Risk factors for breast cancer in black women

Risk factors for breast cancer were examined in black women in a hospital-based case-control study of 529 black women with breast cancer and 589 controls. Late age at menarche was associated with a reduced risk of breast cancer. Women having 5 or more children had a reduced risk relative to that of women with fewer or no children. Late age at first birth was associated with an elevated risk of breast cancer. Among postmenopausal black women, obesity [as measured by body mass index (BMI)] was associated with an increased risk; among premenopausal women, there was no association of breast cancer with BMI. Women whose menopause occurred at or after age 50 were at increased risk relative to those whose menopause occurred earlier. There was no association between number of years of education and breast cancer in black women. History of benign breast disease and history of breast cancer in mother or sisters both were risk factors. The risk factor profile for breast cancer in black women was similar to that observed in whites.     

Risk factors for breast cancer in Chinese women in Shanghai

Five hundred thirty-four histologically confirmed incident cases of breast cancer in Chinese women of Shanghai and an equal number of age and sex-matched population controls were interviewed as part of an epidemiological study of breast cancer risk factors. Early age at menarche was positively associated with breast cancer risk whereas early age at first full term pregnancy, high parity, and long duration of nursing were each negatively associated. We found high average body weight to be a risk factor, especially among women over age 60. Use of oral contraceptives after age 45 also was a risk factor, but use in general was not. Personal history of benign breast disease and history of breast cancer in first degree female relatives both increased risk. Multivariate analysis showed that each of these risk (or protective) factors was independently related to breast cancer. In addition to confirming most of the breast cancer risk factors of Western populations in a low risk developing Asian country, this study demonstrates a clear beneficial effect on breast cancer risk of lactation in a population characterized by a long cumulative duration of nursing in the majority of women. Finally, this study supports several other recent reports of a residual and beneficial effect of parity on breast cancer risk after controlling for age at first full term pregnancy.     

Risk factors for breast cancer among Filipino women in Manila

Age‐adjusted incidence rates of breast cancer vary greatly worldwide with highest rates found in the typically ‘westernised’ countries of North America and Europe. Much lower rates are observed in Asian and African populations but an exception to this has been reported for the Manila Cancer Registry in the Philippines. The reason for this high rate is unknown but may be associated with the change in lifestyle that has occurred in urban Manila since the 1960s. In 1995, a randomised controlled trial was set up in Manila to evaluate the feasibility of a screening intervention by clinical breast examination as an alternative to mammography. The cohort of 151,168 women was followed‐up to 2001 for cancer incidence and a nested case‐control study carried out. This aimed to evaluate the increase in breast cancer risk associated with known risk factors. Increased risks were seen for a high level of education (OR = 1.9 95%CI 1.1–3.3 for education stopped at ≥13 versus <13 years), nulliparity (OR = 5.0 95% CI 2.5–10.0 for nulliparity versus five or more children), and late age at first birth (OR = 3.3 95% CI 1.3–8.3 for age ≥30 versus <20 years). We found no association with excess body weight, height, use of exogenous hormones or alcohol consumption. From this study, the recognised “classical” risk factors do not fully explain the high breast cancer incidence in Metro Manila, especially when compared to other urban Asian populations. We conclude that it is too simplistic to ascribe the high risk to ‘westernisation’.     

Risk factors for breast cancer in Chinese women of Beijing

A self-administered questionnaire was completed by 497 Chinese women in Beijing with histologically confirmed breast cancer and by an equal number of age- and neighborhood-matched control women. High body weight (71 + kg) was a risk factor for breast cancer in women aged 50 + (RR = 1.90), but this effect did not quite reach statistical significance. Nulliparity and late age at first birth were associated with an elevated risk of breast cancer. In comparison to parous women who had their first child before age 20, those who delayed this event until after age 29 had an RR of 1.65. The comparable RR for nulliparous women was 3.72. Late age at menopause was a risk factor for breast cancer. The RR for menopause after age 50 compared to menopause before age 45 was 2.16. High parity and long duration of lactation were protective factors against breast cancer. These 2 factors were highly correlated with each other and also with age at first birth. The effect of each on breast cancer risk was somewhat reduced after adjustment for the other two. A personal history of benign breast disease (RR = 3.21) and a family history of breast cancer (RR = 2.17) were also associated with an increased risk of breast cancer.     

