Occupation and occupational exposure to endocrine disrupting chemicals in male breast cancer: a case-control study in Europe.

OBJECTIVES: Male breast cancer is a rare disease of largely unknown aetiology. In addition to genetic and hormone-related risk factors, a large number of environmental chemicals are suspected of playing a role in breast cancer. The identification of occupations or occupational exposures associated with an increased incidence of breast cancer in men may help to identify mammary carcinogens in the environment. METHODS: Occupational risk factors for male breast cancer were investigated in a multi-centre case-control study conducted in eight European countries which included 104 cases and 1901 controls. Lifetime work history was obtained during in-person interviews. Occupational exposures to endocrine disrupting chemicals (alkylphenolic compounds, phthalates, polychlorinated biphenyls and dioxins) were assessed on a case-by-case basis using expert judgement. RESULTS: Male breast cancer incidence was particularly increased in motor vehicle mechanics (OR 2.1, 95% CI 1.0 to 4.4) with a dose-effect relationship with duration of employment. It was also increased in paper makers and painters, forestry and logging workers, health and social workers, and furniture manufacture workers. The OR for exposure to alkylphenolic compounds above the median was 3.8 (95% CI 1.5 to 9.5). This association persisted after adjustment for occupational exposures to other environmental oestrogens. CONCLUSION: These findings suggest that some environmental chemicals are possible mammary carcinogens. Petrol, organic petroleum solvents or polycyclic aromatic hydrocarbons are suspect because of the consistent elevated risk of male breast cancer observed in motor vehicle mechanics. Endocrine disruptors such as alkylphenolic compounds may play a role in breast cancer.

Adolescent milk fat and galactose consumption and testicular germ cell cancer.

Recent case-control studies suggested that dairy product consumption is an important risk factor for testicular cancer. We examined the association between consumption of dairy products, especially milk, milk fat, and galactose, and testicular cancer in a population-based case-control study including 269 case and 797 controls (response proportions of 76% and 46%, respectively). Dietary history was assessed by food frequency questions for the index persons and through their mothers including diet 1 year before interview and diet at age 17 years. We used conditional logistic regression to calculate odds ratios as estimates of the relative risk (RR), 95% confidence intervals (95% CI), and to control for social status and height. The RR of testicular cancer was 1.37 (95% CI, 1.12-1.68) per additional 20 servings of milk per month (each 200 mL) in adolescence. This elevated overall risk was mainly due to an increased risk for seminoma (RR, 1.66; 95% CI, 1.30-2.12) per additional 20 milk servings per month. The RR for seminoma was 1.30 (95% CI, 1.15-1.48) for each additional 200 g milk fat per month and was 2.01 (95% CI, 1.41-2.86) for each additional 200 g galactose per month during adolescence. Our results suggest that milk fat and/or galactose may explain the association between milk and dairy product consumption and seminomatous testicular cancer.

Carpenters, cabinetmakers, and risk of testicular germ cell cancer.

OBJECTIVE: A recent cohort study showed an increased risk of testicular cancer among members of the United Brotherhood of Carpenters and Joiners of America. We explored our data of a German population-based case-control study on the etiology of testicular cancer with regard to this association. METHODS: The case-control study included 269 testicular cancer cases and 797 controls. We applied conditional logistic regression to calculate odds ratios (OR) and 95% confidence intervals (95% CIs). RESULTS: People who worked as cabinetmakers or carpenters had an OR of 0.84 (95% CI = 0.45-1.56). Risks were increased among cabinetmakers who worked at least 15 years ago (OR = 5.81, 95% CI = 1.20-28.09). Ever being employed as a carpenter was associated with a reduced OR of 0.59 (95% CI = 0.24-1.46). CONCLUSIONS: Cabinetmakers may be at an increased risk of testicular cancer.

Testicular, other genital, and breast cancers in first-degree relatives of testicular cancer patients and controls.

Previous studies showed an increased prevalence of testicular cancer among fathers and brothers of testicular cancer patients. We examined whether testicular, other genital, and breast cancers aggregate in parents and siblings of testicular cancer patients in a population-based case-control study, including males, ages 15 to 69 years at diagnosis, with primary malignant tumors of the testes or extragonadal germ cell tumors. Controls were ascertained through the mandatory registries of residents and frequency matched to the cases by age and region of residence. In a face-to-face interview, 269 cases and 797 controls provided health-related information on parents and siblings. We calculated odds ratios (OR) and corresponding 95% confidence intervals (95% CI) based on the generalized estimating equations technique, adjusting for the matching variables and relatives' age. Three (1.1%) fathers and eight (3.2%) brothers of cases were affected with testicular cancer compared with four (0.5%) fathers and two (0.2%) brothers of controls. The OR (95% CI) of familial testicular cancer was 6.6 (2.35-18.77). Only nonseminoma patients had fathers with testicular cancer, whereas the affected brothers were all related to seminoma patients. Overall, we found an increased risk for genital other than testicular cancers (OR 2.5, 95% CI 1.43-4.43). For breast cancer, we detected an increased risk in sisters (OR 9.5, 95% CI 2.01-45.16, adjusted for age of study participant and age of sister) but not in mothers. Our findings support the hypothesis that testicular and other genital cancers have a common familial component that may be due to genetic and shared exogenous factors such as estrogen exposure during fetal development.

