Radiation literature survey

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This was a meta-analysis investigating the possible relationship between childhood leukaemia and living near power lines. The study included 4879 cases and 4835 controls. Exposure to power lines was assessed by assessing magnetic field strength and residential distance to power lines. Homes that were determined to be close enough to power lines and of sufficient voltage to have elevated magnetic fields had measurements taken. Additionally, all residences close to power lines over 100 kV had their exposure modelled and calculated. All other residences were considered to be exposed to a magnetic field of less than 0.1 µT. The study found that there was no statistically significant increased risk of childhood leukaemia associated with living within 50 meters of a power line (odds ratio (OR) of 1.44 with a 95% confidence interval (CI) of 0.63 - 3.29) or being exposed to a magnetic field above 0.4 µT (OR of 1.24 with a 95% CI of 0.50 – 3.05). However, when the authors examined participants who lived within 50 meters of 200 kV power lines and had a magnetic field above 0.4 µT, there was an increased risk of childhood leukaemia (OR of 4.06 with a 95% CI of 1.16 – 14.3). The authors concluded that their results suggest magnetic field exposure is not causally related to childhood leukaemia. They further suggest that there could be an unidentified explanation for the possible link between power lines and childhood leukaemia. 
 

Childhood leukemia risk in the California Power Line Study: Magnetic fields versus distance from power lines

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A similar study by Draper et al 2005 also found an association between distance to power lines and a small increased risk of childhood leukaemia. However, Draper et al did not calculate or measure the magnetic field exposure of the included participants. When the Crespi et al study examined exposure to magnetic fields, it was found that elevated exposure alone was not associated with childhood leukaemia. Both authors conclude that their results did not casually link magnetic field exposure to childhood leukaemia. 

The major positive result in the Crespi et al study was limited by a small sample size, as there was only 13 cases and 3 controls who lived within 50 meters from a power line and were exposed to magnetic fields greater than 0.4 µT. The epidemiological and laboratory evidence for an association between childhood leukaemia and magnetic field exposure has been reported as weak and it is not known how magnetic field exposure could cause childhood leukaemia (WHO, 2007).
 

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This was a case-control study in Iran, investigating a possible link between high voltage power lines and female infertility. The study included 462 women with infertility and 471 match controls with no history of infertility. The exposure to the participants was assessed by residential distance to high voltage power lines. The authors reported statistically significant associations between female infertility and high voltage power lines at distances of less than 500 meters (odds ratio (OR) of 4.14 with a 95% confidence interval (CI) of 2.61-6.57) and between 500-1000 meters (OR of 1.61 with a 95% CI of 1.05-2.47). When the results were adjusted for confounders, the association was no longer significant at distances between 500 and 1000 meters (OR of 1.53 with a 95% CI of 0.99 to 2.37). Based on the association at distances of less than 500 metres, the authors concluded that the current safety guidelines for exposure to electric and magnetic fields (EMF) are inadequate to protect people from the hazardous effects of these fields.

Exposure to Electromagnetic Fields of High Voltage Overhead Power Lines and Female Infertility.

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The study suggested that exposure to EMF from high voltage power lines is associated with female infertility. However, the exposure assessment was based on residential distance to high voltage power lines, not by EMF strength. This association was reported when homes were less than 500 meters from power lines. However, at distances over 50 meters, the EMF from high voltage power lines is indistinguishable from typical background levels in the home (Karipidis, 2014). This indicates that exposure to EMF is unlikely to be the cause of the reported association.

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This study was a systematic review and meta-analysis of 12 previously published articles that investigated the risk of melanoma and keratinocyte cancers (KC) in airline pilots and cabin crew. The studies included in the analysis consisted of both retrospective and prospective cohort studies and provided data on both the incidence of these cancers and the resulting mortality as established by death registries, death certificates and physician records. The authors reported that, based on the available evidence, airline pilots and cabin crew had approximately twice the risk of developing melanoma and other skin cancers when compared to the general population. For melanoma incidence the pooled Standardised Incidence Ratio (SIR) was 2.03 (95% Confidence Interval (CI) 1.71-2.40) for airline pilots and 2.12 (95% CI 1.71-2.62) for cabin crew. This was similar for KC in pilots (SIR: 1.86 (95% CI 1.54-2.25) and cabin crew (SIR: 1.97 (95% CI 1.25-2.96). Further, airline pilots were about twice as likely to die from melanoma pooled Standardised Mortality Ratio (SMR) of 1.99 (95% CI 1.17-3.40). This higher mortality rate was not observed in cabin crew. The exposure agents considered as possible explanations for the higher than normal risk factors were occupational ultraviolet radiation (UVR) exposure and cosmic ionising radiation. 

