Residential and occupational exposure to 50 Hz magnetic fields and malignant melanoma: a population based study

Aims: To test the hypothesis that exposure to electromagnetic fields from high voltage power lines increases the incidence of cutaneous malignant melanoma in adults aged 16 and above. Methods: Nested case-control study. The study population comprised subjects aged 16 and above who had lived in a residence situated in a broad corridor around a high voltage power line in 1980, or one of the years from 1986 to 1996. The cases were incident cases that were diagnosed in 1980–96 and reported to the Cancer Registry of Norway. Two controls were matched to each case by year of birth, sex, municipality, and first year entering the cohort. Time weighted average exposure to residential magnetic fields generated by the power lines was calculated for the exposure follow up from 1 January 1967 until diagnosis by means of a computer program, in which distance from residency to the line, line configuration, and current load were taken into account. Exposure was analysed using cut off points at 0.05 and 0.2 microtesla (µT). Exposure to magnetic fields at work was classified by an expert panel who assessed magnetic field exposure by combining branch and occupation into one of three levels: <4 hours, 4–24 hours, and >24 hours per week above background (0.1 µT). The categories were cumulated over the occupationally active years for the exposure follow up from 1 January 1955 until diagnosis, and cut off points at 18 and 31 category-years were evaluated. Results: Analysis of the two upper residential magnetic field categories showed an odds ratio of 2.01 (95% CI 1.09 to 3.69) and 2.68 (95% CI 1.43 to 5.04) for women, and an odds ratio of 1.70 (95% CI 0.96 to 3.01) and 1.37 (95% CI 0.77 to 2.44) for men, respectively. Occupational exposure showed no significant association with cutaneous malignant melanoma, and analysis of both residential and occupational exposure simultaneously, showed no additional effect. Conclusion: The present study provides some support for an association between exposure to calculated residential magnetic fields and cutaneous malignant melanoma, but because of the lack of a biological hypothesis and the known strong association between solar radiation and melanoma, no firm conclusions can be drawn and further studies would be of interest.     

Feasibility of a cohort study on health risks caused by occupational exposure to radiofrequency electromagnetic fields

Background  

The aim of this study was to examine the feasibility of performing a cohort study on health risks from occupational exposure to radiofrequency electromagnetic fields (RF-EMF) in Germany.     

Population-based case-control study of occupational exposure to electromagnetic fields and breast cancer

PURPOSE: This population-based case-control study examined occupational exposure to electromagnetic fields in relation to female breast cancer incidence among 843 breast cancer cases and 773 controls. METHODS: Exposure was classified based on work in the two longest-held jobs, and indices of cumulative exposure to magnetic fields based on a measurement survey. RESULTS: Female breast cancer was not associated with employment as an office or industrial worker. For the total study population, cumulative exposure over the entire career, and in the past 0-10 and 10-20 years generally showed odds ratios (ORs) close to the null. Moderately elevated risks were found for intermediate but not high levels of cumulative exposure accumulated 20 or more years ago (OR = 1.5; 95% CI = 1.1-2.0). Associations were stronger for premenopausal women (OR = 1.7; 95% CI = 1.1-2.7) in the past 10-20 years, and those with estrogen-receptor positive (ER+) breast tumors (OR = 2.06; 95% CI = 1.1-4.0). No consistent dose-response patterns were observed. CONCLUSIONS: These findings give little support to the hypothesis that electromagnetic fields cause cancer of the female breast.     

Paternal occupational exposure to electromagnetic fields and neuroblastoma in offspring

Investigators in Texas have reported an association between paternal employment in jobs linked with exposure to electromagnetic fields and risk of neuroblastoma in offspring. In an attempt to replicate this finding, the authors conducted a case-control study in Ohio. A total of 101 incident cases of neuroblastoma were identified through the Columbus (Ohio) Children's Hospital Tumor Registry. All cases were born sometime during the period 1942-1967. From a statewide roster of birth certificates, four controls were selected for each case, with individual matching on the case's year of birth, race, and sex, and the mother's county of residence at the time of the (index) child's birth. Multiple definitions were employed to infer the potential for paternal occupational exposure to electromagnetic fields from the industry/occupation statements on the birth certificates. Case-control comparisons revealed adjusted odds ratios ranging in magnitude from 0.5 to 1.9. For two of the exposure definitions employed--both of which are similar to one used by the Texas investigators--the corresponding odds ratios were modestly elevated (odds ratios = 1.6 and 1.9). Notably, the magnitude of these odds ratios is not inconsistent with the Texas findings, where the exposure definition referred to yielded an odds ratio of 2.1. Because the point estimates in this study are imprecise, and because the biologic plausibility of the association is uncertain, the results reported here must be interpreted cautiously. However, the apparent consistency between two independent studies suggests that future evaluation of the association is warranted.     

