Breast cancer risk factors in women participating in a breast screening program: a study on 11,850 Iranian females

Systematic Review and Meta-Analysis of Lifestyle and Reproductive Factors Associated with Risk of Breast Cancer in Asian Women

BACKGROUND

Assessing breast cancer risks from lifestyle and reproductive factors is critical for developing population-specific risk prediction tools. However, limited studies have evaluated these risks in recent Asian birth cohorts.

METHODS

We systematically reviewed articles published from January 2010 to December 2023, examining breast cancer risk factors in Asian women. Data were described narratively, estimates pooled, and prevalence and attributable proportions compared across Asian populations.

RESULTS

Of the 128 studies reviewed, 103 reported adjusted effect sizes for meta-analysis. Lifestyle and reproductive factors were predictive of breast cancer risk in Asian women, with varying impacts on premenopausal and postmenopausal women. Relative risks were similar within Asian populations and in comparison to European populations, except for menarche, menopause, and hormone receptor therapy. However, risk factor distributions differed across populations. While alcohol intake (21%) and oral contraceptive use (20%) emerged as the most attributable modifiable risk factors in Europeans, passive smoking (24%) and higher BMI (17%, ≥24 kg/m2 among postmenopausal women) were predominant in Asians.

CONCLUSIONS

Our study shows that while the effects of lifestyle and reproductive breast cancer risk factors are largely similar across different populations, their distributions vary.

IMPACT

Our analysis underscores the importance of considering population-specific risk factor distributions when developing risk prediction tools for Asian populations.

Association of imaging and pathological findings of breast cancer in very young women: Report of a twenty-year retrospective study

PURPOSE

In this study, we aimed to assess the new trends in characteristics, molecular subtypes, and imaging findings of breast cancer in very young women.

METHODS

We retrospectively reviewed the database of a primary breast cancer referral center in southern Iran in 342 cases of 30-year-old or younger women from 2001 to 2020. Pathologic data, including nuclear subtype and grade, tumor stage, presence of in situ cancer, imaging data including lesion type in mammogram and ultrasound, and treatment data were recorded. Descriptive statistics were applied. Differences between categorical values between groups were compared using Pearson's Chi-square test.

RESULTS

The mean age was 27.89 years. The tumor type was invasive ductal carcinoma in 82 % of cases. Fourteen patients (4.4 %) had only in situ cancer, and 170 patients had in situ components (49.7 %). Molecular subtypes were available in 278 patients, including 117 (42.1 %) Luminal A, 64 (23.0 %) Luminal B, 58 (20.9 %) triple negative, and 39 (14 %) HER2 Enriched. In those with mammograms available, 63 (30.1 %) had no findings, 53 (25.3 %) had mass, 27 (12.9 %) had asymmetry, whether focal or global, 21 (10 %) had microcalcifications solely, and 45 (21.5 %) had more than one finding. Microcalcifications were significantly more common in Luminal cancers than HER2 and triple-negative cancers (p = 0.041).

CONCLUSION

Our study shows the most common subtype to be Luminal A cancer, with 74 % of the tumors being larger than 2 cm at the time of diagnosis. Irregular masses with non-circumscribed margins were the most common imaging findings.

The impact of BMI on breast cancer - an updated systematic review and meta-analysis

BACKGROUND

Breast cancer is the most frequent form of cancer in women all over the world. It is the main cause of cancer death and the most often diagnosed cancer in women in 140 of the world's 184 countries. The link between breast cancer risk and body mass index (BMI) has gotten increasing attention in recent years, although the results are still debatable. Therefore, the current systematic review and meta-analysis evaluate the impact of BMI on breast cancer.

METHODS

The current study was carried out as a systematic review and meta-analysis, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We systematically searched Cochrane, Google Scholar, PubMed, EMBASE and Scopus databases to identify eligible articles impact of BMI on breast cancer with the appropriate Medical Subject Headings (MeSH). The Newcastle-Ottawa checklist was used for the risk of assessment for the included studies. Meta-analysis was performed using Review Manager 5.3 software.

