Dietary fish intake and risk of leukaemia, multiple myeloma, and non-Hodgkin lymphoma.

This study aimed to determine whether fish intake was protective against leukemia, multiple myeloma, and non-Hodgkin lymphoma (NHL), and if our previous finding of a protective effect of fish-related occupations on the risk of these diseases was due to dietary intake of fish. We used data from a population-based case-control study undertaken in Canada in 1994-1998. Dietary information was available for 919 leukemia cases, 287 myeloma cases, 1418 NHL cases, and 4202 controls. The risk of each of the three cancers was determined using multiple logistic regression analysis according to quartiles of weekly fresh fish intake, percentage of total energy intake from fresh fish, and percentage of total fat intake from fresh fish. After adjusting for age, sex, smoking, BMI, and proxy status, people who consumed greater proportions of their total energy intake from fresh fish had a significantly lower risk of each of the three types of cancer, and there was a significant dose-response for risk of leukemia and NHL. Those in the highest quartile for percentage of fat intake from fish were at lowest risk: leukemia odds ratio (OR) 0.72, 95% confidence interval (CI) 0.58-0.89; multiple myeloma OR 0.64, 95% CI 0.45-0.90; NHL OR 0.71, 95% CI 0.60-0.85; and all LH cancers combined OR 0.70, 95% CI 0.61-0.81. The protective effect previously observed for working with fish on the risk of leukemia and lymphoma was independent of fish intake. These findings suggest that a diet high in fish may be protective against lymphohematopoietic cancers and confirm the reduced risk among fish workers.     

Lymphohematopoietic Cancers in the United Farm Workers of America (UFW), 1988–2001

Objective:  Agricultural risk factors for lymphohematopoeitic cancers (LHC) in Hispanic farm workers in California were examined in a nested case–control study embedded in a cohort of 139,000 ever members of a farm worker labor union in California.Methods:  Crop and pesticide exposures were estimated by linking county/month and crop specific job history information from union records with California Department of Pesticide Regulation pesticide use reports during the 20-year period prior to cancer diagnosis.Results:  A total of 131 LHC diagnosed in California between 1988 and 2001 were included in the analysis. Analyses were conducted by gender and subtype of non-Hodgkins lymphoma (nodal, extra nodal) and by leukemia histology (lymphocytic, granulocytic). Odds ratios were calculated by stratification and by unconditional logistic regression. Risk for all LHC was elevated in workers cultivating vegetables (OR = 1.67, 95% CI = 1.12–2.48). Risk of leukemia was associated with exposure to the pesticides mancozeb (OR = 2.35, 95% CI = 1.12–4.95) and toxaphene (OR = 2.20, 95% CI = 1.04–4.65) while NHL risk was increased in association with 2,4-D (OR = 3.80, 95% CI=1.85–7.81). Risk of leukemia was particularly elevated among female workers and for granulocytic versus lymphocytic leukemia for several chemicals. No associations were noted for multiple myeloma.Conclusions:  California farm workers employed where mancozeb and toxaphene were used had an increased risk of leukemia compared to farm workers employed elsewhere. Employment in farms using 2,4-D was associated with an increased risk of NHL.     

Smoking and Hematolymphopoietic Malignancies

Objective: Tobacco use is the most prominent cause of respiratory cancers. Little is known, however, about the influence of smoking on hematolymphopoietic malignancies. To evaluate this relation, a population-based case–control study was carried out in 12 areas of Italy. Methods: Detailed interviews on tobacco smoking habits were administered to 1450 non-Hodgkin's lymphoma (NHL), 365 Hodgkin's disease (HD), 270 multiple myeloma (MM), and 649 leukemia (LEU) patients occurring from 1990 to 1993, and 1779 population controls. Results: We found a slightly increased risk for NHL in smokers (odds ratio 1.2, 95% confidence interval 1.0–1.4 for ever smokers), but a consistent positive association was shown only for follicular NHL. In this subtype, a significant excess risk was observed for ever versus never smokers, after adjustment for gender, age, geographic residence, education, and respondent (OR = 1.8, 95%, CI 1.3–2.7), with a positive exposure–response gradient for smoking duration (p<0.01). The risk for follicular NHL was significantly elevated only among women, with ever smokers showing OR = 2.3 (CI 1.4–3.8), while for men we found OR = 1.3 (CI 0.69–2.3). No major differences were shown according to age. Female subjects also showed significant positive exposure–response trends for duration. Conclusion: Cigarette smoking could be a risk factor for follicular NHL among women. For HD, MM, or LEU, no clear association was observed.     

