|MINI SYMPOSIUM: BREAST CANCER
|Year : 2013 | Volume
| Issue : 1 | Page : 65-70
Risk factors of female breast carcinoma: A case control study at Puducherry
SM Balasubramaniam1, SB Rotti2, S Vivekanandam3
1 Department of Monitoring, Evaluation and Research, Jhpiego, India
2 Department of Community Medicine, Father Muller Medical College, Mangalore, India
3 Department of Radiotherapy, Jawaharlal Institute of Postgraduate Medical Education & Research, Pondicherry, India
|Date of Web Publication||20-May-2013|
S M Balasubramaniam
Department of Monitoring, Evaluation and Research, Jhpiego
Source of Support: None, Conflict of Interest: None
Objective: To identify and quantify various demographic, reproductive, socio-economic and dietary risk factors among women with breast cancer. Study Design: Case control study. Study Period: February 2004 to May 2005. Study Setting: Departments of Surgery, Medicine and Radiotherapy of Jawaharlal Institute of Postgraduate Medical Sciences and Research (JIPMER), Pondicherry. Materials and Methods: Cases were women with pathologically confirmed breast cancer. Controls were age-matched women from medicine and surgery wards without any current breast problem or previous breast cancer. A total of 152 cases and 152 controls were enrolled. They were interviewed for parity, breast feeding, past history of benign breast lesion, family history and dietary history with a pre-tested interview schedule after obtaining informed written consent. Results: The significant risk factors were (odds ratios with 95% CI) previous history of biopsy for benign breast lesion 10.4 (1.3-86.3), nulliparity 2.4 (1.14-5.08), consumption of fats more than 30 g/day 2.4 (1.14-5.45) and consumption of oils containing more of saturated fat 2.0 (1.03-4.52). Conclusions: Nulliparity, past history of benign breast lesion, high fat diet and consumption of oils with more saturated fats were the risk factors.
Keywords: Breast cancer, case control study, risk factors
|How to cite this article:|
Balasubramaniam S M, Rotti S B, Vivekanandam S. Risk factors of female breast carcinoma: A case control study at Puducherry. Indian J Cancer 2013;50:65-70
|How to cite this URL:|
Balasubramaniam S M, Rotti S B, Vivekanandam S. Risk factors of female breast carcinoma: A case control study at Puducherry. Indian J Cancer [serial online] 2013 [cited 2017 Oct 17];50:65-70. Available from: http://www.indianjcancer.com/text.asp?2013/50/1/65/112307
| » Introduction|| |
Breast cancer is the commonest cancer among women with a global incidence (2004) of 6,148,000, and it contributed to 20% of all cancers in women. Worldwide mortality estimates revealed that 474,000 women died (2003) due to breast cancer, accounting for 1.7% of all deaths in women.  In the Indian scenario, data from the population-based cancer registry (1997) showed that in eight of the 10 registries, breast cancer was the first among the cancers in women and second in the other two registries.  Inherited breast cancer is associated with germline mutations in BRCA1, BRCA2, p53 and PTEN genes. There have been attributions to CHEK2, ATM, NBS1, RAD50, BRIP1, and PALB2 associated with doubling of breast cancer risks.  In the local context of Pondicherry Union territory, Vilupuram, and Cuddalore districts of Tamil Nadu, breast cancer constituted 13.4%, 8.9% and 10.1% of all cases in females, respectively, and was second in the list among cancers in females.  Very few analytical studies have been done in the Indian context, which have concentrated on the menstrual and reproductive factors. With the improvement in socio-economic status, westernization in the lifestyle and alteration in the fertility patterns of the Indian women, various factors that were not studied in previous studies in India have been included in this study, e.g., role of dietary factors, socio-economic factors and anthropometric measurements. There is a need for more epidemiological studies in this context. JIPMER caters to the needs of breast cancer patients through its regional cancer center and surgery department. More than 150 breast cancer patients get treated annually. This makes JIPMER a suitable setting for studies on breast cancer. Finding of those risk factors can help us to contain the burden by setting up of appropriate screening tests and providing education to high-risk individuals.
| » Objectives|| |
To study and quantify the associations of various socio-economic, demographic, reproductive and dietary risk factors of female breast carcinoma among patients attending JIPMER hospital who are confirmed to have the disease.
| » Materials and Methods|| |
The study was a case control study conducted between February 2004 and May 2005 in the Departments of Surgery, Radiotherapy and Medicine, JIPMER. Sample size for the study was calculated with odds ratio for nulliparity with power of 80% and confidence level of 95% using the data from Rao et al. study. 
