Prevalence of non-specific health symptoms in livestock dense areas: Looking beyond respiratory conditions.

The aim of this study was to gain more insight in the association between prevalence of diverse acute non-specific symptoms (NSS) and livestock density as a possible risk factor among residents of livestock-dense and non-dense regions, taking into account socio-demographic factors and psychological morbidity. Prevalence of NSS and psychological morbidity were assessed for the year 2017, based on electronic health records from 39 general practices in the Netherlands. The study group consisted of people who lived in rural areas with high numbers of livestock (n = 74093), while the control group included people in rural areas with low numbers of livestock (n = 50139). For a large portion of the study group, exposure estimates (to livestock) were calculated. Multiple logistic multilevel regression analyses were performed. Two methods were used: 1) area comparisons between study and control areas in relation to health problems, and 2) estimates of livestock exposure (to goats, poultry, pigs, and cattle) within the study area. It was found that prevalence of diarrhea, headache, sleep disturbance, respiratory symptoms, and skin problems were higher in the study group. The data suggest that there may be a protective effect of livestock exposure: in general, there was a lower risk of NSS closer to livestock (within the exposure analyses). The study suggests that the previously identified higher risk of respiratory health problems in livestock dense areas might also apply to the prevalence of various other NSS. Longitudinal research taking into account different or more individual and contextual characteristics could possibly elucidate why prevalence of NSS in closer proximity to livestock is lower compared to people who live further away, whilst a more overarching analysis indicated that living in livestock dense areas was associated with more NSS.

Individual variation in temporal relationships between exposure to radiofrequency electromagnetic fields and non-specific physical symptoms: A new approach in studying 'electrosensitivity'.

BACKGROUND: Everyday exposure to radiofrequency electromagnetic fields (RF-EMF) emitted from wireless devices such as mobile phones and base stations, radio and television transmitters is ubiquitous. Some people attribute non-specific physical symptoms (NSPS) such as headache and fatigue to exposure to RF-EMF. Most previous laboratory studies or studies that analyzed populations at a group level did not find evidence of an association between RF-EMF exposure and NSPS. OBJECTIVES: We explored the association between exposure to RF-EMF in daily life and the occurrence of NSPS in individual self-declared electrohypersensitive persons using body worn exposimeters and electronic diaries. METHODS: We selected seven individuals who attributed their NSPS to RF-EMF exposure. The level of and variability in personal RF-EMF exposure and NSPS were determined during a three-week period. Data were analyzed using time series analysis in which exposure as measured and recorded in the diary was correlated with NSPS. RESULTS: We found statistically significant correlations between perceived and actual exposure to wireless internet (WiFi - rate of change and number of peaks above threshold) and base stations for mobile telecommunications (GSM + UMTS downlink, rate of change) and NSPS scores in four of the seven participants. In two persons a higher EMF exposure was associated with higher symptom scores, and in two other persons it was associated with lower scores. Remarkably, we found no significant correlations between NSPS and time-weighted average power density, the most commonly used exposure metric. CONCLUSIONS: RF-EMF exposure was associated either positively or negatively with NSPS in some but not all of the selected self-declared electrohypersensitive persons.