Medical radiation,family history of cancer,and benign breast disease in relation to breast cancer risk in young women,USA

OBJECTIVE: In previous studies breast cancer risk has been increased among women who received high doses (above 100–200 cGy) of ionizing radiation or those exposed to lower doses prior to age 20. Some evidence suggests that such risk may be distinctly elevated among women with a family history of breast or ovarian cancer (probably only carriers of specific gene mutations) and women with benign breast disease (BBD).METHODS: A population-based case–control study in Los Angeles County obtained interview data from 744 women who were aged 40 or younger and diagnosed with breast cancer during 1983–1988, and from 744 matched controls. Women with a positive family history of breast or ovarian cancer reported cancer in a mother, sister, or grandmother. Women with BBD reported a physician diagnosis. Radiation exposure was defined as a history of either radiation therapy or moderate exposure to medical radiography.RESULTS: Breast cancer risk was elevated among women exposed to medical radiation prior to age 20 years (odds ratio (OR) = 1.4, 95% confidence interval (CI) = 1.2–1.8), relative to unexposed women. This increased risk was observed only among women with a history of BBD (OR = 2.4, 95% CI = 1.6–3.7). Overall, risk was not associated with exposure to medical radiation after age 20 years, although among women with a positive family history of breast or ovarian cancer, exposed women had an increased risk (OR = 1.8, 95% CI = 1.0–3.1). Breast cancer risk was not increased among women with a family history of breast/ovarian cancer exposed to medical radiation before age 20 years or those with BBD exposed to medical radiation after age 20 years.DISCUSSION: Study participants may have received radiation doses that are no longer common, hampering study generalizability. Although differences in recall between cases and controls cannot be completely excluded, women with BBD or a family history of breast cancer appear to have greater breast cancer risk following relatively low ionizing radiation exposure than other women in this study.     

Family history and risk of breast cancer in hispanic and non-hispanic women: the New Mexico Women's Health Study

Objectives: Many epidemiologic studies have demonstrated that an increased risk of breast cancer is associated with positive family history of this disease. Little information had been available on the relationship of breast cancer risk with family history in Hispanic women. To investigate the association of family history of breast cancer on the risk of breast cancer, we examined the data from the New Mexico Women's Health Study (NMWHS), a statewide case–control study. Methods: In this study 712 women (332 Hispanics and 380 non-Hispanic whites) with breast cancer and 844 controls (388 Hispanics and 456 non-Hispanic whites) were included. Conditional logistic regression was used to estimate the odds ratio (OR) and 95% confidence interval (95% CI), adjusted for sociodemographic, medical, and reproductive factors. Results: We found an increased risk in women with a history of breast cancer in one or more first-degree or second-degree relatives (OR = 1.5, 95% CI 1.2–1.9), first-degree relatives (OR = 1.3, 95% CI 1.0–1.8) and second-degree relatives (OR = 1.6, 95% CI 1.2–2.2). Hispanic women had higher risk estimates for a positive family history (OR = 1.7, 95% CI 1.1–2.5) than non-Hispanic white women (OR = 1.4, 95% CI 1.0–2.0); however, the differences were not statistically significant. In both ethnic groups a higher risk was observed in premenopausal women compared with postmenopausal women and women diagnosed with breast cancer before age 50years compared with older women. Conclusions: The results indicate that Hispanic women with a family history of breast cancer are at increased risk of breast cancer.     

Effect of pregnancy as a risk factor for breast cancer in BRCA1/BRCA2 mutation carriers

