review and meta-analysis. Pooled relative risks (RRs) were calculated using the DerSimonian and Laird methods. I2 was used to evaluate inconsistency, the τ2 test was used to assess heterogeneity, and The Newcastle-Ottawa Quality Assessment Scale were applied to evaluate the risk of bias. This study was previously registered in PROSPERO, with the registration number CRD42022315864.

Results

Seventy-three studies were included in the systematic review, and 26 were included in the meta-analysis. The pooled RR for the effect of wine consumption on the risk of gynecological cancers was 1.03 (95% CI: 0.99, 1.08), that for colorectal cancer was 0.92 (95% CI: 0.82, 1.03), and that for renal cancer was 0.92 (95% CI: 0.81, 1.04). In general, the heterogeneity was substantial.

Conclusion

The study findings reveal no association between wine consumption and the risk of developing any type of cancer. Moreover, wine drinking demonstrated a protective trend regarding the risk of developing pancreatic, skin, lung, and brain cancer as well as cancer in general.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022315864, identifier CRD42022315864 (PROSPERO).

What Is Known about Breast Cancer in Young Women?

Breast cancer (BC) is the second leading cause of cancer-related death in women under the age of 40 years worldwide. In addition, the incidence of breast cancer in young women (BCYW) has been rising. Young women are not the focus of screening programs and BC in younger women tends to be diagnosed in more advanced stages. Such patients have worse clinical outcomes and treatment complications compared to older patients. BCYW has been associated with distinct tumour biology that confers a worse prognosis, including poor tumour differentiation, increased Ki-67 expression, and more hormone-receptor negative tumours compared to women >50 years of age. Pathogenic variants in cancer predisposition genes such as BRCA1/2 are more common in early-onset BC compared to late-onset BC. Despite all these differences, BCYW remains poorly understood with a gap in research regarding the risk factors, diagnosis, prognosis, and treatment. Age-specific clinical characteristics or outcomes data for young women are lacking, and most of the standard treatments used in this subpopulation currently are derived from older patients. More age-specific clinical data and treatment options are required. In this review, we discuss the epidemiology, clinicopathologic characteristics, outcomes, treatments, and special considerations of breast cancer in young women. We also underline future directions and highlight areas that require more attention in future studies.

A Review of Modifiable Risk Factors in Young Women for the Prevention of Breast Cancer

Breast cancer is the most common cancer diagnosis in women aged less than 40 years and the second most common cause of cancer death in this age group. Global rates of young onset breast cancer have risen steadily over the last twenty years. Although young women with breast cancer have a higher frequency of underlying pathogenic mutations in high penetrance breast cancer susceptibility genes (CSG) than older women, the vast majority of young breast cancer patients are not found to have a germline CSG mutation. There is therefore a need to inform young women regarding non-genetic breast cancer risk factors which have the potential to be influenced by changes in individual behaviour. A Pubmed search was performed using the search terms “young” or “early onset”, and “breast cancer” and “modifiable risk”. Titles and abstracts from peer-reviewed publications were screened for relevance. This review presents evidence for potentially modifiable risk factors of breast cancer risk in young women, including lifestyle factors (physical activity, body habitus, alcohol use, smoking, shift work and socioeconomic factors), reproductive and hormonal factors and iatrogenic risks. The extent to which these factors are truly modifiable is discussed and interactions between genetic and non-genetic risk factors are also addressed. Health care professionals have an opportunity to inform young women about breast health and risk when presenting at a “teachable moment”, including the benefits of physical activity and alcohol habits as risk factor. More focussed discussions regarding individual personal risk and benefit should accompany conversations regarding reproductive health and take into consideration both non-modifiable and iatrogenic BC risk factors.

Alcohol and Tobacco Use in an Ethnically Diverse Sample of Breast Cancer Patients, Including Sea Island African Americans: Implications for Survivorship

Background/Objective: Data suggest that modifiable risk factors such as alcohol and tobacco use may increase the risk of breast cancer (BC) recurrence and reduce survival. Female BC mortality in South Carolina is 40% higher among African Americans (AAs) than European Americans (EAs). Given this substantial racial disparity, using a cross-sectional survey design we examined alcohol and tobacco use in an ethnically diverse statewide study of women with recently diagnosed invasive breast cancer. This included a unique South Carolina AA subpopulation, the Sea Islanders (SI), culturally isolated and with the lowest European American genetic admixture of any AA group.

Methods: Participants (42 EAs, 66 non-SI AAs, 29 SIs), diagnosed between August 2011 and December 2012, were identified through the South Carolina Central Cancer Registry and interviewed by telephone within 21 months of diagnosis. Self-reported educational status, alcohol consumption and tobacco use were obtained using elements of the Behavior and Risk Factor Surveillance System questionnaire.

Results:Alcohol: EAs were approximately twice as likely to consume alcohol (40%) and to be moderate drinkers (29%) than either AA group (consumers: 24% of non-SI AAs, 21% of SIs; moderate drinkers 15 and 10% respectively). Users tended to be younger, significantly among EAs and non-SI AAs, but not SIs, and to have attained more education. Heavy drinking was rare (≤1%) and binge drinking uncommon (≤10%) with no differences by race/ethnicity. Among both AA subgroups but not EAs, alcohol users were six to nine times more likely to have late stage disease (Regional or Distant), statistically significant but with wide confidence intervals. Tobacco: Current cigarette smoking (daily or occasional) was reported by 14% of EAs, 14% of non-SI AAs and 7% of SIs. Smoking was inversely associated with educational attainment. Use of both alcohol and cigarettes was reported by 3–6% of cases.

Conclusions: Prevalences of alcohol and cigarette use were similar to those in the general population, with alcohol consumption more common among EAs. Up to half of cases used alcohol and/or tobacco. Given the risks from alcohol for disease recurrence, and implications of smoking for various health outcomes, these utilization rates are of concern.

Links between alcohol consumption and breast cancer: a look at the evidence

Alcohol consumption by adult women is consistently associated with risk of breast cancer. Several questions regarding alcohol and breast cancer need to be addressed. Menarche to first pregnancy represents a window of time when breast tissue is particularly susceptible to carcinogens. Youth alcohol consumption is common in the USA, largely in the form of binge drinking and heavy drinking. Whether alcohol intake acts early in the process of breast tumorigenesis is unclear. This review aims to focus on the influences of timing and patterns of alcohol consumption and the effect of alcohol on intermediate risk markers. We also review possible mechanisms underlying the alcohol-breast cancer association.

Methodological biases in estimating the relationship between alcohol consumption and breast cancer: the role of drinker misclassification errors in meta-analytic results

BACKGROUND

While alcohol consumption has been linked to breast cancer in women, few studies have controlled for possible biases created by including former or occasional drinkers in the abstainer reference group. We explored the potential for such misclassification errors as sources of bias in estimates of the alcohol-breast cancer relationship.

METHODS

Meta-analyses of population case-control, hospital case-control, and cohort studies to examine relationships between level of alcohol use and breast cancer morbidity and/or mortality in groups of studies with and without different misclassification errors.