Personal and Occupational Exposure to Organic Solvents and Risk of Non-Hodgkin’s Lymphoma (NHL) in Women (United States)

Objectives: The authors assessed whether home and occupational exposure to organic solvents is associated with risk of NHL in women. Methods: A population-based, incidence case-control study was conducted in upstate New York, involving 376 NHL cases and 463 population controls selected from the Medicare beneficiary files and State driver’s license records. Exposure information was obtained by telephone interview. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using an unconditional logistic regression model, adjusting for a number of risk factors for NHL. Results: Overall, history of exposure to organic solvents was not associated with the risk of NHL. A statistically significant increase in risk associated with occupational exposure was observed only for the subjects whose first exposure occurred before 1970 (OR=1.87, 95% CI 1.03–3.40). When occupational and home exposures to paint thinners/turpentine were combined and analyzed together, the risk of NHL associated with any exposure, compared to no exposure at either job or home, was a statistically significantly increased (OR=1.46, 95% CI: 1.05–2.03). This observation was more pronounced for B-cell lymphoma and for low-grade lymphoma with ORs of 1.52 (95 CI: 1.08–2.14) and 2.20 (95% CI; 1.42–3.41), respectively. Conclusions: The results of this case-control study do support of a major role of organic solvents in the development of NHL among women currently living in the US. However, relatively intensive exposure in past occupations and use of paint thinners/turpentine may deserve further investigation.     

Occupational exposure to pesticides and risk of hematopoietic cancers: meta-analysis of case–control studies

Objective In this study we conducted a meta-analysis of 13 case–control studies that examined the occurrence of hematopoietic cancers in pesticide related occupations in order to undertake a qualitative and quantitative evaluation of a possible relationship. Methods Pubmed databases were searched for case–control studies published between 1990 and 2005 investigating the relation between hematopoietic cancers and occupational exposure to pesticides. Fixed and random effect meta-analysis models were used depending on the presence of heterogeneity between studies. Results The overall meta-odds ratio obtained after pooling 44 ORs from 13 studies was 1.3 (95% CI: 1.3–1.5). We realized stratified analysis on three different types of hematopoietic cancers (non-Hodgkin lymphoma (NHL), leukemia and multiple myeloma). A significant increased risk of NHL was found (OR = 1.35; 95% CI = 1.2–1.5). Moreover, increased risks of Leukemia (OR = 1.35; 95% CI = 0.9–2) and multiple myeloma (OR = 1.16; 95% CI = 0.99–1.36) were also detected but these results were not statistically significant. Significant heterogeneity existed among the different studies and a publication bias was detected. Therefore, a meta-regression was carried out. Our results showed that a long period of exposure (more than 10 years) provided an increase in the risk of all hematopoietic cancers and for NHL by fractions of 2.18 (95% CI = 1.43–3.35) and 1.65 (95% CI = 1.08–2.51), respectively. Conclusions: The overall meta-odds ratio suggests that there is a significantly positive association between occupational exposure to pesticides and all hematopoietic cancers as well as NHL. A major limitation of our meta-analysis is the lack of sufficient data about exposure information and other risk factors for hematopoietic cancer (genetic predisposition, ethnic origin, immunodepression…). In addition, data concerning specific subtypes of hematopoietic cancers are often confusing. Thus, future epidemiological studies should undertake a major effort to assess the identity and the level of pesticides exposure and should control for the most likely potential confounders.     