Association between exposure to radiofrequency electromagnetic fields assessed by dosimetry and acute symptoms in children and adolescents: a population based cross-sectional study

Background  

The increase in numbers of mobile phone users was accompanied by some concern that exposure to radiofrequency electromagnetic fields (RF EMF) might adversely affect acute health especially in children and adolescents. The authors investigated this potential association using personal dosimeters.     

Maternal periconceptional occupational exposure to pesticides and selected musculoskeletal birth defects

This population-based U.S. study investigated the association between major musculoskeletal malformations and periconceptional maternal occupational pesticide exposure for a wide range of occupations. We conducted a multi-site case–control analysis using data from the National Birth Defects Prevention Study among employed women with due dates from October 1, 1997 through December 31, 2002. Cases included 871 live-born, stillborn, or electively terminated fetuses with isolated craniosynostosis, gastroschisis, diaphragmatic hernia, or transverse limb deficiencies. Controls included 2857 live-born infants without major malformations. Using self-reported maternal occupational information, an industrial hygienist used a job-exposure matrix and expert opinion to evaluate the potential for exposure to insecticides, herbicides or fungicides for each job held during one month pre-conception through three months post-conception. Exposures analyzed included any exposure (yes/no) to pesticides, to insecticides only, to both insecticides and herbicides (I + H) and to insecticides, herbicides and fungicides (I + H + F). We used logistic regression to evaluate the association between exposures and defects, controlling for infant and maternal risk factors. Occupational exposure to I + H + F was associated with gastroschisis among infants of women aged 20 years or older (adjusted odds ratio [aOR] = 1.88; 95% confidence interval [CI]: 1.16–3.05), but not for women under age 20 (aOR = 0.48; 95% CI: 0.20–1.16). We found no significant associations for the other defects. Additional research is needed to validate these findings in a separate population.     

Maternal occupational exposure and risk of specific birth defects

BACKGROUND: Gregg identified the teratogenic effect of maternal rubella infection in 1941 and since then there has been a focus on risk factors for birth defects. In nearly 70% of all birth defects, there is still no known risk factor and close to 30% of all pregnancies end in a foetal loss or spontaneous abortion, often because of a defect in the foetus. A large percentage of the workforce consists of women of reproductive age. METHODS: A search in MEDLINE for original literature and examination of the association between exposure during pregnancy and the risk of birth defects. RESULTS: Five specific birth defects were identified: neural tube defects, cleft lip and cleft palate, congenital heart defects, urinary tract defects and limb defects. The next step was to include studies with information on occupational exposure during pregnancy. CONCLUSION: There seems to be growing concern as to whether organic solvents, including glycol ethers, pesticides and heavy metals may play a teratogenic role. There is no convincing evidence linking occupational exposure during pregnancy and birth defects.     

Occupational exposure to 50 Hz magnetic fields in workers employed in various jobs

