The current Danish prospective study was designed to examine the impact of smoking, body mass index (BMI), alcohol consumption, hormone replacement therapy (HRT), and physical activity on survival after breast cancer diagnosis. The study included 528 women diagnosed with primary breast cancer and enrolled in the Copenhagen City Heart Study. Self-reported information was collected a total of four times during the periods 1976 to 1978, 1981 to 1983, 1991 to 1994, and 2001 to 2003. Kaplan-Meier survival curves and multivariate Cox regression analyses were performed while adjusting for age, tumor stage, adjuvant treatment, menopausal status, number of children, alcohol intake, smoking, BMI, physical activity, and use of HRT. For purposes of the study, overall or total mortality referred to death from all causes, and included non-breast cancer specific mortality. Smoking was found to be associated with total mortality (hazard ratio (HR) = 1.16, 95% confidence interval (CI) = 1.05-1.29) after breast cancer diagnosis. Obesity was associated with both with increased total mortality (HR = 1.61, 95% CI = 1.12-2.33) and breast cancer-specific mortality (HR = 1.82, 95% CI = 1.11-2.99). Moderate levels of alcohol consumption of 1 to 6 units per week (HR = 0.85, 95% CI = 0.64-1.12) or 7 to 14 units per week (HR = 0.77, 95% CI = 0.56-1.08) were not significantly associated with survival, nor was using HRT (HR = 0.79, 95% CI = 0.59-1.05). Neither moderate physical activity of two to four hours per week (HR = 1.07, 95% CI = 0.77-1.49) nor a higher level of physical activity of more than four hours per week (HR = 1.00, 95% CI = 0.69-1.45) were associated with increased survival after breast cancer diagnosis.

The current prospective study was designed to evaluate how alcohol-related risk varies by breast cancer subtype among postmenopausal women. The consumption of alcohol is a well-established risk factor for breast cancer. The influence of alcohol on risk of breast cancer is thought to be primarily hormonally driven, implying that alcohol intake may be more strongly associated with hormonally-sensitive types of breast cancer. The study included 87,724 participants in the Women's Health Initiative Observational Study prospective cohort from 1993 to 1998 who reported their own alcohol consumption. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using multivariable adjusted Cox regression models. All statistical tests were two-sided. A total of 2,944 invasive breast cancers were diagnosed in the study group during the follow-up period, which lasted until September 15, 2005. Alcohol consumption was found to be associated with increased risk of invasive breast cancer overall, as well as invasive lobular carcinoma and hormone receptor-positive tumors when examined by subtype. Alcohol intake was also found to be more strongly related to risk of certain breast cancer types than others. Compared with those who reported no use of alcohol, women who consumed seven or more alcoholic beverages per week had almost two times the risk of hormone receptor-positive (ER+/PR+) invasive lobular carcinoma (HR = 1.82, 95% CI = 1.18-2.81). The women who had seven or more drinks per week also had a slightly increased risk of invasive ductal carcinoma, but this association was not statistically significant (HR = 1.14, 95% CI = 0.87-1.50). The absolute rate of hormone receptor-positive lobular cancer among never drinkers was 5.2 per 10,000 person-years compared to 8.5 for current drinkers. On the other hand, for hormone receptor-positive ductal breast cancer, the rates were 15.2 and 17.9 per 10,000 person-years, respectively. The authors conclude that alcohol use may be more strongly associated with the risk of hormone-sensitive breast cancers than hormone-insensitive subtypes, suggesting distinct etiologic pathways for these two breast cancer subtypes.

The present prospective study was designed to examine the association between alcohol consumption and risk of ductal carcinoma in situ (DCIS) in postmenopausal women. Previous population studies have reported an association between higher alcohol consumption and a modest increase in risk of invasive breast cancer, studies have not examined the association with risk of DCIS. The association between adulthood alcohol consumption (assessed at baseline) and subsequent risk of DCIS was examined in a cohort of 63,822 postmenopausal women participating in the Women's Health Initiative clinical trials. Alcohol consumption was assessed by a semiquantitative food-frequency questionnaire. Mammography was protocol-mandated in the trials. DCIS cases were verified using central pathology report review. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). A total of 489 cases of DCIS were diagnosed in the study group after a median follow-up of 8.0 years. In the primary analysis, invasive breast cancer was treated as a competing risk, and follow-up time was censored at the date that any invasive breast cancer was diagnosed. After adjustment for covariates, the risk of DCIS among women who consumed 14 or more servings of alcohol per week was slightly lower that that of nondrinkers, but this result was not statistically significant (HR = 0.87, 95% CI = 0.50-1.51). Alcohol consumption also was not found to be associated with risk by DCIS grade (high-grade or low-/moderate-grade). The authors conclude that alcohol consumption was not associated with risk of DCIS in this large cohort of postmenopausal women. If the findings are confirmed by other studies, this would suggest that alcohol may have an effect later in the carcinogenic process.