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.     

Risk factors for breast cancer among young women in southern Iran

Age standardized incidence rates of breast cancer in developed countries is nearly threefold higher than in developing countries. Iran has had one of the lowest incidence rates for breast cancer in the world, but during the last four decades increasing incidence rates of breast cancer made it the most prevalent cancer in Iranian women. After adjustment for age, Iranian young women are at relatively higher risk of breast cancer than their counterparts in developed countries. The purpose of this study was to investigate some established risk factors of breast cancer in Iranian young women. A hospital-based case control study comprising 521 women with histologically confirmed, incident breast cancer and 521 controls frequency-matched by age and province of residence was conducted. Logistic regression performed to investigate associations of reproductive and anthropometric factors with breast cancer risk. In multivariate analysis, family history [odds ratio (OR): 1.61; 95% confidence interval (CI): 1.07-2.42], oral contraceptives (OC) usage (OR: 1.52; 95% CI: 1.11-2.08), low parity (OR parity ≥ 3 vs. 1-2: 0.33; 95% CI: 0.23-0.49), employment (OR: 1.83; 95% CI: 1.05-3.23) and shorter period of breast feeding (OR ≥ 37 months vs. < 37: 0.61; 95% CI: 0.44-0.84) were related to a higher risk of breast cancer in young women. This was the first study focusing on risk factors of breast cancer in Iranian young women. The trend of decreasing parity and shortened duration of breast feeding along with OC usage might partly explain the rapid rising of breast cancer incidence in Iranian young women.     

Risk factors for hormone receptor-defined breast cancer in postmenopausal women.

The effect of classic breast cancer risk factors on hormone receptor-defined breast cancer is not fully clarified. We explored these associations in a Swedish population-based study. Postmenopausal women ages 50 to 74 years, diagnosed with invasive breast cancer during 1993 to 1995, were compared with 3,065 age frequency-matched controls. We identified 332 estrogen receptor (ER-) and progesterone receptor (PR-) negative, 286 ER+PR-, 71 ER-PR+, 1,165 ER+PR+, and 789 tumors with unknown receptor status. Unconditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (95% CI). Women ages >or=30 years, compared with those ages 20 to 24 years at first birth, were at an increased risk of ER+PR+ tumors (OR, 1.5; 95% CI, 1.2-1.8) but not ER-PR- tumors (OR, 1.1; 95% CI, 0.8-1.6). Women who gained >or=30 kg in weight during adulthood had an approximately 3-fold increased relative risk of ER+PR+ tumors (OR, 2.7; 95% CI, 1.9-3.8), but no risk increase of ER-PR- tumors (OR, 1.0; 95% CI, 0.5-2.1), compared with women who gained <10 kg. Compared with never users, women who used menopausal estrogen-progestin therapy for at least 5 years were at increased risk of ER+PR+ tumors (OR, 3.0; 95% CI, 2.1-4.1) but not ER-PR- tumors (OR, 1.3; 95% CI, 0.7-2.5). In conclusion, other risk factors were similarly related to breast cancer regardless of receptor status, but high age at first birth, substantial weight gain in adult age, and use of menopausal estrogen-progestin therapy were more strongly related to receptor-positive breast cancer than receptor-negative breast cancer.     

Risk factors for breast cancer in postmenopausal Caucasian and Chinese-Canadian women

Introduction  

Striking differences exist between countries in the incidence of breast cancer. The causes of these differences are unknown, but because incidence rates change in migrants, they are thought to be due to lifestyle rather than genetic differences. The goal of this cross-sectional study was to examine breast cancer risk factors in populations with different risks for breast cancer.     

Risk factors for breast cancer in East Asian women relative to women in the West

The incidence of breast cancer in women of East Asian ancestry (Chinese, Japanese and Korean) is lower than in women of European ancestry but is currently rising. This review explores potential reasons for this inter‐ethnic difference in incidence by profiling breast cancer risk factors reported for East Asian and Western women. Factors such as endogenous hormone exposure, lifestyle choices, diet and genetic predisposition are associated with breast cancer risk in both East Asian and Western women. However, the relative exposure to these risk factors may vary according to a woman's geographical ancestry and culture. For example, age at menarche and menopause, parity, breast‐feeding history, low fat and high soy consumption as well as the prevalence of high risk genetic alleles may vary with a woman's geographical ancestry and/or culture. Differences in exposure to these risk factors in East Asian and Western women are consistent with the inter‐ethnic differences in breast cancer incidence observed. Understanding the underlying factors contributing to differences in the profile of breast cancer across populations is important when considering screening and prevention programs for East Asian women resident in the East or the West.     