RESULTS

Forty-six studies were included in the current review, which met the selection criteria of the current review. Among included 46 studies in this review, 50% (n = 23) of the studies found the HER2 type of breast cancer followed by triple-negative and HR-positive. The obesity was significantly higher in the case group compared with the control group (P < .001). Heterogeneity between the 14 studies is medium (I2 = 72%). In this review, there was no significant relation between overweight and breast cancer in women (P > .05). Heterogenecity between the 14 studies is medium (I2 = 89%). However, after removing the publication bias a significant relation between overweightness and breast cancer in women (P = .0005) was observed.

CONCLUSION

Obese breast cancer patients are a specific type of patient. They are more likely to develop cancer. Their need to surgery and radiation may cause greater difficulties. Obesity and overweight in women greatly increase the risk of breast cancer, according to the findings of the current meta-analysis. To confirm these findings and understand the pathogenic pathways, more research is required.

The Effect of Chemotherapy on Estradiol Levels in Patients with HER 2-Overexpression Breast Cancer in Dr Moewardi General Hospital, Surakarta, Indonesia

AIM: This study aims to evaluate the effect of adjuvant chemotherapy on estradiol levels in patients with HER 2-overexpression breast cancer in a developing country. METHODS: This comparative study with pre- and post-design model observation approach, involving patients with HER 2-overexpression breast cancer who had undergone surgery and had never received chemotherapy or hormonal therapy before, who were then given adjuvant chemotherapy. Estradiol levels were measured before and after chemotherapy. The study was carried out in the surgical oncology division of RSUD Dr. Moewardi (RSDM) Surakarta from January 2020-December 2020. Descriptive data are presented in a frequency table based on age, menstrual status, parity status, breastfeeding status, contraception, contraception duration, family history, stage, and histological grade. Before and after chemotherapy in patients with breast cancer, the estradiol levels employed the paired sample t-test of the Wilcoxon rank test because the data did not meet the normality assumption. RESULTS: From the total data of 21 patients, 15 patients experienced a decrease in estradiol levels after chemotherapy, while six patients underwent an increase. The mean estradiol level before chemotherapy was 89.41 pg/ml, whereas the mean estradiol level after chemotherapy was 55.90 pg/ml. It indicates a difference in the decrease in estradiol levels of 33.51 pg/ml. The statistical test results also obtained a p-value of = 0.033 (p < 0.05), which signifies a significant difference between estradiol levels before and after chemotherapy. Thus, chemotherapy is effective in lowering estradiol levels in patients with breast cancer. CONCLUSION: Chemotherapy affects decreasing estradiol levels in patients with HER2 overexpression breast cancer.

Oral Contraceptive Use and Breast Cancer Risk Assessment: A Systematic Review and Meta-Analysis of Case-Control Studies, 2009-2020

To perform a meta-analysis of case-control studies that addressed the association between oral contraceptive pills (OC) use and breast cancer (BrCa), PubMED (MEDLINE), Embase, and the Cochrane Library were searched to identify case-control studies of OC and BrCa published between 2009 and 2020. We used the DerSimonian-Laird method to compute pooled odds ratios (ORs) and confidence intervals (CIs), and the Mantel-Haenszel test to assess the association between OC use and cancer. Forty-two studies were identified that met the inclusion criteria and we included a total of 110,580 women (30,778 into the BrCa group and 79,802 into the control group, of which 15,722 and 38,334 were using OC, respectively). The conducted meta-analysis showed that the use of OC was associated with a significantly increased risk of BrCa in general, OR = 1.15, 95% CI: 1.01 to 1.31, p = 0.0358. Regarding other risk factors for BrCa, we found that increased risk was associated significantly with early menarche, nulliparous, non-breastfeeding, older age at first parity, postmenopause, obesity, smoking, and family history of BrCa. Despite our conclusion that birth control pills increase the cancer risk being supported by extensive previous studies and meta-analyzes, further confirmation is required.

