Familial ovarian cancer: a population-based case-control study

Data from a multicenter population-based case-control study were analyzed to assess the degree of aggregation of ovarian cancer in families. Included as cases were 493 women aged 20-54 who had been newly diagnosed with epithelial ovarian cancer. The frequency with which cases reported a family history of ovarian cancer was compared with the frequency for a group of 2,465 controls selected by random digit dialing. The odds ratios for ovarian cancer in first- and second-degree relatives were 3.6 (95% confidence interval (Cl) 1.8-7.1) and 2.9 (95% Cl 1.6-5.3), respectively, compared with women with no family history of ovarian cancer. The null hypothesis of no association was excluded on both the maternal and paternal sides of the families studied. Ovarian cancer in relatives was reported by women with malignant lesions but not by women with borderline lesions. These results did not seem to be attributable to the possible confounding effects of any of several covariates or to errors in reporting family history of ovarian cancer.     

Infertility and breast cancer: a population-based case-control study

To investigate whether a history of infertility affects a woman's risk of developing breast cancer, the authors analyzed case-control data collected between 1980 and 1982 as part of the Cancer and Steroid Hormone Study. The 4,730 cases were women aged 20-54 years with a first diagnosis of breast cancer ascertained from eight population-based cancer registries; the 4,688 controls were women randomly selected from the general population of these same eight areas. After controlling for age, age at first birth, and parity, the odds ratio (OR) for breast cancer associated with infertility was 1.01 (95% confidence interval (CI) 0.89-1.15) among gravid women. Controlling for age, the odds ratio was 0.82 (95% CI 0.59-1.14) among nulligravid women. Women who reported that the reason for their infertility was a problem with their ovaries had a risk similar to that for women without a history of infertility (OR = 0.75, 95% CI 0.48-1.24). Women whose physicians reported that the reason for their infertility was anovulation or Stein-Leventhal syndrome also had risks similar to those for women without a history of infertility (OR = 1.26 (95% CI 0.67-2.34) and OR = 1.13 (95% CI 0.46-2.78), respectively). Menopausal status, age at menarche, history of spontaneous abortions, drinking or smoking behavior, use of exogenous hormones, or family history of breast cancer did not appreciably alter the observed odds ratios. If infertility has an effect on breast cancer that is independent of age at first birth, then the effect is small.     

An inverse association between preserved fish and prostate cancer: results from a population-based case-control study in Canada

Epidemiological studies suggest that fish consumption may be a protective factor against the development of prostate cancer. We investigated the association between prostate cancer risk and fresh and preserved fish consumption among participants of a population-based case-control study (1,534 cases, 1,607 controls). Fish intake was measured using a dietary questionnaire that collected both frequency of consumption of a given portion size. Logistic regression analysis demonstrated an inverse association between preserved fish and prostate cancer risk for all levels of consumption, but reductions only reached statistical significance for the category of 1 to 3 servings of preserved fish per month (odds ratio = 0.78, confidence interval = 0.64-0.95). Consumption of any fat or energy from preserved fish was also associated with reduced risk. There was no suggestion of reduced prostate cancer risk with consumption of fresh and canned fish. Our results suggest that consumption of preserved fish may reduce the risk of developing prostate cancer.     

Occupation and bladder cancer: a population-based,case-control study in Iowa

While considerable efforts have been made to investigate the role of occupation and industry in the risk of bladder cancer, many reported associations have not been consistent, and strong evidence of increased risk is apparent for few occupational groups. To further examine the issue, a large, population-based, case-control study was conducted in the state of Iowa among both men and women. A total of 1452 incident bladder cancer cases and 2434 controls were included in the study. Occupational history was collected from respondents for each job held for 5 years or longer since age 16. Among men, excess risk was observed for industries including plumbing, heating, and air conditioning (odds ratio [OR], = 2.2; 95% confidence interval [CI], 1.0 to 5.0); rubber and plastic products (OR = 3.1; 95% CI, 1.2 to 8.5), motor vehicle parts and supplies (OR = 4.5; 95% CI, 1.2 to 16.5), and occupations including supervisors for transportation and material moving (OR = 6.5; 95% CI, 1.4 to 29.9), material-moving-equipment operators (OR = 1.9; 95% CI, 1.0 to 3.6), automobile mechanics (OR = 1.6; 95% CI, 1.0 to 2.6), painters (OR = 2.7; 95% CI, 1.0 to 7.7), and metal- and plastic-working machine operators (OR = 2.0; 95% CI, 1.1 to 3.4). Among women, significant excess risk was observed for secondary school teachers and record clerks. Housekeepers and butlers and workers in laundering and dry cleaning were also at increased risk. In conclusion, these results suggest that occupational exposures may play a significant role in the risk of bladder cancer.     

