Breast Cancer Risk Factors in Women Participating in a Breast Screening Program: a Study on 11,850 Iranian Females

The incidence rate of breast cancer in developed countries is almost three-fold higher than in developingcountries. Iran has had one of the lowest incidence rates for breast cancer in the world, but during the recentdecades a marked increase has been seen. The purpose of this study was to investigate some established riskfactors of breast cancer in Iranian women. A study of 11,850 women participating in abreast screening programwas conducted. The 197 women diagnosed with breast cancer and 11,653 healthy women were compared. Logisticregression was performed to investigate associations of reproductive and anthropometric factors with breastcancer risk. Family history of breast cancer (OR=1.94 , 95%CI=1.35-2.78), occupation (OR= 1.65,95%CI=1.20-2.25), education level (OR=0.50,95%CI=0.28-0.91), parity (OR=0.27, 95%CI=0.12-0.59), menopausal status(OR=3.15, 95%CI=2.35-4.21), age at menarche (OR=0.33, 95%CI=0.15-0.70), and age at the first pregnancy(OR=4.10 , 95%CI=1.13-14.77) were related to the risk of breast cancer. Decrease in parity may to some extentexplain the rising trend of incidence of breast cancer incidence in Iranian women.     

Risk Factor Analysis for Breast Cancer in Premenopausal and Postmenopausal Women of Punjab,India

Objective: Amritsar, the second largest town of agrarian state of Punjab, India reports high number of breast cancer cases every year. The present study investigated the etiology of breast cancer using various obesity indices and other epidemiological factors among breast cancer patients residing in and around Amritsar city. Methods: In this case control study, risk factors for breast cancer were analyzed in 542 female subjects: 271 females with breast cancer patients and 271 unrelated healthy females matched for age as control females. Results: Bivariate analysis for risk factors in cases and controls showed a lower risk (OR=0.65, 95% CI 0.43-0.99, p=0.04) in obese cases with BMI≥25kg/m2 as compared to subjects with normal BMI. Risk factor analysis showed that parameter which provided risk for cancer in postmenopausal women was obesity and in premenopausal women was parity. Postmenopausal women with BMI (overweight: OR=0.39, 95% CI 0.17-0.92, p=0.03; obese: OR= 0.26, 95% CI 0.13-0.52, p=0.00), WC (OR=0.17, 95% CI 0.05-0.52, p=0.00) and WHtR (p=0.02) had highr risk. Premenopausal women with 3 or less than 3 children had a higher risk (OR=5.54, 95 % CI 2.75-11.19, p=0.00) than postmenopausal women when compared to women with more than 3 children. Binary logistic regression analysis revealed that low parity (≤3) substantially increased the risk for breast cancer (OR=4.80, 95% CI 2.34-9.85, p=0.00) in premenopausal women. Conclusion: Obesity, parity associated breast cancer risk and reduced breastfeeding cumulatively predispose the premenopausal women of this region to higher risk of breast cancer.     

Reproductive factors associated with breast cancer risk in northern Iran

Breast cancer is a common malignancy for women in most parts of the world and the incidence in Iranian women is growing. The patients are relatively younger than their western counterparts. The aim of study was to investigate the roles of reproductive factors for breast cancer in Babol. In a case–control study in Babol, we recruited a total of 100 new patients with histologically confirmed breast cancer and 200 age-matched controls selected from outpatient clinics. Demographic and reproductive factors were ascertained by in-person interview using a constructed questionnaire. Several potential confounding factors were adjusted using multiple logistic model. The adjusted odds ratio showed that having higher age at first pregnancy and abortion were associated with increased breast cancer risk (the adjusted OR = 4.1, 95% CI: 1.3–13.2 and 2.93, 95% CI: 1.64–5.24, respectively). By increasing parity, the risk had reduced significantly; among women with parity ≥5, the adjusted OR was 0.09 (95% CI 0.01–0.7) compared with nulliparous women, and also for each additional parity, the risk reduced by 50% (OR = 0.50, 95% CI: 0.34–0.71). The duration of breast feeding was inversely associated with breast cancer risk, while after additional adjustment for parity, no longer the protective effect of breast feeding was observed. Nulliparity, late age at first birth and abortion were the most important reproductive factors associated with breast cancer risk; therefore, it is recommended to women with these risk factors to perform breast cancer screening tests earlier.     