Reproductive Determinants of Breast Cancer in Women in Indonesia

BACKGROUND: The number of breast cancer cases has increased every year both in the world and in Indonesia, so that breast cancer has become a major health problem both in the world and in Indonesia. The specific cause of breast cancer is still not known with certainty, but many factors are thought to influence the development of breast cancer which are called risk factors. In women, reproductive factors are thought to influence the incidence of breast cancer. AIM: This study aims to determine the determinants of breast cancer in women in terms of reproductive factors. METHOD: This research is a quantitative research with a case control study design through a retrospective approach using a questionnaire instrument. The sample size obtained was 100 women with breast cancer (case sample) and 100 women without breast cancer (control sample) (1:1), so the total sample was 200 people. Data were analyzed bivariately using chi-square test, and multivariate using logistic regression test. RESULTS: From this study it is known that the reproductive factor associated with the incidence of breast cancer in women is the age of menarche with a value of p = 0.034 OR = 1.83 CI = 1.045-3.207, the age of giving birth to the first child with a value of p = 0.000 OR = 6.39 CI = 2,521-16,243, parity with p-value = 0.022 OR = 2.14 CI = 1.107-4.152, and history of breastfeeding with p-value = 0.000 OR = 4.16 CI = 1.967-8.830. Meanwhile, the age of menopause had no relationship with the incidence of breast cancer where the p-value was 0.384. Based on the results of multivariate analysis, it was found that the most dominant factor was the age at birth of the first child with a value of p = 0.002, Exp (B) = 5, 11 and CI = 1, 85-14, 10. CONCLUSION: The results of this study indicate that reproductive factors in women (age of menarche, age at first birth, parity, and history of breastfeeding) are risk factors for breast cancer. Based on the results of this study, women must get married immediately if they have entered the ideal age for marriage and do not delay having children so that they can immediately carry out the breastfeeding process to minimize risk factors to avoid breast cancer.

Breast Cancer Incidence Trends in Isfahan Province Compared with those in England over the Period 2001-2013

BACKGROUND

Figures from Iranian cancer registries indicate that Isfahan ranks first in female breast cancer incidence. Although few previous studies have examined whether the breast cancer incidence trend in Isfahan province has increased over a given period of time, this study employed a joint point regression analysis to answer the same question. Moreover, it compared the data of Isfahan province, from a developing country, with those of England, as a representative of developed countries, and tried to explain the causes of the differences observed between the trends.

METHODS

This repeated cross-sectional study was conducted on the data of 6057 women in Isfahan province and of 141,011 women in England with breast cancer over the years 2001-2013. The incidence rates were calculated using direct standardization method and based on the 2013 standard European population. For an analysis of the trends in breast cancer incidence rates, Joint Point Regression program, version 4.3.1.0, released in April 2016, was employed.

RESULTS

The mean age-standardized incidence rate (ASR) was calculated to be 34.7 per100,000 population over the years 2001 to 2013, which indicated an increase from 22 to 68 in Isfahan province. The corresponding mean ASR for England has also risen from 147.5 to 170.1 per 100,000 women during the same time period. The average annual percentage changes (AAPCs) for Isfahan and England were also calculated to be 9.6 and 1.1, respectively. This indicated an increasing trend in breast cancer incidence rates for Isfahan province over the period in question.

CONCLUSIONS

The drastic discrepancy in breast cancer incidence rates between these two regions may be attributed to differences in an improved cancer registry system in Iran and women's developing awareness of the cancer over time.

PD-L1 expression in tumor lesions and soluble PD-L1 serum levels in patients with breast cancer: TNBC versus TPBC

BACKGROUND

Block of programmed cell death protein 1 (PD-1) interaction with its ligand, PD-L1, enhances anti-tumor activity.

