Risk factors for breast cancer: A case-control study of screen-detected breast cancer in Miyagi Prefecture, Japan

We examined the associations between reproductive factors and the risk of breast cancer on the basis of information from a total of 201,363 breast cancer screening program participants in Miyagi Prefecture, Japan, during 1987-1991. A case-control study method was applied on analysis. Data on 204 breast cancer cases identified and 810 screening year-, age- and screening area-matched normal controls were extracted. After adjustment for potential confounders, a trend of decreasing risk of breast cancer with increasing number of parity was observed (p for trend=0.03). Among parous women, lactation for the last child decreased the risk of breast cancer (odds ratio (OR) = 0.61, 95% confidence interval (95% CI) 0.39–0.94). These findings were consistent with those in clinical breast cancer reported previously. When cases were divided into two age groups, younger ( 49 y.o.) and older (50 y.o. ), family history of breast cancer among mother and sisters (OR=3.51, 95% CI 1.05–11.80), and lactation for the last child (OR=0.46, 95% CI 0.25–0.84) were associated with younger age breast cancer, whereas number of parity was associated with older age breast cancer (p for trend=0.03). The results by age group suggest that different mechanisms may exist in breast cancer developing at early and late onsets.     

Risk factors for breast cancer among women in Bhopal urban agglomerate: a case-control study

Background: Breast cancer is the most common cancer in females worldwide, and the second leading cause of cancer deaths in women. The incidence is on the rise in India, and breast cancer is the second most common malignancy in Indian women. Objective: To assess the risk factors for breast cancer patients living in Bhopal. Study Design and Method: This case-control study was conducted in Bhopal urban agglomerate for a period of a year from October 2008 to August 2009. Demographic data and reproductive risk factor related information was collected using a structured questionnaire with analyses by Epi-info and SPSS 16. Results: A history of oral contraceptive pill use (OR=2.77, 95% CI: 1.15-6.65), history of not having breastfeeding (OR=3.49, 95% CI:1.22-9.97), over weight (OR=0.11, 95%CI:0.02-0.49), obese women ( OR=0.24, 95%CI: 0.06-0.88) and family history of breast cancer (OR=3.89, 95% CI: 1.01-14.92) were associated significantly with the occurrence of breast cancer on multivariate analysis. Conclusions: The findings of the present study suggests that positive family history of breast cancer and history of using OCP may be the epigenetic factors promoting the occurrence of breast cancer while breastfeeding reduces the possibility of acquiring breast cancer.     

Risk factors for breast cancer in Turkish women: a hospital-based case-control study

The aim of this study was to investigate the association between risk factors and breast cancer in Turkish women. In a hospital-based case-control study in Istanbul, 405 patients with histologically confirmed breast cancer were compared with 1050 controls, who were admitted to different departments of the same hospital. Unadjusted odds ratios (ORs) and 95% confidence intervals (CIs) for each risk factor were obtained from logistic regression analyses. Risk factors for breast cancer were found to be early menarche age (OR 3.87, 95% CI 2.46-6.08), use of alcohol (OR 3.87, 95% CI 1.79-8.37), history of diabetes (OR 3.31, 95% CI 2.36-4.64) or hypertension (OR 3.44, 95% CI 2.07-5.71), oral contraceptive use (OR 1.98, 95% CI 1.38-2.85) and hormone replacement therapy (HRT) use (OR 1.94, 95% CI 1.15-3.29). The findings of the present study indicated that history of diabetes or hypertension, use of alcohol, oral contraceptive and HRT, never having breastfed and delayed age at first birth associated with changing of lifestyle led to an increased risk of breast cancer in Turkish women.     