A case was defined as any female patient histopathologically confirmed to have breast cancer, reporting to radiotherapy department or tumor clinic. Those who were very sick or terminally ill were excluded. A total of 152 cases were enrolled. One age-matched control (± 3 years) without any current breast problems or previous history of breast cancer was enrolled from the medical or surgical wards of JIPMER from admissions of the week next to that of enrolment of the case. If more number of controls were present, controls were selected randomly, by numbering the controls and a number was selected from random number table with a drop of pen and by a pre-determined standard criterion to go always to the right until we get one number within the number of controls present at that time. If less number of controls were present or if it was not possible to take controls, controls were taken at a later date. A total of 152 controls took part in this study. Participation rate was 100% for cases and controls.
The study subjects were interviewed with a pre-tested interview schedule after obtaining informed consent. Presence of female attendant was ensured during the interview of the subject. Variables studied were socio-economic status, religion, caste, height, weight, age at menarche, age at marriage, age at first child, number of children, number of abortions, total months of breast feeding, age at menopause, use of hormones (oral contraceptive pills), previous benign breast disease, biopsy, family history, exposure to radiation, previous gynecological disease, type of the diet, calories and fat taken and oil consumed predominantly. The height and weight of the study subjects were measured. Controls were enrolled after explaining to them in detail about the purpose of the study and their role in the study. Their queries regarding health problems were answered as an incentive to their participation in the study. This study was done after getting clearance from JIPMER research council and ethical committee.
Standard definitions were used for data collection. A literate is one who can read and write with understanding at least in one language. The economic status of an individual was determined by Prasad's classification based on per-capita income and Consumer Price Index as per May 2005 (current prices). , Below poverty line was determined by the cut off Rs. 421 per month to provide calories per day for rural settings. The Registrar general classification for occupation was used for classifying manual and non-manual laborers. Body Mass Index (BMI) was classified according to WHO criteria.  Dietary allowances were assessed by 24 hour recall method. The Indian Council of Medical Research (ICMR) recommendations for a reference Indian woman were used for calculating calories and fat. Statistical analysis was done using SPSS version 13.0. Mean and standard deviation were used to summarize data. Chi-square test, Odds ratio and logistic regression (backward stepwise method) were used to identify and quantify the risk.
| » Results|| |
Mean age of cases was 49.1 ± 10.85 years and mean age of controls was 47.2 ± 10.31 years. This difference of ages between cases and controls (P<0.113) was not statistically significant. [Table 1] shows the age group-wise distribution among cases and controls. The age of women in both groups varied from 28 years to 76 years. The maximum number of cases as well as controls was in the 41 to 50 age group (35.5% and 40.8% of the cases and controls, respectively). There was no statistical difference between the two groups. (Chi-square 4.57 and P<0.47). [Table 2] shows the significant reproductive risk factors for breast cancer by univariate analysis. Women who were married after 21 years had 2.5 times more risk than who married before 21 years. Nulliparous women had 6 times more risk than those who had 5 children or more (OR 6.22; 95% CI 1.6-23.7). On analyzing the duration between age at menarche and age at first child, women with a duration of more than 6 years had 2.6 times higher risk than those who had a duration less than 3 years. Duration between 3 and 6 years was not associated with breast cancer risk. Among the postmenopausal women (107 cases and 87 controls), those who attained menopause after 50 years had twice the risk than women who attained menopause up to 50 years. Women who had a history of at least one abortion had twice the risk than those who did not have a history of abortion. Women who had their first child after the age of 25 years were at twice the risk for breast cancer than who had their child before the age of 25 years. Women who breastfed their child up to 6 months had 2.2 times more risk than who had breastfed for more than 6 months. [Table 3] Literate women had 1.8 times more risk than illiterate women. Analysis of occupation showed that non-manual laborers had 1.7 times more risk than manual laborers. Women belonging to class 1, 2 and 3 had twice the risk than those belonging to class 4 and 5. Women with past history of biopsy for a benign breast lesion had 9 times higher risk. Women with family history of cancer had 3 times more risk than women without a family history of cancer. If women used oils containing more of saturated fats, they had twice the risk than those who used oils containing less of saturated fats. Women who consumed 25% more calories than required had 25 times more risk than who did not. Women who consumed fat more than 30 g/day were having 3.6 times more risk than who consumed up to 30 g/day. [Table 4] gives the factors independently associated with breast cancer as identified by a backward stepwise logistic regression analysis of all factors, which were significant in controls by univariate analysis. Past history of biopsy for a benign breast lesion was independently associated with breast cancer with an adjusted OR 10.42 (95% CI 1.25-86.29) showing that they were at 10 times higher risk. Women, who consumed fat more than 30 g/day, had twice the risk than others (adjusted OR 2.4; 95% CI 1.14-5.08). Nulliparity had an adjusted OR of 2.39 and 95% CI (1.04-5.45) showing that they were at 2.4 times higher risk. Women who consumed oils containing more of saturated fat were at twice the risk than who consumed oils containing more of unsaturated fat (adjusted OR 2.16; 95% CI 1.03-4.52).