Risk Factors for Breast Cancer in Iranian Women Aged Less than 40 Years

This case-control study was carried out in a university-affiliated teaching hospital, Tehran city, Iran. A total of312 newly diagnosed cases aged less than 40 years old participated and were matched for age and ethnicity with312 controls. The results showed that in women who never married (OR=2.42 95%CI=1.51-3.88) (P<0.001), hada family history of breast cancer (OR=7.07 95%CI=2.95-16.99) (P<0.001), a low age of menarche (OR=0.1 95%CI=0.04-0.23) (P<0.001)), lower parity (OR=13.3 95% CI=3.89-45.66) (P<0.001) and took oral contraceptive pills(OR= 2.83 95% CI=1.87-4.24) (P<0.000) were at increased risk. A direct association with age at first birth wasalso evident(P=0.041), with a significantly inverse association between duration of lactation and breast cancer risk(p=0.016). On multivariate logistic regression, parity, family history of breast cancer, use of oral contraceptivepills, and age at first birth remained significant. In women lower than 40 years of age, breast cancer risk wassignificantly higher in women with parity ≥4 compared with nulliparity but no association emerged with historyof breast-feeding. Other risk factors were similar to those described in breast cancer epidemiology at any age.     

Early oral contraceptive use and breast cancer among premenopausal women: final report from a study in southern Sweden

In southern Sweden during the 1960s, women began to use oral contraceptives (OCs) extensively at a young age. This case-control study investigates the relationship between the use of OCs and breast cancer development in women in southern Sweden diagnosed in the early 1980s. The risk for breast cancer after OC use among premenopausal women was modeled, after adjustment was made for age, age at menarche, and age at first full-term pregnancy or parity. Both the duration of OC use before 25 years of age and commencement of OC use at a young age were associated with a significant increase in the risk of breast cancer as well as a significant trend. The duration of OC use before the first full-term pregnancy was associated with an increased risk of breast cancer, but it did not show a significant trend. The total duration of OC use was weakly, but not significantly, associated with breast cancer development. The odds ratio for women starting OC use before 20 years of age was 5.8 [95% confidence interval (CI), 2.6-12.8]; for women using OCs for greater than 5 years before age 25, it was 5.3 (95% CI, 2.1-13.2); and for women using OCs for greater than or equal to 8 years before first full-term pregnancy, it was 2.0 (95% CI, 0.8-4.7). In multivariate analyses including the different measurements of OC use, only starting age of OC use was significantly associated with breast cancer. The exposure-response relationship between duration of OC use and risk of breast cancer depended on the age at first use of OCs. Given a fixed duration of OC use, the risk increased with younger starting age of OC use. The findings point to the importance of the early reproductive years as risk determinants for breast cancer after OC use.     

No Increase in Breast Cancer Risk in Japanese Women Taking Oral Contraceptives: a Case-Control Study Investigating Reproductive,Menstrual and Familial Risk Factors for Breast Cancer

Background: Low-dose oral contraceptives (OC) were approved by the Japanese Ministry of Health, Laborand Welfare in 1999, yet despite their contraceptive and non-contraceptive health benefits, only 5% of the targetpopulation use them. Fear of increased cancer risk, particularly breast cancer, is one reason for this. Due tolow OC uptake and low screening participation, a paucity of data is available on the risk of OC use and breastcancer in Japanese women. The present study investigated OC use and breast cancer risk, as well as menstrual,reproductive and family factors. Materials and Methods: This was a clinic-based case-control study of womenaged 20-69yrs who had undergone breast screening between January 2007 and December 2013 in central Tokyo.In all, 28.8% of the participants had experience with OC use. Cases were 155 women with a pathologicallyconfirmed diagnosis of breast cancer. Controls were the remaining 12,333 women. Results: Increased age was asignificant risk factor for breast cancer (p<0.001). A lower risk was found in premenopausal women presentlytaking OC compared to never users (OR 0.45; 95% CI 0.22-0.90) after adjusting for age, parity and breastfeeding, and a family history of breast cancer. Conclusions: Increased age rather than OC use had a greatereffect on breast cancer risk. This risk may be decreased in premenopausal women with OC use, but furtherlong-term prospective studies are necessary.     