The current prospective study was designed to investigate the association between alcohol consumption after a diagnosis of early-stage breast cancer and breast cancer recurrence and mortality. The study included 1,897 women primarily from the Kaiser Permanente Northern California Cancer Registry who had been diagnosed with early-stage breast cancer between 1997 and 2000. Participants were recruited two years after diagnosis, on average. Alcohol consumption (wine, beer, and liquor) was assessed upon enrollment in the study using a food frequency questionnaire. Hazard ratios (HR) and 95% confidence intervals (CIs) with adjustment for known prognostic factors were calculated using Cox proportional hazards models. A total of 293 breast cancer recurrences and 273 deaths from all causes occurred during an average follow-up period of 7.4 years. Nine hundred and fifty-eight of the women (51%) were considered to be alcohol drinkers (> 0.5 g/day of alcohol); the majority drank wine (89%). Compared with abstinence from alcohol, drinking at least 6 g/day of alcohol was found to be associated with an increased risk of breast cancer recurrence (HR = 1.35, 95% CI = 1.00-1.83) and death due to breast cancer (HR = 1.51, 95% CI = 1.00-2.29). The increased risk of recurrence was higher among postmenopausal (HR = 1.51, 95% CI = 1.05-2.19) and overweight and obese women (HR = 1.60, 95% CI = 1.08-2.38). Alcohol intake was not associated with all-cause death. In fact, there appeared to be a decreased risk of death from causes other than breast cancer. The authors conclude that consuming three to four alcoholic drinks or more per week after a breast cancer diagnosis may increase risk of breast cancer recurrence, particularly among postmenopausal and overweight/obese women. However, the data also suggests a cardioprotective effect of moderate alcohol consumption based on a reduction in non-breast cancer deaths.

The present nested case-control study was designed to investigate the associations between obesity, consumption of alcohol, and cigarette smoking on risk of second primary invasive contralateral breast cancer (i.e., new breast cancer in the other breast). Evidence concerning lifestyle factors that could influence the development of a second primary breast cancer among breast cancer survivors is limited. The study included 365 patients initially diagnosed with estrogen receptor positive (ER+) invasive breast cancer who were subsequently diagnosed with new primary contralateral invasive breast cancer, as well as 726 matched controls diagnosed with ER+ invasive breast cancer (but no subsequent contralateral breast tumors). Medical records and personal interviews were used to gather information concerning obesity at diagnosis, alcohol use, and smoking. Conditional logistic regression was used to calculate the associations between these three factors and risk of second primary contralateral breast cancer. Obesity, consumption of at least seven alcoholic beverages per week, and current cigarette smoking all were found to be associated with increased risk of contralateral breast cancer (odds ratio (OR) = 1.4; 95% confidence interval (CI) = 1.0 - 2.1 for obesity versus body mass index lower than 25 kg/m2; OR = 1.9; 95% CI = 1.1 - 3.2 for more than seven alcoholic drinks per week; and OR = 2.2; 95% CI = 1.2 - 4.0 for smoking). The combination of moderate to high alcohol consumption and current smoking appeared to act synergistically to heighten risk. Study participants who consumed seven drinks per week and were current smokers had 7.2 times the risk (95% CI = 1.9 - 26.5) of contralateral breast cancer of participants who consumed fewer than seven servings of alcoholic per week and had never smoked or were former smokers. The authors conclude that the results suggest that obesity, smoking, and alcohol consumption increase contralateral breast cancer risk, implying that breast cancer survivors can decrease this risk by reducing or avoiding these risk factors.