Relationship between mammographic density and the risk of breast cancer in japanese women: a case-control study

BACKGROUND: The relationship between mammographic density and the risk of breast cancer was examined in Japanese women. The study was a matched case-control study comparing the mammographic densities of both breast cancer cases and healthy controls. MATERIALS AND METHODS: We selected 237 women who were diagnosed with a histologically verified breast cancer, and who underwent surgery at Gihoku General Hospital in Gifu, from January, 1998 to December, 1999. During the time of this study, 3,650 people participated in breast cancer screening with mammography and ultrasound together. We selected 742 women as a control group from the screening participants and matched them by age and the number of deliveries with the cancer patients. The same mammography machine was used for both cases and controls. For evaluation, we used a visual method (Wolfe's classification) and a computer assisted method to classify the mammograms based on mammographic density. RESULTS: (1) According to Wolfe's classification, the DY group had a significantly increased breast cancer risk compared with the N1 group (Relative risk (RR)=2.20, 95% confidence interval (95%CI) (1.02-4.77). (2) The group showing a high mammographic density had a significantly increased risk of breast cancer compared with the group with low mammographic density (RR=2.83, 95%CI=1.33-5.98) as classified by the computer assisted method. CONCLUSION: It is suggested that women with high mammographic densities, classified visually or by computer, have an elevated risk of breast cancer compared with those with low mammographic densities.     

Risk factors for breast cancer in Iran: a case-control study

Background  

Iranian breast cancer patients are relatively younger than their Western counterparts. The objective of the present study was to investigate risk factors for breast cancer in Iranian women.     

A case-control study of lung cancer among Czech women

Few data are available to explain the continuing increase in lung cancer mortality among Czech women. The study was designed to examine the role of active smoking and other known or suspected factors. Data collected by personal interviews during the 15 months of a hospital-based case control study are reported. A total of 140 microscopically confirmed cases and 280 frequency-matched controls were analysed using multiple logistic regression. Cigarette smoking was the most important factor associated with excess risk for lung cancer among women. Significantly increased risk was found both among current smokers (OR=11.20, 95% CI 5.9-21.2), and ex-smokers (OR=10.02, 95% CI 5.5-18.4). Positive dose-response gradients (P<0.001) were observed between lung cancer risk and the daily number of cigarettes, duration of smoking, number of pack-years, inhaling, and grade of nicotine dependence assessed by the Fagerstr?m test (Heatherton TF, Kozlowski LT, Frecker RC, Fagerstr?m KO. Br J Addict 1991;86:1119-1470; Pomerleau OF. In: Bolliger CT, Fagerstr?m KO, editors. The Tobacco Epidemic. Basle: Karger, 1997: 122-131). Exposure to environmental smoke was associated with elevated lung cancer risk (OR=3.58, for lifetime non-smokers exposed both in childhood and in adult age). Physical exercise and body mass index were inversely associated with lung cancer risk. For the category of physical exercise of more than 5 h per week, the odds ratio was 0.38, compared to subjects admitting no physical exercise. For body mass index, the odds ratio for the highest (compared to the lowest) quartile was 0.50. Chronic cough and phlegm (at least 3 months per year) were associated with excess risk (OR=6.07) only if their duration was less than 2 years before diagnosis of lung cancer, and, therefore, they were suspected of being more likely early symptoms of preclinical lung cancer rather than its cause. Our results support the statement that cigarette smoking is by far the most important cause of the on-going epidemic of lung cancer among Czech women, and are consistent with the concept of a balance between risk and protective factors whose eventual maintenance or alteration determine the development of disease (as suggested by Rylander R, Axelsson G, Andersson L, Liljequist T, Bergman B. Lung Cancer 1996;14(Suppl 1): S75-S83). Concerted control of smoking appears to be an urgent priority in lung cancer prevention among women, including specific approaches targeted on the female population.     