Risk factors for breast cancer in East Asian women relative to women in the West

The incidence of breast cancer in women of East Asian ancestry (Chinese, Japanese and Korean) is lower than in women of European ancestry but is currently rising. This review explores potential reasons for this inter-ethnic difference in incidence by profiling breast cancer risk factors reported for East Asian and Western women. Factors such as endogenous hormone exposure, lifestyle choices, diet and genetic predisposition are associated with breast cancer risk in both East Asian and Western women. However, the relative exposure to these risk factors may vary according to a woman's geographical ancestry and culture. For example, age at menarche and menopause, parity, breast-feeding history, low fat and high soy consumption as well as the prevalence of high risk genetic alleles may vary with a woman's geographical ancestry and/or culture. Differences in exposure to these risk factors in East Asian and Western women are consistent with the inter-ethnic differences in breast cancer incidence observed. Understanding the underlying factors contributing to differences in the profile of breast cancer across populations is important when considering screening and prevention programs for East Asian women resident in the East or the West.     

Risk factors for arm lymphedema following breast cancer diagnosis in Black women and White women

Purpose Lymphedema of the arm is a potential complication of breast cancer therapy. This study examines pre-disposing factors that may operate in conjunction with treatment-related factors in the development of arm lymphedema in a large cohort of White and Black breast cancer survivors. Methods 494 women (271 White and 223 Black) with in situ to Stage III-A primary breast cancer completed a baseline interview within 18 months of diagnosis. Information on lymphedema was collected during a follow-up interview, conducted on average 50 months after diagnosis. Self-reported data were used to classify women with or without lymphedema. Multivariable logistic regression models were developed to identify risk factors for arm lymphedema. Results Arm lymphedema was associated with younger age at diagnosis (odds ratio, OR per year of age = 0.96; 95% confidence interval, CI = 0.93–0.99), positive history of hypertension (OR = 2.31; 95% CI = 1.38–3.88), obesity (OR for body mass index, BMI≥30 = 2.48; 95% CI = 1.05–5.84) and having had surgery where 10 or more lymph nodes were excised (OR = 2.16; 95% CI = 1.12–4.17). While Black women had higher prevalence of arm lymphedema than White women (28% vs. 21%), race was not associated with lymphedema risk in models adjusted for multiple factors (adjusted OR = 1.01; 95% CI = 0.63–1.63). Conclusion Risk of arm lymphedema did not differ significantly for Black and White women. Risk factors identified in this study offer opportunities for interventions (weight loss, control of blood pressure, use of sentinel node biopsy where possible) for reducing incidence of lymphedema or controlling the symptoms associated with this condition.     

Risk factors for breast cancer in Turkish women: a hospital-based case-control study

The aim of this study was to investigate the association between risk factors and breast cancer in Turkish women. In a hospital-based case-control study in Istanbul, 405 patients with histologically confirmed breast cancer were compared with 1050 controls, who were admitted to different departments of the same hospital. Unadjusted odds ratios (ORs) and 95% confidence intervals (CIs) for each risk factor were obtained from logistic regression analyses. Risk factors for breast cancer were found to be early menarche age (OR 3.87, 95% CI 2.46-6.08), use of alcohol (OR 3.87, 95% CI 1.79-8.37), history of diabetes (OR 3.31, 95% CI 2.36-4.64) or hypertension (OR 3.44, 95% CI 2.07-5.71), oral contraceptive use (OR 1.98, 95% CI 1.38-2.85) and hormone replacement therapy (HRT) use (OR 1.94, 95% CI 1.15-3.29). The findings of the present study indicated that history of diabetes or hypertension, use of alcohol, oral contraceptive and HRT, never having breastfed and delayed age at first birth associated with changing of lifestyle led to an increased risk of breast cancer in Turkish women.     