Diagnostic radiation and the risk of multiple myeloma (United States)

Objective: To evaluate the relationship between cumulative lifetime exposure to diagnostic radiation and the risk of multiple myeloma using data from a large, multi-center, population-based case–control study. Methods: Study subjects included a total of 540 cases with newly diagnosed multiple myeloma and 1998 frequency-matched population controls living in three areas of the United States (Georgia, Michigan, New Jersey). Information on exposure to diagnostic X-rays was obtained by personal interview. Results: No association was found between case–control status and the total number of reported diagnostic X-rays of any type (odds ratio (OR) for 20 or more compared to less than 5 X-rays = 0.9, 95% confidence interval (95% CI) = 0.7–1.2). There was no evidence of an excess risk of multiple myeloma among individuals who reported exposure to 10 or more diagnostic X-rays that impart a relatively high radiation dose to the bone marrow, as compared to individuals reporting no such exposures (OR 0.7, 95% CI 0.4–1.3). Conclusions: These data suggest that exposure to diagnostic X-rays has a negligible impact, if any, on risk of developing multiple myeloma.     

Alcohol use and risk of non-Hodgkin's lymphoma among Connecticut women (United States)

Objective: Incidence rates of non-Hodgkin's lymphoma (NHL) have risen dramatically over the past several decades; however, the etiology of NHL remains largely unknown. Previous studies of the relationship between alcohol consumption and NHL have yielded conflicting results. Data from a population-based case–control study among women in Connecticut were analyzed to determine the potential impact of alcohol consumption on risk of NHL. Methods: The study included 601 histologically confirmed, incident cases of NHL and 718 population-based controls. In-person interviews were administered using standardized, structured questionnaires to collect data on history of consumption for beer, wine, and liquor. Results: When compared to non-drinkers, women who reported consumption of at least 12 drinks per year of any type of alcohol experienced slightly reduced risk of NHL (OR: 0.82; 95% CI: 0.65–1.04). Further stratification by alcohol type revealed that the inverse association was mainly limited to wine consumption (OR: 0.75; 95% CI: 0.59–0.96), with no clear association for beer or liquor consumption. Risk of NHL was further reduced with increasing duration of wine consumption (p for linear trend = 0.02). Consumption of wine for greater than 40 years was associated with approximately 40% reduction in risk (OR: 0.63; 95% CI: 0.44–0.91). Conclusion: Our results are consistent with several recent epidemiologic studies that have also suggested an inverse association between wine consumption and risk of NHL. The reduction in risk of NHL associated with increased duration of wine consumption warrants further investigation in other populations.     

The effect of atopy,childhood crowding,and other immune-related factors on non-Hodgkin lymphoma risk

Objective Since adult immune responsiveness is influenced by early childhood exposures, we examined the role of family size, history of atopic disease, and other childhood immune-related exposures in a multi-center case–control study of NHL. Methods Interviews were completed with 1,321 cases ascertained from population-based cancer registries in Seattle, Detroit, Los Angeles and Iowa, and with 1,057 frequency-matched controls, selected by random-digit dialing and from the Medicare files database. Multivariable logistic regression was used to estimate risk. Results A history of any allergy (excluding drug allergies), decreased risk of all NHL (Odds Ratio [OR] = 0.7, 95% Confidence Interval [CI] = 0.6–1.0), diffuse large B-cell lymphoma [DLBCL] (OR = 0.6, 95% CI = 0.4–0.9), and follicular NHL (OR = 0.7, 95 CI = 0.5, 1.0). A similar effect was observed for hay fever. A history of eczema was associated with an increased risk of follicular lymphoma (OR = 1.9, 95% CI = 1.1–3.4), but not DLBCL (OR = 1.1, 95% CI = 0.6–2.0). Asthma did not affect risk. Youngest compared to oldest siblings had a 90% increased risk of DLBCL (95% CI = 1.2–3.1; p for trend with increasing birth order = 0.006), but not follicular lymphoma (OR = 1.1, 95% CI = 0.6–1.8). Conclusions We infer that some childhood and immune-related factors may alter NHL risk.     