Risk for breast cancer among women with endometriosis

Although several risk factors are common to endometriosis and breast cancer, the results of observational studies of an association have so far been inconsistent. We evaluated the relationship between endometriosis and breast cancer on the basis of data on selected cancers and medical histories from the Danish nationwide cancer and hospital registries used in a large case-cohort study. A total of 114,327 women were included in the study of whom 1,978 women had received a diagnosis of endometriosis and 16,983 had had a diagnosis of breast cancer between 1978 and 1998. Of the women with endometriosis, 236 subsequently received a diagnosis of breast cancer. The crude overall rate ratio for breast cancer after endometriosis was 1.00 and after adjustment for reproductive factors, calendar-period, bilateral oophorectomy and benign breast disease, the rate ratio was 0.97 (95% confidence interval, 0.85-1.11). The risk for breast cancer increased with age at diagnosis of endometriosis, so that women in whom endometriosis was diagnosed at a young age (approximately <40 years) had a reduced risk for breast cancer and women in whom endometriosis was diagnosed at older ages (approximately > or =40 years) tended to have an increased risk for breast cancer. The reduced risks observed among young women may reflect their exposure to drugs with antiestrogenic effects. The increased risk associated with endometriosis among postmenopausal women may be due to common risk factors between postmenopausal endometriosis and breast cancer or an altered endogenous estrogen.     

Risk factors for male breast cancer: a Franco-Swiss case-control study

In order to evaluate risk factors in male breast cancer, a case-control study of 91 histologically diagnosed cases and 255 cancer controls, matched for age and year of diagnosis, was conducted in Villejuif (France) and Geneva (Switzerland). Factors studied included marital history, occupational exposure, associated diseases, family history of breast cancer, history of radiation exposure and drugs which increase or are suspected of increasing prolactin or estrogen levels. Cases were significantly more likely to be bachelors or to work as butchers than were the controls. Other statistically significant risk factors identified were family history of breast cancer and therapeutic use of digitalis. Elevated risks, although not significant, were observed for individuals with a past history of tuberculosis, hyperthyroidism, liver cirrhosis or gallstone, who had been treated with isoniazid, or who had worked in high environmental temperatures. Further studies are needed to confirm our results particularly as regards hormonal imbalance and genetic factors.     

Risk Factors for Screen-Detected Breast cancer a case-control study

Risk factors for breast cancer (BC) detected in mammography screening were sought using a questionnaire among 31 927 women aged from 40 to 74 years who attended screening. Data from 204 women with screen-detected BC were compared with those of 612 controls who did not have EC in screening. Mothers of women with BC had more often BC than those of the controls (8% vs. 3%, odds ratio, OR, 3.18, 95% CI 1.59-6.35). Women with screen-detected BC were older at their first, childbirth (25.7 years vs. 24.7 years, OR 1.61, 1.14-2.33), and younger at menarche (13.6 years vs. 13.8 years, OR 1.38, 1.00-1.91), but there was no significant difference in the body mass index, number of pregnancies, breast size, smoking, or in the use of contraceptive pills between the cases and the controls. In multivariate logistic regression analyses, late age at the first childbirth, BC in the mother, and early age at menarche were independent risk factors for screen-detected BC but they appear to be of limited value in targeting screening in the female population aged from 40 to 74 in order to improve its cost-effectiveness.     

Risk factors for premenopausal breast cancer: a case-control study in Uruguay

In order to thoroughly analyze risk factors of breast cancer (BC) in premenopausal Uruguayan women, a case-control study was carried out at the Pereira Rossell Women's Hospital, Montevideo, where 253 incident BC cases and 497 frequency-matched healthy controls were interviewed on menstrual and reproductive story, were administered a short food frequency questionnaire and undertook a series of body measurements necessary to calculate body composition and somatotype. Odds ratio (OR) coefficients were taken as estimates of relative risk derived from unconditional logistic regression. Among the classical risk factors, only the family history of BC in first degree relatives was significantly associated with risk of premenopausal BC (OR=2.20, 95% CI 1.33-3.62). Interestingly, this risk factor was found to be stronger in women of ages >40 (OR=4.05, 95% CI 2.10-7.81), late menarche (OR= 2.39, 95% CI 1.18-4.85), early age for their first delivery (OR=3.02, 95% CI 1.26-7.22), short time between menarche and first delivery (OR=3.22, 95% CI 1.29-8.07), and with high parity (OR=4.10, 95% CI 1.79-9.36), although heterogeneity was detected only for age and parity. High consumption of red meat was positively associated with the disease risk (OR=2.20, 95% CI 1.35-3.60), in the same way as fried foods (OR=1.79, 95% CI 1.12-2.84). Conversely, a high intake of plant foods displayed a protective effect (OR=0.41, 95% CI 0.26-0.65). Except for hypertension (OR=1.55, 95% CI 1.03-2.35), none of the analyzed components of metabolic syndrome were associated to BC risk. Particular increases of risk for premenopausal BC were found for family history in first degree relatives in certain subsets derived from the menstrual-reproductive history. Preventive strategies could broaden their scope if new studies confirm the present results, in view of the limited prevention measures that premenopausal BC currently has.     