Sun exposure and number of nevi in 5- to 6-year-old European children.

The occurrence and number of melanocytic nevi are among the most important known risk factors for the development of malignant melanoma. Studying the causes of nevi should lead to successful strategies in the prevention of melanoma. Among 11,478 white German children of preschool age the association between benign melanocytic nevi and a number of risk factors for skin cancer was examined. We found that subjects with a reported history of increased sun exposure, for example, painful sunburns, and an increased number of holidays in foreign countries with a sunny climate had significantly higher nevus counts than individuals without these characteristics. Our results provide further evidence that nevus counts may not only be part of a genetic predisposition but also a result of increased exposure to ultraviolet radiation. Together with the fact that a high nevus count is the most relevant risk factor for malignant melanoma, the results strongly indicate a connection between UV-radiation and the development of melanocytic skin cancer. In conclusion, strategies to reduce the incidence of melanoma should begin with young children.

A population-based case-control study on social factors and risk of testicular germ cell tumours.

OBJECTIVES: Incidence rates for testicular cancer have risen over the last few decades. Findings of an association between the risk of testicular cancer and social factors are controversial. The association of testicular cancer and different indicators of social factors were examined in this study. DESIGN: Case-control study. SETTING: Population-based multicentre study in four German regions (city states Bremen and Hamburg, the Saarland region and the city of Essen). PARTICIPANTS: The study included 797 control participants and 266 participants newly diagnosed with testicular cancer of which 167 cases were classified as seminoma and 99 as non-seminoma. The age of study participants ranged from 15 to 69 years. METHODS: Social position was classified by educational attainment level, posteducational training, occupational sectors according to Erikson-Goldthorpe-Portocarrero (EGP) and the socioeconomic status (SES) on the basis of the International SocioEconomic Index of occupational status (ISEI). ORs and corresponding 95% CIs (95% CIs) were calculated for the whole study sample and for seminoma and non-seminoma separately. RESULTS: Testicular cancer risk was modestly increased among participants with an apprenticeship (OR=1.7 (95% CI 1.0 to 2.8)) or a university degree (OR=1.6 (95% CI 0.9 to 2.8)) relative to those whose education was limited to school. Analysis of occupational sectors revealed an excess risk for farmers and farm-related occupations. No clear trend was observed for the analyses according to the ISEI-scale. CONCLUSIONS: Social factors based on occupational measures were not a risk factor for testicular cancer in this study. The elevated risk in farmers and farm-related occupations warrants further research including analysis of occupational exposures.

Residential exposure to overhead high-voltage lines and the risk of testicular cancer: results of a population-based case-control study in Hamburg (Germany).

BACKGROUND: In a population-based case-control study we examined the association between residential exposure to overhead high-voltage lines and testicular cancer. METHODS: We recorded the residential biography of cases with testicular cancer identified by the Hamburg Cancer Registry and of controls that were randomly selected from the mandatory registry of residents in Hamburg. The study included 145 incident cases between 15 and 69 years of age, diagnosed between 1995 and 1997, and 313 controls, matched for age in 5-year strata. In model A, exposure was defined by distance (ever vs never). Model B took into account residence time and the inverse distance from the nearest high-voltage line. It distinguished between low and high exposure, the never exposed persons serving as a reference group. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated by unconditional logistic regression. For men below the age of 40 years and men aged 40 years and over separate analyses were carried out. RESULTS: Within a corridor of 100 m the prevalence of exposure to high-voltage lines in Hamburg was 6.9% in cases and 5.8% in controls (OR=1.3; 95% CI=0.56-2.80). In the more complex model B we found an OR of 1.2 (95% CI=0.60-2.47) for low exposure and 1.7 (95% CI=0.91-3.32) for high exposure. Younger men show slightly increased risks in both models. CONCLUSIONS: In all, residential exposure to high-voltage lines did not seem to be a major risk factor for testicular cancer in our study. Yet, the fact that risks for men below the age of 40 years were slightly increased in both exposure models deserves further attention.

Firefighting and risk of testicular cancer: results from a German population-based case-control study.