Early age at first birth and multiparity have been associated with a decrease in the risk of breast cancer in women in the general population. We examined whether this relationship is also present in women at high risk of breast cancer due to the presence of a mutation in either of the 2 breast cancer susceptibility genes, BRCA1 or BRCA2. We performed a matched case-control study of 1,260 pairs of women with known BRCA1 or BRCA2 mutations, recruited from North America, Europe and Israel. Women who had been diagnosed with breast cancer were matched with unaffected control subjects for year of birth, country of residence, and mutation (BRCA1 or BRCA2). Study subjects completed a questionnaire detailing their reproductive histories. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived by conditional logistic regression. Among BRCA1 carriers, parity per se was not associated with the risk of breast cancer (OR for parous vs. nulliparous = 0.94; 95% CI = 0.75-1.19; p = 0.62). However, women with a BRCA1 mutation and 4 or more children had a 38% decrease in breast cancer risk compared to nulliparous women (OR = 0.62; 95% CI = 0.41-0.94). In contrast, among BRCA2 carriers, increasing parity was associated with an increased risk of breast cancer; women with 2 or more children were at approximately 1.5 times the risk of breast cancer as nulliparous women (OR = 1.53; 95% CI = 1.01-2.32; p = 0.05). Among women with BRCA2 mutations and who were younger than age 50, the (adjusted) risk of breast cancer increased by 17% with each additional birth (OR = 1.17; 95% CI = 1.01-1.36; p = 0.03). There was no significant increase in the risk of breast cancer among BRCA2 carriers older than 50 (OR for each additional birth = 0.97; 95% CI = 0.58-1.53; p = 0.92). In the 2-year period following a birth, the risk of breast cancer in a BRCA2 carrier was increased by 70% compared to nulliparous controls (OR = 1.70; 95% CI = 0.97-3.0). There was a much smaller increase in breast cancer risk among BRCA2 carriers whose last birth was 5 or more years in the past (OR = 1.24; 95% CI = 0.79-1.95). A modest reduction in risk of breast cancer was observed among BRCA1 carriers with 4 or more births. Among BRCA2 carriers, increasing parity was associated with a significant increase in the risk of breast cancer before age 50 and this increase was greatest in the 2-year period following a pregnancy.     

Analysis of menstrual, reproductive, and life-style factors for breast cancer risk in Turkish women

The aim of this study was to investigate the association between menstrual, reproductive, and life-style factors and breast cancer in Turkish women. In a hospital-based case-control study in Ankara, 622 patients with histologically confirmed breast cancer were compared with 622 age-matched controls, admitted to the same hospital for acute and non-neoplastic diseases. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CI) related to risk factors. Overall, menopausal status and age at menopause were found to be significantly associated with breast cancer. Having a full-term pregnancy and early age at first birth were associated with decreased breast cancer risk (OR=0.45, 95% CI=0.30–0.66; OR=0.34, 95% CI=0.22–0.53, respectively). Postmenopausal women with lactation longer than 48 mo had reduced risk of breast cancer (OR=0.36, 95% CI=0.14–0.93). In conclusion, decreased parity, late age at first birth, early menopause, and shorter duration of lactation were the most important determinants of breast cancer risk in Turkish women.     

克拉玛依市区女性乳腺癌危险因素的病例对照研究

 目的　探讨克拉玛依市区女性乳腺癌的危险因素。方法　用病例对照研究方法调查129例女性乳腺癌和对应的129名对照者,用Logistic回归模型进行乳腺癌危险因素分析。结果　乳腺癌的危险因素有乳腺癌家族史（OR＝2.744,95 % CI＝1.884～4.674）、乳腺增生症（OR＝1.423,95 % CI＝1.160～1.810）、 乳腺炎（OR＝2.363,95 % CI＝2.039～3.934）、子宫肌瘤（OR＝1.623,95 % CI＝1.263～2.024）、 流产（OR＝1.723,95 % CI＝1.143～2.600）、 饮酒（OR＝1.243,95 % CI＝1.040～1.483）、精神创伤（OR＝2.184,95 % CI＝1.753～3.025）、长期接触电离辐射（OR＝1.374,95 % CI＝1.152～1.699）; 保护因素有初潮年龄增大（OR＝0.773,95 % CI＝0.674～0.956）、累计哺乳时间（OR＝0.672,95 % CI＝0.480～0.941）、坚持运动（OR＝0.572,95 % CI＝0.391～0.837）。结论　以上11个因素为克拉玛依市区女性乳腺癌重要的危险因素和保护因素。     

Method of Cooking and Risk of Breast Cancer in the Philippines

Objective Among Asian countries, the highest age-standardized rates of breast cancer have been reported for the Philippines. The influence of diet and lifestyle factors as possible contributors to these high rates has not been well-studied. We conducted a case-control study in Manila to examine the association between methods of cooking and the risk of breast cancer. Methods Eligible subjects were women undergoing evaluation at the Philippine General Hospital (PGH), Manila for a breast problem. All of the women completed a risk factor questionnaire prior to the determination of their case (n = 240) or control (n = 240) status. Information regarding current, as well as usual method of cooking in the household at 12 years of age was obtained. Results Boiling food in coconut milk was associated with a significantly increased risk of breast cancer (odds ratio (OR) = 2.2; 95% confidence interval (CI) 1.3–3.8). There were positive associations between boiling food in coconut milk and the risk of breast cancer currently (OR = 1.9; 95% CI 1.0–3.3), and at 12 years of age (OR = 2.9; 95% CI 1.6–5.5). A positive association between frying food and breast cancer risk was restricted to women whose household fried food at 12 years of age (OR = 1.89; 95% CI 1.1–3.4). Conclusions The results of this study suggest that various cooking methods during adolescence and possibly in adulthood may be associated with an increased risk of breast cancer. These findings require confirmation.     