Smoking and non-Hodgkin's lymphoma: a case-control study in the Rhône-Alpes region of France

Objective: To study the relation between smoking and non-Hodgkin/s lymphoma (NHL), in the Rhône-Alpes region of France. Methods: We conducted a hospital-based case–control study that included 180 cases of NHL and 360 age-, gender-matched hospital controls. Matched univariable and multivariable logistic regression models were used for analysis. Results: For the whole study population as well as for men, smoking does not elevate the risk of NHL. However, the risk of NHL is higher for women who currently smoke compared to women who have never smoked (odds ratio [OR] = 2.40, 95% confidence interval [95% CI] = 1.19–4.84). Among ever smokers, the OR of NHL is 5.04 (95% CI = 1.40–18.12) for women who have smoked for more than 30 years compared with those who have never smoked. Similarly, women who started to smoke before the age of 20 years compared with women who have never smoked are at greater risk of developing NHL (OR = 2.40, 95% CI = 0.99–5.85). In the total population (women and men), smoking may be associated with one histologic subtype, follicular NHL with an adjusted OR for the current smokers compared to subjects having never smoked of 3.20, 95% CI = 0.79–12.97. Conclusions: In spite of the small number of subjects in the subgroups, a relation is observed between smoking and NHL among women, but not men, and in the total population a relation is suggested between smoking and follicular NHL.     

Environmental Risk Factors for non-Hodgkin's Lymphoma: A Population-based Case–Control Study in Languedoc-Roussillon, France

Objective: To investigate the occupational and environmental risk factors related to non-Hodgkin's lymphoma (NHL). Methods: A case–control study was performed during the 1992–1996 period in Languedoc-Roussillon, southern France. Four hundred and forty-five cases of histologically diagnosed NHL were declared. One thousand and twenty-five randomly selected population controls were interviewed about their medical histories; occupational exposures, such as chemicals, pesticides, and electromagnetic radiation; and toxic habits. Results: The following factors were independently and significantly related to NHL as a result of the multivariate analysis: a previous hematopoietic malignancy (OR_a=11.5, 95% CI 2.4–55.4), a history of hives (OR_a=1.7, 95% CI 1.2–2.2), benzene exposure >810 days (OR_a=4.6, 95% CI 1.1–19.2), daily welding (OR_a=2.5, 95% CI 1.2–5.0), and activity of radio operator (OR_a=3.1, 95% CI 1.4–6.6). To be an agricultural professional seemed slightly related to NHL in reference to non-professionals (OR_a=1.5, 95% CI 1.0–2.1). All of these results have also been adjusted for age, gender, education level, and urban setting. Conclusions: As some of the reported associations were based on a very small proportion of exposed subjects, further investigations are necessary to confirm our results. However, the findings suggest that factors related to altered immune functions such as a history of hematopoietic malignancy, history of hives, occupational exposure to benzene, or being an agricultural professional might increase the risk of NHL. Currently, underlying mechanisms for these associations are still unclear, and further investigations focused on interactions between immunity alterations and different chemicals would be of great interest.     

Occupational exposure to meat and risk of lymphoma: a multicenter case-control study from Europe