The present study was designed to examine the association between alcohol consumption and breast cancer in postmenopausal women by breast cancer type. The study group included 184,418 postmenopausal women 50 to 71 years old in the National Institutes of Health-AARP Diet and Health Study (1995–2003). A mailed questionnaire was used at baseline to assess alcohol use, diet, and potential risk factors for cancer. Relative risks and 95% confidence intervals were calculated by using Cox proportional hazards regression. State cancer registries were used to identify breast cancer cases and estrogen receptor and progesterone receptor status. During a mean seven year follow-up period, 5,461 breast cancer cases were identified. Alcohol consumption was found to be significantly positively associated with risk of breast cancer: Even a moderate amount of alcohol (greater than 10 g/day) was shown to significantly increase risk of breast cancer. In a comparison of greater than 35 g per day versus no alcohol intake, the multivariate relative risks were found to be 1.35 (95% confidence interval (CI): 1.17-1.56) for total breast cancer, 1.46 (95% CI: 1.22-1.75) for ductal breast cancer, and 1.52 (95% CI: 0.95-2.44) for lobular tumors. The multivariate relative risk for estrogen receptor-positive/progesterone receptor-positive (ER+/PR+) tumors was 1.46 (95% CI: 1.12-1.91) for greater than 35 g per day versus no alcohol intake. The estrogen receptor-positive/progesterone receptor-negative (ER+/PR-) multivariate relative risk was 1.13 (95% CI: 0.73-1.77) for greater than 20 g versus no alcohol intake. The estrogen receptor-negative/progesterone receptor-negative (ER-/PR-) multivariate relative risk was 1.21 (95% CI: 0.79-1.84) for greater than or equal to 20 g versus no alcohol intake. The authors conclude that moderate consumption of alcohol is associated with breast cancer, especially hormone receptor-positive tumors.

Researchers interviewed 6,327 women aged 20 to 69 from Wisconsin, Massachusetts and New Hampshire who had breast cancer and 7,558 age-matched controls who did not. A questionnaire was used to determine how often the women drank alcohol (red wine, white wine, spirits/liquor, and beer) and other factors relevant to breast cancer risk, such as age of first pregnancy, family history of breast cancer, and use of hormone replacement therapy. The breast cancer group and control group were matched for the frequency and amount of alcohol consumed and the proportion of women consuming red and white wine. Women who consumed 14 or more drinks per week, regardless of type (red wine, white wine, liquor or beer) were 24% more likely to have breast cancer compared with women who did not drink any alcohol. The authors conclude that neither red nor white wine appear to have any benefits with respect to breast cancer risk and that red and white wine increase breast cancer risk equally.

The current population study was designed to investigate the relationship between level of alcohol consumption and the risk of breast cancer. The study cohort included 70,033 women, of whom 2,829 developed invasive breast cancer. The study found the following relative risks (95% confidence intervals (CI)) for breast cancer for those who consumed alcohol versus lifelong abstainers: (1) fewer than one drink per day: 1.08 (CI: 0.95-1.22); (2) one to two drinks per day: 1.21 (CI: 1.05-1.40); (3) more than three drinks per day: 1.38 (CI: 1.13-1.68). The increased breast cancer risk was concentrated in women with estrogen receptor positive tumors and there were no major differences in risk associated with the choice of wine, liquor, beer or type of wine (red, white, other). The authors conclude that with a threshold below one to two drinks daily, a hormone-related mechanism mediates a relation of alcohol drinking to an increased risk of breast cancer.

1,280,296 middle-aged women living in the United Kingdom were routinely followed for cancer. During the follow-up period (averaging 7.2 years), 68,775 new invasive cancers occurred. Alcohol consumption was associated with increased risk of cancer in a dose-dependent manner for cancers of the breast, oral cavity and pharynx, rectum, esophagus, and liver. The trends were similar for women who drank wine exclusively compared to consumers of other alcohol. For cancers of the upper digestive tract, the alcohol-associated risk was confined to current smokers. Increasing levels of alcohol consumption were associated with a decreased risk of thyroid cancer, non–Hodgkin lymphoma and renal cell carcinoma. The authors conclude that low to moderate alcohol consumption in women increases the risk of some cancers. In particular, for each additional drink regularly consumed per day, the increase in incidence (up to age 75) per 1000 women is estimated to be about 11 for breast cancer, 1 for cancers of the oral cavity and pharynx, 1 for cancer of the rectum, and 0.7 each for cancers of the esophagus, larynx and liver.

Women who are diagnosed with breast cancer in one breast are at increased risk of subsequently developing a second primary breast cancer in the opposite breast. The current study examined the impact of alcohol consumption and smoking on asynchronous contralateral breast cancer in the Womens Environmental Cancer and Radiation Epidemiology Study (1985-2001). The women studied, who were under 55 years of age upon first breast cancer diagnosis, were identified from five population-based cancer registries in the U.S. and Denmark. 708 women with asynchronous contralateral breast cancer (the cases) were selected and compared to 1,399 women with breast cancer in one breast (the controls). Cases and controls were matched with respect to birth year, diagnosis year, registry region, race and whether they had received radiation treatment. Information concerning breast cancer risk factors was collected by means of telephone interview. Ever regular drinking was found to be associated with an increased risk of asynchronous contralateral breast cancer (rate ratio = 1.3, 95% confidence interval: 1.0-1.6) and the risk was found to increase over time. Smoking was found not to be related to subsequent contralateral breast cancer.