RESULTS

Of 60 studies identified, only 6 were free of all misclassification errors. The abstainer reference group was biased by the inclusion of former drinkers in 49 studies, occasional drinkers (<10 g ethanol [EtOH] per week) in 22 and by both these groups in 18. Occasional drinkers were also mixed with light or hazardous-level drinkers in 22 studies. Unbiased estimates of the odds ratio (OR) for breast cancer were 1.011 (95% confidence interval [CI]: 0.891 to 1.148) among former drinkers (n = 11) and 1.034 (95% CI: 1.003 to 1.064) among occasional drinkers (n = 17). Hazardous-level drinking (>20 g < 41 g EtOH/d) was not significantly associated with breast cancer in studies with occasional drinker bias. However, in studies free from occasional drinker bias, the OR for breast cancer was 1.085 (95% CI: 1.015 to 1.160) for low-level (<21 g/d) drinkers (n = 17), 1.374 (95% CI: 1.319 to 1.431) for hazardous-level drinkers (n = 26), and 1.336 (95% CI: 1.228 to 1.454) for harmful-level (>40 g/d) drinkers (n = 9).

CONCLUSIONS

While the great majority of studies of the alcohol-breast cancer link include misclassification errors, only misclassification of occasional drinkers was found to bias risk estimates significantly. Estimates based on error-free studies confirmed that low, hazardous and harmful levels of alcohol use each significantly increase the risk of breast cancer.

Moderate alcohol consumption during adult life, drinking patterns, and breast cancer risk

CONTEXT

Multiple studies have linked alcohol consumption to breast cancer risk, but the risk of lower levels of consumption has not been well quantified. In addition, the role of drinking patterns (ie, frequency of drinking and "binge" drinking) and consumption at different times of adult life are not well understood.

OBJECTIVE

To evaluate the association of breast cancer with alcohol consumption during adult life, including quantity, frequency, and age at consumption.

DESIGN, SETTING, AND PARTICIPANTS

Prospective observational study of 105,986 women enrolled in the Nurses' Health Study followed up from 1980 until 2008 with an early adult alcohol assessment and 8 updated alcohol assessments.

MAIN OUTCOME MEASURES

Relative risks of developing invasive breast cancer.

RESULTS

During 2.4 million person-years of follow-up, 7690 cases of invasive breast cancer were diagnosed. Increasing alcohol consumption was associated with increased breast cancer risk that was statistically significant at levels as low as 5.0 to 9.9 g per day, equivalent to 3 to 6 drinks per week (relative risk, 1.15; 95% CI, 1.06-1.24; 333 cases/100,000 person-years). Binge drinking, but not frequency of drinking, was associated with breast cancer risk after controlling for cumulative alcohol intake. Alcohol intake both earlier and later in adult life was independently associated with risk.

CONCLUSIONS

Low levels of alcohol consumption were associated with a small increase in breast cancer risk, with the most consistent measure being cumulative alcohol intake throughout adult life. Alcohol intake both earlier and later in adult life was independently associated with risk.

Substance use and women's health

Scientific findings show that substance abuse in women yields a higher risk of a variety of health problems than substance abuse in men. Research suggests that women experience addiction telescoping when they abuse alcohol, tobacco, specific stimulants, and possibly opioids. Medical side effects also develop more rapidly in women than men when they abuse many substances. Cancer and cardiac complications, specifically, pose a significant threat for women who abuse almost all types of substances. However, the physical consequences are not the only ones women suffer when they engage in substance abuse. Research on substance abuse in women ties opioids to mood and anxiety disorders, heroin to neurological deficiencies, cocaine to immune system suppression, and alcohol to intimate partner abuse. Additionally, female substance abusers, on average, have a lower level of education and lower rates of employment. In light of these gender-specific concerns, physicians should give particular consideration to detecting substance abuse in women.

Effect of prediagnostic alcohol consumption on survival after breast cancer in young women

BACKGROUND

Alcohol consumption has been comprehensively investigated as an etiologic risk factor for breast cancer but has received little attention in terms of its effect on prognosis after breast cancer, particularly for young women.

METHODS

1,286 women diagnosed with invasive breast cancer at age < or =45 years from two population-based case-control studies in the Seattle-Puget Sound region were followed from their diagnosis of breast cancer (between January 1983 and December 1992) for survival through June 2002, during which time 364 women had died. Cox proportional hazards modeling was used to assess the effect of prediagnostic alcohol consumption on the risk of dying.

RESULTS

After adjusting for age and diagnosis year, compared with nondrinkers, women who consumed alcohol in the 5 years before diagnosis had a decreased risk of death [>0 to <3 drinks per week: hazard ratio, 0.7; 95% confidence interval (95% CI), 0.6-0.95; 3 to <7 drinks per week: risk ratio, 0.6; 95% CI, 0.4-0.8;7 drinks per week: risk ratio, 0.7; 95% CI, 0.5-0.9]. This association was unchanged on additional adjustment for potential confounders including most notably treatment, stage at diagnosis, and mammogram history.

CONCLUSION

These results suggest that women who consume alcohol before a diagnosis of breast cancer have improved survival, which does not appear to be attributable to differences in stage, screening, or treatment.

Alcohol Drinking and Risk of Breast Cancer

Using a case-control design, the authors studied female residents of five Massachusetts towns between 1983 and 1986. The objective was to measure the association between breast cancer occurrence and drinking alcohol. Cohort and case-control studies have often observed an association between drinking alcohol and breast cancer risk. In this study, women with any history of drinking alcohol had a risk of breast cancer 1.2-fold greater than women who never drank alcohol (95% confidence interval 0.7-1.8). The relative risk of breast cancer did not depend on the usual number of drinks per day or drinking history relative to time of diagnosis. Women who reported ever having a period of 6 months or more during which they drank more than average had an adjusted relative risk of breast cancer equal to 2.6 (95% confidence interval 1.1-5.8). The estimates of effect are consistent with the positive dose-response trends reported in a pooled analysis of large cohort studies and a meta-analysis of a broader spectrum of studies. Alcohol drinking remains one of the few risk factors for breast cancer amenable to intervention.

Alcohol intake and breast cancer risk among young women

INTRODUCTION

Alcohol intake has been consistently associated with breast cancer risk, but the importance of timing of intake and the impact of beverage type are unclear.

METHODS

We evaluated whether early, lifetime or recent alcohol intake was associated with breast cancer risk, and whether risk varied by type of alcoholic drinks in 1,728 newly diagnosed population-based breast cancer patients and 435 control subjects aged 20-49 years. We used multivariable logistic regression models to estimate odds ratios (OR) and 95% confidence intervals (CI) as measures of the relative risk of breast cancer associated with intake of alcoholic drinks.

RESULTS

Intake of alcoholic drinks during the recent five year period before the breast cancer diagnosis was associated with increased breast cancer risk (P (trend) = 0.04). Intake of two or more alcoholic drinks per day during this five year period was associated with an 82% increase in breast cancer risk relative to never drinkers (OR = 1.82, 95% CI = 1.01-3.28). No risk increase was observed for alcohol intake at ages 15-20 years or for lifetime alcohol intake. Risk did not vary by type of alcohol consumed.

CONCLUSIONS

Our results suggest that recent alcohol consumption may be associated with increased breast cancer risk in young women.