Several studies have suggested an increased risk of lymphoma among workers exposed to meat, without conclusive evidence. We conducted a multicenter case-control study during 1998-2004 in the Czech Republic, France, Germany, Ireland, Italy and Spain, including 2,007 cases of non-Hodgkin lymphoma, 339 cases of Hodgkin lymphoma and 2,462 controls. We collected detailed information on occupational history and assessed exposure to meat in general and several types of meat via expert assessment of the questionnaires. The odds ratio (OR) of non-Hodgkin lymphoma for ever occupational exposure to meat was 1.18 (95% confidence interval [CI] 0.95-1.46), that for exposure to beef meat was 1.22 (95% CI 0.90-1.67), and that for exposure to chicken meat was 1.19 (95% CI 0.91-1.55). The ORs were higher among workers with longer duration of exposure. An increased risk among workers exposed to beef meat was mainly apparent for diffuse large B-cell lymphoma (OR 1.49, 95%CI 0.96-2.33), chronic lymphocytic leukemia (OR 1.35, 95% CI 0.78-2.34) and multiple myeloma (OR 1.40, 95%CI 0.67-2.94). The latter 2 types were also associated with exposure to chicken meat (OR 1.55, 95% CI 1.01-2.37, and OR 2.05, 95%CI 1.14-3.69). Follicular lymphoma and T-cell lymphoma, as well as Hodgkin lymphoma did not show any increase in risk. Occupational exposure to meat does not appear to represent an important risk factor of lymphoma, although an increased risk of specific types of non-Hodgkin lymphoma cannot be excluded.     

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.     

Diet and nutrition as risk factors for multiple myeloma among blacks and whites in the United States

Objectives: To explore whether dietary factors contribute to the risk of multiple myeloma and the two-fold higher incidence among blacks compared to whites in the United States. Methods: Data from a food-frequency questionnaire were analyzed for 346 white and 193 black subjects with multiple myeloma, and 1086 white and 903 black controls who participated in a population-based case–control study of multiple myeloma in three areas of the United States. Results: Elevated risks were associated with obese vs. normal weight (OR = 1.9, 95% confidence interval (CI) = 1.2–3.1 for whites and OR = 1.5, 95% CI = 0.9–2.4 for blacks), while the frequency of obesity was greater for black than white controls. Reduced risks were related to frequent intake of cruciferous vegetables (OR = 0.7, 95% CI = 0.6–0.99) and fish (OR = 0.7, 95% CI = 0.5–0.9) in both races combined, and to vitamin C supplements in whites (OR = 0.6, 95% CI = 0.5–0.9) and blacks (OR = 0.8, 95% CI = 0.5–1.4), with the frequency of vitamin supplement use being greater for white than black controls. However, frequent intake of vitamin C from food and supplements combined was associated with a protective effect in whites (OR = 0.6, 95% CI = 0.4–0.9), but not blacks (OR = 1.2, 95% CI = 0.8–2.1). Conclusions: The greater use of vitamin C supplements by whites and the higher frequency of obesity among blacks may explain part of the higher incidence of multiple myeloma among blacks compared to whites in the United States. In addition, the increasing prevalence of obesity may have contributed to the upward trend in the incidence of multiple myeloma during recent decades.     

No increased risk of non-Hodgkin's lymphoma with steroids, estrogens and psychotropics (Netherlands)

Objective: Earlier studies with data on drug use from interview suggested that corticosteroids, estrogens and psychotropics may increase the risk of non-Hodgkin's lymphoma (NHL). The objective of this case–control study with complete pharmacy records was to investigate whether these results could be reproduced. Methods: Cases were all subjects aged 20 years and older in a population of approximately 300,000 residents in the Netherlands who were registered with an incident primary discharge diagnosis of NHL between January 1, 1991 and December 31, 1998. Controls were matched to cases on sex, year of birth, community pharmacy, calendar period and total duration of medication history. Conditional logistic regression was used to evaluate the association between categories of cumulative drug use in days and the risk of NHL. Results: 997 controls were matched to 251 cases of NHL that occurred during the study period. In multivariate analyses, there was no statistically significant risk increase of NHL after exposure to corticosteroids, estrogens or psychotropics. Moreover, long-term use of benzodiazepines showed an unexpected statistically significant protective effect (OR 0.34; 95% confidence interval 0.18–0.64). Conclusions: In our population-based study, corticosteroids, estrogens and psychotropics were not associated with an increased risk of NHL.     

