Despite public concern about potential adverse health effects of concentrated animal feeding operations, objectively assessed data on environmental exposure to concentrated animal feeding operations and respiratory health are sparse. We aimed to assess respiratory health in neighbors of confined animal feeding operations. A survey was done in 2002-2004 among all adults (18-45 years old) living in 4 rural German towns with a high density of confined animal feeding operations. Questionnaire data were available for 6937 (68%) eligible subjects. In a random sample we measured the following outcomes: specific IgE to common and farm-specific allergens, lung function, and bronchial hyperresponsiveness to methacholine. Exposure was measured by collecting data on odor annoyance and geo-coded data on the number of animal houses within 500 m of the home. Locally optimal estimating and smoothing scatter plots were used to model the association between exposure and outcome. Analyses were restricted to subjects without private or professional contact with farming environments. The prevalence of self-reported asthma symptoms and nasal allergies increased with self-reported odor annoyance. The number of animal houses was a predictor of self-reported wheeze and decreased forced expiratory volume in 1 second, but not allergic rhinitis or specific sensitization. Self-reported exposure and results of clinical measurements were poorly correlated. Confined animal feeding operations may contribute to the burden of respiratory disease among their neighbors. Our findings underline the importance of objective assessment of exposure and outcome in environmental epidemiology.

OBJECTIVE. The aim of this study was to test the association between farm animal contact in infancy and the development of juvenile Crohn disease and ulcerative colitis. METHODS. A case-control study was conducted in 13 children's hospitals by using a mailed questionnaire. Case subjects with Crohn disease or ulcerative colitis who were registered in these hospitals were eligible (response rate: 90%). Children who underwent strabismus surgery at 11 of the 13 centers served as control subjects (response rate: 85%). All children 6 to 18 years of age who were born in Germany without malformations were included (444 case subjects with Crohn disease, 304 case subjects with ulcerative colitis, and 1481 control subjects). RESULTS. Regular contact with farm animals during the first year of life was associated inversely with Crohn disease and ulcerative colitis. In addition, regular contact with cats in infancy was linked inversely with case status. Allergic rhinitis was correlated significantly with Crohn disease but not with ulcerative colitis. CONCLUSION. Contact with farm environments in infancy might decrease the risk of juvenile Crohn disease and ulcerative colitis.

The development of new wireless communication technologies that emit radio frequency electromagnetic fields (RF-EMF) is ongoing, but little is known about the RF-EMF exposure distribution in the general population. Previous attempts to measure personal exposure to RF-EMF have used different measurement protocols and analysis methods making comparisons between exposure situations across different study populations very difficult. As a result, observed differences in exposure levels between study populations may not reflect real exposure differences but may be in part, or wholly due to methodological differences. The aim of this paper is to develop a study protocol for future personal RF-EMF exposure studies based on experience drawn from previous research. Using the current knowledge base, we propose procedures for the measurement of personal exposure to RF-EMF, data collection, data management and analysis, and methods for the selection and instruction of study participants. We have identified two basic types of personal RF-EMF measurement studies: population surveys and microenvironmental measurements. In the case of a population survey, the unit of observation is the individual and a randomly selected representative sample of the population is needed to obtain reliable results. For microenvironmental measurements, study participants are selected in order to represent typical behaviours in different microenvironments. These two study types require different methods and procedures. Applying our proposed common core procedures in future personal measurement studies will allow direct comparisons of personal RF-EMF exposures in different populations and study areas.

With respect to asthma, the evidence is conflicting at first glance. While some studies indicated an increased risk of asthma after endotoxin exposure, others have shown that endotoxin exposure protects from asthma. However, these differences can be explained when different asthma phenotypes are taken into account. The risk of atopic asthma, mainly dominated by eosinophilic response, is decreased in those exposed to endotoxins. In contrast, the risk of non-atopic asthma, characterised by neutrophilic response, is enhanced in subjects with higher endotoxin exposure. These data are in accordance with the so-called hygiene hypothesis and have been supported by animal studies and at the cellular level.