|Table 2: Certain significant reproductive risk factors for breast cancer by univariate analysis|
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|Table 3: Socio-demographic, past history of biopsy for breast lesion, family history and dietary factors for breast cancer|
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|Table 4: Factors found to be independently associated with breast cancer (backward stepwise method)|
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| » Discussion|| |
Breast cancer has been increasing in Indian women in the recent past as indicated in the cancer registries.  The change in lifestyle dietary patterns and demographic features may be contributing to this increase. This study was hence planned to explore these risk factors. This study was feasible because JIPMER had a tertiary care cancer specialty center. All incident cases were chosen to avoid the survival bias due to prevalent cases. Controls were chosen by random sampling and no major exclusion criteria were used to avoid selection bias. The major confounders were identified from prior literature and their individual risks were quantified. Confounding was adjusted using the multiple logistic regression methods.
Our study population consisted of hospital population, which was mainly from adjoining rural areas of Tamil Nadu. Majority were illiterate (39% among cases and 53% among controls), from poorer sections. Early marriage and early age at first birth was another notable feature. There was no sufficient gradient with respect to many variables. Hence, we found large confidence intervals, even for significant variables.
The present study found that nulliparous women were twice at risk of breast cancer after adjusting for confounders. Margaret et al. from USA showed no association between parity and breast cancer.  Rao et al. found that nulliparous women had twice higher risk as compared and Hajian Tilaki et al. from Iran have shown that nulliparity was strongly associated with breast cancer. , Our study too showed a two-fold risk with nulliparity.
NG et al. from Singapore showed that past history of biopsy for benign lesion was an independent risk factor and was having a three-fold risk  . The findings of our study were also in agreement with their findings although showed a 10-fold increase in risk. This high odds ratio and wide confidence interval may be due to small number of cases.
La vecchia et al. from Italy showed that women consuming animal fats like butter were at a higher risk for breast cancer.  Our study's findings were also consistent with their findings as type of oil used predominantly was an independent risk factor. This is also reflected in the world cancer research fund report. 
Wakai et al. from Indonesia revealed that with increase in fat intake there was an increased risk of breast cancer.  Our study finding was also consistent with theirs as it showed that consumption of fat more than 30 g/day was associated with breast cancer. It was notable that previous studies in India have not looked into this modifiable aspect of dietary fats.
Our study did not show any association between breast feeding and breast cancer. Purwanto et al. from Indonesia and Brinton et al. from USA have shown that duration of breast feeding (2-16 weeks) was not an independent risk factor for breast cancer. ,[ 16] One of the reason for the lactation not showing up as a factor may be that the sample size was ineffective to find this risk.
The strength of this study design was the care taken to control bias. Selection bias was controlled with careful selection of controls. Information was collected over a year by the same interviewer avoiding information bias. Confounding was managed well with regression models and this model was fitting the data well. This was the first study to look at the dietary patterns in women with breast cancer in India. The main limitation of this study was that it was a hospital-based study and may not be representative of the underlying population. Many of the factors after adjustment had wide confidence intervals even though they were statistically significant. This may be due to small numbers in the risk group and needs careful interpretation .The other limitation was that we had calculated fat from one day's diet as it was not the primary exposure of interest. This study gives an insight into the dietary fats but needs detailed dietary assessment on this aspect.
| » Conclusions and Recommendations|| |
Women with previous history of biopsy for benign breast lesion, nulliparity, consumption of more than 30 g/day of fat and consumption of oils containing more of saturated fat were the risk factors. Restriction of fat in the diet to not more than 20 g/day by a balanced diet (as recommended by ICMR) and using oils with more unsaturated fats would reduce the risk, and screening of high-risk group by yearly breast examination of nulliparous women and women with previous history of biopsy for a benign breast lesion can help in early detection. Teaching self-breast examination to these individuals will be beneficial. Although this study included some dietary factors, a detailed dietary assessment can shed more light on association of various dietary patterns and breast cancer.
| » Acknowledgments|| |
We sincerely thank The Director, The Dean, and The heads of the departments of Radiotherapy, Surgery and Medicine for giving permission for conducting the study. Our heartfelt thanks to Dr. K. A. Narayan, Former Professor and Head, Department of Preventive and Social Medicine, JIPMER. Our special thanks to all the women who took part in this study.
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[Table 1], [Table 2], [Table 3], [Table 4]
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