Epidemiology of reproductive and hormonal factors in thyroid cancer: evidence from a case-control study in the Middle East.

Thyroid cancer is the second most common neoplasm among women in Kuwait and several other countries in the Middle East. Most of these countries also have relatively high birth and total fertility rates. To examine potential relationships between reproductive and hormonal factors and thyroid cancer, we conducted a population-based case-control interview study among 238 women diagnosed with thyroid cancer and a similar number of individually matched controls in Kuwait. Among the demographic variables, women with 12+ years of education had a significantly reduced risk of thyroid cancer (OR = 0.4; 95% CI: 0.2-0.8; p-trend <0.05). The average age at diagnosis (+/-SD) of thyroid cancer was 34.7 +/- 11 years. Events such as age at menarche, pregnancy, menopausal status and age at menopause were not associated with thyroid cancer. There was an association with age at last pregnancy and parity. Women who had their last pregnancy at ages > or = 30 years were at a significantly increased risk (OR = 2.1; 95% CI: 1.2-3.8); there was also a significant trend in risk with increasing age at last pregnancy. There was a modest increase in risk among women who had borne > or = 5 children (OR = 1.5; 95% CI: 0.9-2.5). A joint analysis of these factors showed that childbearing during the latter half of reproductive life had a substantial effect on the incidence of thyroid cancer; for any given level of parity, there was about a 2-fold increased risk if the age at last pregnancy was > or = 30 years. A substantial recent-birth effect, in relation to subsequent diagnosis of thyroid cancer, was observed during the second and third year after a birth (OR = 2.0; 95% CI: 1.0-4.1). In contrast, spontaneous abortion seemed to have a protective effect. There was a significant decrease in risk among women who had a miscarriage as outcome of first pregnancy (OR = 0.1; 95% CI: 0.03-0.4) and those who had experienced > or = 3 miscarriages (OR = 0.3; 95% CI: 0.1-0.8; p-trend <0.05). Overall, any female hormone use was not associated with thyroid cancer risk. New association is suggested for a history of post-partum thyroiditis (OR = 10.2; 95% CI: 2.3-44.8). These data support the hypothesis that reproductive factors and patterns may influence, or contribute to, the risk of thyroid cancer among women.     

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.     

Oral contraceptive use and mammographic patterns.

High-risk mammographic patterns represent an increased risk of contracting breast cancer and may be used as a surrogate endpoint for the disease. We examined the relationship between oral contraceptive (OC) use and mammographic patterns among 3218 Norwegian women, aged 40-56 years. Information on ever OC use, duration, and age of first OC use and other epidemiological data were obtained through questionnaires. The mammograms were categorized into five groups. Patterns I-III were combined into a low-risk group and patterns IV and V into a high-risk group. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression and adjusted for age, menopausal status, parity, age at first birth, and body mass index. Women who reported ever having used OCs were 20% more likely (OR 1.27, 95% CI 1.0-1.6) to have high-risk mammographic patterns compared with those reporting never having used OCs. There was no dose response between different measures of OC use and high-risk patterns. Among nulliparous women, ever OC users were four times more likely (OR 4.65, 95% CI 2.1-10.3) to have high-risk patterns compared with never users. Our findings suggest that, especially among nulliparous women, ever OC use may exert its effect on breast cancer risk through changes in breast tissue, which can be observed on a mammogram.     