Alcohol intake in adolescence and mammographic density

Adolescent exposures may be important in the development of breast cancer later in life. We examined the association of adolescent alcohol consumption and adult mammographic density, a strong risk factor for breast cancer. Women within the Minnesota Breast Cancer Family Cohort with detailed mammogram and risk factor information (n = 1,893) formed our sample. Breast cancer cases were excluded. Adolescent alcohol consumption (before age 18) was solicited through a mailed questionnaire. Percent density (PD) was estimated using the computer-assisted thresholding program, Cumulus. Statistical analyses were performed using linear mixed effect models. Women who reported ever drinking alcohol before age 18 (n = 390; 21%) had a higher unadjusted PD than women who never drank during adolescence (mu(unadj) = 26.5% vs. 22.2%), but this difference disappeared with adjustment for risk factors for mammographic density (mu(adj) = 21.0% vs. 21.2%, p = 0.94). Adult PD was not associated with age at initiation, amount of alcohol consumed at one sitting or frequency of alcohol use before age 18. The lack of differences was seen across strata of menopausal status. There was suggestion of higher PD among heavy and more frequent drinkers (24.0%, 95% CI 21.1-26.8%) compared to lighter (21.3%, 95% CI 20.3-22.3%) and never drinkers (21.4%, 95% CI 20.9-21.9%) and also among regular adolescent drinkers who were daily or weekly adult drinkers (25.0%, 95% CI 23.0-27.0%) compared to less regular drinkers in these 2 time periods (23.0-23.4%). However, these associations were not statistically significant (p = 0.27 and p = 0.22, respectively). In summary, there was no evidence that adolescent alcohol use was associated with large and persistent effects on adult PD.

ADH3 genotype, alcohol intake and breast cancer risk

Moderate alcohol consumption of approximately 1-2 drinks per day has been associated with a 30-50% increase in breast cancer risk. Individuals differ in their ability to metabolize alcohol through genetic differences in alcohol dehydrogenase (ADH), the enzyme that catalyzes the oxidation of approximately 80% of ethanol to acetaldehyde, a known carcinogen. Individuals differ in their ADH genotype, and one locus in particular (ADH3) is polymorphic in Caucasian populations. Using data from the Long Island Breast Cancer Study Project, we examined whether fast metabolizers of alcohol, as measured by the ADH3(1-1) genotype, have a higher risk of breast cancer from alcohol intake compared with those individuals who are slow metabolizers, but consume similar amounts of alcohol. We combined genotyping information with questionnaire data on 1047 breast cancer cases and 1101 controls and used unconditional logistic regression methods to estimate multivariate-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) between alcohol intake and breast cancer risk. Among individuals homozygous for the fast metabolizing allele (ADH(3)1-1), a lifetime alcohol consumption of 15-30 g/day (approximately 1-2 drinks per day) increased breast cancer risk by 2-fold (OR=2.0, 95% CI=1.1-3.5). In contrast, the increase in risk from a lifetime alcohol consumption of 15-30 g/day was less pronounced in the intermediate and slow metabolizing groups, respectively: ADH3(1-2) (OR=1.5, 95% CI 0.9-2.4) and ADH(3)2-2 (OR=1.3, 95% CI 0.5-3.5). Fast metabolizers who drank 15-30 g/day of alcohol had 2.3 times (95% CI 1.3-4.0) greater risk of breast cancer than non-drinkers who were intermediate or slow metabolizers. This association for fast metabolizers who drank 15-30 g/day was particularly pronounced among premenopausal women (premenopausal women OR=2.9, 95 % CI=1.2-7.1; postmenopausal women OR=1.8, 95% CI=0.9-3.8). These population-based data support the hypothesis that fast metabolizers of alcohol have a higher risk of breast cancer risk, from alcohol intake than slow metabolizers.

Investigation of systemic folate status, impact of alcohol intake and levels of DNA damage in mononuclear cells of breast cancer patients

Folate is required for DNA synthesis, repair and methylation. Low folate status has been implicated in carcinogenesis, possibly as a result of higher rate of genetic damage. The aim of this study is to compare folate status and levels of DNA damage between breast cancer and benign breast disease control patients. Fasting blood samples from 64 histologically confirmed untreated breast cancer patients (mean age 57 years) and 30 benign breast disease control patients (mean age 51 years) were obtained. Red cell folate (RCF) and plasma homocysteine were measured. Mononuclear cells (MNC) were isolated for genetic damage analysis using the basic alkaline comet assay. Results are expressed as tail moment. Data were log transformed as appropriate before analysis for normalisation purposes. The geometric mean (95% confidence interval) of RCF (ng ml⁻¹) in breast cancer patients was 339.07 (333.3–404.6) vs 379.5 (335.8–505.2) in control patients (P=0.24). Corresponding plasma homocysteine concentrations (μmol l⁻¹) were 11.9 (10.6–16.4) vs 10.1 (9.3–11.9) (P=0.073), respectively. The mean tail moment (s.d.) of DNA damage in MNC of breast cancer patients detected by the basic comet assay was 1.4 (0.66) vs –0.17 (0.79) in controls (P<0.0001, t-test), the modified comet assay ‘endonuclease III (Endo III)’ was 1.7 (0.70) vs 0.86 (0.81) (P<0.0001, t-test), and the modified comet assay ‘formamidopyrimidine glycosylase (FPG)’ was 1.6 (0.62) vs 0.99 (0.94) (P<0.0001, t-test). There was a significant negative correlation between RCF levels and DNA damage detected by modified comet assay ‘FPG’ (Pearson Correlation Coefficient r²=−0.26, P=0.02) and DNA damage was found to be significantly higher in MNC of breast cancer patients compared to benign breast disease control patients. Breast cancer patients tended to have lower RCF levels and higher levels of plasma homocysteine, but these differences were not significant. The study provides preliminary evidence that reduced folate status may be implicated in the aetiology of breast cancer perhaps by increasing the in vivo level of genetic instability.

Occupational exposure to metalworking fluids and risk of breast cancer among female autoworkers

BACKGROUND

Metalworking fluids (MWF) are used for lubrication during metal manufacturing. Previous studies have observed increased risks of several cancers among MWF-exposed workers. We hypothesized that MWF may be associated with risk of breast cancer because they can contain carcinogenic or endocrine-disrupting chemicals.

METHODS

We conducted a case-control study nested in a cohort of 4,680 female automobile workers employed for at least 3 years between 1/1/41 and 1/1/85, with follow-up through 1994. Cases were identified using the National Death Index (NDI), Michigan cancer registries, and company records. Detailed quantitative MWF exposure data were available for each subject, although data on known breast cancer risk factors were not.

RESULTS

Ninety-nine cases of breast cancer and 626 matched controls were identified. There was a weak positive association between lifetime cumulative exposure to soluble MWF and breast cancer risk, but no evidence of association with either straight or synthetic fluids. When exposure was divided into time-windows, the association was strongest for soluble MWF in the decade preceding diagnosis. Controlling for earlier exposures, there was an odds ratio of 1.18 (95% CI=1.02-1.35) per mg/m3-year of cumulative exposure to soluble MWF in this 10-year period.

CONCLUSION

This hypothesis-generating study provides some preliminary evidence for an association between exposure to soluble MWF and increased risk of breast cancer. Additional studies of MWF and breast cancer, with data on known breast cancer risk factors, are warranted.

Alcohol consumption and risk of prostate cancer in middle-aged men

Alcohol consumption is a modifiable lifestyle factor that may affect prostate cancer risk. Alcohol alters the hormonal milieu and contains chemical substances such as flavonoids (red wine), which may alter tumor cell growth. Data from a population-based case-control study in King County, WA, were utilized to evaluate the association of alcohol consumption with prostate cancer in middle-aged men. A total of 753 newly diagnosed prostate cancer cases, 40-64 years of age, participated in the study. Seven hundred three control subjects, frequency matched to cases by age, were selected through random digit dialing. All participants completed an in-person interview on lifetime alcohol consumption and other risk factors for prostate cancer. Logistic regression models were used to estimate odds ratios (OR) and assess significance (95% confidence intervals [CI]). All tests of statistical significance were two-sided. No clear association with prostate cancer risk was seen for overall alcohol consumption. Each additional glass of red wine consumed per week showed a statistically significant 6% decrease in relative risk (OR = 0.94; 95% CI = 0.90-0.98), and there was evidence for a decline in risk estimates across increasing categories of red wine intake (trend p = 0.02). No clear associations were seen for consumption of beer or liquor. Our present study suggests that consumption of beer or liquor is not associated with prostate cancer. There may be, however, a reduced relative risk associated with increasing level of red wine consumption. Further research is needed to evaluate the potential negative association between red wine intake and prostate cancer risk.