The current study was designed to determine the associations between alcohol consumption and 11 hormones and peptides in postmenopausal breast cancer survivors and to evaluate whether these relationships were different for those who take tamoxifen. A food questionnaire was used to assess alcohol intake 30 months after breast cancer diagnosis in 490 postmenopausal women from three western U.S. states. In addition, a fasting blood sample was analyzed to determined circulating levels of estrone, estradiol, free estradiol, C-peptide, testosterone, free testosterone, dehydroepiandrosterone sulfate (DHEAS), leptin, sex hormone-binding globulin, insulin-like growth factor-I (IGF-I), and IGF-binding protein-3. The associations between alcohol intake and serum hormone and peptide levels were found to differ by tamoxifen use; there were statistically significant inverse associations between alcohol intake and both leptin and sex hormone-binding globulin values, but only among tamoxifen users. In women who were not using tamoxifen (but not those on tamoxifen), the study found a positive association between alcohol intake and DHEAS. The associations found for DHEAS and sex hormone-binding globulin values are in a direction considered unfavorable for breast cancer prognosis. The authors conclude that tamoxifen may modify the associations between alcohol intake and serum hormones and peptides in a manner that increases risk for postmenopausal breast cancer survivors.

The current study was designed to determine whether early, lifetime or recent alcohol consumption was associated with breast cancer risk, and whether the risk varied by type of drink. The study included 1,728 newly-diagnosed breast cancer patients and 435 controls 20 to 49 years of age. Intake of alcoholic during the 5-year period before breast cancer diagnosis was found to be associated with increased risk of breast cancer. Consuming at least two alcoholic drinks per day during this 5-year period was associated with an 82% increase in breast cancer risk compared to those who had never been drinkers (OR = 1.82, 95% CI = 1.01–3.28). No increase in risk was found for alcohol intake at ages 15 to 20 years or for lifetime alcohol intake. Risk also did not vary by type of alcoholic drink consumed. The authors conclude that recent alcohol consumption may be associated with increased breast cancer risk in young women.

The current study was designed to determine whether the risk of breast cancer associated with hormone replacement therapy use is increased by alcohol consumption. Both alcohol and postmenopausal hormone use are well-established risk factors for breast cancer. The study included 5,035 postmenopausal women in the Copenhagen City Heart Study. The women were questioned regarding their alcohol intake and hormone use at baseline during 1981 to 1983. They were followed until 2002 in the Danish cancer registry, with lower than one percent loss to follow-up. During the follow-up period, 267 women developed invasive breast cancer. Alcohol consumption was found to be associated with a small increase in risk of breast cancer (hazard ratio = 1.11 per drink/day, 95% CI: 0.99-1.25). Women who used hormone replacement also were found to have an enhanced risk of breast cancer (HR = 2.00, 95% CI: 1.52-2.61) compared to those who did not use hormones. The study found a strong interaction between these two factors - those who consumed more than two drinks per day and also took hormones had a risk of 4.74 (95% CI: 2.61-8.59) for breast cancer compared to those who neither drank nor took hormones. Alcohol was not found to be associated with breast cancer among women who did not use hormones (HR = 0.98 per drink/day, 95% CI: 0.82-1.78).

The current case-control study was designed to examine the relationship between alcohol consumption and the risk of the most hormonally-responsive breast cancer types (i.e., lobular or hormone receptor positive breast cancers). The study included 975 women 65 to 79 years of age diagnosed with invasive breast cancer during 1997–1999 in Washington State, as well as 1,007 controls. Ever-use of alcohol over the past 20 years was found to be associated with a 1.3-fold [95% confidence interval (CI), 1.0–1.5] increased risk of breast cancer, although this increase was mostly accounted for by women who drank at least 30.0 g per day of alcohol [OR, 1.7; CI: 1.1–2.6]. Ever-use of alcohol also was found to be associated with a 1.8-fold (CI: 1.3–2.5) increased risk of lobular cancer compared to a 1.2-fold (CI: 0.9–1.4) increased risk of ductal cancer. Ever-users of alcohol had an increase in risk of ER+/PR+ tumors (OR, 1.3; CI: 1.1–1.7), but no impact was observed for their risks of ER-/PR- or ER+/PR- breast cancer. The authors conclude that alcohol use appears to be more strongly associated with lobular and hormone receptor-positive cancers than it is with other types of breast cancer.