Risk factors for breast cancer in Turkish women with early pregnancies and long-lasting lactation--a case-control study

A hospital-based case-control study was carried out among 504 women with breast cancer and 610 controls to analyse the risk factors for breast cancer in Turkey. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for each risk factor were obtained from logistic regression analysis. Risk factors for breast cancer were found to be long-term lactation (> or = 5 years versus never OR 0.31, 95% CI 0.12-0.79), young age at menarche (< 15 years versus > or = 15 OR 1.72, 95% CI 1.30-2.28), late age at first full-term pregnancy (> or = 30 versus < 20 OR 2.86, 95% CI 1.32-6.21), oral contraceptive use (ever versus never OR 1.51, 95% CI 1.10-2.08), positive family history (positive versus negative OR 2.81, 95% CI 1.35-5.82), and menstrual irregularity (yes versus no OR 1.61, 95% CI 1.05-2.49). The results of the present study will lead to a better understanding of the risk factors for breast cancer in a developing country.     

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’.     

Physical activity and breast cancer risk among Asian-American women in Los Angeles: a case-control study

BACKGROUND: To the authors' knowledge, there have been few studies published to date regarding physical activity patterns and breast cancer risk in Asian and Asian-American women. METHODS: The authors conducted a population-based case-control study of 501 Asian-American women with incident breast cancer and a control group of 594 Asian-American women in Los Angeles County to evaluate the role of lifetime physical activity on breast cancer risk. Information concerning lifetime recreational physical activity (i.e., type of activity, duration [years], and frequency [average hours per week]) and occupational physical activity was obtained using a structured questionnaire that was administered in person. RESULTS: Increasing years and levels (average metabolic equivalent [MET] hours per week) of lifetime recreational activity were associated with a significantly reduced risk of breast cancer after adjusting for demographic factors, migration history, and menstrual and reproductive factors. Compared with women who had no lifetime recreational physical activity, 3-6 MET hours per week, > 6-12 MET hours per week, and > 12 MET hours per week of activity were associated with significantly reduced risk, with odds ratios (and 95% confidence intervals) of 0.91 (0.55-1.49), 0.65 (0.39-1.10), 0.53 (0.31-0.90), and 0.47 (0.28-0.80), respectively (P value for trend < 0.001). The risk of breast cancer was associated inversely with occupational physical activity, although the result was not statistically significant. CONCLUSIONS: The findings of the current study provide further support for the finding that physical activity has a protective role in breast cancer.     

A case-control study on the dietary intake of mushrooms and breast cancer risk among Korean women

