Effects of personalised exposure on self-rated electromagnetic hypersensitivity and sensibility - A double-blind randomised controlled trial

BACKGROUND

Previous provocation experiments with persons reporting electromagnetic hypersensitivity (EHS) have been criticised because EHS persons were obliged to travel to study locations (seen as stressful), and that they were unable to select the type of signal they reported reacting to. In our study we used mobile exposure units that allow double-blind exposure conditions with personalised exposure settings (signal type, strength, duration) at home. Our aim was to evaluate whether subjects were able to identify exposure conditions, and to assess if providing feedback on personal test results altered the level of self-reported EHS.

METHODS

We used double-blind randomised controlled exposure testing with questionnaires at baseline, immediately before and after testing, and at two and four months post testing. Participants were eligible if they reported sensing either radiofrequency or extremely low frequency fields within minutes of exposure. Participants were visited at home or another location where they felt comfortable to undergo testing. Before double-blind testing, we verified together with participants in an unblinded exposure session that the exposure settings were selected were ones that the participant responded to. Double-blind testing consisted of a series of 10 exposure and sham exposures in random sequence, feedback on test results was provided directly after testing.

RESULTS

42 persons participated, mean age was 55years (range 29-78), 76% were women. During double-blind testing, no participant was able to correctly identify when they were being exposed better than chance. There were no statistically significant differences in the self-reported level of EHS at follow-up compared to baseline, but during follow-up participants reported reduced certainty in reacting within minutes to exposure and reported significantly fewer symptoms compared to baseline.

CONCLUSION

Our results suggest that a subgroup of persons exist who profit from participation in a personalised testing procedure.

Novel exposure units for at-home personalized testing of electromagnetic sensibility

Previous experimental studies on electromagnetic hypersensitivity have been criticized regarding inflexibility of choice of exposure and of study locations. We developed and tested novel portable exposure units that can generate different output levels of various extremely low frequency magnetic fields (ELF-MF; 50 Hz field plus harmonics) and radiofrequency electromagnetic fields (RF-EMF). Testing was done with a group of healthy volunteers (n = 25 for 5 ELF-MF and n = 25 for 5 RF-EMF signals) to assess if units were indeed able to produce double-blind exposure conditions. Results substantiated that double-blind conditions were met; on average participants scored 50.6% of conditions correct on the ELF-MF, and 50.0% on the RF-EMF unit, which corresponds to guessing probability. No cues as to exposure conditions were reported. We aim to use these units in a future experiment with subjects who wish to test their personal hypothesis of being able to sense or experience when being exposed to EMF. The new units allow for a high degree of flexibility regarding choice of applied electromagnetic signal, output power level and location (at home or another environment of subjects' choosing).

Environmental Radiofrequency Electromagnetic Fields Exposure at Home, Mobile and Cordless Phone Use, and Sleep Problems in 7-Year-Old Children

BACKGROUND

We evaluated if exposure to RF-EMF was associated with reported quality of sleep in 2,361 children, aged 7 years.

METHODS

This study was embedded in the Amsterdam Born Children and their Development (ABCD) birth cohort study. When children were about five years old, school and residential exposure to RF-EMF from base stations was assessed with a geospatial model (NISMap) and from indoor sources (cordless phone/WiFi) using parental self-reports. Parents also reported their children's use of mobile or cordless phones. When children were seven years old, we evaluated sleep quality as measured with the Child Sleep Habits Questionnaire (CSHQ) filled in by parents. Of eight CSHQ subscales, we evaluated sleep onset delay, sleep duration, night wakenings, parasomnias and daytime sleepiness with logistic or negative binomial regression models, adjusting for child's age and sex and indicators of socio-economic position of the parents. We evaluated the remaining three subscales (bedtime resistance, sleep anxiety, sleep disordered breathing) as unrelated outcomes (negative control) because these were a priori hypothesised not to be associated with RF-EMF.