Menstrual risk factors and early-onset breast cancer

Objectives: Epidemiologic studies provide evidence for increased breast cancer risk among women with prolonged exposure to endogenous estrogens and progesterone. Menstrual cycle characteristics, such as early menarche, rapid initiation of regular ovulatory cycles, short cycle length, and more days of flow, all potentially contribute to higher cumulative ovarian hormone exposure. Methods: We assessed the associations between these characteristics and breast cancer risk in a population-based, case–control study of 1505 controls and 1647 newly diagnosed cases, all younger than 45 years of age. Results: Compared to women with menarche at 15 years, we observed some increase in risk for women with younger ages at menarche, although those with very early ages were not at particularly high risk [odds ratio (OR) = 1.5, 95% confidence interval (CI) = 1.1–1.9 for menarche at age 12 and OR = 1.2, 95% CI = 0.9–1.7 for menarche at age 10]. Women who reported having regular menstrual cycles within 2 years of menarche were at increased breast cancer risk (OR = 1.7, 95% CI = 1.2–2.3), compared to those never having regular cycles. Stratification by current body mass index revealed slightly stronger associations with menstrual characteristics among thinner women ( < 22.0 kg/m²) compared to heavier women ( > 28.8 kg/m²). Conclusions: These findings suggest that future studies should focus on clarifying how the interrelated effects of body size and menstrual factors, such as age at menarche and cycle regularity, contribute to breast cancer etiology.     

The Investigation of Risk Factors Impacting Breast Cancer in Guilan Province

Introduction: Breast cancer is multifactorial therefore more recognition of risk factors is important in its prevention. Objective: This study was conducted in order to determine the factors influencing breast cancer in women referred to health centers in Guilan province in 2015-2016. Method: In a case- control study, 225 women with breast cancer were investigated. The control group consisted of 225 healthy women of the relatives (third-rank) whose phone numbers were obtained from the patients. Data were collected through telephone interviews. Results: The risk of breast cancer raised in women who have a family history of other cancers (OR= 3.5; 95% CI= 1.96-6.6) ,exposure to X-Ray (OR= 2.5; 95% CI=1.1-5.5), having more than 4 children (OR= 2.695% CI=1.2-4.8), age more than 36 years at first pregnancy(OR=2.3; 95% CI=0.7-5.1),primary levelof education (OR= 5.4;95% CI=2.8-11.2) and inadequate intake of fruit (OR=1.5; 95% CI=1-2.2). Also, presence of the following factors reduced breast cancer risk: regular menstruation (OR= 0.66; CI=0.4- 0.9), duration of breastfeeding more than 12 months, less than 6 months and 7-12 months (OR=0.23; 95% CI=0.09-0.59 , OR=0.29; 95% CI=0.17-0.49 and OR=0.03; 95% CI=0.01-0.08) and parity (OR=0.4; 95% CI=0.27-0.83) In multiple linear regression analysis of higher education (OR=0.16; 95% CI=0.03-0.77), using contraceptives for more than 16 years (OR=2.3; 95% CI=1.4-3.9), family history of other cancers (OR=6.1; 95% CI=1.9-19.3) and a history of X-Ray exposure (OR=4.4; 95% CI=1.07-18.1) were considered as predictive factors. Conclusion: The results of this study emphasize the importance of informing women about breast cancer risk factors. So, identification of these risk factors is required as important means of prevention and treatment of breast cancer.     