To evaluate the association between dietary mushroom intake and breast cancer risk, a total of 362 women between the ages of 30 and 65 years who were histologically confirmed to have breast cancer were matched to controls by age (+/-2 years) and menopausal status. Mushroom intake was measured via a food frequency questionnaire that was administered by well-trained interviewers. The associations between the daily intake and the average consumption frequency of mushrooms with breast cancer risk were evaluated using matched data analysis. Both the daily intake (5th vs. 1st quintile, OR = 0.48, 95% CI = 0.30-0.78, p for trend 0.030) and the average consumption frequency of mushrooms (4th vs. 1st quartile, OR = 0.54, 95% CI = 0.35-0.82, p for trend 0.008) were inversely associated with breast cancer risk after adjustment for education, family history of breast cancer, regular exercise [>or=22.5 MET (metabolic equivalent)-hr/week], BMI (body mass index, Kg/m(2)), number of children and whether they are currently smoking, drinking or using multivitamin supplements. Further adjustments were made for energy-adjusted carbohydrate, soy protein, folate and vitamin E levels, which tended to attenuate these results. After a stratification was performed according to menopausal status, a strong inverse association was found in postmenopausal women (OR = 0.16, 95% CI = 0.04-0.54, p for trend = 0.0058 for daily intake; OR = 0.17, 95% CI = 0.05-0.54, p for trend = 0.0037 for average frequency), but not in premenopausal women. In conclusion, the consumption of dietary mushrooms may decrease breast cancer risk in postmenopausal women.     

Risk of second cancer among women with breast cancer

A large number of women survive a diagnosis of breast cancer. Knowledge of their risk of developing a new primary cancer is important not only in relation to potential side effects of their cancer treatment, but also in relation to the possibility of shared etiology with other types of cancer. A cohort of 525,527 women with primary breast cancer was identified from 13 population-based cancer registries in Europe, Canada, Australia and Singapore, and followed for second primary cancers within the period 1943-2000. We used cancer incidence rates of first primary cancer for the calculation of standardized incidence ratios (SIRs) of second primary cancer. Risk of second primary breast cancer after various types of nonbreast cancer was also computed. For all second cancer sites combined, except contralateral breast cancer, we found a SIR of 1.25 (95% CI = 1.24-1.26) on the basis of 31,399 observed cases after first primary breast cancer. The overall risk increased with increasing time since breast cancer diagnosis and decreased by increasing age at breast cancer diagnosis. There were significant excesses of many different cancer sites; among these the excess was larger than 150 cases for stomach (SIR = 1.35), colorectal (SIR = 1.22), lung (SIR = 1.24), soft tissue sarcoma (SIR = 2.25), melanoma (SIR = 1.29), non-melanoma skin (SIR = 1.58), endometrium (SIR = 1.52), ovary (SIR = 1.48), kidney (SIR = 1.27), thyroid gland (SIR = 1.62) and leukaemia (SIR = 1.52). The excess of cancer after a breast cancer diagnosis is likely to be explained by treatment for breast cancer and by shared genetic or environmental risk factors, although the general excess of cancer suggests that there may be additional explanations such as increased surveillance and general cancer susceptibility.     

Risk factors for prostate cancer: A multifactorial case-control study

Prostate cancer is the third most commonly diagnosed cancer among Pakistani men. It is a multifactorial disease involving genetics together with environmental factors. Countries where men have greater dietary fat intake showed increased prostate cancer mortality rates. A population based case-control study was conducted to evaluate various prostate cancer risk factors. Study subjects were 896 prostate cancer cases (2010-2015) and 900 age matched controls. Odds ratio (OR) and 95% CI were used to estimate the association between different risk factors and prostate cancer. P values for different factors were computed by t-test, chi-square test, and Fisher exact test. Results showed significant association of increased age (OR = 10.6; CI: 7.92-14.31; P = 0.0001; Z = 15.7) and smoking (P = 0.05) with risk of disease. Consistent evidence suggested that fruits (P = 0.0001), vegetables (P = 0.0007), and diabetes mellitus (OR = 0.84; CI: 0.72-0.97; P = 0.02; Z = 2.28) were significantly associated with decreased prostate cancer risk. Comparison of education, marital status, occupation, intake of meat (<100 grams/week, 101-250 grams/week, >250 grams/week), number of cigarettes smoked per day, smoking duration, and family history of disease among cases and controls were not associated (P > 0.05) with risk of prostate cancer. Most of the prostate cancer patients were at stage IV with a Gleason score ranging from 7-9 and had undergone surgery. This epidemiological study illustrated that age and smoking were potential risk factors for prostate cancer in Pakistani men. Furthermore, phytonutrients can reduce its risk to a greater extent. Prospective studies with detailed analysis and greater sample size are required to explore more accurate findings.     