The authors assessed that both pilots and cabin crew were not occupationally exposed to UVR as it was not detectable in the cabin of modern airliners and pilots were exposed to no higher than levels encountered on the ground during their flights. However, the study was not able to take into account recreational UVR exposure. Both pilots and cabin crew are recognised as being the highest exposed occupations to ionising radiation from cosmic rays and in this study this was assessed by measures including duration of employment, type of licence and cumulative flight hours.  Exposure to cosmic radiation, recreational UVR exposure and disruptions in circadian rhythm due to crossing time zones on long haul flights were considered to be potential explanations for the higher risk factors of melanoma and KC within pilots and cabin crew. 

Do airline pilots and cabin crew have raised risks of melanoma and other skin cancers? Systematic review and meta-analysis.

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This review included studies of airline crews where the data was collected mostly between the 1970s to the 1990s, with some data covering the period from 1947. Therefore, the evidence is outdated and the relevance to modern air travel is uncertain. However, the reported higher risk to airline crew of developing skin cancer is a useful indicator for the direction of further research. This research currently includes dose assessments of exposure to cosmic radiation. Further, the recreational solar UVR exposure of airline crew may need to be investigated.
 

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This was a meta-analysis of three cohort studies which investigated the risk of lung cancer mortality to workers exposed to low-level radon in uranium mines. The cohort studies included were from the Czech Republic, France and Canada collectively covering exposure periods from 1953 to 1999. Exposure to workers was assessed by both the concentration of radon in the air and by the length of employment in months. This was then used to derive an exposure unit of working level month (WLM). The study was limited to workers who had received less than 100 WLM in order to investigate low-level effects. The study found was an increased excess relative risk (ERR) risk in lung cancer mortality among workers per WLM of 0.022 (95% confidence interval (CI) of 0.013-0.034). However, the authors report that this risk was no longer statistically significant at an exposure of less than 10 WLM. The authors suggest the higher exposures are compatible with a linear non-threshold model and lower exposures are not. However, the authors state that no conclusion can be made at the low exposures due to the low statistical power.

Low radon exposures and lung cancer risk: joint analysis of the Czech, French, and Beaverlodge cohorts of uranium miners

Low radon exposures and lung cancer risk: joint analysis of the Czech, French, and Beaverlodge cohorts of uranium miners

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This study demonstrates the difficulty of evaluating the risk of lung cancer mortality from low-level exposures to radon. The authors reported that at low radon exposure of less than 10 WLM the risk of lung cancer mortality was no longer significant. A working level month within a uranium mine is approximately equivalent to 10 mSv of dose (ARPANSA, 2019). However, the data by Lane et al showed that this extends further and that at less than 19 WLM there is not a statistically significantly increased risk of lung cancer mortality (1.41 relative risk with a 95% CI of 0.90–2.25). In Australia, RPS C-1 2016 sets out the requirements for the protection of occupationally exposed persons in uranium mines. A number of studies have demonstrated the additional risk of lung cancer from radon exposure is small relative to the risk from tobacco smoking (ICRP, 2010). The best way of reducing the total lung cancer risk, as well as the lung cancer risk from exposure to radon, is to avoid tobacco smoking.

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This was a meta-analysis of 8 case-control and 2 cohort studies investigating the relationship between wireless (mobile and cordless) phone use and risk of adult glioma. Overall, there was no statistically significant association between adult glioma and wireless phone use (odds ratio (OR) of 1.03 with a 95% confidence interval (CI) of 0.92-1.16). When long-term wireless phone use was examined independently, a significant association with adult glioma was found (OR of 1.33 with a 95% CI of 1.05 – 1.67). However, there was inconsistency in the results of the studies included in the meta-analysis. The authors concluded that wireless phone use was not significantly associated with risk of adult glioma, but there could be increased risk in long-term users.