BACKGROUND: Information on occupational exposure to ELF magnetic fields (MF) in workers is largely insufficient, and is mostly based on results obtained in Scandinavian countries and North America. Accordingly, the collection of further data is needed, especially in workers exposed in other countries, including in Italy. METHODS: One hundred and fifty workers (84 males and 66 females) employed in 28 different jobs in the Emilia-Romagna Region of Italy were examined. Individual exposure was measured using personal monitors worn on the hip in a belted pouch during three whole work-shifts (8 hours each) of a normal working week. A sampling interval of 10 seconds was adopted, resulting in the collection of more than 8600 measurements for each worker. The individual Time-Weighted Average (TWA) occupational exposure of workers was calculated as the arithmetic mean of all measurements during each work-shift. Environmental non-occupational exposure was also measured. RESULTS: The 50 degrees percentile of individual TWA in the whole group was 0.15 microT, and the 5 degrees - 95 degrees percentile was respectively 0.02-1.45 microT. Job-related exposure (expressed as the mean of the TWA measured in all workers engaged in that job) was highest in substation electric power plant workers (1.12 microT) and in sewing machine workers (0.84 microT), but was lower than 0.2 microT in more than the 70% of the examined jobs. Considering the geometric mean of individual TWA are 27 out of 28 the jobs inducing an exposure lower than 0.2 microT. The lowest exposure was observed in infant school teachers. A high variability was observed among different workers engaged in the same occupation, mainly in substation electric power plant workers, machine testers and grinders in the engineering industry and in sewing machine workers and quality control in garment production. A marked variability of the pattern of exposure during the work-shift was also observed The overall environmental (non-occupational) exposure was 0.044 microT, and individual exposure was lower than 0.2 microT in about 97% of the examined subjects. Occupational exposure was usually higher and was not correlated with environmental exposure. CONCLUSIONS: The results show that the occupational component of overall exposure must be considered in studies on the biological effects of ELF-MF in populations. The high variability observed among workers engaged in the same occupation and the variability of the pattern of exposure certainly constitute major problems and could be a cause of the scarce coherence of the results of epidemiological studies on biological effects of ELF-MF to date. An improvement in protocols for the evaluation of exposure in workers, including the use of personal monitoring, is certainly needed.     

Weak electromagnetic fields (50 Hz) elicit a stress response in human cells

The aim of this study was to demonstrate the expression of heat shock (HS) genes in human cells in response to extremely low-frequency electromagnetic fields (ELF-EMF) alone and in combination with thermal stress. After exposing human myeloid leukemia (HL-60) cells to the stressor(s) for 30 min we quantified the expression of the HS genes HSP27, HSP60, HSP70 (A, B, and C), HSC70, HSP75, HSP78, and HSP90 (alpha and beta) by RT-PCR. The results clearly show that HS genes, in particular the three HSP70 genes (A, B, and C), are induced by ELF-EMF, a reaction that is enhanced by simultaneous HS (43 degrees C for 30 min). The results show similarities and some significant differences to previous experiments in which transgenic nematodes were used to monitor the induction of the HSP70 gene under similar stress conditions. We also studied the effect of different flux densities on gene expression in the range of 10-140 microT. Even the lowest dose tested (10 microT) resulted in a significant induction of the genes HSP70A, HSP70B, and HSP70C. The reaction to ELF-EMF shows a maximum at a flux density of 60-80 microT. The unusual dose-response relation reveals an interesting difference to other stressors that elicit the HS response.     

Association between occupational exposure to power frequency electromagnetic fields and amyotrophic lateral sclerosis: a review

BACKGROUND: For the past two decades, there has been concern over electromagnetic exposure and human health. While most research has focused on cancer and reproductive outcomes, there is interest in the relationship between electromagnetic fields (EMF) and neurodegenerative diseases. METHODS: We review epidemiological findings and evidence regarding the association between occupational exposure to power frequency EMFs and amyotrophic lateral sclerosis (ALS). Medline was searched for citations related to occupational hazards and ALS, literature reviews and epidemiological evaluations. RESULTS: Nine out of the ten epidemiological studies that have been conducted on the risk of ALS in relation to occupational exposure to EMF show moderate to strong relative risk estimates that supported a link between them. Although data from these studies was consistent, the causal inference to a link between EMF exposure and ALS is restricted mainly due to the lack of direct information on EMF exposure and incomplete consideration of the other potential risk factors for ALS at workplaces. For instance, electric shock, in particular, is more common in electrical occupations than in any other occupations. CONCLUSIONS: This review concludes that further studies should consider investigating the separate effect of EMF exposure and electrical shocks to make more specific interpretations. On-site measurements of EMF should be conducted to include information on EMF exposure from residences as well as workplaces to improve exposure assessment.     

50家企业工频电磁场职业暴露现况调查

目的 探讨职业人群工频电磁场职业暴露现况.方法 对各种存在工频电磁场的工作场所或工作岗位进行工频电场及磁场的测量及统计分析.结果 电厂主变及各种高压变电站近20%点电场强度大于5 kV/m,最高达17.46kV/m;部分变压器、变电站电抗器及变电柜工作场所12个点磁场强度大于100 μT,手动点焊工作岗位工频磁场集中趋势为492.49 μT,最大值为2 092.33 μT,94.7%的作业点磁场强度大于100 μT.结论 电厂主变及各种高压变电站存在高电场强度,手动点焊工人处于高强度工频磁场暴露之中.     