Risk factors for breast cancer subtypes among Black women undergoing screening mammography

Breast Cancer Research and Treatment -     

Risk factors for male breast cancer

To investigate risk factors in male breast cancer, a case-control study of 52 histologically diagnosed cases and 52 controls--matched for age, race, marital status, and hospital--was conducted in 5 U.S. metropolitan areas. Cases were significantly more likely to be Jewish than were the controls, supporting earlier suggestions of an increased risk in Jewish males. A significant association of male breast cancer with mumps infections at age 20 years or older, along with the possible association with antecedent testicular injury and the excess frequency of mumps orchitis among cases, suggests that testicular factors may be important in the development of breast cancer among males. An increased frequency of breast cancer among persons who have worked in blast furnaces, steel works, and rolling mills is of interest because of the possible testicular effect of high environmental temperatures. The observed association between breast cancer and a prior history of swollen breast is difficult to interpret because of potential recall bias, and a possible relationship with military service needs further confirmation.     

Risk factors for colorectal cancer following breast cancer

Objective. To investigate risk factors for colorectal cancer following breast cancer. Methods. In this nested case-control study, all women (n=14,900) with a first primary breast cancer (1978–1992) were identified from the western Washington population-based Surveillance, Epidemiology, and End Results Cancer Registry. Cases (n=160) developed a second primary colorectal cancer before 1995, at least 6 months after the first cancer diagnosis. Controls (n=310, matched to the cases on calendar year, age and breast cancer stage) were randomly selected from those who did not develop a second primary cancer and who survived to the case's colorectal cancer diagnosis date. Characteristics of the cases and controls at initial diagnosis were compared using conditional logistic regression. Results. The incidence of colorectal cancer was associated with a family history of breast cancer (v.s. no family history, matched odds ratio (mOR)=2.1, 95% confidence interval (CI): 1.1–4.1), high body mass index (30 kg/m² v.s. <30 kg/m², mOR=2.2, CI: 1.2–3.9), and lobular breast cancer histology (v.s. ductal, mOR=2.0, CI: 0.9–4.4). Risk was unrelated to menopausal status, prior hormone replacement therapy and estrogen/progesterone receptor status of the breast tumors. Conclusions. The risk of developing a second primary colorectal cancer may be elevated among certain subsets of breast cancer patients.     

Risk factors and natural history of breast cancer in younger Chinese women

AIM: To investigate the age differences in the risk factors, clinicopathological characteristics and patterns of treatment of female breast cancer patients.METHODS: Seven thousand one hundred and fifty-two women with primary breast cancer from the Hong Kong Breast Cancer Registry were recruited after receiving patients’ consent, they were asked to complete standardized questionnaires which captured their sociodemographic characteristics and risk factors associated with breast cancer development. Among them, clinicopathological data and patterns of treatment were further collected from medical records of 5523 patients with invasive breast cancers. Patients were divided into two groups according to the age at diagnosis: younger (< 40 years old) vs older patients (≥ 40 years old) for subsequent analyses.RESULTS: Analysis on the sociodemographic characteristics and exposure to risk factors were performed on 7152 women with primary breast cancer and the results revealed that younger patients were more likely to have unhealthy lifestyles; these include a lack of exercise (85.4% vs 73.2%, P < 0.001), having high stress in life (46.1% vs 35.5%, P < 0.001), having dairy/meat-rich diets (20.2% vs 12.9%, P < 0.001), having alcohol drinking habit (7.7% vs 5.2%, P = 0.002). Younger patients were also more likely to have hormone-related risk factors including nulliparity (43.3% vs 17.8%, P < 0.001) and an early age at menarche (20.7% vs 13.2%, P < 0.001). Analyses on clinicopathological characteristics and patterns of treatment were performed on 5523 women diagnosed with invasive breast cancer. The invasive tumours in younger patients showed more aggressive pathological features such as having a higher percentage of grade 3 histology (45.7% vs 36.5%, P < 0.001), having a higher proportion of tumours with lymphovascular invasion (39.6% vs 33.2%, P = 0.003), and having multifocal disease (15.7% vs 10.3%, P < 0.001); they received different patterns of treatment than their older counterparts.CONCLUSION: Younger patients in Hong Kong are more likely to encounter risk factors associated with breast cancer development and have more aggressive tumours than their older counterparts.     