Family history of hematopoietic and non-hematopoietic malignancies and risk of non-Hodgkin lymphoma

Background Family history of hematopoietic malignancies has been linked to the risk of non-Hodgkin lymphoma (NHL). The relationship between family history of specific hematopoietic and non-hematopoietic malignancies and the risk of NHL and by NHL subtypes are unclear. Methods We analyzed data from a population-based case–control study in Connecticut women. A total of 601 histologically confirmed NHL incident cases and 717 randomly selected controls were included in the study. Unconditional logistic regression was used to estimate the association between family cancer history and risk of NHL overall and by NHL subtypes. Results Compared to women who reported to have no family history of any malignancies in first-degree relatives, those who reported to have a family history of lymphoma (OR = 2.2, 95%CI: 1.1–4.5) or leukemia (OR = 2.5, 95%CI: 1.2–5.2) had an increased risk of NHL. The risk was higher among women who had a sibling with lymphoma or leukemia than those who had parents with lymphoma or leukemia. Several non-hematopoietic malignancies in first-degree relatives, including cancer of the lung (OR = 1.7, 95%CI: 1.1–2.6) in first-degree relatives, stomach (OR = 2.2, 95%CI: 0.8–5.9) and pancreas (OR = 2.6, 95%CI: 0.9–7.1) in parents, as well as liver (OR = 5.0, 95%CI: 1.0–24.6), breast (OR = 2.2, 95%CI: 1.3–3.9), cervix (OR = 7.5, 95%CI: 0.9–64.9), and ovary (OR = 3.5, 95%CI: 1.1–11.5) in siblings were also associated with an increased risk of NHL. Conclusions The risk associated with a family history of malignancies in first degree-relatives appears to vary by type of first-degree relatives.     

Domestic and farm-animal exposures and risk of non-Hodgkin's lymphoma in a population-based study in the San Francisco Bay Area

OBJECTIVE: To assess the association between animal exposures and non-Hodgkin's lymphoma (NHL). METHODS: Exposure data were collected from 1,591 cases and 2,515 controls during in-person interviews in a population-based case-control study of NHL in the San Francisco Bay Area. Odds ratios (OR) and 95% confidence intervals (95% CI) were adjusted for potential confounders. RESULTS: Pet owners had a reduced risk of NHL (OR, 0.71; 95% CI, 0.52-0.97) and diffuse large-cell lymphoma large cell (DLCL; OR, 0.58; 95% CI, 0.39-0.87) compared with those who never had owned a pet. Ever having owned dogs and/or cats was associated with reduced risk of all NHL (OR, 0.71; 95% CI, 0.54-0.94) and of DLCL (OR, 0.60; 95% CI, 0.42-0.86). Longer duration of cat ownership (P(trend) = 0.008), dog ownership (P(trend) = 0.04), and dog and/or cat ownership (P(trend) = 0.004) was inversely associated with risk of NHL. Ownership of pets other than cats and dogs was associated with a reduced risk of NHL (OR, 0.64; 95% CI, 0.55-0.74) and DLCL (OR, 0.58; 95% CI, 0.47-0.71). Exposure to cattle for >or=5 years was associated with an increased risk of NHL (OR, 1.6; 95% CI, 1.0-2.5) as was exposure to pigs for all NHL (OR, 1.8; 95% CI, 1.2-2.6) and for DLCL (OR, 2.0; 95% CI, 1.2-3.4). CONCLUSIONS: The association between animal exposure and NHL warrants further investigation in pooled analyses.     