OBJECTIVES

We aimed to assess the association between PD-L1 expression in tumor cells and CD8+ tumor infiltrating T cells (TILs) as well as soluble (s)PD-L1 serum levels in patients with triple negative breast cancer (TNBC) compared to triple positive (TPBC).

METHODS

A total of 113 tumor sections and 133 serum samples were available from 144 patients with breast cancer (72 TNBC and 72 TPBC). Dual immunohistochemistry staining was applied to determine differential PD-L1 expression in tumor cells and CD8+ TILs. Soluble PD-L1 serum levels were also evaluated in patients compared to 40 healthy women by ELISA method.

RESULTS

Despite TPBC patients which were mostly grades 1/2, TNBC patients were grade 3 (72% versus 66.7%, P < 0.001). Most of the TNBC patients were stages I/II, whereas most of the TPBC patients were stages III/IV (57.3% versus 68.3%,P = 0.005). There was no difference in tumor size and metastasis between TNBC and TPBC patients, although the number of involved lymph nodes was significantly more in TPBC patients (P = 0.0012). PD-L1 expression was detected in 11.5% of samples mostly in TNBC subtype and was associated with advanced grades (P = 0.039). There was no relationship between PD-L1 expression and tumor stage. PD-L1 expression in CD8+ TILs was nonsignificantly higher than tumor cells. Serum levels of sPD-L1 showed no difference between patients and healthy women. We found no correlation between PD-L1 expression in tumor lesions and serum levels of sPD-L1 in patients.

CONCLUSION

PD-L1 expression was more detected in our patients with TNBC. It seems that, these patients who are resistant to standard chemotherapy regimens may get benefit from PD-L1 inhibition therapy and because of its low serum levels, sPD-L1 cannot interfere with this therapy.

Risk Factors Associated with Breast Cancer among Women in Addis Ababa, Ethiopia: Unmatched Case-Control Study

BACKGROUND

Breast cancer is a common public health problem and the main cause of cancer-related death worldwide. There is a paucity of evidence on the risk factors of breast cancer in Ethiopia. Therefore, we aimed to identify the risk factors of breast cancer among women in Addis Ababa, Ethiopia.

METHODS

We conducted an institutional-based unmatched case-control study with a sample of 348 women (116 cases and 232 controls). Participants were selected by a systematic random sampling technique. Data were collected using an interviewer-administered questionnaire. Data were entered using EpiData version 4.6 and analyzed using SPSS version 25. Multivariable analysis was carried out using the adjusted odds ratio (AOR) with a 95% confidence interval (CI). P-value of less than 0.05 was considered statistically significant.

RESULTS

The mean age (+SD) of the participants was 42.7 (±11.3) and 40.7 (±14.6) for the cases and controls, respectively. Early onset of menarche (AOR= 4.10; 95% CI: 1.84, 9.15), rural women (AOR= 3.64; 95% CI:1.38, 9.57), utilization of packed foods or drinks (AOR= 2.80; 95% CI:1.52, 5.15), and smoke-dried meat (AOR= 2.41; 95% CI:1.36, 4.27), family history of cancer (AOR= 2.11; 95% CI:1.04, 4.26), overweight and/or obesity (AOR= 2.38; 95% CI:1.31, 4.31), and women with one or less children (AOR= 1.86; 95% CI:1.01, 3.41) were associated factors with breast cancer risk.

CONCLUSION

In this study, early onset of menarche, rural women, utilization of packed foods or drinks and smoke-dried meat, family history of cancer, overweight and/or obesity, and women with one or fewer children were factors that increased breast cancer risk. Therefore, focusing on modifiable risk factors and increasing awareness of the community such as a healthy diet, promotion of breast self-examination, and creation of programs to increase women's knowledge is important to reduce the increasing burden of breast cancer.