Alcohol Exposure and Breast Cancer: Results of the Women's Contraceptive and Reproductive Experiences Study

Objectives: To explore associated biological outcomes and clarify the role of timing of exposure in the alcohol-breast cancer relationship.

Methods: In a population-based study of 4,575 women ages 35 to 64 years diagnosed with invasive breast cancer between 1994 and 1998 and 4,682 controls, we collected details of lifetime alcohol use and factors that could confound or modify the alcohol-breast cancer relationship. We used conditional logistic regression to compute the odds of breast cancer among drinkers relative to nondrinkers at all ages and at ages 35 to 49 and 50 to 64 years separately.

Results: Recent consumption (at reference age minus two) of ≥7 drinks per week was associated with increased risk [odds ratio (OR), 1.2; 95% CI, 1.01-1.3] and evidence of dose response was observed. Most of the excess was observed among women ages 50-64 years (OR 1.3; 95% CI, 1.1-1.6), although the test for age interaction was not statistically significant. Exposure later in life seemed more important than early exposure. Excess breast cancer associated with recent consumption was restricted to localized disease. When outcome was examined according to tumor hormone receptor status, highest risks were observed for estrogen receptor–positive/progesterone receptor–negative tumors (OR 1.6; 95% CI, 1.2-2.3).

Conclusions: The effect of timing of alcohol exposure on breast cancer risk is complicated and will require additional study focused on this one issue. Further work is needed to explain how alcohol exposure, sex hormones, and tumor receptor status interact.

In utero alcohol exposure increases mammary tumorigenesis in rats

Findings in humans and animal models suggest that in utero hormonal and dietary exposures increase later breast cancer risk. Since alcohol intake by adult women consistently increases their breast cancer risk, we wondered whether maternal alcohol consumption during pregnancy increases female offspring's mammary tumorigenesis. In our study, pregnant female rats were pair-fed isocaloric diets containing either 0 (control), 16 or 25 g alcohol kg(-1) feed between days 7 and 19 of gestation. These alcohol exposures generate blood alcohol levels that correspond to low and moderate alcohol consumption and are lower than those that induce foetal alcohol syndrome. Serum oestradiol levels were elevated in pregnant rats exposed to alcohol (P<0.003). When adult, female offspring of alcohol-exposed dams developed significantly more 7,12-dimethylbenz[a]anthracene -induced mammary tumours, compared to the controls (tumour multiplicity; mean+/-s.e.m., controls: 2.0+/-0.3, 16 g alcohol: 2.7+/-0.4 and 25 g alcohol: 3.7+/-0.4; P<0.006). In addition, the mammary epithelial tree of the alcohol-exposed offspring was denser (P<0.004) and contained more structures that are susceptible for the initiation of breast cancer (P<0.001). Immunohistochemical assessment indicated that the mammary glands of 22-week-old in utero alcohol-exposed rats contained elevated levels of oestrogen receptor-alpha (P<0.04) that is consistent with the changes in mammary gland morphology. In summary, maternal alcohol intake during pregnancy increases female offspring's mammary tumorigenesis, perhaps by programming the foetal mammary gland to exhibit persistent alterations in morphology and gene expression. It remains to be determined whether an increase in pregnancy oestradiol levels mediated alcohol's effects on offspring's mammary tumorigenesis.

Derivation of tolerable upper alcohol intake levels in Germany: a systematic review of risks and benefits of moderate alcohol consumption

BACKGROUND

The objective of this study is to weigh the risks of moderate alcohol consumption against its benefits and, as a result, to derive tolerable upper alcohol intake levels (TUALs) for the German adult population.

METHODS

Human studies assessing the effects of moderate alcohol consumption (< or = 40 g/day) on coronary heart disease, stroke, blood pressure, diseases of the liver, gallbladder, bile duct, and pancreas, cancer of the mouth/pharynx/larynx/oesophagus, stomach, colon/rectum, and breast, foetal alcohol syndrome/foetal alcohol effects, as well as all-cause mortality, published in the 10-15 years before 1999, have been systematically reviewed. The quality of studies has been evaluated using a self-constructed evaluation scheme. As a result of comparing the critical endpoints of alcohol intake related to morbidity and mortality, the TUALs have been derived.

RESULTS

The TUALs have been set at 10-12 g/day for healthy women and 20-24 g/day for healthy men of the adult population (18 years and older). Additional guidelines on alcohol use have been defined, taking into account further important aspects like alcohol consumption patterns and high-risk groups.

CONCLUSIONS

The TUALs are not intended to be recommended intake levels. However, if the TUALs and the additional guidelines are followed, a relation of alcohol consumption to an increased risk of alcohol-associated diseases is unlikely for the majority of the population.

Lifetime alcohol consumption and postmenopausal breast cancer rate in Denmark: a prospective cohort study

Alcohol intake may be one of the few modifiable risk factors for breast cancer. In a prospective cohort of 29,875 women with 423 cases of breast cancer during 1993-2000, we examined the relationship between postmenopausal breast cancer incidence rate and alcohol consumption in different life periods. When alcohol intake during four age ranges, twenties, thirties, forties and fifties was evaluated, only the intake in the fifties increased the risk of breast cancer [rate ratio (RR)=1.12 (95% CI: 1.05-1.19)] per 10 g/d increase in alcohol intake. After adjustment for intake at study entry, this association was no longer present [RR=1.01 (95% CI: 0.91-1.13)]. The cumulative lifetime alcohol intake, adjusted for recent intake, showed no association with postmenopausal breast cancer risk. Recent alcohol intake, adjusted for the alcohol intake in the other life time periods, showed a significant association of RR=1.09 (95% CI: 1.00-1.18) per 10 g/d. There was no indication of a higher risk among women with early drinking start, nor did women who started to drink before their first birth have a higher risk than women who started to drink later in life. Our results suggest that baseline intake of alcohol is a more important determinant of postmenopausal breast cancer risk than earlier lifetime exposure.