Passive and active smoking and breast cancer risk in Canada, 1994–97

Background: Studies comparing ever smokers with never smokers have found little increase in breast cancer risk. However, the five published studies examining passive smoking and breast cancer have all suggested associations with both passive and active smoking, particularly premenopausal risk. Methods: We analyzed data collected through the Canadian National Enhanced Cancer Surveillance System, from 805 premenopausal and 1512 postmenopausal women with newly diagnosed (incident), histologically confirmed, primary breast cancer and 2438 population controls. The mailed questionnaire included questions on breast cancer risk factors and a lifetime residential and occupational history of exposure to passive smoking. Results: Among premenopausal women who were never active smokers, regular exposure to passive smoke was associated with an adjusted breast cancer odds ratio (OR) of 2.3 (95% confidence interval [CI] 1.2–4.6). Passive exposure showed a strong dose–response trend (test for trend p=0.0007) with an OR of 2.9 (95% CI 1.3–6.6) for more than 35 years of passive residential and/or occupational exposure. When premenopausal women who had ever actively smoked were compared with women never regularly exposed to passive or active smoke, the adjusted OR for breast cancer was also 2.3 (95% CI 1.2–4.5). Among postmenopausal women who were never-active smokers, regular exposure to passive smoke was associated with an adjusted breast cancer OR of 1.2 (95% CI 0.8–1.8) and an OR of 1.4 (95% CI 0.9–2.3) for the most highly exposed quartile of women. The adjusted OR for postmenopausal breast cancer risk for ever-active smokers compared with women never regularly exposed to passive or active smoke was 1.5 (95% CI 1.0–2.3). Statistically significant dose–response relationships were observed with increasing years of smoking, increasing pack-years and decreasing years since quitting. Women with 35 or more years of smoking had an adjusted OR of 1.7 (95% CI 1.1–2.7). Conclusions: Active and passive smoking may be associated with increased breast cancer risk, particularly premenopausal risk.     

Risk of breast cancer associated with short-term use of oral contraceptives

Objective To estimate breast cancer risk associated with short-term (<6 months) oral contraceptive use, and explore variation in estimates by use characteristics and medical, menstrual, and reproductive history. Methods We analyzed data from the Women’s Contraceptive and Reproductive Experiences Study. Case subjects were white women and black women, 35–64 years old, diagnosed with invasive breast cancer in July 1994–April 1998. Control subjects identified by random-digit dialing were matched to case subjects by age, race, and study site. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results Overall, short-term oral contraceptive use was not associated with breast cancer risk (OR = 1.0; 95% CI = 0.8–1.1). However, significant interaction between short-term use and menopausal status led to an observed increased breast cancer risk in pre-menopausal women (OR = 1.3; 95% CI = 1.0–1.7) and a reduced risk in post-menopausal women (OR = 0.8; 95% CI = 0.6–1.0) associated with short-term use. The association was more pronounced in women with non-contraceptive reasons for use and underlying risk factors for breast cancer. Conclusions These associations may result from underlying characteristics of users or unmeasured factors influencing duration of use and breast cancer risk. The majority of the work on this paper was completed while Dr. Berlin was a Professor of Biostatistics at the University of Pennsylvania. Robert Spirtas is retired.     

Reproductive history in relation to breast cancer risk among Hispanic and non-Hispanic white women

Objective To evaluate reproductive history risk factors in breast cancer among Hispanic (HISP) women in the U.S. southwest, a population with approximately 33% lower breast cancer incidence than non-Hispanic whites (NHW). Methods Population-based case–control study of HISP (796 cases, 919 controls) and NHW (1,525 cases, 1,596 controls) women. Results 19.3% of HISP women reported five or more births and had a reduced risk of breast cancer, adjusted odds ratio (OR) 0.70 (95% confidence interval (CI): 0.50, 0.98) compared to those with one or two births. Breast cancer risk for HISP increased with older age at first birth, p trend = 0.008. Parity and age at first birth associations were specific to ER positive tumors. HISP women who had given birth within five years had higher breast cancer risk than women with 16–25 years since a birth, OR 2.62 (95% CI: 1.44, 4.78); the trend with years since last birth was stronger than for NHWs, p interaction = 0.05. Conclusions Reproductive history influences on breast cancer risk among HISP were similar to associations reported for NHWs. Differences in the prevalence of reproductive risk factors would explain an estimated 6.6% lower breast cancer incidence for HISP compared to NHWs.     