Asthma history, occupational exposure to pesticides and the risk of non-Hodgkin's lymphoma

We previously reported that, although asthma did not increase the risk of non-Hodgkin's lymphoma (NHL), the risk from pesticide exposures was higher among asthmatics than that among nonasthmatics. To further evaluate this finding, we analyzed data from a population-based case-control study of NHL conducted in Iowa, Detroit, Los Angeles and Seattle. Cases (n = 668) diagnosed with NHL from 1998 to 2000 and controls (n = 543) randomly selected from the same geographical areas as that of the cases were included in this analysis. Odds ratios (OR) for the risk of NHL from potential occupational exposure to pesticides tended to be higher among asthmatics (OR = 1.7; 95% CI 0.3-9.1) when compared with that among nonasthmatics (OR = 0.9; 95% CI 0.6-1.5). The risks of NHL associated with pesticide exposure were also higher among asthmatics who had history of hospitalization (OR = 2.1; 95% CI 0.2-29.0) or daily medication for asthma (OR = infinite) than those among asthmatics who did not have such histories. Our results support the previous finding that the risk of NHL from pesticide exposure may be greater among asthmatics.     

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 & equals; 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.     

Physical activity and postmenopausal endometrial cancer risk (Sweden)

Objectives:To examine the hypothesis that sedentary women have an increased risk of endometrial cancer compared to physically active women. Methods:This is a population-based case–control study in the entire Swedish female population aged 50–74 years in 1994–1995. We obtained self-reported information on leisure-time physical activity during childhood, at ages 18–30, and recently from 709 incident case women with endometrial cancer and 3368 population controls. Occupational physical activity was estimated through record linkage to the Swedish census data from 1960, 1970, 1980, and 1990. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for different activity levels by multivariate logistic regression, taking into account potential confounders. Results:Comparing lowest to highest (reference) levels of physical exercise, we observed statistically significant associations with risk of endometrial cancer for leisure-time activity at age 18–30 years (multivariate OR = 1.4; 95% CI = 1.0–1.8; p for trend 0.01) and in recent years (multivariate OR=1.3; 95% CI = 1.0–1.7; p for trend 0.01). We found similar associations comparing lowest to highest (reference) levels of occupational activity assessed at the censuses in 1980 (multivariate OR = 1.4; 95% CI = 1.0–1.9; p for trend 0.03) and 1990 (multivariate OR = 1.3; 95% CI = 0.9–1.9, p for trend 0.05), but a less consistent association with censuses in 1960 and 1970. The increased risk associated with low level of occupational physical activity was confined to women who were not obese and to women who were smokers. Conclusion:Our data, in conjunction with past epidemiological studies, indicate that both occupational and leisure-time physical activity may reduce the risk for postmenopausal endometrial cancer.     

Acute leukemia in electrical workers: a New Zealand case-control study

Objectives: To assess the risks for adult-onset acute leukemia associated with electrical employment in New Zealand. Methods: The occupational and environmental exposures histories of 110 incident leukemia cases and 199 general population controls were compared. The cases were recruited through referrals to treatment centers in New Zealand between 1989 and 1991. For subjects classified as having worked in one or more of the electrical occupations, the degree of exposures to extremely low frequency electromagnetic fields (ELF-EMFs) was assessed in detail using a job-exposure matrix. Results: An odds ratio of 1.9 (95% Cl 1.0–3.8) was found for subjects who had ever worked in an electrical occupation. Significantly increased risks for leukemia are seen amongst welders/flame cutters (OR = 2.8 (95% Cl 1.2–6.8)) and telephone line workers (OR = 5.81 (95% Cl 1.2–27.8)). The excess leukemia risk appeared to be confined to acute non-lymphocytic leukemia (OR = 2.31 (95% Cl 1.2–4.6)), in comparison to acute lymphoblastic leukemia (OR = 0.9 (95% Cl 0.3–2.9)) but for the latter category the numbers were very small. A dose–response effect was also found, with acute leukemia risk rising with increasing occupational magnetic field exposure, based on both current and historical occupational field exposure estimates. Conclusions: The findings of the current study indicate a significantly elevated risk of acute leukemia for electrical workers overall, and for the specific occupational categories of welders/flame cutters and telephone line workers. A dose–response effect was also found, indicating that acute leukemia risk was related to historical and current magnetic field exposures in an occupational context.