Wireless Phone Use and Risk of Adult Glioma: Evidence from a Meta-Analysis

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Since the 2010 interphone study, there has been a number of meta-analyses and other case-control studies examining the evidence of a possible association between wireless phone use and the risk of brain tumours, particularly gliomas. Overall, these examinations do not show an increased risk of glioma. However, the evidence for an increased risk of glioma for heavy mobile phone users is not clear and further research is needed to clarify these results. The results reported by the authors of this study are in-line with the current state of the science and ARPANSA’s current advice on mobile phone use.

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This was a systematic review and meta-analysis of 14 case-control and 8 cohort studies. The study investigated the relationship between Alzheimer’s disease and occupational exposure to extremely low frequency magnetic fields (ELF MF). The exposure to participants was categorised by a job exposure matrix, which included specific jobs that were assigned an exposure level, based on the work history of the participants. The authors reported an association between occupational exposure to ELF MF and Alzheimer’s disease (Risk Ratio (RR) 1.63; 95% confidence interval (CI): 1.35 – 1.96). The differences between gender was also examined with females having a higher RR (RR of 2.39 and 95% CI of 1.29 – 4.40) than males (RR of 1.50 and 95% CI of 1.22 – 1.85). There was moderate to high inconsistency between the studies included, which could indicate limitations of the methods. The meta-analysis also reported indications of publication bias, where papers showing effects are more likely to be published. The authors concluded that occupational exposure to ELF MF may increase the risk of Alzheimer’s disease. However, the authors suggest that this conclusion should be taken with caution due to the limitations of the research in the area.

Occupational exposure to extremely low frequency magnetic fields and risk of Alzheimer disease: A systematic review and meta-ana

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Some epidemiological studies observing outcomes from exposure to ELF MF have shown an association with Alzheimer’s disease. However, this association has not been established by consistent scientific evidence. This is reinforced by the current study, which also demonstrates the inconsistencies in the literature. The 2015 SCENIHR review assessed the impact of ELF MF on Alzheimer’s disease and indicated the need for further research.

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This was a population-based, case-control study that analysed the effects of birth weight and infant to early life ultraviolet (UV) radiation exposure on the risk of melanoma in children, adolescents and young adults in the state of California, United States of America. The study compared 1396 cases of melanoma diagnosed before the age of 30 from 1988 to 2013 and 27 920 controls. Birth weights were obtained from birth records and UV exposure was assigned based on measurements of environmental UV levels in the place of birth. Cases and controls were further categorised by other factors such as race, ethnicity, gender and gestational age in order to account for adjust for these variables in the population. 

The authors reported an overall increased risk of melanoma for birthplaces where UV levels were higher. The risk was highest in people aged over 15 years where one group exposed to higher UV levels showed an 85% increase in melanoma risk (Odds ratio, OR: 1.85; 95% Confidence Interval, CI: 1.37, 2.50). However, the overall relationship did not show a clear trend of increasing risk with increasing UV levels. It was also reported that a birthweight greater than 4000 grams was associated with a 19% higher risk of melanoma and birth weights less than 2500 grams were associated with a 41% lower risk of melanoma. There was also evidence of a dose response where the risk increased per 1000 grams. The authors identified that the UV exposure data was limited in that it did not account for sun exposure based on factors such as behaviour, occupation, migration etc. The increased risk of melanoma in high birthweight cases was attributed to a greater surface area of skin being expose to UV from infancy.

High Birth Weight, Early UV Exposure, and Melanoma Risk in Children, Adolescents and Young Adults

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Overall, the results reported by the authors support ARPANSA’s sun protection messaging. Further, the study has indicated that birth weights may change the risk of melanoma development at a young age. Despite the limitations in the data used to assess UV exposure, the results indicate that sun protection may be advised from infancy.