Association between alcohol consumption and postmenopausal breast cancer: results of a case-control study in Montreal,Quebec, Canada

OBJECTIVES: To determine the association between postmenopausal breast cancer and prior consumption of alcoholic beverages.METHODS: This case–control study, conducted in all Montreal hospitals between 1996 and 1997, included 556 postmenopausal women (age 50–75 years) who had a new histologically confirmed diagnosis of primary, malignant breast cancer. Control subjects (577) were selected from other histologically confirmed sites of cancer. A detailed history of alcohol consumption and other risk factors was obtained by interview. Indices reflecting alcohol consumption were developed and unconditional logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI).RESULTS: Current regular drinkers of any type of alcohol were at an increased risk of breast cancer (OR = 1.5; 95% CI 1.0–2.2). For all beverages considered, current regular drinkers showed higher risks than ever regular drinkers. The risk of breast cancer was highest among women who reported exclusive drinking of wine on a weekly or daily basis (e.g. current regular drinking: OR = 2.3; 95% CI 1.2–4.3). Women who started to drink wine on or before the age of 40 were at a 2.5 times increased risk (95% CI 1.4–4.4).CONCLUSIONS: Our findings provide further support for a positive association between the risk of postmenopausal breast cancer and alcohol consumption.     

Risk of breast cancer in women exposed to diethylstilbestrol in utero: prelimiinary results (United States)

BACKGROUND: A synthetic estrogen, diethylstilbestrol (DES), was widely prescribed to pregnant women during the 1950s and 1960s but was later discovered to be associated with an increased risk of clear-cell carcinoma of the vagina and cervix in female offspring. DES has not been linked to other cancers in female offspring, but studies of other prenatal factors such as twin gestation and pre-eclampsia have indicated that in-utero estrogen levels may influence breast cancer risk. We evaluated the relation of in-utero DES exposure to the risk of adult breast cancer.METHODS: A cohort of 4821 exposed women and 2095 unexposed women, most of whom were first identified in the mid-1970s, were followed by mailed questionnaires for an average of 19 years. Reported cancer outcomes were validated by medical record review. Breast cancer incidence in DES-exposed daughters was compared with cancer incidence in unexposed daughters with use of Poisson regression analysis, adjusting for year of birth, age at menarche, age at first birth, and number of births.FINDINGS: The rate ratio for incidence of invasive breast cancer in exposed versus unexposed women was 1.4 (95% confidence interval (CI) = 0.7–2.6). DES exposure was not associated with an increased risk of breast cancer in women under 40 years, but among women aged 40 and older the rate ratio was 2.5 (95% CI = 1.0–6.3). The rate ratio for the association of DES exposure with estrogen receptor-positive tumors was 1.9 (95% CI = 0.8–4.5).INTERPRETATION: While not statistically significant, the overall 40% excess risk, arising exclusively from the subset of estrogen receptor-positive cases, raises a concern calling for continued investigation.     

Alcohol Consumption and Breast Cancer among Black and White Women in North Carolina (United States)

Objective: The purpose of this study was to investigate the effects of alcohol consumption on breast cancer risk in black and white women. Methods: We used data from the Carolina Breast Cancer Study, a population-based, case-control study of black and white women in North Carolina. Interviews were conducted with 890 cases and 841 controls frequency-matched on age and race. Results: Overall, the prevalence of moderate to high levels of alcohol consumption was low. Compared with abstainers, the multivariate odds ratio for recent intake of one or two drinks per day was 1.4 (95% CI = 0.9 2.1) and two or more drinks a day was 1.0 (95% CI = 0.6–1.6); increasing consumption was not associated with risk (p for trend = 0.6). The associations were similar, but somewhat weaker, for average lifetime consumption. Among women who consumed 91 g/week or more of alcohol, a nonsignificant increased risk of breast cancer was observed for women reporting binge drinking (OR = 1.5; 95% CI = 0.9–2.3), but not for those who consumed less than 91 g/week reporting binge drinking (OR = 1.0; 95% CI = 0.6–1.5). Odds ratios did not differ meaningfully by race, age, menopausal status, exogenous hormone use, or body mass index. Conclusions: These data provide little evidence for an association between alcohol consumption and risk of breas cancer among either black or white women.     