Serum selenium level and prostate cancer: a case-control study

Selenium is a potential chemopreventive agent against prostate cancer. This study sought to evaluate and compare the serum selenium level in men with newly diagnosed prostate cancer and noncancerous patients. Between 2005 and 2006, this prospective case-control study was performed on patients referred to Sina and Imam University hospitals, Tehran, Iran; it included 62 men with clinicopathologically confirmed diagnosis of prostate cancer (case group) and 68 men with no detectable prostate cancer [normal digital rectal examination and prostate-specific antigen (PSA) level] or any other malignant disease (control group). The serum selenium level was assessed using Zeeman graphite furnace atomic absorption spectrometer (Varian Company, Australia). The mean serum selenium level in the case and control group was 66.3 +/- 17.7 microg/l and 77.5 +/- 22.5 microg/l, respectively (P = 0.002). Serum selenium was inversely associated with prostate cancer risk. After adjustment for age, body mass index (BMI), and smoking, the odds ratio was 0.16 and 95% confidence intervals were 0.06 to 0.47 (P trendq = 0.001) comparing the highest with the lowest tertile (> or = 89.3 microg/l). No correlation was observed between serum selenium level and age, BMI, or PSA level. In conclusion, serum selenium levels in prostate cancer cases were lower than in controls, which supports the hypothesis that selenium may protect against prostate cancer.     

Occupation and breast cancer risk in Polish women: a population-based case-control study

BACKGROUND: The etiology of breast cancer is not well understood and the role of occupational exposures in breast carcinogenesis is still uncertain. METHODS: The population-based case-control study included 2,386 incident breast cancer cases diagnosed in 2000-2003, and 2,502 controls. Lifetime occupational histories and information on other potential breast cancer risk factors were obtained through personal interviews. Conditional logistic regression analyses calculated odds ratios (ORs) associated with various occupations and industries after control for potential confounders. RESULTS: We found statistically significant excesses of breast cancer among engineers (OR=2.0; 95% CI: 1.0-3.8), economists (2.1; 1.1-3.8), sales occupations-retail (1.2; 1.0-1.5), and other sales occupations (1.2; 1.0-1.5). Industries showing significantly elevated risks included special trade contractors (2.2; 1.2-4.3), electronic and electric equipment manufacturers (1.7; 1.1-2.7); and public administration/general government n.e.c. (2.7; 1.3-5.7). Each of these findings was supported by a statistically significant positive trend for duration of employment (P<0.05). A decreased breast cancer risk was observed in janitors and cleaners (0.7; 0.5-0.8). CONCLUSIONS: In this study, we found few associations for breast cancer and occupations or industries. The suggestive findings for the electronic and electric equipment manufacturing industry and for the occupations with potential exposure to magnetic fields deserve further evaluation.     

Occupation and risk of pancreatic cancer: a population-based case-control study in iowa

OBJECTIVE: Previous epidemiological studies have inconsistently linked various occupations and industries to pancreatic cancer risk. METHODS: We analyzed data from a population-based case-control study conducted in Iowa involving 376 histologically confirmed incident pancreatic cancer cases and 2434 control subjects. RESULTS: A significantly increased risk was observed among men who worked in the following industries: chemical and allied products, transportation, and elementary and secondary schools. Increased risks also were observed in men who were employed as truck drivers; railroad brake, signal, and switch operators; purchasing agents and buyers; teachers; insurance agents; and retail supervisors. Among women, a significantly increased risk of pancreatic cancer was found for employment in furniture and home furnishing stores, and a borderline significantly increased risk among textile sewing machine operators and tenders. CONCLUSIONS: Working in several occupations and industries was associated with an increased risk of pancreatic cancer in this study, and these associations warrant further investigation.     

Factors associated with prostate cancer screening: a population-based study

The aim of this study was to analyze the prevalence of prostate cancer screening among men aged 50 years or older based on socioeconomic, demographic, and health-related behavioral variables and the presence of morbidity. A population-based cross-sectional study was performed. The following factors were associated with failure to undergo screening: age under 70 years; less than eight years of schooling; per capita household income less than one-half the minimum wage; not having diabetes; lack of visual impairment; and lack of visit to the dentist in the previous year. The Brazilian public healthcare system accounted for 41% of the reported prostate cancer screening tests. According to the present study, despite controversy over the effectiveness of digital rectal examination and prostate-specific antigen for detecting prostate cancer, a significant portion of the male population has been undergoing these tests, the access to which displays significant socioeconomic inequalities.     