Risk factors for oral cancer in Brazil: A case-control study

A case-control study of risk factors for carcinomas of the tongue, gum, floor, and other specified parts of the mouth was conducted in 3 metropolitan areas in Brazil: São Paulo (South-east), Curitiba (South), and Goiãnia (Central-West). We analyzed information on demographics, occupational history, environmental exposures, tobacco smoking and alcohol drinking habits, as well as diet, oral and other health characteristics obtained from interviews with 232 cases and 464 hospital non-cancer controls matched for 5-year age-group, sex, hospital catchment area and trimester of admission. Tobacco and alcohol consumption were the strongest risk factors irrespective of the anatomical site. The adjusted relative risks (RR) for ever vs. never smokers were: 6.3, 13.9, and 7.0, for industrial-brand cigarettes, pipe, and hand-rolled cigarettes, respectively. A strong correlation was seen between number of pack-years and risk. The RR for the heaviest vs. the lowest consumption categories (>100 vs. <1 pack-years) was 14.8. Risk levels generally decreased to those of never smokers after 10 years had elapsed since stopping smoking. The risk associated with alcohol was mostly evident for wine (cancer of the tongue) and “cachaça” (all sites), a hard liquor distilled from sugar cane. Other important risk factors were drinking “chimarrão” (a type of maté), use of a wood stove for cooking, and frequent consumption of charcoal-grilled meat and manioc. Oral hygiene characteristics represented correlates of disease risk. A significant protective effect was observed for consumption of carotene-rich vegetables and citric fruits, but not for green vegetables in general.     

Risk factors for prostate cancer: A national case-control study

Statutory notification of cancer in New Zealand provided an opportunity to investigate risk factors for prostate cancer in a large national population-based case-control study. We analyzed data obtained from telephone interviews with 923 cases and 1,224 controls. For inclusion in the study, all subjects had to have been married at some time. We found an increased risk of prostate cancer among those with a history of prostate cancer in first degree relatives (RR 2.6; 95% CI, 1.9-3.7) and an increased risk of prostate cancer with length of marriage among men married only once and still married at interview. For a consecutive subgroup of 550 cases and 819 controls, data on height and weight at age 20 and at 5 years before interview were collected. Men less than or equal to 1.7 m in height at age 20 years had a lower risk of prostate cancer than men taller at that age. There was no association between weight or body mass index and risk of prostate cancer.     

Risk factors for breast cancer among young women in southern Iran

Age standardized incidence rates of breast cancer in developed countries is nearly threefold higher than in developing countries. Iran has had one of the lowest incidence rates for breast cancer in the world, but during the last four decades increasing incidence rates of breast cancer made it the most prevalent cancer in Iranian women. After adjustment for age, Iranian young women are at relatively higher risk of breast cancer than their counterparts in developed countries. The purpose of this study was to investigate some established risk factors of breast cancer in Iranian young women. A hospital-based case control study comprising 521 women with histologically confirmed, incident breast cancer and 521 controls frequency-matched by age and province of residence was conducted. Logistic regression performed to investigate associations of reproductive and anthropometric factors with breast cancer risk. In multivariate analysis, family history [odds ratio (OR): 1.61; 95% confidence interval (CI): 1.07-2.42], oral contraceptives (OC) usage (OR: 1.52; 95% CI: 1.11-2.08), low parity (OR parity ≥ 3 vs. 1-2: 0.33; 95% CI: 0.23-0.49), employment (OR: 1.83; 95% CI: 1.05-3.23) and shorter period of breast feeding (OR ≥ 37 months vs. < 37: 0.61; 95% CI: 0.44-0.84) were related to a higher risk of breast cancer in young women. This was the first study focusing on risk factors of breast cancer in Iranian young women. The trend of decreasing parity and shortened duration of breast feeding along with OC usage might partly explain the rapid rising of breast cancer incidence in Iranian young women.