Overexpression of ErbB2 enhances ethanol-stimulated intracellular signaling and invasion of human mammary epithelial and breast cancer cells in vitro

Both epidemiological and experimental studies indicate that ethanol is a tumor promoter and may promote metastasis of breast cancer. However, the molecular mechanisms underlying ethanol-mediated tumor promotion remain unknown. Overexpression of ErbB proteins in breast cancer patients is generally associated with poor prognosis. The ErbB proteins are a family of receptor kinases that include four closely related members: epidermal growth factor receptor (EGFR/ErbB1), ErbB2/neu, ErbB3, and ErbB4. Particularly, ErbB2 plays a pivotal role in ErbB-mediated activities. Here we demonstrated that amplification of ErbB2 expression sensitized a specific cellular response to ethanol. Human breast cancer cells or mammary epithelial cells with a high expression of ErbB2 exhibited an enhanced response to ethanol-stimulated cell invasion in vitro. Ethanol also stimulated cell proliferation; however, this stimulation was independent of ErbB2 levels. Ethanol triggered divergent intracellular signaling among cells expressing different ErbB2 levels. In the cells overexpressing ErbB2, ethanol was more effective in the activation of c-Jun NH2 terminal protein kinases (JNKs) and p38 mitogen-activated protein kinase (p38 MAPK) as well as the induction of reactive oxygen species (ROS) than the cells with normal ErbB2 expression. Blockage of either JNKs or p38 MAPK activation eliminated ethanol-mediated cell invasion. In contrast, the reduction of hydrogen peroxide concentration by catalase exposure had little effect on ethanol-induced cell invasion. These results indicated that ethanol-induced cell invasion was primarily mediated by JNKs and p38 MAPK, whereas the involvement of ROS formation might be minimal. Our study suggests that overexpression of ErbB2 may augment ethanol-elicited signaling and promote ethanol-stimulated tumor metastasis.

Exposures in childhood, adolescence and early adulthood and breast cancer risk: a systematic review of the literature

A growing body of work indicates that exposures over the life course have important roles to play in the aetiology of breast cancer. This review synthesises the literature that has been published in the area of early life events and female breast cancer risk. The review finds some evidence, primarily from cohort studies on the relationship between birthweight and breast cancer, to suggest that in utero events are related to breast cancer risk in adulthood. Strong evidence to support a positive association between height and breast cancer exists. Postulated mechanisms for this relationship include the role of early diet in subsequent disease risk, and the influence of endogenous growth factors mediating the relationship. There is some evidence to suggest that leg length is the component of height which is generating the observed associations between height and breast cancer. There is no consistent pattern of association between relative weight in childhood or adolescence and risk of breast cancer. The evidence to suggest an association between physical activity in early life and breast cancer risk is convincing from case-control studies, but is not fully substantiated by the results of three cohort studies. There are inconsistent results regarding the association between smoking at a young age and breast cancer risk. There is little evidence for an association between passive smoking in early life and breast cancer risk. No clear association between early drinking and breast cancer risk exists. These results are discussed in relation to possible underlying mechanisms and health promotion strategies which could reduce breast cancer risk.

Alcohol, tobacco and breast cancer--collaborative reanalysis of individual data from 53 epidemiological studies, including 58,515 women with breast cancer and 95,067 women without the disease

Alcohol and tobacco consumption are closely correlated and published results on their association with breast cancer have not always allowed adequately for confounding between these exposures. Over 80% of the relevant information worldwide on alcohol and tobacco consumption and breast cancer were collated, checked and analysed centrally. Analyses included 58,515 women with invasive breast cancer and 95,067 controls from 53 studies. Relative risks of breast cancer were estimated, after stratifying by study, age, parity and, where appropriate, women's age when their first child was born and consumption of alcohol and tobacco. The average consumption of alcohol reported by controls from developed countries was 6.0 g per day, i.e. about half a unit/drink of alcohol per day, and was greater in ever-smokers than never-smokers, (8.4 g per day and 5.0 g per day, respectively). Compared with women who reported drinking no alcohol, the relative risk of breast cancer was 1.32 (1.19-1.45, P<0.00001) for an intake of 35-44 g per day alcohol, and 1.46 (1.33-1.61, P<0.00001) for >/=45 g per day alcohol. The relative risk of breast cancer increased by 7.1% (95% CI 5.5-8.7%; P<0.00001) for each additional 10 g per day intake of alcohol, i.e. for each extra unit or drink of alcohol consumed on a daily basis. This increase was the same in ever-smokers and never-smokers (7.1% per 10 g per day, P<0.00001, in each group). By contrast, the relationship between smoking and breast cancer was substantially confounded by the effect of alcohol. When analyses were restricted to 22 255 women with breast cancer and 40 832 controls who reported drinking no alcohol, smoking was not associated with breast cancer (compared to never-smokers, relative risk for ever-smokers=1.03, 95% CI 0.98-1.07, and for current smokers=0.99, 0.92-1.05). The results for alcohol and for tobacco did not vary substantially across studies, study designs, or according to 15 personal characteristics of the women; nor were the findings materially confounded by any of these factors. If the observed relationship for alcohol is causal, these results suggest that about 4% of the breast cancers in developed countries are attributable to alcohol. In developing countries, where alcohol consumption among controls averaged only 0.4 g per day, alcohol would have a negligible effect on the incidence of breast cancer. In conclusion, smoking has little or no independent effect on the risk of developing breast cancer; the effect of alcohol on breast cancer needs to be interpreted in the context of its beneficial effects, in moderation, on cardiovascular disease and its harmful effects on cirrhosis and cancers of the mouth, larynx, oesophagus and liver.

The Long Island Breast Cancer Study Project: description of a multi-institutional collaboration to identify environmental risk factors for breast cancer

The Long Island Breast Cancer Study Project is a federally mandated, population-based case-control study to determine whether breast cancer risk among women in the counties of Nassau and Suffolk, NY, is associated with selected environmental exposures, assessed by blood samples, self-reports, and environmental home samples. This report describes the collaborative project's background, rationale, methods, participation rates, and distributions of known risk factors for breast cancer by case-control status, by blood donation, and by availability of environmental home samples. Interview response rates among eligible cases and controls were 82.1% (n = 1,508) and 62.8% (n = 1,556), respectively. Among case and control respondents who completed the interviewer-administered questionnaire, 98.2 and 97.6% self-completed the food frequency questionnaire; 73.0 and 73.3% donated a blood sample; and 93.0 and 83.3% donated a urine sample. Among a random sample of case and control respondents who are long-term residents, samples of dust (83.6 and 83.0%); soil (93.5 and 89.7%); and water (94.3 and 93.9%) were collected. Established risk factors for breast cancer that were found to increase risk among Long Island women include lower parity, late age at first birth, little or no breast feeding, and family history of breast cancer. Factors that were found to be associated with a decreased likelihood that a respondent would donate blood include increasing age and past smoking; factors associated with an increased probability include white or other race, alcohol use, ever breastfed, ever use of hormone replacement therapy, ever use of oral contraceptives, and ever had a mammogram. Long-term residents (defined as 15+ years in the interview home) with environmental home samples did not differ from other long-term residents, although there were a number of differences in risk factor distributions between long-term residents and other participants, as anticipated.

Defining alcohol-related fatal medical conditions for social-cost studies in western societies: an update of the epidemiological evidence

OBJECTIVES

To elaborate a state-of-the-art list of alcohol-related fatal medical conditions for future social-cost studies in Western societies.

METHODS

Three major social-cost studies were compared with regard to their respective section on fatal health effects attributable to long-term as well as short-term use of alcohol. On discordant conditions, a systematic literature search was conducted in the Medline and ETOH databases.

RESULTS

There is no consensus between social-cost studies with respect to alcohol-related causes of mortality. Based on the recent epidemiological evidence on alcohol and health, this paper suggests an up-to-date list of fatal medical conditions for which the causal relationship has been established with sufficient scientific evidence. A further investigation is needed, however, to reestimate relative risks by meta-analysis.

CONCLUSIONS

Evaluating new epidemiological evidence regularly is necessary for the purpose of up-to-date social-cost studies.