RESULTS

Sleep onset delay, night wakenings, parasomnias and daytime sleepiness were not associated with residential exposure to RF-EMF from base stations. Sleep duration scores were associated with RF-EMF levels from base stations. Higher use mobile phones was associated with less favourable sleep duration, night wakenings and parasomnias, and also with bedtime resistance. Cordless phone use was not related to any of the sleeping scores.

CONCLUSION

Given the different results across the evaluated RF-EMF exposure sources and the observed association between mobile phone use and the negative control sleep scale, our study does not support the hypothesis that it is the exposure to RF-EMF that is detrimental to sleep quality in 7-year old children, but potentially other factors that are related to mobile phone usage.

Daily changes of peak expiratory flow and respiratory symptom occurrence around a soy processing factory

OBJECTIVES

To evaluate sensitization and acute respiratory health effects in inhabitants living in the vicinity of a factory producing soy oil.

METHODS

Two panels of potential responders were created on the basis of a response to a short screening questionnaire sent to random samples of 1,000 exposed and 1,000 non-exposed individuals living around the factory and a control area. Individuals responding to the questionnaire were invited for a medical evaluation, including a respiratory symptom questionnaire and skin prick testing, for a panel of common allergens and a soy allergen extract. This resulted in 53 atopic and/or asthmatic inhabitants from the area surrounding the factory and 30 comparable control subjects. In these subjects, morning and evening Peak Expiratory Flow (PEF), respiratory symptoms and medication use were recorded daily during a 10-week period in the autumn. At the same time, soy allergen and endotoxin concentrations were determined in airborne dust in the exposed and the control area. The wind direction relative to the location of a subjects' house and the factory was used to determine whether an individual was exposed on a particular day.

RESULTS

Only few of the atopic subjects were sensitized to soy. PEF showed a decrease, respiratory symptoms and bronchodilator use, an increase among soy sensitized subjects after having been downwind from the factory. Airborne soy allergen was found more frequently in the area surrounding the factory and levels were higher than in the control area. Highest levels were found on the factory premises. Only a weak association was found with wind direction. Airborne endotoxin concentrations did not show a consistent pattern with distance, but levels were clearly higher on the factory premises.

CONCLUSION

Sensitization to soy allergen was not increased among the population sample living in the vicinity of the factory. Soy sensitized individuals living in the surroundings of the factory reported more respiratory symptoms, used bronchodilators more often and had a lower PEF after having been downwind of the factory.

Effects on pulmonary health of neighboring residents of concentrated animal feeding operations: exposure assessed using optimized estimation technique

Potential adverse health effects of concentrated animal feeding operations (CAFOs), which were also shown in the authors' Lower Saxony Lung Study, are of public concern. The authors aimed to investigate pulmonary health effect of neighboring residents assessed using optimized estimation technique. Annual ammonia emission was measured to assess the emission from CAFO and from surrounding fields. Location of sampling points was optimized using cluster analysis. Individual exposure of 457 nonfarm subjects was interpolated by weighting method. Mean estimated annual ammonia levels varied between 16 and 24 μg/m³. Higher exposed participants were more likely to be sensitized against ubiquitous allergens as compared to lower exposed subjects (adjusted odds ratio [OR] 4.2; 95% confidence interval [CI] 1.2-13.2). In addition, they showed a significantly lower forced expiratory volume in 1 second (FEV₁) (adjusted mean difference in % of predicted -8%; 95% CI -13% to -3%). The authors' previous findings that CAFOs may contribute to burden of respiratory diseases were confirmed by this study.

Does early indoor microbial exposure reduce the risk of asthma? The Prevention and Incidence of Asthma and Mite Allergy birth cohort study

BACKGROUND

Exposure to microbial agents might inhibit the development of atopy and asthma.

OBJECTIVE

We measured the association between microbial exposure assessed at 3 months and the development of atopic sensitization and doctor-diagnosed (DD) asthma and wheeze in the first 4 years in a birth cohort study of children with atopic mothers.