BACKGROUND: There is some evidence of an elevated risk for testicular cancer among firefighters. METHODS: We performed a population-based case-control study including 269 testicular cancer cases and 797 controls matching on age and region with a special focus on occupational exposures. Job tasks were coded according to the International Standard Classification of Occupations (ISCO 68). We used conditional logistic regression to calculate odds ratios (OR). RESULTS: Three controls (0.4%) and four cases (1.5%) ever worked as firefighters. Firefighters showed an increased odds of testicular cancer in the matched evaluation (OR = 4.3, 95% confidence interval (95% CI) 0.7-30.5). The adjustment for a history of cryptorchidism or family history of testicular cancer did not alter our results. CONCLUSION: Although the association between firefighting and testicular cancer risk is based on only small numbers of exposed subjects in our study, the finding is consistent with a recent cohort study from New Zealand. Occupational hazards experienced by firefighters may increase the risk of testicular cancer.

Testicular cancer and electromagnetic fields (EMF) in the workplace: results of a population-based case-control study in Germany.

OBJECTIVES: In a population-based case-control study, we examined the association of testicular cancer and electromagnetic fields (EMF) in the workplace. METHODS: Incident cases (n = 269) were recruited between 1995 and 1997. A total of 797 controls matched on age and region were randomly selected from mandatory registries of residents. EMF exposure was assessed for five categories in standardized face-to-face interviews using closed questions. For each exposure category, odds ratios (OR) were calculated, stratified by age and region, and in a more complex model weighted by duration and distance using conditional logistic regression. Subgroup analyses were conducted for seminoma and non-seminoma and for blue- and white-collar workers. Additionally, potential radar exposure was individually assessed by experts based on all available information including free text. RESULTS: There was no excess risk for cases who reported to have ever worked near the following: radar units (OR = 1.0; 95% CI = 0.60-1.75); radiofrequency emitters (OR = 0.9; 95% CI = 0.60-1.24); electrical machines (OR = 1.0; 95% CI = 0.72-1.33): high-voltage lines or high-voltage electrical transmission installations (OR = 0.7; 95% CI = 0.38-1.18); or visual display units or complex electrical environments (OR = 0.9; 95% CI = 0.67-1.21). The results for the weighted exposure and subgroup analyses did not differ substantially. For radar exposure as assessed by the experts, the OR was 0.4 (95% CI = 0.13-1.16). CONCLUSIONS: EMF exposure in the workplace does not seem to be a relevant risk factor for testicular cancer in our study.

Cooking and uveal melanoma risk: results from two German case-control studies.

OBJECTIVE: Two recent studies indicated that cooks may have an increased risk of uveal melanoma. Here we report findings of two German case-control studies regarding cooking and uveal melanoma risk. METHODS: We conducted a hospital and population-based case-control study of uveal melanoma and occupational exposures. We then pooled these results. Overall, 118 cases and 475 controls matching on age, sex and study regions were interviewed. We classified subjects as exposed to an occupational category (i.e. cooks) if they had ever worked within this category for at least six months or more. Subjects who had worked as cooks were rated as either (a) having prepared food without having cooked and therefore unexposed to cooking or (b) having cooked. We used conditional logistic regression models to calculate pooled odds ratios (OR) and 95% confidence intervals (95% CI). RESULTS: Subjects who had ever cooked had an OR of 6.1 (95% CI: 1.7-22.2). Cooking was associated with an OR of 4.0 (95% CI: 0.8-20.1) for a job duration of 0.5-2 years and with an OR of 11.4 (95% CI: 1.6-81.9) for a job duration more than 2 years. CONCLUSIONS: In light of the similar finding in other studies, the association deserves further attention.

Alcohol drinking may increase risk of breast cancer in men: a European population-based case-control study.

OBJECTIVE: It has been estimated that alcohol drinking increases the risk of breast cancer in women by approximately 7% for each increment of 10 g alcohol per day. However, the few studies conducted on breast cancer among men have failed to detect an association with quantitative measures of alcohol drinking, even if the alcohol intake is generally higher in men than in women. On the other hand, increased risks of male breast cancer were inconsistently reported in alcoholics or patients with liver cirrhosis. We have investigated the role of alcohol drinking in male breast cancer using data collected in a population-based case-control study on seven rare cancers, conducted in Denmark, France, Germany, Italy, and Sweden. METHODS: The cases were 74 histologically verified male breast cancer patients aged 35-70 years. The controls (n = 1432) were selected from population registers, and frequency-matched to the cases by age group and geographic area. To check for consistency, a separate analysis was conducted using as controls the patients with a rare cancer other than male breast recruited simultaneously in the European study (n = 519 men). RESULTS: Based on population controls, the risk of developing breast cancer in men increased by 16% (95% CI: 7-26%) per 10 g alcohol /day (p < 0.001). An odds ratio of 5.89 (95% CI: 2.21-15.69) was observed for alcohol intake greater than 90 g per day, as compared with light consumers (< 15 g per day). Similar associations were observed when other rare cancers patients were used as controls. CONCLUSION: We found that the relative risk of breast cancer in men is comparable to that in women for alcohol intakes below 60 g per day. It continues to increase at high consumption levels not usually studied in women.