Paternal occupational exposure to radiofrequency electromagnetic fields and risk of adverse pregnancy outcome

Background: During the last decades, public concern that radiofrequency radiation (RFR) may be related to adverse reproductive outcomes has been emerging. Our objective was to assess associations between paternal occupational exposure to RFR and adverse pregnancy outcomes including birth defects using population-based data from Norway. Methods: Data on reproductive outcomes derived from the Medical Birth Registry of Norway were linked with data on paternal occupation derived from the general population censuses. An expert panel categorized occupations according to exposure. Using logistic regression, we analyzed 24 categories of birth defects as well as other adverse outcomes. Results: In the offspring of fathers most likely to have been exposed, increased risk was observed for preterm birth (odds ratio (OR): 1.08, 95% confidence interval (CI): 1.03, 1.15). In this group we also observed a decreased risk of cleft lip (OR: 0.63, 95% CI: 0.41, 0.97). In the medium exposed group, we observed increased risk for a category of ‚other defects’ (OR: 2.40, 95% CI: 1.22, 4.70), and a decreased risk for a category of ‚other syndromes’ (OR: 0.75, 95% CI: 0.56, 0.99) and upper gastrointestinal defects (OR: 0.61, 95% CI: 0.40, 0.93). Conclusion: The study is partly reassuring for occupationally exposed fathers.These two authors share first authorship     

Occupational exposure to electromagnetic fields and acute leukaemia: analysis of a case-control study

Aims: To investigate whether the risk of acute leukaemia among adults is associated with occupational exposure to electromagnetic fields.     

极低频电磁场职业接触限值研究概况

极低频电磁场(Extremely low frequency electromagnetic fields,ELF-EMF)指频率在100 kHz以下的电磁场.随着电力的广泛应用,ELF-EMF在生活中广泛存在.自WERTHEIMER等[1]报道接触低频电磁场与儿童白血病显著相关以来,ELF-EMF的非致热效应受到了国内外学者的广泛关注.WHO确认了短期、高水平接触ELF-EMF的健康影响,但也指出仍没有明确的证据证明ELF-EMF与致癌性有因果关联[2].     

供电企业工频电磁场职业暴露现况

目的 检测和评估某供电企业工频电磁场职业暴露现况.方法 采用德国PMM8053电磁场测量系统(EHP-50工频电磁场测量探头)对作业环境进行测量,使用美国EMDEX LITE个体磁场剂量仪对作业岗位进行抽样测量,运用GBZ 2.2 2007《工作声所物理因素测量第3部分:工频电场》以及ICNIRP的限值标准对结果进行评估.结果 超高压变电站500 kV电压区90％以上测点工频电场强度超过5 kV/m,电抗器和电容器附近磁场强度常超过100μT,可达几百微特斯拉.供电作业工人日暴露平均水平在0.04～5.0 μT之间,70％作业工人高于0.4 μT.结论 500 kV及以上超高压变电站高压区、各级变电站电抗器和电容器为供电企业工频电磁场关键控制点,存在急性健康影响风险.供电企业作业工人累计磁场暴露水平较高.     

Risk of cognitive impairment in relation to elevated exposure to electromagnetic fields.

Occupational exposure to power-frequency electromagnetic fields (PF-EMF) has been suspected of being associated with adverse neurological outcomes. We performed a case-control study to assess the relationship between exposure to PF-EMF and the risk of cognitive impairment, an indication of certain adverse neurological diseases such as Alzheimer's disease and dementia. Among 2198 elderly individuals aged 65 years or older, 290 persons with score-based cognitive impairment were compared with 580 sex-matched controls to assess the risk of cognitive impairment in relation to PF-EMF exposure. Participants who were former electrical workers or living within 100 meters of high-voltage transmission lines were considered to have higher exposure. Compared with background exposure, the risk was equal or close to unity for participants with higher exposure from a previous occupation (odds ratio [OR], 1.3; 95% confidence interval [CI], 0.7 to 2.3), higher residential exposure (OR, 0.9; 95% CI, 0.3 to 2.6), or higher exposure in both occupation and residential environments (OR, 1.0; 95% CI, 0.2 to 4.6). Our findings provide little support for the link between PF-EMF and cognitive impairment. Nevertheless, the study results do not preclude the possible association between PF-EMF and any specific neurodegenerative disease previously investigated.