Modulation of expression of ribosomal protein L7a (rpL7a) by ethanol in human breast cancer cells

Epidemiological studies indicate that there is a positive correlation between alcohol consumption and the risk of breast cancer. Experimental results demonstrate that ethanol is a tumor promoter and chronic ethanol exposure enhances metastasis and growth of breast cancer. The present study used an in vitro model to investigate the molecular mechanism(s) underlying tumor promoting effects of ethanol. With differential display reverse transcription polymerase chain reaction, we demonstrated that human ribosomal large subunit protein L7a (rpL7a) was an ethanol-responsive factor in T47D breast cancer cells. The results of northern blot hybridization revealed that the effect of ethanol on L7a expression was duration- and concentration-dependent. Initial exposure resulted in a 2-fold increase in rpL7a level, whereas a longer exposure period produced a down-regulation. Ethanol had little effect on the stability of rpL7a mRNA; however, the transcription rate of rpL7a was significantly increased by ethanol. Ethanol-induced up-regulation of rpL7a was not a simple stress response, because other stress inducers, such as heat shock, did not affect the expression of rpL7a. Furthermore, breast cancer cells expressed higher level of rpL7a than normal mammary epithelial cells. Ribosomal proteins are known to play an important role in translational regulation, and they have been implicated in the control of cellular transformation, tumor growth, aggressiveness and metastasis. Specially, rpL7a activates the trk oncogene by contributing an amino-terminal-activating sequence to the receptor kinase domain of trk. Thus, ethanol-induced alteration of rpL7a expression may mediate the promoting effects of ethanol on breast cancer development.

Alcohol consumption and urinary concentration of 6-sulfatoxymelatonin in healthy women

Consumption of alcoholic beverages may suppress circulating melatonin levels at night, possibly resulting in an increase in circulating estrogen. An increased estrogen burden could increase the risk of breast cancer. This study was designed to investigate whether alcohol consumption is associated with a decrease in nighttime melatonin levels in a group of healthy women. A total of 203 randomly selected healthy women between the ages of 20 and 74 years were recruited for a broader study of the effects of exposure to power-frequency magnetic fields on nocturnal levels of urinary 6-sulfatoxymelatonin. For the purposes of this analysis, data collection consisted of the following during two seasons of the year: (1) an in-person interview, (2) a daily activity diary, and (3) nocturnal urine collection for each of 3 consecutive nights. We found that the nocturnal urinary concentration of the primary metabolite of melatonin (6-sulfatoxymelatonin) decreased in a dose-dependent manner with increasing consumption of alcoholic beverages in the preceding 24-hour period, after taking into account the independent effects on melatonin of age, hours of darkness, use of medications that affect melatonin levels, and body mass index. A categorical analysis revealed no effect of one drink, but a 9% reduction with two drinks, a 15% reduction with three drinks, and a 17% reduction with four or more drinks. It remains unknown whether such a change could affect estrogen levels or breast cancer risk.

Cancer risk among Swedish female alcoholics by age, birth cohort and severity of alcoholism

We have previously reported increased risk for cancer in 15508 alcoholic women registered in the Swedish Temperance Boards compared with individually matched controls. Age at first registration was found for 14818 of these women. The women were divided into early and late alcoholic onset groups. Age 45 was used as an approximation for reproductive senescence. For subjects < 45 years at first registration with the Temperance Board we found an increased relative risk (RR) of 1.8 (95% CI 1.5-2.0), whereas for the older age at onset group we found an RR of 1.5 (95% CI 1.3-1.7). Early onset was associated with higher risk of cancer at all sites studied and in all age cohorts. We used the number of Temperance Board registrations as an index of severity of alcoholism; this measure was not associated with risk for cancer.

Ethanol enhances erbB-mediated migration of human breast cancer cells in culture

Growth factor systems (ligands and their receptors) are targets of ethanol toxicity. Inasmuch as alcohol consumption may increase the risk and development of breast cancer, we hypothesize that ethanol enhances cell migration by up-regulating the activities of erbB receptors. Of the three tested breast cancer cell lines that exhibit low invasion capacity (BT-20, MCF-7, and T47D cells), erbB receptors were specifically affected by ethanol only in the T47D cells. Ethanol increased erbB2, erbB3, and erbB4 expression in T47D human breast cancer cells in a concentration-dependent manner. ErbB1 (epidermal growth factor receptor) was unaffected. Heregulin beta 1 (ligand for erbB3 and erbB4) induced a modest increase in the invasion potential of the T47D cells. Ethanol alone also promoted modest invasion by the T47D cells, however, ethanol dramatically increased their heregulin-mediated invasion. Knocking-out erbB2 with an anti-sense oligonucleotide eliminated heregulin beta 1-promoted migration and blocked ethanol-induced chemo-migration. Thus, these data suggest that alcohol may enhance metastasis by altering an erbB system, and pivotally, erbB2.

Tubal ligation and risk of breast cancer

Although it has been demonstrated in previous studies that tubal ligation can have widespread effects on ovarian function, including a decrease in the risk of subsequent ovarian cancer, few studies have evaluated effects on breast cancer risk. In a population-based case-control study of breast cancer among women 20-54 years of age conducted in three geographic areas, previous tubal ligations were reported by 25.3% of the 2173 cases and 25.8% of the 1990 controls. Initially it appeared that tubal ligations might impart a slight reduction in risk, particularly among women undergoing the procedure at young ages (<25 years). However, women were more likely to have had the procedure if they were black, less educated, young when they bore their first child, or multiparous. After accounting for these factors, tubal ligations were unrelated to breast cancer risk (relative risk (RR) = 1.09, 95% confidence interval (CI) 0.9-1.3), with no variation in risk by age at, interval since, or calendar year of the procedure. The relationship of tubal ligations to risk did not vary according to the presence of a number of other risk factors, including menopausal status or screening history. Furthermore, effects of tubal ligation were similar for all stages at breast cancer diagnosis. Further studies would be worthwhile given the biologic plausibility of an association. However, future investigations should include information on type of procedure performed (since this may relate to biologic effects) as well as other breast cancer risk factors.

Lifetime alcohol consumption and breast cancer: a case-control study in Finland

OBJECTIVE

To study the association between lifetime alcohol consumption and the risk of breast cancer.

DESIGN AND SETTING

A case-control study carried out in eastern Finland. Information about alcohol consumption was obtained by two methods: a self-administered food frequency questionnaire (FFQ) including alcohol consumption during the previous 12 months, and a lifetime alcohol consumption questionnaire (AQ) which was administered by the study nurse.

SUBJECTS

The study consisted of 301 breast cancer cases (25-75 years old) and 443 population controls.

RESULTS

The subjects reported higher current alcohol consumption in the AQ compared to the FFQ. According to the AQ, premenopausal cases consumed on average 28 g and controls 24 g alcohol week(-1); in postmenopausal women the values were 15 and 14 g, respectively. About 30% of premenopausal and 60% of postmenopausal women were classified as non-drinkers. The correlation for current alcohol consumption between the FFQ and the AQ was 0.80 in premenopausal women but only 0.40 in postmenopausal women. Current alcohol consumption seemed to influence the reporting of total lifetime alcohol consumption. Current alcohol consumption was not associated with the risk of breast cancer either in premenopausal or postmenopausal women; neither were associations found between alcohol consumption at age of first use, use before the age of 30, or total lifetime alcohol consumption and the risk of breast cancer.

CONCLUSIONS

On average, one to three drinks per week did not increase the risk of breast cancer in this study. Consumption levels were, however, too low to exclude increased risk with high regular consumption. Further research is necessary on lifetime alcohol consumption.

