Risk Factors of Breast Cancer Among Women – A Cross-Sectional Study in Selected Slums of Bhubaneswar City, India

Background: Breast carcinoma is the most commonly diagnosed cancer (27·7%) and the leading cause of death (23·5%) among women in India as per GLOBOCAN 2018. There is considerable evidence that breast cancer risk is related to certain modifiable and nonmodifiable lifestyle factors. Thus, this study was conducted to estimate the prevalence of risk factors of breast cancer in women of age group 18-70 years in selected urban slums. Methodology: This community based cross sectional study was conducted in selected 13 urban slums of Bhubaneswar which comes under the field practice area of Department of Community Medicine, Bhuba-neswar, IMS and SUM Hospital Bhubaneswar, Odisha from September 2018 to October 2020. Data were entered to an excel sheet and SPSS software version 20 was used for analysis. Results: Among the total population of 300, the mean age of the study subjects was 42 + 12 years ranging from 20 to 69 years. Married women in the study were 95.3%. Including both modifiable and non-modifiable risk factors, 57% of the participants were having risk factors of breast cancer. Conclusion: Women need to be aware of both modifiable and non-modifiable risk factors for breast cancer to adopt appropriate practices for prevention of Breast cancer.

INTRODUCTION "BREAST CANCER" is a malignant cell growth in the breast. If left untreated, the cancer spreads to other areas of the body. 1 Breast cancer is the most common cancer among women worldwide and most common cause of cancer-related deaths in women. 2 Breast carcinoma is the most commonly observed cancer (14% of overall cases) in India. Among females, it is the most commonly diagnosed cancer (27·7%) and is the leading cause of death (23·5%) in India. In urban areas, 1 in 22 women and in rural areas, 1 in 60 women develops breast cancer in her lifetime. 3 It is prevalent not only in the developed part of the world but is commonly reported in the developing countries as well. 4 The breast cancer risk is higher in the following groups: increased age, history of breast cancer especially in the first-degree relatives before menopause; history of ovarian cancer especially before the age of 50; history of breast cancer or ovarian cancer in two relatives first-and second-degree, high calorie and fat diet; reproductive and hormonal factors; a personal history of breast and ovarian cancers. 5 The risk of breast cancer increases in current users or 5 years and more use of combined hormone replacement therapy and the risk decreases after 10 years of stopping oral contraceptive use. 6,7 History of radiotherapy for Hodgkin lymphoma increases the risk. It takes a minimum of about 5-10 years after exposure before a radiation induced breast cancer would develop and usually many more years. 8 Consuming alcohol and smoking also have evidence of having some risk in causing breast cancer. 9,10 There is considerable evidence that breast cancer risk is related to modifiable lifestyle factors where it is possible for women to reduce their risk by changing lifestyles like making them physically active, avoiding weight gain, limiting alcohol intake, and taking healthy diet. 11 The study was conducted with the objective to estimate the prevalence of risk factors of breast cancer in women of age group 18-70 years in selected urban slums of Bhubaneswar.

MATERIALS AND METHODS
It was a community based cross-sectional study conducted in selected 13 urban slums of Bhubaneswar which was the field practice area of the Department of Community Medicine of IMS & SUM Hospital from September 2018 to October 2020. The study population included women aged 18-70 years of thirteen slums.
Sample size: The sample size was estimated by using the formula 4pq/d 2 where prevalence of age at menarche <12 years (important risk factor of breast cancer) was taken as 24.4% from a study be Shadap A et al. 12 with allowable error as 20%.
The sample size was calculated to be 297 and rounded off to 300 participants.
Inclusion criteria: Women aged 18 years to 70 years and only one woman from a household were included in the study.
Exclusion criteria: Women who were sick or terminally ill and diagnosed case of breast cancer were excluded from the study.
Sampling: The population of thirteen slums under the field practice area of IMS & SUM Hospital, Bhubaneswar were listed. The sample size 300 was divided into thirteen slums equally i.e 23 participants from 12 slums and 24 participants from 1 slum. Systematic sampling method was used to choose the households in each slum. Sampling unit in the study was the household. On an average 128 households are there in each slum. 23 women were selected from 128 households with the sampling interval 128/23 = 5.56 ≈ 6. Starting from any random number between 1 and 6 first household was chosen and then every 6 th household was chosen for the study. Woman of highest age group was chosen where more than one woman was present in the household.
Data collection: Data were collected by house to house visit by interview method using the predesigned, pre-tested & semi-structured interview schedule. Informed written consent was obtained. The questions were explained in local language after establishing a good rapport. The data were checked to assess completion of the schedule and accuracy of the data coding. Privacy and confidentiality were maintained. It took around 30-40 minutes for complete data collection of each respondent. In a day maximum 5 participants were interviewed.