Spatio-temporal analysis of colorectal cancer using a geographic information system in the Iranian military community during the period 2007-2016

INTRODUCTION

Colorectal cancer (CRC) is one of the most prevalent cancers among Iranian people. The study of spatio-temporal distribution of disease has an important role in the design of disease prevention programmes. The purpose of the current study was to describe the spatio-temporal distribution of CRC in the Iranian military community as a sample of the Iranian population.

METHODS

In the current ecological study, all registered cancer cases in the Iranian military community during the period 2007-2016 were considered. To identify hotspots, Getis-Ord Gi statistics were used. All analyses were performed using ArcGIS 10.5 and Excel 2010.

RESULTS

The highest incidences of CRC in 2007-2008, 2009-2010 and 2011-2012 were recorded in Kermanshah province. The highest incidences of CRC in 2013-2014 were seen in Kermanshah, Ghilan, Tehran and North Khorasan. In 2007-2008 and 2009-2010, hotspots were detected in West Azarbayjan. In 2011-2012, hotspots were detected in Zanjan and Qazvin. In 2013-2014, a hotspot was detected in Qazvin. Finally, West Azerbaijan was the hotspot for CRC in 2015-2016.

CONCLUSIONS

The incidence of CRC in men was higher than in women. Also it appeared that North and North West Iran were risk areas for this disease, and so these areas should be considered in the design of disease prevention programme for this cancer type. Additionally, the determination of individual risk factors in the aforementioned geographical areas can play an important role in the prevention of this type of cancer.

Breast cancer risk factors in Iran: a systematic review & meta-analysis

OBJECTIVES

Breast cancer is known as one of the deadliest forms of cancer, and it is increasing globally. There are a variety of proven and controversial risk factors for this malignancy. Herein, we aimed to undertake a systematic review and meta-analysis focus on the epidemiology of breast cancer risk factors in Iran.

METHODS

We performed a systematic search via PubMed, Scopus, Web of Science, and Persian databases for identifying studies published on breast cancer risk factors up to March 2019. Meta-analyses were done for risk factors reported in more than one study. We calculated odds ratios (ORs) with corresponding 95% confidence intervals (CIs) using a fixed/random-effects models.

RESULTS

Thirty-nine studies entered into the meta-analysis. Pooling of ORs showed a significant harmful effect for risk factors including family history (OR: 1.80, 95%CI 1.47-2.12), hormonal replacement therapy (HRT) (OR: 5.48, 95%CI 0.84-1.74), passive smokers (OR: 1.68, 95%CI 1.34-2.03), full-term pregnancy at age 30 (OR: 3.41, 95%CI 1.19-5.63), abortion (OR: 1.84, 95%CI 1.35-2.33), sweets consumption (OR: 1.71, 95%CI 1.32-2.11) and genotype Arg/Arg (crude OR: 1.59, 95%CI 1.07-2.10), whereas a significant protective effect for late menarche (OR: 0.58, 95%CI 0.32-0.83), nulliparity (OR: 0.68, 95%CI 0.39-0.96), 13-24 months of breastfeeding (OR: 0.68, 95%CI 0.46-0.90), daily exercise (OR: 0.59, 95%CI 0.44-0.73) and vegetable consumption (crude OR: 0.28, 95%CI 0.10-0.46).

CONCLUSIONS

This study suggests that factors such as family history, HRT, passive smokers, late full-term pregnancy, abortion, sweets consumption and genotype Arg/Arg might increase risk of breast cancer development, whereas late menarche, nulliparity, 13-24 months breastfeeding, daily exercise and vegetable consumption had an inverse association with breast cancer development.

Dietary Habits and Physical Activity are Associated With the Risk of Breast Cancer Among Young Iranian Women: A Case-control Study on 1010 Premenopausal Women

BACKGROUND

Several studies conducted in developed countries introduced diet and physical inactivity as major risk factors for several types of cancers. However, the impact of diet and physical inactivity on the risk of breast cancer (BC) is understudied, and the limited findings are controversial. In addition, no or limited knowledge is available from the developing world.