Risk factors for uncommon histologic subtypes of breast cancer using centralized pathology review in the Breast Cancer Family Registry

Epidemiologic studies of histologic types of breast cancer including mucinous, medullary, and tubular carcinomas have primarily relied on International Classification of Diseases-Oncology (ICD-O) codes assigned by local pathologists to define histology. Using data from the Breast Cancer Family Registry (BCFR), we compared histologic agreement between centralized BCFR pathology review and ICD-O codes available from local tumor registries among 3,260 breast cancer cases. Agreement was low to moderate for less common histologies; for example, only 55 and 26 % of cases classified as mucinous and medullary, respectively, by centralized review were similarly classified using ICD-O coding. We then evaluated risk factors for each histologic subtype by comparing each histologic case group defined by centralized review with a common set of 2,997 population-based controls using polytomous logistic regression. Parity [odds ratio (OR) = 0.4, 95 % confidence interval (95 % CI): 0.2-0.9, for parous vs. nulliparous], age at menarche (OR = 0.5, 95 % CI: 0.3-0.9, for age ≥13 vs. ≤11), and use of oral contraceptives (OCs) (OR = 0.5, 95 % CI: 0.2-0.8, OC use >5 years vs. never) were associated with mucinous carcinoma (N = 92 cases). Body mass index (BMI) (OR = 1.05, 95 % CI: 1.0-1.1, per unit of BMI) and high parity (OR = 2.6, 95 % CI: 1.1-6.0 for ≥3 live births vs. nulliparous) were associated with medullary carcinoma (N = 90 cases). We did not find any associations between breast cancer risk factors and tubular carcinoma (N = 86 cases). Relative risk estimates from analyses using ICD-O classifications of histology, rather than centralized review, resulted in attenuated, and/or more imprecise, associations. These findings suggest risk factor heterogeneity across breast cancer tumor histologies, and demonstrate the value of centralized pathology review for classifying rarer tumor types.     

Factors Associated with Development of High-Grade Squamous Intraepithelial Lesions of the Uterine Cervix in Women Younger than 30 Years

Objective: To determine the factors associated with the increased risk of developing high-grade squamousintraepithelial lesions (HSIL) of the uterine cervix in women younger than 30 years compared with those aged ≥ 30years who also had HSIL. Methods: Patients with HSIL who underwent loop electrosurgical excision procedure (LEEP)between January 2006 and July 2017 at Chiang Mai University Hospital were retrospectively reviewed. We analyzedthe factors associated with the development of HSIL by comparing two age groups between women aged < 30 yearsand those aged ≥ 30 years. The factors analyzed included the well-recognized risk factors for cervical cancer, i.e. ageat sexual debut, number of sexual partners, use of oral contraceptive (OC) pills, smoking history, sexually transmitteddiseases and HIV status. Univariate and multivariate logistic regressions were used to assess factors associated withthe increased risk of developing HSIL in women younger than 30 years compared with those aged ≥ 30 years. Results:During the study period, there were 345 patients with HSIL, 30 were < 30 years (case group) and 315 aged ≥ 30 years(control group). By multivariate analyses , early sexual debut(OR, 2.86; 95% CI, 1.01-8.13; P=0.047), multiple sexualpartners (OR, 2.94; 95% CI, 1.23-7.02; P=0.015), history of genital warts (OR, 20.46; 95% CI, 2.27-183.72; P=0.007)and history of smoking (OR, 2.95; 95% CI, 1.10-7.93; P=0.032) were significantly associated with the developmentof HSIL in women younger than 30 years when compared with those aged ≥ 30 years. The OC use, HIV status andunderlying diseases were not significantly different in both groups. Conclusion: Early age at sexual debut, multiplesexual partners, history of genital warts and smoking are significant risk factors for developing HSIL in women youngerthan 30 years. Cervical cancer screening should be considered in young women with such factors.     

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.     

Risk factors by molecular subtypes of breast cancer across a population-based study of women 56 years or younger

Differences in incidence, prognosis, and treatment response suggest gene expression patterns may discern breast cancer subtypes with unique risk factor profiles; however, previous results were based predominantly on older women. In this study, we examined similar relationships in women ≤ 56 years, classified by immunohistochemical staining for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 for 890 breast cancer cases and 3,432 frequency-matched population-based controls. Odds ratios (OR) and 95% confidence intervals (CI) for tumor subtypes were calculated using multivariate polytomous regression models. A total of 455 (51.1%) tumors were considered luminal A, 72 (8.1%) luminal B, 117 (13.1%) non-luminal HER-2/neu+, and 246 (27.6%) triple negative. Triple negative tumors were associated with breast feeding duration (per 6 months: OR = 0.76, 95% CI 0.64-0.90). Among premenopausal women, increasing body size was more strongly associated with luminal B (OR = 1.73, 95% CI 1.07-2.77) and triple negative tumors (OR = 1.67, 95% CI 1.22-2.28). A history of benign breast disease was associated only with increased risk of luminal A tumors (OR = 1.89, 95% CI 1.43-2.50). A family history of breast cancer was a risk factor for luminal A tumors (OR = 1.93, 95% CI 1.38-2.70) regardless of age, and triple negative tumors with higher risks for women <45 (OR = 5.02, 95% CI 2.82-8.92; P for age interaction = 0.005). We found that little-to-no breastfeeding and high BMI were associated with increased risk of triple negative breast cancer. That some risk factors differ by molecular subtypes suggests etiologic heterogeneity in breast carcinogenesis among young women.     