METHODS

Endotoxin, fungal (1-->3)-beta-D-glucans, extracellular polysaccharides from the genera Penicillium and Aspergillus (EPS-Pen/Asp), and dust on living room floors were measured at 3 months of age. Serum IgE levels against common allergens were determined at 1 and 4 years, and questionnaire information about respiratory morbidity was collected yearly.

RESULTS

Microbial levels in mattresses were low and not associated with serum IgE levels, DD asthma, and wheeze. Floor levels of biocontaminants and dust, on the other hand, were inversely associated with DD asthma, being most pronounced for endotoxin (odds ratio [OR], 0.40; 95% CI, 0.21-0.77) and EPS-Pen/Asp (OR, 0.42; 95% CI, 0.18-0.99). Mutual adjustment for other exposures did not significantly alter the results for endotoxin and only moderately affected the results for EPS-Pen/Asp. Persistent wheeze was also consistently less common in the high-exposure group, being significant only for EPS-Pen/Asp (OR, 0.37; 95% CI, 0.15-0.96). Transient wheeze and wheeze in the past 12 months were also reduced, but effects were smaller and not significant. Relationships with serum-specific IgE levels, which could only be assessed in 41% at age 4 years, were less pronounced and statistically significant only for EPS-Pen/Asp.

CONCLUSIONS

Early exposure to common microbial contaminants, including fungal agents, might protect against asthma.

CLINICAL IMPLICATIONS

Microbial exposure in early life might protect against asthma and might constitute a novel target for prevention.

Ambient endotoxin level in an area with intensive livestock production

High levels of endotoxin are found inside and near to animal houses. However, there is a lack of data on environmental endotoxin in areas with intensive animal production facilities. We conducted a cross-sectional study of respiratory health in two villages of Lower Saxony with intensive livestock production. We assessed the level of endotoxin exposure in the backyards of 32 participants with two 24-hours measurements of inhalable fraction (one in winter and one in summer). The geometric mean (geometric standard deviation) of the levels of endotoxin varied between 2.0 (2.9) EU/m3 in winter and 2.9 (2.4) EU/m3 in summer. Potential predictors--season, sampling sites, and weather conditions--explained 24% of the variability in ambient endotoxin concentration in the study area. The results indicate that, compared with urban residents, exposure to endotoxin is greater among people living in rural areas with intensive animal production. This might affect their respiratory health. However, these exposures are characterized by a large spatial variability.

The prevention and incidence of asthma and mite allergy (PIAMA) birth cohort study: design and first results

The Prevention and Incidence of Asthma and Mite Allergy (PIAMA) birth cohort study was initiated in 1996. Children born to allergic mothers were enrolled in a double-blind placebo-controlled trial for evaluating the use of mite-impermeable mattress and pillow covers. Children born to allergic and non-allergic mothers were enrolled in a 'natural history' study to assess the role of environmental and dietary risk factors for the development of allergic disease in childhood. Recruitment started by distributing a validated screening questionnaire among >10,000 pregnant women during their first visit to a prenatal health clinic. Allergic mothers-to-be were invited to participate in the intervention study. Allergic, and a random sample of non-allergic, mothers-to-be were invited to participate in the 'natural history' arm of the study. In the intervention study, homes were visited before birth, 3 months after birth, and 12 months after birth for the collection of dust samples from floors and mattresses. In addition, the homes of about one-third of the children in the 'natural history' part of the study were visited for dust collection when the children were 3 months of age. The intervention study started with 855 participants and the 'natural history' study with 3,291 participants. Follow-up at 3 years of age has now been completed with satisfactory compliance (>90%). A medical investigation and home visit at 4years of age are nearing completion. Preliminary results show that mite-allergen levels were lower than found in previous Dutch studies, and that the intervention measure had a significant effect on mite-allergen levels, without important clinical benefits up to age 2 years old. The allergic families lived in homes with fewer 'triggers' such as pets, smoking and carpets than the non-allergic families, regardless of the intervention. The ongoing PIAMA cohort study will probably reveal useful information concerning effects of allergen load and reduction in the setting of a relatively low mite-allergen exposure, as well as other variables on the development of allergic manifestions and asthma.