RESULTS
Among participants, the mean age of the study subjects was 42 + 12 years ranging from 20 to 69 years. Majority of them (97.3%) were Hindu. More than 40% belonged to other backward classes (41.7%). Most of the study participants had nuclear family structure (80.3%). Married women in the study were 95.3%. Majority had education up to middle school  It was observed that, 19.3% of the participants had menarche at less than 12 years of age. There were 6.7 % of the participants with age at menopause > 49 years. Family history of breast cancer was present in 1.7% of the participants among which 40% were first degree relative and 60% were second degree relative. Only 0.7% of the participants had got biopsy done for benign breast disease and none of the study participants got a mammography done. (Table 2) Among the participants, 86.7% were having mixed diet. Participants who had low physical activity were 27%. Only 1.3% of the participants were current alcohol consumers and 0.7% were current smokers. Obese participants were 11.7% and 26% of the participants consumed fruits rarely. Those who had vegetables rarely were 8%. Among non-vegetarians those taking non veg item like meat/fish >3days/week were 5.05%. Red meat consumption was common in 12.4%. Soya item was rarely consumed by 3.7% and 12% participants rarely took dairy products. 12% of the participants takes junk items more than 3 days in a week. (Table 3) In this study group, among married women only 3.1% were nulliparous. 2% women gave birth after the age of 30 years. Among those who were married and parous, 4% had not breastfeed their child and 2% had not done exclusive breastfeeding. More than half of the study participants has history of oral contraceptive pill use was 49% and among them only 4% used it for more than 5 years. (Table 4) Different sociodemographic variables were compared with presence of non-modifiable risk factor by univariate logistic regression. Socio economic class and age were significantly associated with having non-modifiable risk factor. Middle socio-economic class has 1.7 times more chance of having modifiable risk than lower socioeconomic class and age group 18-45 years was less likely of having non-modifiable risk factor than >60 years age group. (Table 5) Different sociodemographic variables are compared with presence of modifiable risk factors by univariate logistic regression. Participants having higher level of education had 3.3 times chance of having modifiable risk factor, participants employed were at 2.172 times more chances of having modifiable risk factors, those from middle socio-economic class had 2.4 times more chance of having modifiable risk factor and married participants had 3.5 times more chance of having modifiable risk factor. (Table 6) In multivariate logistic regression, we found employed participants, educated, higher Socioeconomic class and married individuals to be significantly associated with having modifiable risk factor. (Table 7) 4   It is reported that women with family history of breast cancer have more tendency to develop breast cancer. In this study, it was observed that 1.7% participants had a family history of breast cancer. Similar to our study, a study in Mumbai reported, 1% participants had a family history of breast or ovarian cancer. 18 In a cross-sectional study among slum women above 35 years in Mumbai by Aurangabadkar SK et al. in 2019 reported a higher proportion (12.5%) of participants had family history of breast cancer and 4% participants had underwent breast biopsy for history of benign breast disease. 19 In comparison the prevalence of family history of breast cancer and a history of previous biopsy due to benign breast disease in this study is lower. This may be attributed to the difference in geographical location and difference socio-cultural factors.
In this study, among married women 3.1% were nulliparous. Only 2% gave birth after the age of 30.
Higher prevalence was seen in the study by Aurangabadkar SK et al. in Mumbai. The study reported 8% women to be nulliparous, 5.5% participants gave birth after the age of 30. 19 Lower prevalence of nulliparous women and women giving birth after age of 30 in this study might be because this study is conducted in the urban slums and therefore the participants get married at an early age and also give birth at an early age of life.