Occupational risk factors for brain cancer: a population-based case-control study in Iowa

A number of occupations and industries have been inconsistently associated with the risk of brain cancer. To further explore possible relationships, we conducted a population-based case-control study of brain glioma in the state of Iowa, involving 375 histologically confirmed incident cases and 2434 population-based controls. Among men, the industries and/or occupations that had a significantly increased risk for employment of more than 10 years included roofing, siding, and sheet metalworking; newspaper work; rubber and plastics products, particularly tires and inner tubes; miscellaneous manufacturing industries; wholesale trade of durable goods, grain, and field beans; cleaning and building service occupations; miscellaneous mechanics and repairers; and janitors and cleaners. Subjects who worked in plumbing, heating, and air conditioning; electrical services; gasoline service stations; and military occupations also experienced a significantly increased risk. Among women, significant excess risk was observed for occupations in agricultural services and farming, apparel and textile products, electrical and electronic equipment manufacturing, various retail sales, record-keeping, and restaurant service. Workers in industries with a potential for gasoline or motor exhaust exposures experienced a non-significant excess risk of brain glioma.     

Exposure to residential radon and lung cancer in Spain: a population-based case-control study

Although high radon concentrations have been linked to increased risk of lung cancer by both experimental studies and investigations of underground miners, epidemiologic studies of residential radon exposure display inconsistencies. The authors therefore decided to conduct a population-based case-control study in northwest Spain to determine the risk of lung cancer associated with exposure to residential radon. The study covered a total of 163 subjects with incident lung cancer and a population sample of 241 cancer-free subjects since 1992-1994. Odds ratios for radon were estimated using logistic regression adjusted for sex, age, lifetime tobacco use, family history, and habitat. The adjusted odds ratios for the second, third, and fourth quartiles of radon (breakpoints: 37.0, 55.2, and 148.0 Bq/m(3)) were 2.73 (95% confidence interval (CI): 1.12, 5.48), 2.48 (95% CI: 1.29, 6.79), and 2.96 (95% CI: 1.29, 6.79), respectively. An additive synergic effect between radon and tobacco was found. The results from this study suggest that, even at concentrations far below official guideline levels, radon may lead to a 2.5-fold rise in the risk of lung cancer. Furthermore, the synergy found between smoking and radon may prove useful when it comes to drafting public health recommendations.     

Occupation and asthma: a population-based incident case-control study

The authors assessed the relations between occupation and risk of developing asthma in adulthood in a 1997-2000 population-based incident case-control study of 521 cases and 932 controls in south Finland. The occupations were classified according to potential exposure to asthma-causing inhalants. Asthma risk was increased consistently for both men and women in the chemical (adjusted odds ratio (OR) = 5.69, 95% confidence interval (CI): 1.08, 29.8), rubber and plastic (OR = 2.61, 95% CI: 0.92, 7.42), and wood and paper (OR = 1.72, 95% CI: 0.71, 4.17) industries. Risk in relation to occupation was increased only for men-for bakers and food processors (OR = 8.62, 95% CI: 0.86, 86.5), textile workers (OR = 4.70, 95% CI: 0.29, 77.1), electrical and electronic production workers (OR = 2.83, 95% CI: 0.82, 6.93), laboratory technicians (OR = 1.66, 95% CI: 0.17, 16.6), and storage workers (OR = 1.57, 95% CI: 0.40, 6.19). Of the predominantly men's occupations, metal (OR = 4.52, 95% CI: 2.35, 8.70) and forestry (OR = 6.00, 95% CI: 0.96, 37.5) work were the strongest determinants of asthma. For women, asthma risk increased for waiters (OR = 3.03, 95% CI: 1.10, 8.31), cleaners (OR = 1.42, 95% CI: 0.81, 2.48), and dental workers (OR = 4.74, 95% CI: 0.48, 46.5). Results suggest an increased asthma risk both in traditional industries and forestry and in several nonindustrial occupations.     

Chlorinated drinking water and pancreatic cancer: A population-based case-control study

In order to examine the potential association between chlorinateddrinking water and the incidence of pancreatic cancer, a population-basedcase-control study was performed on data obtained from the Turkuarea in Finland. The study base was approximately 220,000 persons.All 183 pancreatic cancer cases, diagnosed during 1989–1991,were included in the study. Each case had 2 randomly selectedcontrols. The criterion for the exposure to chlorination by-products(CBPs) was that the subject had had chlorinated drinking waterfrom a surface source available at home. Residential addresseswith chlorinated or non-chlorinated water were obtained forup to the previous 20 years prior to diagnosis. The odds ratios(OR) varied between 0.20 and 0.66 depending on the length ofthe cumulative exposure time. This indicates that those exposedto chlorinated drinking water had a lower risk of contractingpancreatic cancer than the unexposed. The result is in grossagreement with earlier investigations which have mainly shownnegative or inadequate associations. The side-effects of drinkingwater disinfection are unproven, because the published researchresults are inconsistent. The benefits of chlorination, however,are undeniable. Continuous water disinfection is needed in orderto avoid waterborne epidemics and chlorination is the only availablemethod in many countries.     