Potential gain in efficiency and power to detect gene-environment interactions by matching in case-control studies

BACKGROUND

There is growing interest in interactions between genetic and environmental risk factors of disease, but adequate power to detect such interactions in epidemiologic studies is of concern. The aim of this paper is to quantify the effect of matching on the efficiency of estimation and power to detect gene-environment interactions in case-control studies.

METHODS

Starting from an empirical example in cancer epidemiology, we simulated frequency matched and unmatched case-control studies for a wide range of assumptions regarding the prevalence and the effects of an environmental and a genetic factor on disease risk as well as the quality and quantity of the interaction between these factors. Simulated studies were analyzed with multivariable logistic regression.

RESULTS

Matching increased the efficiency and power in most scenarios. The gain was most pronounced in scenarios assuming a low prevalence of the environmental exposure. In such scenarios, equivalent power was only obtained with more than twice as many unmatched than matched controls.

CONCLUSIONS

Frequency matching for known environmental risk factors with a low prevalence in the population may increase the efficiency of estimation and power of case-control studies to detect gene-environment interactions considerably. Investigators should weigh the gain in efficiency and power against known potential disadvantages of matching.

Alcohol intake and late-stage promotion of breast cancer

Breast cancer risk in women rises with increasing alcohol intake and is widely assumed to be mediated by increased oestrogen concentrations. However, observations that mechanisms and risk are likely to differ between pre- and postmenopausal women suggest that the postmenopausal disease in particular, may involve a promoting role for concomitants of hyperinsulinaemia which is commonly associated with alcoholic cirrhosis of the liver. The MEDLINE database and ongoing studies were examined for clinical, epidemiological and laboratory data on; (a) alcohol-related increase in the incidence of breast cancer in relation to menopausal status, oestrogen concentrations and the oestrogen receptor (ER) status of the tumour; (b) activation of insulin-like growth factor 1 receptor (IGF1R) in mammary tissue by alcohol-related hyperinsulinaemia; (c) interaction between ER and IGF1R in breast cancer cell systems. Epidemiological association between alcohol intake and increased breast cancer risk is more clearly seen in postmenopausal than premenopausal women, and a significant risk is associated with intake of more than two drinks (over 30 g) daily over a period of years. Alcohol-related hyperinsulinaemia is reported to increase with increasing degrees of cirrhosis and damage to liver function. Laboratory evidence suggests that hyperinsulinaemia can stimulate expression of IGF1R in mammary tissue, and this protein is likely to have a crucial role in mitogenesis and transformation to an oestrogen-independent malignant phenotype. It is postulated that in women with a history of long-term intake of moderate quantities of alcohol, the concomitants of hyperinsulinaemia may help to stimulate progression in precancerous breast lesions in the years leading up to the menopause and may increase the risk of breast cancer manifesting after the menopause.

Moderate alcohol consumption: the gentle face of Janus

OBJECTIVES

The regular consumption of alcohol in moderate amounts (defined in North America as up to 2 drinks per day for men and 1 drink per day for females) has been recognized in the last decade as a negative risk factor for atherosclerosis and its clinical sequelae: coronary heart disease (CHD), ischemic stroke, and peripheral vascular disease. Mortality and morbidity attributable to CHD are 40-60% lower in moderate drinkers than among abstainers. Among the mechanisms accounting for these reductions, increased circulating concentrations of HDL-cholesterol and inhibition of blood coagulation appear to be paramount. Additional benefits are, in certain beverages, conferred by the presence of constituents other than alcohol (e.g., flavonoids and hydroxystilbenes), which prevent oxidative damage, free radical formation, and elements of the inflammatory response.

CONCLUSIONS

A number of other diseases appear to be beneficially modulated by moderate alcohol consumption based on epidemiologic surveys and, in some instances, experimental evidence. These include duodenal ulcer, gallstones, enteric infections, rheumatoid arthritis, osteoporosis, and diabetes mellitus (type II). Compared with abstainers, moderate drinkers exhibit improved mental status characterized by decreased stress and depression, lower absenteeism from work, and decreased incidence of dementia (including Alzheimer's disease). Although limits of safe drinking have been conservatively defined, it is regrettable that political considerations are hampering the clinical application of this knowledge and its dissemination to the lay public.

Predictors of breast cancer in women recalled following screening

BACKGROUND

Established risk factors are associated with between 25 and 56% of breast cancer cases, but the relative importance and relevance to different age groups is unclear.

METHODS

This case-control study examines established risk factors in 298 women with breast cancer and 1926 women without breast cancer aged 40-87 who were recalled for assessment following routine mammography.

RESULTS

The cancer group were significantly older than the non-cancer group (F1,222 = 107.6; P < 0.0001). Postmenopausal obesity increased the odds of developing breast cancer (OR: 2.35; CI: 1.33-4.16). The breast cancer group were more likely to have used oral contraceptives (OR: 1.50; CI: 1.09-2.05), and women who used contraceptives for more than 10 years in total were at the highest risk (OR: 1.73; CI: 1.13-2.65). Daily consumption of alcohol was also associated with increased risk of developing breast cancer (OR: 1.62; CI: 1.13-2.33). Reproductive factors and a family history of breast cancer did not affect the odds of developing breast cancer and the reasons for these findings are explored.

CONCLUSIONS

Results suggest that the effects of weight reduction in reducing postmenopausal breast cancer risk should be assessed.

Risk factors for breast cancer in women under 40 years

The relation between hormonal and lifestyle factors and breast cancer risk in women younger than 40 years was investigated using data from two case-control studies conducted in Italy between 1983 and 1994. Cases were 579 women with histologically confirmed, incident breast cancer and controls were 668 women admitted to hospital for acute, non-neoplastic, non-hormone-related diseases. Breast cancer risk was inversely related to age at menarche with a multivariate odds ratio (OR) of 0.53 (95% confidence interval, CI, 0.31-0.89) for women reporting menarche at the age of > or = 15 years compared with < 12 years. Breast cancer risk was significantly higher in parae than in nulliparae (OR 1.58), and was directly associated with age at first birth (OR 5.31 among women aged > or = 30 years at first birth compared with those aged < 20), and inversely with time since last birth (OR 3.80 for < 3 years compared with > or = 12). Compared with women reporting no abortion, the OR were 1.10 for any spontaneous, 0.87 for any induced and 0.90 for > or = 2 abortions. With reference to oral contraceptive use, the OR was 1.05 for ever users compared with never users, and no material association was evident with duration, time since first and last use. The OR was 1.79 for more than 13 years of education compared with < 9, 1.85 for a family history of breast cancer and 1.85 for a history of benign breast disease. Breast cancer risk was inversely related to body mass index with an OR of 0.51 (95% CI 0.26-0.97) for > or = 30 kg/m2 compared to < 20. Total energy and alcohol intake were directly related to the risk (OR 1.38 and 1.27 for the highest tertiles of intake compared with the lowest), although the estimates were not significant, whilst raw vegetable and beta-carotene consumption were inversely related to breast cancer risk (OR 0.57 and 0.67 for the highest tertile of intake compared with the lowest). Thus, most risk factors in this large dataset of women aged less than 40 years were similar to those described in breast cancer epidemiology at any age. Of interest are the inverse associations with body mass index, age at menarche and time since last birth, the direct ones with age at first and last birth, and the higher risk of parous women compared with nulliparae.