Risk factors for male breast cancer.

Risk factors for male breast cancer were investigated in a case-control study of 21 cases and 82 controls admitted to hospital for acute, non-neoplastic, non-hormone-related diseases in the Greater Milan area between 1988 and 1994. More educated men tended to be at higher risk of breast cancer, with a multivariate odds ratio (OR) of 2.6 [95% confidence interval (CI) 0.7-9.4]. The OR was 3.2 (95% CI 1.1-9.6) for those in the higher social class. Men with no offspring were at higher risk than fathers, with an OR of 5.5 (95% CI 1.8-16.7). A history of breast cancer in female relatives was reported by two cases and one control, giving an OR of 8.5 (95% CI 1.1-69.0). Cases were somewhat heavier than controls, and significantly taller, with an OR of 5.7 (95% CI 1.6-19.9) for subjects taller than 170 cm vs shorter ones. The association with weight, however, decreased after allowance for height, and no difference was observed for body mass index. Socioeconomic correlates and family history are similar to well-assessed risk factors for female breast cancer. The associations with anthropometric measures and childlessness may find an explanation in chromosomal abnormalities, such as Klinefelter''s syndrome, or other hormone-related disorders.     

Risk for breast cancer among women with endometriosis

Although several risk factors are common to endometriosis and breast cancer, the results of observational studies of an association have so far been inconsistent. We evaluated the relationship between endometriosis and breast cancer on the basis of data on selected cancers and medical histories from the Danish nationwide cancer and hospital registries used in a large case-cohort study. A total of 114,327 women were included in the study of whom 1,978 women had received a diagnosis of endometriosis and 16,983 had had a diagnosis of breast cancer between 1978 and 1998. Of the women with endometriosis, 236 subsequently received a diagnosis of breast cancer. The crude overall rate ratio for breast cancer after endometriosis was 1.00 and after adjustment for reproductive factors, calendar-period, bilateral oophorectomy and benign breast disease, the rate ratio was 0.97 (95% confidence interval, 0.85-1.11). The risk for breast cancer increased with age at diagnosis of endometriosis, so that women in whom endometriosis was diagnosed at a young age (approximately <40 years) had a reduced risk for breast cancer and women in whom endometriosis was diagnosed at older ages (approximately > or =40 years) tended to have an increased risk for breast cancer. The reduced risks observed among young women may reflect their exposure to drugs with antiestrogenic effects. The increased risk associated with endometriosis among postmenopausal women may be due to common risk factors between postmenopausal endometriosis and breast cancer or an altered endogenous estrogen.     

Risk factors for breast cancer in young women by oestrogen receptor and progesterone receptor status

We used data from 765 cases and 564 controls in the population-based Australian Breast Cancer Family Study to investigate whether, in women under the age of 40, the profile of risk factors differed between breast cancer subtypes defined by joint oestrogen and progesterone receptor status. As hypothesised, no significant differences were found.     

Risk factors for breast cancer among women in Bhopal urban agglomerate: a case-control study

Background: Breast cancer is the most common cancer in females worldwide, and the second leading cause of cancer deaths in women. The incidence is on the rise in India, and breast cancer is the second most common malignancy in Indian women. Objective: To assess the risk factors for breast cancer patients living in Bhopal. Study Design and Method: This case-control study was conducted in Bhopal urban agglomerate for a period of a year from October 2008 to August 2009. Demographic data and reproductive risk factor related information was collected using a structured questionnaire with analyses by Epi-info and SPSS 16. Results: A history of oral contraceptive pill use (OR=2.77, 95% CI: 1.15-6.65), history of not having breastfeeding (OR=3.49, 95% CI:1.22-9.97), over weight (OR=0.11, 95%CI:0.02-0.49), obese women ( OR=0.24, 95%CI: 0.06-0.88) and family history of breast cancer (OR=3.89, 95% CI: 1.01-14.92) were associated significantly with the occurrence of breast cancer on multivariate analysis. Conclusions: The findings of the present study suggests that positive family history of breast cancer and history of using OCP may be the epigenetic factors promoting the occurrence of breast cancer while breastfeeding reduces the possibility of acquiring breast cancer.