Breastfeeding is a very common practice in India. In this study among married and parous women, only 4% did not breastfeed their child and 2% did not do exclusive breastfeeding. Almost half of the study participants has history of oral contraceptive pill use (49%) and among them only 4% used it for more than 5 years. In comparison in the study done in Delhi by Khokhar A in 2013 where 3.2% participants did not breastfeed which is almost similar to this study (4%) and 11.6% breastfed only till 3 months. 41.5% women were using oral contraceptive pill which is lower than this study. 18 In the study done in Brazil the women who used oral contraceptive pills or hormone replacement therapy for more than 6 years was 8%. 20 In a study in Mumbai 16.9% did not give breastfeeding to their child which is higher than this study. 21 The difference in breastfeeding may be due to difference in socio-cultural background.
In the present study, red meat was consumed more frequently by 12.4% of the participants. In comparison a lower prevalence of red meat consumption of 3.9% was seen in the study done in Delhi. 18 Obese participants were (11.7%) in this study and prevalence of low physical activity is observed in 27% of the participants. However, in the study conducted in Delhi, 15.2% did not have any physical activity and 38% women were obese. 18 Increased Body Mass Index shows an association with breast cancer. In India, according to National Family Health Survey (NFHS) the percentage of ever married women aged 18-49 years who are overweight or obese increased from 15% in NFHS-3 to 20% in  In this study only 1.3% of the participants are current alcoholic beverage consumers and 0.7% are current smokers. 26% of the participants rarely consumed fruits. In the study done in Nepal the prevalence of current smokers was 32% and alcohol consumers were 45.7%. 17 .
In this study those who rarely consumed vegetables were 8%. Soya item was rarely consumed by 3.7% and 12% participants rarely took dairy products. 12% of the participants takes junk items three or more days in a week.  26 In a systematic review and meta-analysis in Europe a significantly increased incidence (RR 1.25) was observed for women with higher socioeconomic status. 27 As stated by CDC, the risk of breast cancer increases after 50 years of age. In this study we also observed that the non-modifiable risk factors were significantly more in >60 years age group. In another study "Breast Cancer Risk from Modifiable and Non-Modifiable Risk Factors among Women in Southeast Asia: A Meta-Analysis" by Nindrea RD et al. in 2017, OR of age>40 years being a risk factor was 1.53. 28 In this study the sociodemographic characteristics were significantly associated with higher risk of having modifiable risk factors were higher education, higher socioeconomic class and marital status. In comparison a study on risk factors of breast cancer among patients attending the tertiary care hospital, in Udupi district reported that the cases of breast cancer with 7-12 years of education had 4.84 times more risk of breast cancer. 29 In the present study, participants having education above high school showed 3.353 times higher presence of risk factors of breast cancer, married women had 3.55 times higher chances of have modifiable risk factors. Similar to this study in a case-control study cancer in Iranian Women incidence of breast cancer was significantly more in married women. 30 The risk factors in married women might be more because of the lack of time and knowledge of risk factors.
In a study by Robert SA et al. in 2004, it was observed that after adjusting individual education and other individual level risk factors the odds of risk of breast cancer were more in people living in highest SES communities. This study also observed that women had a greater risk of breast cancer if they had a higher level of education. 31 The odds of having modifiable risk factors are more in higher socioeconomic class may be because of their unhealthy lifestyle and also late marriages which has become more common.
Since number of participants having modifiable risk factors were more in this study it is necessary to raise awareness and to provide education about the reproductive risk factors as well as lifestyle related risk factors to the community. It is important to educate the society about the healthy diets and the need to change their unhealthy dietary patterns. Decreasing the risk of breast cancer through prevention of modifiable risk factors is a task that requires the participation of all of society, especially the health professionals.

CONCLUSION
Proportion of participants having risk factors of breast cancer were more than 50% in this study. Women in my study population need to be aware of both modifiable and non-modifiable risk factors for breast cancer to adopt appropriate practices for prevention of Breast cancer.

RECOMMENDATIONS
As the proportion of participants having risk factor was more than half, it is necessary to target modifiable risk factors to reduce the burden of breast cancer. Standard calibrated model considering risk factors which are more relevant for Indian population should be designed and implemented for calculating the percentage risk in future five years or for lifetime.