Dietary carotenoids and vitamins A, C, and E and risk of breast cancer

BACKGROUND

Data on intake of specific carotenoids and breast cancer risk are limited. Furthermore, studies of vitamins A, C, and E in relation to breast cancer risk are inconclusive. We have conducted a large, prospective study to evaluate long-term intakes of these nutrients and breast cancer risk.

METHODS

We examined, by use of multivariate analysis, associations between intakes of specific carotenoids, vitamins A, C, and E , consumption of fruits and vegetables, and breast cancer risk in a cohort of 83234 women (aged 33-60 years in 1980) who were participating in the Nurses' Health Study. Through 1994, we identified 2697 incident cases of invasive breast cancer (784 premenopausal and 1913 postmenopausal).

RESULTS

Intakes of beta-carotene from food and supplements, lutein/zeaxanthin, and vitamin A from foods were weakly inversely associated with breast cancer risk in premenopausal women. Strong inverse associations were found for increasing quintiles of alpha-carotene, beta-carotene, lutein/zeaxanthin, total vitamin C from foods, and total vitamin A among premenopausal women with a positive family history of breast cancer. An inverse association was also found for increasing quintiles of beta-carotene among premenopausal women who consumed 15 g or more of alcohol per day. Premenopausal women who consumed five or more servings per day of fruits and vegetables had modestly lower risk of breast cancer than those who had less than two servings per day (relative risk [RR] = 0.77; 95% confidence interval [CI] = 0.58-1.02); this association was stronger among premenopausal women who had a positive family history of breast cancer (RR = 0.29; 95% CI = 0.13-0.62) or those who consumed 15 g or more of alcohol per day (RR = 0.53; 95% CI = 0.27-1.04).

CONCLUSIONS

Consumption of fruits and vegetables high in specific carotenoids and vitamins may reduce premenopausal breast cancer risk.

Alcohol-induced breast cancer: a proposed mechanism

Alcohol consumption increases the risk for breast cancer in women by still undefined means. Alcohol metabolism is known to produce reactive oxygen species (ROS), and breast cancer is associated with high levels of hydroxyl radical (*OH) modified DNA, point mutations, single strand nicks, and chromosome rearrangement. Furthermore, ROS modification of DNA can produce the mutations and DNA damage found in breast cancer. Alcohol dehydrogenase (ADH) and xanthine oxidoreductase (XOR) are expressed and regulated in breast tissues and aldehyde oxidase (AOX) may be present as well. Mammary gland XOR is an efficient source of ROS. Recently, hepatic XOR and AOX were found to generate ROS in two ways from alcohol metabolism: by acetaldehyde consumption and by the intrinsic NADH oxidase activity of both XOR and AOX. The data obtained suggests that: (1) expression of ADH and XOR or AOX in breast tissue provides the enzymes that generate ROS; (2) metabolism of alcohol produces acetaldehyde and NADH that can both be substrates for XOR or AOX and thereby result in ROS formation; and (3) ROS generated by XOR or AOX can induce the carcinogenic mutations and DNA damage found in breast cancer. Accumulation of iron coupled with diminished antioxidant defenses in breast tissue with advancing age provide additional support for this hypothesis because both result in elevated ROS damage that may exacerbate the risk for ROS-induced breast cancer.

Alcohol consumption and risk of breast cancer: a multicentre Italian case-control study

The relationship between alcohol consumption and breast cancer risk was investigated using data from a co-operative case-control study conducted in Italy between 1991 and 1994 on 2569 incident, histologically confirmed breast cancer cases and 2588 controls in hospital for acute, non-neoplastic, non-hormone related conditions. Overall, 915 (38%) cases and 1048 (43%) controls were abstainers. Compared with them, the odds ratio (OR), adjusted only for age, was 1.31 (95% confidence interval (CI) 1.13-1.53) for drinkers and became 1.39 (95% CI 1.(1)21-1.60) after correction for measurement error. The multivariate OR was 1.21 for drinkers of < or = 5.87 g/day and 1.23, 1.19, 1.21, 1.41 for drinkers of 5.88-13.40, 13.41-24.55, 24.56-27.60, > 27.60 g/day, respectively. The trend in risk was significant (chi 2 = 12.28, P < 0.0005). The association was apparently stronger in premenopausal women (OR = 1.80 for > 27.60 g/day). Considering the different types of alcoholic beverages (wine, beer, digestives, grappa and other spirits), a significant direct trend in breast cancer risk was seen for wine with an OR of 1.27 (95% CI 1.06-1.53) for the category > 26.34 g/day. The ORs were also above unity for beer, grappa, digestives and spirits drinkers. No appreciable interaction was observed between alcohol drinking and body mass index, smoking, or any other covariate considered. Thus, the present data, based on a validated alcohol consumption questionnaire and on a population characterised by a relatively high alcohol consumption in women, confirmed that alcohol drinking is moderately related to breast cancer risk. If causal, this association could explain 12% (95% CI, 5-19%) of breast cancers in Italy, thus representing one of the major avoidable risk factor for breast cancer.

Diet during adolescence and risk of breast cancer among young women

BACKGROUND

A variety of breast cancer risk factors pertain to a woman's adolescence and may be related to nutritional influences. We assessed risk of early-onset breast cancer related to diet during adolescence in a case-control study.

METHODS

Study participants were accrued from the following three geographical regions covered by cancer registries: Atlanta, GA; Seattle/Puget Sound, WA; and central New Jersey. Case patients (n = 1647) were newly diagnosed with breast cancer, and control subjects (n = 1501) were identified by random-digit-dialing techniques. In an interview, each subject was asked to recall the frequency of consumption and portion size of 29 key food items at ages 12-13 years. Mothers of a subset of respondents completed questionnaires, and food groups were recalculated after removal of foods with poor agreement between mother and daughter. Logistic regression analyses were used to calculate odds ratios and 95% confidence intervals.

RESULTS

When high versus low quartiles of consumption were compared, there was a suggestion of a reduced risk associated with high consumption of fruits and vegetables, although this finding was not statistically significant. Slight increases (of borderline statistical significance) in risk of breast cancer were found for intake of chicken or high-fat meat. Intake of animal fat, high-fat foods, high-fat snacks and desserts, or dairy products during adolescence had no apparent influence on breast cancer risk. Removal of foods suspected to be poorly recalled by the daughters did not change any of the risk estimates.

CONCLUSION

These data do not provide evidence for a strong influence of dietary intakes during adolescence on risk of early-onset breast cancer.

Within- and between-person variations in portion sizes of foods consumed by the Japanese population

There has been considerable controversy about the utility of asking separate questions on portion sizes in addition to items on consumption frequencies in food frequency questionnaires. One argument against this type of inquiry is that, for most foods, within-person variation of portion size is greater than between-person variation, making it difficult to characterize "usual" or long-term average serving sizes. The authors studied the relative effects of within- and between-person variances in portion sizes of 69 food items using three-day food record data collected from 335 Japanese men and women. Total variance in the portion size for each food was partitioned into within- and between-person components by analysis of variance. Although the ratios of within- to between-person variances in log(e)-transformed portion sizes were > 1.0 for the majority of foods (50 of 69 items, median = 1.7), they were smaller than or close to unity for subgroups of foods that were the major sources of nutrient variables of relevance to diet-cancer associations, such as total energy (rice, calcium (milk), sodium (pickled vegetables), and alcohol (beer, shochu, whiskey). These results indicate that the relative contributions of within- and between-person variations in portion size may vary among foods, and therefore investigators should consider the balance between the advantages and disadvantages of obtaining portion size data separately from intake frequencies when designing food frequency questionnaires.