Allergy and risk of breast cancer among young women (United States)

Objective: To investigate the relationship between allergy and risk of breast cancer in women 45 years of age and younger. Methods: Data were analyzed from a population-based case–control study of breast cancer in western Washington. Cases were women born after 1944 who were diagnosed with invasive breast cancer (n = 747) between January 1983 and April 1990. Controls (n = 958) were similarly aged women ascertained through random-digit dialing. Cases and controls were interviewed about their history of doctor diagnosed allergies, including detailed information on the specific types of allergies and the age of onset. Using logistic regression we examined the associations between allergy history and breast cancer. Results: A history of allergies was associated with a reduced risk of breast cancer for women older than 35 (odds ratio (OR) = 0.77; 95% confidence interval (CI) = 0.60–0.99), but not for women 35 years or younger (OR = 1.30; 95% CI = 0.94–1.81). There was little difference in effect when age of first allergy onset was examined. No specific type of allergy was associated with breast cancer risk. Conclusion: Our results provide some evidence that a history of allergy may be associated with a reduced risk of breast cancer for women who develop breast cancer between 35 and 45 years of age. Future studies are needed to verify the relationship between immune responses and breast cancer risk.     

Risk of non-small cell lung cancer and the cytochrome P4501A1 Ile462Val polymorphism

Objective The Ile462Val substitution in the cytochrome P450 1A1 gene (CYP1A1) results in increased enzymatic activity. Preliminary data suggesting a link between this polymorphism and lung cancer risk in Caucasians are inconsistent, reflecting small sample sizes and the relatively low frequency of the variant.Methods The data set consisted of 1050 primary non-small cell lung cancer cases and 581 controls, a large homogenous population designed specifically to address previous inconsistencies. Patients were genotyped using a PCR-RFLP technique.Results Carriers of the valine allele, CYP1A1*2C, (Ile/Val or Val/Val genotypes) were significantly over-represented in non-small cell lung cancer compared to controls (OR=1.9; 95% CI=1.2–2.9; p=0.005) when adjusted for confounders, particularly in women (OR=4.6; 95% CI=1.7–12.4; p=0.003). The valine variant was statistically significantly over-represented in cases of lung cancer younger than the median age (64 years) (OR=2.5; 95% CI=1.3–4.8; p=0.005) and cases with less than the median cumulative tobacco-smoke exposure (46 pack-years) (OR=2.4; 95% CI=1.3–4.7; p=0.007).Conclusions These new data establish an association between the CYP1A1 Ile462Val polymorphism and the risk of developing non-small cell lung cancer, especially among women.     

Pregnancy complications and subsequent breast cancer risk in the mother: a Nordic population‐based case–control study

Certain features of pregnancy are important risk factors for breast cancer, such as protection afforded by young age at first birth. Preeclampsia, a pregnancy complication, is associated with reduced maternal breast cancer risk. However, questions remain regarding causality, biological mechanisms and the relation of other hypertensive conditions to risk. We conducted a population‐based case–control study of breast cancer cases (n = 116,196) in parous women identified through linkage of birth and cancer registries in Denmark, Finland, Norway and Sweden (1967–2013), including up to 10 matched controls per case (n = 1,147,192) sampled from the birth registries (complete data were not available on all variables). Odds ratios (ORs) with 95% confidence intervals (CIs) were derived from unconditional logistic regression models including matching factors (country, maternal birth year) and parity. Hypertension diagnosed before pregnancy (OR 0.87; 95% CI 0.78–0.97), gestational hypertension (OR 0.90; 95% CI 0.86–0.93) and preeclampsia (OR 0.91; 95% CI 0.88–0.95) were associated with reduced breast cancer risk. Results remained similar after adjustment for smoking and maternal body mass index before first pregnancy, and were generally similar stratified by parity, age at breast cancer diagnosis, time since first and last birth, sex of the offspring and calendar time. Except for retained placenta (OR 1.14; 95% CI 0.98–1.32), no other pregnancy complication appeared associated with breast cancer risk. The mechanisms mediating the modest risk reductions for history of preeclampsia or hypertension preceding or arising during pregnancy, and possible increased risk with history of retained placenta are unknown and warrant further laboratory, clinical and epidemiological investigation.     