PATIENTS AND METHODS

This case-control study was performed from November 2014 to March 2016 on 1010 young women aged 20 to 50 years who were newly diagnosed with BC. Data was obtained via a validated questionnaire and the global physical activity questionnaire (GPAQ2). Also, patients' medical and histopathology reports were reviewed.

RESULTS

The results of multiple logistic regression suggested that, except for the common risk factors for BC (older marital age, family history of BC, smoking, and being a passive smoker), eating red meat (adjusted odds ratio [aOR] >8 portions/week [p/w] vs. 0-2 p/w, 1.15; 95% confidence interval [CI], 1.04-1.28); eating fish (aOR >8 p/w vs. 0-2 p/w, 1.55; 95% CI, 1.12-2.76), fruit consumption (aOR 0-4 p/w vs. >8 p/w, 1.96; 95% CI, 1.07-3.82), pickle consumption (aOR >8 p/w vs. 7-8 p/w, 1.46; 95% CI, 1.31-1.70), and intensity of physical activity (aOR light vs. vigorous, 1.68; 95% CI, 1.47-1.98) were directly associated with a higher risk of BC in young women.

CONCLUSION

Our study supported the hypothesis that unhealthy dietary habits and physical inactivity are risk factors for BC. We found that a healthy diet containing low fat and high fruits and vegetables with regular exercise are effective ways to reduce the risk of BC among young women.

Knowledge, Attitudes and Practices Regarding Breast Cancer amongst Lebanese Females in Beirut

Objectives: Regular screening for breast cancer is associated with better survival, but compliance with guidelines depends on good knowledge and attitudes. This study aimed to assess the level of breast cancer knowledge, attitudes and screening practices in Lebanese females, and identify their socio-demographic determinants as well as barriers to mammography use. Methods: This cross-sectional study was conducted with 371 Lebanese females residing in Beirut aged 18-65 with no history of breast cancer. The questionnaire applied was adapted from Stager and Champion. The overall knowledge score was determined with sections on general knowledge, curability, symptoms, and screening; the overall attitude score concerned attitudes towards breast cancer, screening, and barriers; and the overall practices score was for breast self examination (BSE), clinical breast examination (CBE) and mammography. Bivariate and multivariate analyses of socioeconomic determinants were performed for each score. Results: The mean knowledge score was 55.5±17.1% and that for attitudes was 71.9±8.3%. For self-examination, mammography and clinical examination practices, individual means were 45.7±42.3%, 77.9±36.5% and 29.1±45.5%, respectively. Knowledge, attitudes and practices correlated positively with each other (p<0.0001). The highest average was the knowledge of symptoms (72.8±24.7%), and the lowest that of curability (49.6±25.7%). Most frequent barriers to mammography were fear of learning bad news, pain, costs, and staff unpleasantness. Higher education was associated with better knowledge (p=0.002) and smoking with lower levels (p=0.003). Older age (p=0.002), higher education (p=0.02), and taking exercise (p=0.02) were associated with better attitudes. Higher education (p=0.02) and having children (p=0.003) were associated with better practices. Conclusion: More emphasis should be placed on educating females on the curability of breast cancer and specific targeting of the barriers identified.

Assessment of potential risk factors for breast cancer in a population in Southern Brazil

PURPOSE

The aim of this study is to assess potential risk factors for breast cancer in a population in Southern Brazil and build a multivariate logistic model using these factors for breast cancer risk prediction.

METHODS

A total of 4242 women between 40 and 69 years of age without a history of breast cancer were selected at primary healthcare facilities in Porto Alegre and submitted to mammographic screening. They were evaluated for potential risk factors.