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This was a meta-analysis of 11 case-control studies investigating the relationship between childhood leukaemia and overhead power lines. The meta-analysis included 29,000 cases and 68,000 controls. Exposure to participants was assessed by residential distance to power lines. Further, exposure was also categorised by the voltage of the power lines. There was a small association found for residential distances of less than 50 meters from power lines with voltages of 200 kilovolts or higher when the diagnosis was made before 5 years of age (odds ratio (OR) = 1.65 (95% confidence interval (95% CI) of 1.02-2.67). The study also examined possible confounders including extremely low frequency (ELF) magnetic field exposure. Adjustment of the data to take into account magnetic field exposure had little impact on the reported association. This may suggest that childhood leukaemia may not be related to magnetic field exposure.

Proximity to overhead power lines and childhood leukaemia: an international pooled analysis

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Some epidemiological studies observing outcomes from exposure to ELF magnetic fields greater than 0.3 or 0.4 microtesla have shown an association with childhood leukaemia. However, this association has not been established by consistent scientific evidence. The majority of the evidence comes from studies assessing exposure via residential distance to power lines. There is less evidence from studies performing residential magnetic field measurements. The Amour et al study provides further evidence that a possible association with living next to power lines is due to factors other than ELF magnetic fields.

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This was a population-based, case-control study that investigated the role of sunscreen use during childhood in reducing the incidence of melanoma in adults. The cases were aged between 18 and 39 years and had received a diagnosis of first primary melanoma between July 2000 and December 2002. The cases were compared with one group of unrelated controls comprising of individuals selected from the electoral roll combined with nominated friends or spouses, and another group consisting of siblings of the cases. Information on sun exposure was self-reported. Participants also provided information about their demographics (e.g. education level), ethnicity, family history of melanoma, sunbed use and other risk factors in addition to self and parent reported sunscreen use.

The analysis included data for 603 cases and 1088 controls. The authors reported that the risk of melanoma was less with higher sunscreen use in childhood (odds ratio, OR: 0.60; 95% confidence interval, CI, 0.42-0.87) and use across a lifetime (OR, 0.65: 95% CI, 0.45-0.93). More specific analysis indicated that sunscreen use was more protective for people that reported they were prone to blistering sunburn, had some or many nevi and had received a diagnosis of melanoma at a younger age. There was no association with lifetime sun exposure and melanoma risk, however, when sun exposure unprotected by sunscreen was taken into account, it was reported that there was a significant risk of melanoma (OR, 1.80; 95% CI 1.22-2.65). This association was especially stronger for people with lighter pigmented skin or some or many nevi using sunscreen to stay out in the sun for longer.

Sub-optimal Application of a High SPF Sunscreen Prevents Epider-mal DNA Damage in Vivo

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The results of the study were able to demonstrate the protective effect of childhood sunscreen use in reducing the risk of melanoma. It was also able to identify personal risk factors for melanoma (skin colour, sun exposure behaviour). The study was limited in not being able to determine whether sunscreen was applied effectively. Also, sunscreen during the data period was commonly rated at SPF8 compared to the SPF30+ types in current use. However, it is possible that the higher SPF sunscreens would show a higher protective effect. Further, exposure to solar ultraviolet radiation was characterised by self-reported time in the sun. This limits reliability and introduces potential misclassification of the exposure data. The results strengthen the advice from both ARPANSA and Cancer Council that sunscreen use is an effective measure in preventing skin cancer.

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This was a human provocation study that investigated if messages emphasizing adverse health effects of radiofrequency (RF) electromagnetic field (EMF) can exacerbate a nocebo response. Of the participants, 22 watched an alarmist video and 22 a control video before receiving both sham and real RF-EMF exposure. The participants that watched the alarmist video when they were exposed to RF-EMF, reported a statistically significant increase in subjective symptoms, anxiety state and risk perception. There was no significant difference between the sham exposure and real RF exposure for symptoms or belief of exposure reported by participants. The authors concluded these results suggest that it is belief of exposure, not the RF-EMF exposure itself, which was sufficient to trigger symptoms in healthy participants.

Can explicit suggestions about the harmfulness of EMF exposure exacerbate a nocebo response in healthy controls?

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Negative symptoms attributed to RF exposure can have serious effects on the wellbeing of individuals. However, current scientific evidence suggests that RF exposure is not the cause of electromagnetic hypersensitivity symptoms. The evidence from double-blind provocation studies have previously shown that belief of exposure is sufficient to induce symptoms via a nocebo effect (SCENIHR, 2013).