The associations of adolescent cigarette smoking, alcoholic beverage consumption, environmental tobacco smoke, and ionizing radiation with subsequent breast cancer risk (United States)

Objectives: Studies of breast cancer among survivors of the World War II atomic bomb blasts over Japan suggest that the adolescent breast may be particularly sensitive to carcinogenic insult. To further explore that possibility we examined the relationships of cigarette smoking, alcohol consumption, environmental tobacco smoke (ETS) exposure, and medical treatment with ionizing radiation during adolescence with subsequent breast cancer risk. Methods: Data from the Carolina Breast Cancer Study, a population-based, case–control study of breast cancer in North Carolina women aged 20–74years (864 cases, 790 controls), were analyzed. Results: A modest increase in breast cancer risk was suggested for women who began to smoke cigarettes between the ages of 10 and 14 years (OR: 1.5, CI: 0.9–2.5), and for women exposed to ionizing radiation between ages 10 and 19 years to treat or monitor a medical condition (OR: 1.6, CI: 0.5–2.5). Neither exposure to ETS at home prior to age 18 years (OR: 1.1, CI: 0.9–1.3) nor initiation of alcoholic beverage consumption between ages 10 and 15 years (OR: 1.1, CI: 0.6–1.8) appeared to increase risk. Conclusions: Our results are consistent with previous evidence suggesting that some adolescent exposures could influence future breast cancer risk.     

Breast Cancer and Dietary Factors in Taiwanese Women

Objectives To examine the effect of the consumption of dietary factors on the risk of breast cancer in a case–control study in Taiwan.Methods Two-hundred-and-fifty cases and 219 age-matched controls between the ages of 25 and 74 were interviewed in person between 1996 and 1999. Usual consumption of dietary habits including 100 foods was assessed using a food frequency questionnaire and a nutrient database developed and validated in Taiwanese populations.Results Cases consumed significantly more fat than controls. Cases also consumed statistically significant less supplements such as vitamins and mineral than controls. Food group analyses showed that highest quartile of beef and pork intake significantly increased risk in younger women (OR = 2.5, 95% CI = 1.0–6.0) and all women (OR = 2.5, 95% CI = 1.1–3.3). The age- education- and total calorie-adjusted odds ratio (OR) of breast cancer risk comparing the highest and second highest quartile of fat intake to the lowest quartile was 5.1, 95% confidence interval (CI): 2.1–13 and 3.5, 95% CI: 1.4–8.7 among those younger cases (≤40). A multiple regression model indicates a protective effect of supplements (OR: 0.40, 95% CI: 0.3–07) and a harmful effect of dietary fat (OR: 2.6, 95% CI: 1.4–5.0) for the highest versus lowest quartile in all women.Conclusions Our results indicate a strong protective effect of dietary supplements and a harmful effect of dietary fats on the risk of breast cancer among women in Taiwan. These findings should be confirmed in future follow-up studies. Specific amount of dietary supplements and dietary fats should be quantified for a more accurate evaluation on the risk for breast cancer in this population.^★ Supported by the Koo Foundation Cancer Center Research Fund.     

Modification of BRCA1- and BRCA2-associated breast cancer risk by AIB1 genotype and reproductive history.

Women who have inherited a germ-line mutation in the BRCA1 or BRCA2 (BRCA1/2) genes have a greatly increased risk of developing breast cancer compared with the general population. However, there is also substantial interindividual variability in the occurrence of breast cancer among BRCA1/2 mutation carriers. We hypothesize that genes involved in endocrine signaling may modify the BRCA1/2-associated age-specific breast cancer penetrance. We studied the effect of alleles at the AIB1 gene using a matched case-control sample of 448 women with germ-line BRCA1/2 mutations. We found that these women were at significantly higher breast cancer risk if they carried alleles with at least 28 or 29 polyglutamine repeats at AIB1, compared with women who carried alleles with fewer polyglutamine repeats [odds ratio (OR), 1.59; 95% confidence interval (CI), 1.03-2.47 and OR, 2.85; 95% CI, 1.64-4.96, respectively]. Late age at first live birth and nulliparity have been associated with increased breast cancer risk. We observed increases in BRCA1/2-associated breast cancer risk in women who were either nulliparous or had their first live birth after age 30 (OR, 3.06; 95% CI, 1.52-6.16). Women were at significantly increased risk if they were nulliparous or had a late age at first live birth and had AIB1 alleles no shorter than 28 or 29 or more AIB1 polyglutamine repeats (OR, 4.62; 95% CI, 2.02-10.56 and OR, 6.97; 95% CI, 1.71-28.43, respectively) than women with none of these risk factors. Our results support the hypothesis that pathways involving endocrine signaling, as measured through AIB1 genotype and reproductive history, may have a substantial effect on BRCA1/2-associated breast cancer risk.