RESULTS

In all, 73 participants among the 4242 women had a breast cancer diagnosis during the follow-up of the project (10 years). The multivariate analysis considering all the patients aged 40-69 years showed that older age (OR 1.08, 95% CI 1.04-1.12), higher height (OR 1.04, 95% CI 1.01-1.09), and history of previous breast biopsy (OR 2.66, 95% CI 1.38-5.13) were associated with the development of breast cancer. Conversely, the number of pregnancies (OR 0.87, 95% CI 0.78-0.98) and use of hormone replacement therapy (OR 0.39, 95% CI 0.20-0.75) were considered a protective factor. Additionally, we performed an analysis separating the participants into groups of 40-49 and 50-69 years old, since a risk factor could have a specific behavior in these age groups. No additional risk factors were identified within these age brackets, and some factors lost statistical significance.

CONCLUSION

The risk prediction model indicates that the following variables should be assessed in this specific population: age, height, having had previous breast biopsies, number of pregnancies, and use of hormone replacement therapy. These findings may help to better understand the causal model of breast cancer in Southern Brazil.

Breast Cancer Status in Iran: Statistical Analysis of 3010 Cases between 1998 and 2014

Background

Breast cancer is the 5th leading cause of cancer death in Iranian women. This study analyzed 3010 women with breast cancer that had been referred to a cancer research center in Tehran between 1998 and 2014.

Methods

In this retrospective study, we analyzed 3010 breast cancer cases with 32 clinical and paraclinical attributes. We checked the data quality rigorously and removed any invalid values or records. The method was data mining (problem definition, data preparation, data exploration, modeling, evaluation, and deployment). However, only the descriptive analyses' results of the variables are presented in this article. To our knowledge, this is the most comprehensive study on breast cancer status in Iran.

Results

A typical Iranian breast cancer patient has been a 40–50-year-old married woman with two children, who has a high school diploma and no history of abortion, smoking, or diabetes. Most patients were estrogen and progesterone receptor positive, human epidermal growth factor (HER) negative, and P53 negative. Most cases were detected in stage 2 with intermediate grade.

Conclusion

This study revealed original findings which can be used in national policymaking to find the best early detection method and improve the care quality and breast cancer prevention in Iran.

Hair Coloring, Stress, and Smoking Increase the Risk of Breast Cancer: A Case-Control Study

PURPOSE

Epidemiologic characteristics of breast cancer in Iran are significantly different from those in the West and even other regional countries, but little is known about the related factors.

PATIENTS AND METHODS

A hospital-based case-control study was conducted on 1052 women (526 new cases and 526 controls). Logistic regression was performed to investigate associations of study factors with breast cancer risk.

RESULTS

This study introduced occupation (odds ratio [OR]_{employed/household}, 1.77; 95% confidence interval [CI], 1.15-2.69), marital age (OR_{24-30 y/< 18 y}, 2.13; 95% CI, 1.03-4.40), age at first delivery (OR_{≥ 30 y/< 18 y}, 3.53; 95% CI, 1.73-7.18), parity (OR_{1-2/Nulliparous or never married}, 2.61; 95% CI, 1.13-6.02), birth interval (OR_{30-50 mos/< 18 mos}, 2.38; 95% CI, 1.45-3.89), lifetime breastfeeding (OR_{≥ 42 mos/< 6 mos}, 0.37; 95% CI, 0.18-0.77), and menarche age (year) (OR, 0.87; 95% CI, 0.79-0.96) as significant associates of breast cancer. In addition, body mass index (OR, 1.07; 95% CI, 1.02-1.11) and some health-related behaviors including hair coloring on a regular basis (OR_yes/no, 1.93; 95% CI, 1.41-2.62), smoking (OR_yes/no, 2.02; 95% CI, 1.22-3.34), oral contraceptive usage (OR_ever/never. 1.46; 95% CI, 1.05-2.04), physical inactivity (OR_{inactive/regular activity}, 1.54; 95% CI, 1.39-1.75), past life stress (OR_{often stressful/often calm}, 2.40; 95% CI, 1.62-3.56), and regular bedtime (OR_{often regular/no}, 0.32; 95% CI, 0.19-0.54) were related to a higher risk of breast cancer.

CONCLUSION

This study revealed a significant number of factors that seem to contribute to the risk of breast cancer even more than the other previously introduced factors.