Breast Cancer Risk From Modifiable and Non-Modifiable Risk Factors among Women in Southeast Asia: A Meta-Analysis

Objective: The aim of this study was to determine breast cancer risk from modifiable and non-modifiable factors among women in Southeast Asia. Methods: This meta-analysis was performed on research articles on breast cancer risk factors in PubMed, ProQuest and EBSCO databases published between 1997 and October 2017. Pooled odds ratios (OR) are calculated using fixed and random-effect models. Data were processed using Review Manager 5.3 (RevMan 5.3). Results: From a total of 1,211 articles, 15 studies (1 cohort and 14 case control studies) met the criteria for systematic review. Meta-analysis results showed that of the known modifiable risk factors for breast cancer, parity (nulipara) had the highest odd ratio (OR = 1.85 [95% CI 1.47-2.32]) followed by body mass index (overweight) (OR = 1.61 [95% CI 1.43-1.80]) and use of oral contraceptives (OR = 1.27 [95% CI 1.07-1.51]). Of non-modifiable risk factors, family history of breast cancer had the highest odd ratio (OR = 2.53 [95% CI 1.25-5.09]), followed by age (≥ 40 years) (OR = 1.53 [95% CI 1.34-1.76]) and menopausal status (OR = 1.44 [95% CI 1.26-1.65]). Conclusion: This analysis confirmed associations between both modifiable risk factors (parity, body mass index and use of oral contraceptives) and non-modifiable risk factors (family history of breast cancer, age and menopausal status) with breast cancer.     

Oral contraceptive use, reproductive factors, and colorectal cancer risk: findings from Wisconsin.

We investigated the association of oral contraceptive (OC) use and reproductive factors with colorectal cancer risk in a large population-based case-control study. Cases were women ages 20 to 74 years, living in Wisconsin, with a new diagnosis of colon (n = 1,122) or rectal (n = 366) cancer. Control participants were randomly selected from population lists of similarly aged female Wisconsin residents (n = 4,297). Risk factor information was collected through structured telephone interviews. Compared with never users, OC users had an odds ratio (OR) of 0.89 [95% confidence interval (95% CI), 0.75-1.06] for colorectal cancer. OC use associations did not differ significantly between colon and rectal cancer sites; however, when compared with never users, recent OC users (<14 years) seemed at reduced risk of rectal cancer (OR, 0.53; 95% CI, 0.28-1.00). Women with age at first birth older than the median (23 years) had 0.83 times the risk of colon cancer compared with women with age at first birth below the median (95% CI, 0.70-0.98). We observed an inverse trend between increasing parity and rectal cancer risk (P = 0.05). Compared with nulliparous women, women with five or more births had 0.66 times the risk of rectal cancer (95% CI, 0.43-1.02). Compared with postmenopausal women, premenopausal women were at reduced risk (OR, 0.67; 95% CI, 0.47-0.97) of colorectal cancer. No significant associations were observed between colorectal cancer risk and age at menarche or age at menopause. These findings suggest differential roles of reproductive factors in colon and rectal cancer etiology.     

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’.     