Phytoestrogen intake and prostate cancer: a case-control study using a new database

In the last several years, attention has been focused on comparing the Western diet, which is rich in fat, protein, and refined carbohydrates, with the Asian diet, which is rich in phytoestrogens, as a possible explanation for the contrasting rates of clinically relevant prostate cancer. Phytoestrogens, plant-derived nutrients, include several isoflavones, flavonoids, lignans, phytosterols, and coumestans, some of which have been postulated as having anticarcinogenic properties. Using a new database, we examined the role of phytoestrogen intake and prostate cancer risk in 83 Caucasian cases and 107 controls. Controls reported consuming higher amounts of foods containing genistein, daidzein, and coumestrol and lower amounts of foods containing campesterol and stigmasterol. Multivariate analysis, after adjustment for age, family history of prostate cancer, alcohol consumption, and total calorie intake, showed an inverse association between coumestrol (p = 0.03) and daidzein (p = 0.07) and prostate cancer risk. Genistein, the most studied phytoestrogen, showed a slight protective effect (p = 0.26). However, a positive association was found between campesterol (p = 0.08) and stigmasterol (p = 0.03) and risk of prostate cancer. These results are suggestive of a possible relationship between phytoestrogen intake and prostate cancer risk. Larger comprehensive studies are needed to further refine the role of phytoestrogen intake in prostate cancer risk.     

Methylenetetrahydrofolate reductase (MTHFR) variants and bladder cancer: a population-based case-control study

Functional variants in the methylenetetrahydrofolate reductase (MTHFR) gene, including the 677C>T and 1298A>C polymorphisms, have been associated with a moderately reduced risk of several cancers, including colorectal cancers. While recent studies have investigated the role of these polymorphisms on bladder cancer susceptibility, results have been mixed. To clarify the role of MTHFR polymorphisms on bladder cancer risk, we genotyped MTHFR 677C > T and MTHFR 1298A > C in a population-based study of bladder cancer of 352 patients and 551 controls from New Hampshire, USA. The allelic frequency was 35.6% for MTHFR 677C>T and 40.4% for MTHFR 1298A > C among controls. We found no evidence of a main gene effect for either polymorphism (adjusted OR for MTHFR 677C>T variants versus the reference genotype = 1.1; 95% CI, 0.8-1.4 and adjusted OR for MTHFR 1298A>C variants versus the reference genotype = 1.0; 95% CI, 0.7-1.4). Odds ratios did not appear to differ by smoking status or gender. We observed differences in the risk estimates for the MTHFR polymorphisms by arsenic exposure, but they were not statistically significant (P = 0.67 for MTHFR 677C > T and P = 0.12 for MTHFR 1298A>C). Thus, our findings do not support the presence of a main gene effect. The possibility that MTHFR polymorphism affects susceptibility to environmental exposures warrants further consideration.     

Clinical features of colorectal cancer before emergency presentation: a population-based case-control study

OBJECTIVE: To identify the clinical features of colorectal cancer presenting as a surgical emergency. DESIGN: Population-based case-control study. SETTING: All general practices in Exeter Primary Care Trust, Devon, UK. Participants. 349 patients with colorectal cancer, 62 of these having an emergency presentation. Five randomly selected controls matched by age, sex and general practice for each case. DATA: The entire primary care record, from 24 months to 30 days before diagnosis, was coded using the International Classification of Primary Care-2. MAIN OUTCOME MEASURES: Symptom reporting by patients with emergency presentation of colorectal cancer compared with matched controls and non-emergency presentations. RESULTS: Eight features of colorectal cancer were associated with the 62 emergency presentations of colorectal cancer. 39 (63%) of patients had reported at least one symptom to their doctors a minimum of 30 days before the diagnosis. In multivariable analysis, three features remained independently associated with cancer: abdominal pain, odds ratio 6.2 (95% CI 2.8-14), P<0.001; loss of weight 3.4 (1.3-8.5), P=0.01; and diarrhoea 3.4 (1.2-5.7), P=0.02. When emergency presentations were compared with elective cases, abdominal pain was more common [interaction odds ratio 2.3 (1.6-3.3); P=0.047] and rectal bleeding less common [0.30 (0.08, 1.0); P=0.040]. CONCLUSION: The majority of patients destined to have an emergency presentation of colorectal cancer have reported symptoms of their cancer to their doctor well before the emergency. Some emergency presentations should therefore be preventable.