Radiation literature survey

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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).

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The SCHEER conducted an extensive literature review to assess the potential health risks from exposure to light emitting diodes (LEDs). Exposures included the use of LED display technology (smartphones, tablets and computer screens) and emissions from LED lights found in toys, car lighting and lamps for area illumination. Effects were assessed separately for the general population and in vulnerable and susceptible populations (e.g. children and the elderly).

The review concluded that, for normal use of LED displays and lamps, there was no evidence of any adverse health effects. However, there was some evidence to suggest that these types of exposures in the late evening may impact the circadian rhythm (sleep/wake cycle). This is thought to be due primarily to the blue light components of the emissions from the displays. At this time, it is unclear if this disturbance leads to any adverse health effects.

Although emissions from LEDs, including those found in children’s toys, may not be harmful, the committee concluded that blue LEDs may be dazzling to young children and may potentially induce photochemical retinopathy (light induced damage to the retina). This is due to the structure of children’s eyes making them more sensitive to blue light, especially under the age of three. Also, it was concluded that older people may experience discomfort from exposure to LEDs rich in light due to the effects of scattering. Due to flickering in some models of LEDs, there have been reports of stroboscopic effects which make moving objects appear stationary or as a series of stationary images when viewed under these types of lighting systems. The combination of these effects may lead to distraction or disorientation resulting in indirect safety concerns.

Finally, because LED technology is still evolving, the committee considered it important to monitor the risk of adverse health effects in the general population.

Final Opinion on Light Emitting Diodes (LEDs)

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Although there is research showing potential health effects from LED sources, these occurred at exposure levels that were greater than those likely to occur with the use of LEDs in practice.

The potential disruption of the circadian rhythm in humans supports reducing the use of LED displays in the late evening, or engaging functions such as “night-shift” for reducing the intensity of the blue light from the display.

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Summary:

This was a retrospective cross-sectional study that investigated the prevalence of specific cancers within flight attendants in the U.S. compared to the general population. Data on cancer prevalence was gathered by surveys returned from 5366 flight attendants and 2729 controls matched by similar socioeconomic status. The study reported a higher prevalence in flight attendants compared to the general population for breast cancer (risk estimate 1.51 with a 95% confidence interval (CI) of 1.02-2.24), melanoma (2.27, 95% CI 1.27-4.06) and non-melanoma cancer (4.09, 95% CI 2.70-6.20). There were no statistically significant associations with the other cancers examined (uterine, cervical, gastrointestinal and thyroid). The authors concluded that there was a higher prevalence of specific cancers within the flight attendant occupation than the general population.

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Commentary by ARPANSA:

Although the authors reported an elevated risk of some cancers in the flight attendant cohort, these associations were based on prevalence of the disease compared to the general population. Prevalence of disease is limited in that it measures the occurrence of a disease at a point in time. Although this can serve as an indicator of the disease, the evidence supporting the associations is weakened by a limited understanding of how the disease rates changed over time. A better indication of the risk factors would have been achieved by measuring the incidence of the cancers examined where cases would have been recorded over the time period.

The study relied on tenure in the occupation as a surrogate for exposure. The authors identified a number of known and probable carcinogens that flight attendants would be exposed including ionising radiation, circadian rhythm disruptions from night shift work, irregular schedules and crossing time zones and, poor cabin air quality such as second hand tobacco smoke from before the implementation of smoking bans. The authors also identified but did not adjust for confounders such as recreational ultraviolet radiation exposure.

Overall, the results of the study were consistent with similar studies but given it’s limitations further studies with improved methods are required. In Australia, ARPANSA is involved in a study lead by QIMR Berhofer Medical Research Institute, investigating the incidence of melanoma in commercial pilots in Australia. The first results from this research are expected later in 2018.

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This was an in vivo study investigating the effect of sunscreen application in preventing human skin DNA damage that potentially is the basis for most skin cancers. A sunscreen with a very high level of UV protection (SPF 50+) was applied to 16 healthy young subjects with Fitzpatrick skin phototypes I and II.  Sunscreen was applied at thicknesses of 0.75, 1.3 and 2.0 milligrams per square centimetre of skin (mg/cm²). The volunteers were split into two exposure groups; a group that received a single UV radiation exposure (acute exposure group) and a group that received a daily UV radiation exposure for 5 consecutive days (repeated exposure group).  UV radiation exposure was provided artificially with characteristics closely matching sun exposure. The acute exposure group received 30 standard erythema doses (SED) per sunscreen application thickness. The repeated exposure group received 15 SEDs daily for all application thicknesses to simulate a typical holiday exposure at a tropical latitude. The repeated exposure group also received 30 SEDs daily at an additional site with a 2 mg/cm² sunscreen thickness. Unprotected skin was exposed to 4 SEDs in the acute exposure group and 1 SED daily in the repeated exposure group for experimental control.

The authors reported that sunscreen significantly reduced DNA damage at application thicknesses of 1.3 and 2.0 mg/cm². Application thickness of 0.75 mg/cm², representative of typical application, was only significant in reduction of DNA damage in the repeated exposure group.

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The study showed that the use of a very high SPF factor sunscreen can inhibit DNA damage in human skin caused by exposure to UV radiation. Although typical sunscreen application showed some value in providing UV protection in people going out in the sun for consecutive days, the importance of better sunscreen application was supported by the reduction of DNA damage in going out in the sun on occasion.

Overall, the results reported by the authors support ARPANSA’s sun protection messaging. Further, the study emphasises the importance of communicating the most appropriate way to apply sunscreen to offer the best protection outcomes.

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Summary:

This was a double-blind provocation study investigating the association between providing precautionary information on electromagnetic fields (EMF) and the nocebo response. The study included 73 participants who received basic information on the use of Wi-Fi and 64 controls who received basic and precautionary information. All subjects were then sham exposed to EMF three times and asked if they could perceive the field or experience any health symptoms. There was no statistical significant difference between the risk perceived when given basic information or basic plus precautionary information. The authors concluded that precautionary information does not trigger the nocebo effect.

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Commentary by ARPANSA:

The nocebo effect is the unspecified adverse effect caused by the expectation or belief that something is harmful to health, this can result in negative symptoms for individuals.  It has been suggested that in electromagnetic hypersensitivity the belief of exposure is enough to cause symptoms and the nocebo effect may play a role in their development (SCENIHR 2009). 

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Summary:

This was a case-control study that investigated the association between exposure to radiofrequency electromagnetic fields (RF-EME) from broadcast and mobile phone antennas and risk of lymphoma. The study included 322 cases and 444 controls. Exposure to RF was assessed via self-reported and quantified distance from the RF transmitters to the residential address and some residential measurements. There was an association between self-reported residential distances less than 50 meters (odds ratio 2.7, 95% confidence interval 1.5-4.6). However there was no statistically significant association with any type of lymphoma when exposure was assessed via quantifying distance to addresses or residential measurements. The authors concluded that there was no association between RF-EME exposure from mobile phone antennas and lymphoma development.

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Commentary by ARPANSA:

The evidence on the effects of RF fields and human health has been reviewed recently by the European Scientific Committee on Emerging and Newly Identified Health Risks (SCENHIR, 2015). SCENHIR concluded that there is no substantiated evidence that exposure to RF from base stations and broadcast antennas increases cancer risk.