Analysis of the risk factors of breast cancer

Department of Diagnostic Imaging, Baoan District Hospital, Shenzhen, China.
Nan fang yi ke da xue xue bao = Journal of Southern Medical University 03/2010; 30(3):622-3.
Source: PubMed


To explore the risk factors of breast cancer for better control and prevention of the malignancy.
The clinical data of 232 patients with pathologically established breast cancer were investigated in this 1:1 case-control study to identify the risk factors of breast cancer.
The history of benign breast diseases, family history of carcinoma and multiple abortions were the statistically significant risk factors of breast cancer, while breast feeding was the protective factor.
A history of benign breast diseases, family history of carcinoma and multiple abortions are all risk factors of breast cancer.

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    • "A study covering 150,000 females in 30 countries conducted by the Breast Cancer Estrogen Intergroup showed that for breastfeeding (in excess of 12 months) could reduce the risk of breast cancer by 4.3%, and that breastfeeding is an independent risk factor for breast cancer, and is not affected by other confounders such as age at first birth, parturition times, or race [17]. Studies from China have made similar findings [14,18]. Therefore, based on our findings and on the available literature, it is possible that the decreasing duration of breastfeeding due to reduced pregnancies may partly contribute to the increasing incidence of breast cancer in China. "
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    ABSTRACT: There has been a sharp increase in the incidence of breast cancer in China in recent years. A number of female physical characteristics, such as age at menarche, menopause, first birth and the duration of breastfeeding, have been linked to breast cancer, yet data on these factors in Chinese women is largely missing both for aggregate and age-specific data. Thus, the objective of this study was to explore changes in female menstrual and childbearing characteristics as a possible explanation for increasing rates of breast cancer in this country. From July to September 2008, a population based cross-sectional breast cancer survey covering 124,758 females from 4 provinces or cities in Eastern China was carried out, using multi-stage and cluster methods. In-person interviews based on a self-designed structured questionnaire were performed, in which female physiological and reproductive factors, such as age at menarche and menopause, menstrual cycle history, childbearing history, breastfeeding methods, abortions or miscarriage, were included. For every 10-year age category, the subjects were divided, and across those age groups, all the above factors were compared respectively and changes in physical and childbearing characteristics were evaluated. ANOVA was used to compare the differences across the groups. A total of 122058 subjects were included in the final analysis. The mean age at menarche was 15.39 years, the mean number of full-term pregnancies was 1.58, the mean duration of breastfeeding was 22.68 months, the mean age at first birth was 23.75 years, the mean frequency of miscarriage was 0.36, and the mean age at menopause was 48.63 years. Significant differences across the several age groups were noted for the age at menarche, number of full-term pregnancies, accumulated duration of breastfeeding, age at first birth, number of miscarriages, and age at menopause. These data clearly showed a gradual shift towards an earlier age at menarche, fewer pregnancies and shorter breastfeeding lengths. Significant changes in female physical and childbearing characteristics across a number of different age ranges were detected. These changes may be related to the increasing trend of breast cancer in China.
    BMC Public Health 05/2012; 12(1):368. DOI:10.1186/1471-2458-12-368 · 2.26 Impact Factor
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    ABSTRACT: Background The characteristics of established risk factors for breast cancer may vary among countries. A better understanding of local characteristics of risk factors may help in devising effective prevention strategies for breast cancer. Methods Information on exposures to risk factors was collected from the medical charts of 4211 women with breast cancer diagnosed during 1999–2008. The distributions of these exposures among regions, and by menopausal status and birth period, were compared with the χ2 test. Crude associations between the selected factors and breast cancer were estimated using the cases in the present study and a representative control population, which was selected from qualified published studies. Results As compared with cases from less developed regions, those from more developed regions were significantly more likely to be nulliparous, had fewer childbirths (P < 0.05), and were less likely to have breastfed (P = 0.08). As compared with premenopausal cases, postmenopausal cases were more likely to be overweight and to have breastfed and had more childbirths (P < 0.05). The number of live births and rate of breastfeeding decreased in relation to birth period (P for trends <0.001). Overweight, late menopause, and family history of breast cancer were significantly associated with breast cancer among Chinese women. Conclusions Breast cancer incidence was associated with nulliparity and history of breastfeeding. Population attributable risks should be assessed, especially for more developed areas and young women. The effects of body mass index, age at menopause, and family history of breast cancer should be given priority during assessment of breast cancer risk among Chinese women.
    Journal of Epidemiology 11/2013; 24(1). DOI:10.2188/jea.JE20120217 · 3.02 Impact Factor
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    ABSTRACT: To evaluate the association between induced abortion (IA) and breast cancer risk among Chinese females. We searched three English databases (PubMed, ScienceDirect, and Wiley) and three Chinese databases (CNKI, WanFang, and VIP) for studies up to December 2012, supplemented by manual searches. Two reviewers independently conducted the literature searching, study selection, and data extraction and quality assessment of included studies. Random effects models were used to estimate the summary odds ratios (ORs) and the 95 % confidence intervals (CIs). A total of 36 articles (two cohort studies and 34 case-control studies) covering 14 provinces in China were included in this review. Compared to people without any history of IA, an increased risk of breast cancer was observed among females who had at least one IA (OR = 1.44, 95 % CI 1.29-1.59, I (2) = 82.6 %, p < 0.001, n = 34). No significant publication bias was found among the included studies (Egger test, p = 0.176). The risk increased to 1.76 (95 % CI 1.39-2.22) and 1.89 (95 % CI 1.40-2.55) for people who had at least two IAs and at least three IAs, respectively. Subgroup analyses showed similar results to the primary results. Meta-regression analysis of the included studies found that the association between IA and breast cancer risk attenuated with increasing percent of IA in the control group (β = -0.022, p < 0.001). IA is significantly associated with an increased risk of breast cancer among Chinese females, and the risk of breast cancer increases as the number of IA increases. If IA were to be confirmed as a risk factor for breast cancer, high rates of IA in China may contribute to increasing breast cancer rates.
    Cancer Causes and Control 11/2013; 25(2). DOI:10.1007/s10552-013-0325-7 · 2.74 Impact Factor