Behavioral risk factors of breast cancer in Bangui of Central African Republic: A retrospective case-control study

Breast cancer is recognized as a major public health problem in developing countries; however, there is very little evidence of behavioral factors associated with breast cancer risk. This study was conducted to identify lifestyles as risk factors for breast cancer among Central African women. A case-control study was conducted with 174 cases confirmed histologically by the pathology unit of the National Laboratory and 348 age-matched controls. Data collection tools included a questionnaire with interviews and medical records of patients. Data were analyzed using SPSS software version 20. Odd ratio (OR) and 95% confidence intervals (95% CI) were obtained by unconditional logistic regression. In total, 522 women were studied with a mean age of 45.8 (SD = 13.4) years. By unconditional logistic regression model, women with breast cancer were more likely to have attained illiterate and elementary education level [11.23 (95% CI, 4.65-27.14) and 2.40 (95% CI, 1.15-4.99)], married [2.09 (95% CI, 1.18-3.71)], positive family history [2.31 (95% CI, 1.36-3.91)], radiation exposure [8.21 (95% CI, 5.04-13.38)], consumption charcuterie [10.82 (95% CI, 2.39-48.90)], fresh fish consumption [4.26 (95% CI, 1.56-11.65)], groundnut consumption [6.46 (95% CI, 2.57-16.27)], soybean consumption [16.74 (95% CI, 8.03-39.84)], alcohol [2.53 (95% CI, 1.39-4.60)], habit of keeping money in bras[3.57 (95% CI, 2.24-5.69)], overweight [5.36 (95% CI, 4.46-24.57)] and obesity [3.11(95% CI, 2.39-20.42)]. However, decreased risk of breast cancer was associated with being employed [0.32 (95% CI, 0.19-0.56)], urban residence [0.16 (95% CI, 0.07-0.37)], groundnut oil consumption [0.05 (95% CI, 0.02-0.14)], wine consumption [0.16 (95% CI, 0.09-0.26)], non habit of keeping cell phone in bras [0.56 (95% CI, 0.35-0.89)] and physical activity [0.71(95% CI, 0.14-0.84)]. The study showed that little or no education, marriage, positive family history of cancer, radiation exposure, charcuterie, fresh fish, groundnut, soybean, alcohol, habit of keeping money in bras, overweight and obesity were associated with breast cancer risk among Central African women living in Bangui. Women living in Bangui should be more cautious on the behavioral risk associated with breast cancer.

The Role of Oral Contraceptive Pills on Increased Risk of Breast Cancer in Iranian Populations: A Meta-analysis

BACKGROUND

Cancer is one of the main public health issues in the world. Breast cancer is one of the most common types of cancer among women. It is also the second cause of mortality in women. The association between the use of oral contraceptive pills and breast cancer is controversial and a main issue in public health. Some findings have shown that taking these pills does not have a significant effect in increasing the risk of breast cancer, while others have confirmed the carcinogenic effect of these products. These contradictory findings necessitated this meta-analysis, through of all correlated studies in Iran.

METHODS

All published studies were considered from June 2000 until June 2015, using reliable Latin databases like PubMed, Google Scholar, Google search, Scopus, and Science Direct, and Persian database like SID, Irandoc, IranMedex, and Magiran. Finally, 26 papers were selected: 24 studies were case control while two were population based studies. A total of 26 papers with 46,260 participants were assessed since 2001.

RESULTS

Overall estimate of OR for the effect of oral contraceptive pills on breast cancer is 1.521 (CI = 1.25-1.85), which shows that the intervention group had more chance (52%) compared to the control group (P = 0.001). Using these pills increased the risk of breast cancer up to 1.52 times.

CONCLUSIONS

Because of directly increasing levels of estrogen and the role of estrogen in gaining weight indirectly, oral contraceptive pills can stimulate the occurrence of breast cancer. More studies should be conducted for controlling the period of pill use.