Anthropometry and the risk of epithelial ovarian cancer

BACKGROUND: The association between anthropometric factors and ovarian cancer risk was investigated using data from 762 cases and 1348 controls participating in a population-based case-control study in the Delaware Valley from 1994-1998. Because factors such as oral contraceptive (OC), hormone therapy (HT), and parity may affect weight and hormone levels, the associations were examined in women with and without these characteristics. METHODS: Unconditional logistic regression was used to calculate odds ratios and 95% confidence intervals while controlling for age, race, parity, family history of ovarian cancer, tubal ligation, and OC use. RESULTS: Compared with controls, cases were taller and heavier in recent years and at age 18. Results did not differ by OC or HT use. However, anthropometric associations differed significantly based on parity, as increasing anthropometric measures were associated with increased ovarian cancer risk among nulliparous women only. Adjusted OR for recent body mass index (BMI) quartile 4 compared with quartile 1 for nulliparous women was 2.53 (95% confidence interval [CI]: 1.39, 4.61) compared with 0.96 (95% CI: 0.70, 1.31) for parous women. Additionally, adult weight gain was significant only for nulliparous women. Adjusted OR for weight change (recent to age 18) quartile 4 compared with quartile 1 for nulliparous women was 3.73 (95% CI: 1.88, 7.42) versus 1.09 (95% CI: 0.78, 1.51) for parous women. CONCLUSIONS: BMI and weight in women's adult lifetime may be positively associated with ovarian cancer risk. Observations were most apparent for nulliparous women, possibly reflecting an interaction between local inflammation caused by incessant ovulation and increased estrogen exposure on ovarian epithelium.     

Reproductive Risk Factors Differ Among Breast Cancer Patients and Controls in a Public Hospital of Paraiba,Northeast Brazil

The incidence and mortality rates of breast cancer in Northeast Brazil are increasing and little is known aboutprevailing reproductive factors contributing to this increase. A case-control study was conducted in a publichospital of Campina Grande, state of Paraíba, including 81 women with diagnosed invasive breast cancer and 162age matched (±5 years) controls. Binominal logistic regression analysis was applied to estimate odds ratio (OR)and confidence intervals (CI) of risk factors. In this model, age at menarche ≤12 (OR= 2.120; CI: 1.043- 4.308;p=0.038), single parity (OR=3.748; CI: 1.459- 9.627; p=0.06) and reproductive period >10 years (OR=3.042;CI: 1.421- 6.512; p=0.04) were identified as independent variables that significantly increased breast cancerrisk of parous women. Compared to parous women who never practised breastfeeding, total breastfeeding time> 24 months decreased the risk of breast cancer (OR=0.258; CI: 0.084- 0.787; p= 0.017). The results indicatedthat modifiable reproductive factors contribute to breast cancer risk in women included in the present study.Women’s knowledge about factors such as the protective effect of breastfeeding could reduce the risk of breastcancer.     

Impact of teenage oral contraceptive use in a population-based series of early-onset breast cancer cases who have undergone BRCA mutation testing

Oral contraceptive (OC) use in young women has been associated with an increased risk of breast cancer. This matched case-control study aims to elucidate the combined effects of OC use and genetic factors in a population-based series of BRCA1/2 mutation-tested early-onset breast cancers. A first invasive breast cancer was diagnosed in 259 women aged 40 years between 1990 and 1995 in the South Swedish Health Care Region. A total of 245 women were included in this study. Information on family history of cancer, reproductive factors, smoking and OC use was obtained from questionnaires or patient charts. Three age-matched controls per case were chosen from a prospective South Swedish cohort. Ever OC use and current OC use were not associated with breast cancer. Cases were more likely to have used OCs before age 20 years (adjusted odds ratio (OR) 2.10 (95% CI 1.32-3.33)) and before their first child (adjusted OR 1.63 (95% CI 1.02-2.62)). When stratified by age, the effect of early OC use was limited to women diagnosed prior to age 36 years (OR 1.53 (1.17-1.99) per year of OC use prior to age 20 years). The risks were similar for low-dose and high-dose OCs. The probability of being a BRCA1/2 mutation carrier was three times higher among cases who started OC use prior to age 20 years compared with cases who started at age 20 years or older or who had never used OCs. However, the duration of OC use was similar among cases with and without BRCA1/2 mutations. No association was seen with a first-degree family history of breast cancer. Each year of OC use prior to age 20 years conferred a significantly increased risk for early-onset breast cancer, while there was no risk associated with use after age 20 years.