Background Studies on the association of farm environments with asthma and atopy have repeatedly observed a protective effect of farming. However, no single specific farm-related exposure explaining ...this protective farm effect has consistently been identified. Objective We sought to determine distinct farm exposures that account for the protective effect of farming on asthma and atopy. Methods In rural regions of Austria, Germany, and Switzerland, 79,888 school-aged children answered a recruiting questionnaire (phase I). In phase II a stratified random subsample of 8,419 children answered a detailed questionnaire on farming environment. Blood samples and specific IgE levels were available for 7,682 of these children. A broad asthma definition was used, comprising symptoms, diagnosis, or treatment ever. Results Children living on a farm were at significantly reduced risk of asthma (adjusted odds ratio aOR, 0.68; 95% CI, 0.59-0.78; P < .001), hay fever (aOR, 0.43; 95% CI, 0.36-0.52; P < .001), atopic dermatitis (aOR, 0.80; 95% CI, 0.69-0.93; P = .004), and atopic sensitization (aOR, 0.54; 95% CI, 0.48-0.61; P < .001) compared with nonfarm children. Whereas this overall farm effect could be explained by specific exposures to cows, straw, and farm milk for asthma and exposure to fodder storage rooms and manure for atopic dermatitis, the farm effect on hay fever and atopic sensitization could not be completely explained by the questionnaire items themselves or their diversity. Conclusion A specific type of farm typical for traditional farming (ie, with cows and cultivation) was protective against asthma, hay fever, and atopy. However, whereas the farm effect on asthma could be explained by specific farm characteristics, there is a link still missing for hay fever and atopy.
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•Largest occupational cohort study conducted in a subway system.•PM2.5 mass concentration on the London Underground can be 15 times higher than outdoor air in London.•Subway PM ...exposure amongst staff is heterogenous and drivers have the highest exposures.•Office staff had lower sickness absence rates from all-causes and infections.•No exposure response relationship between PM2.5 and sickness absence was seen to support causal associations.
The London Underground (LU) employs over 19,000 staff, some of whom are exposed to elevated concentrations of particulate matter (PM) within the network. This study quantified the occupational exposure of LU staff to subway PM and investigated the possible association with sickness absence (SA).
A job exposure matrix to quantify subway PM2.5 staff exposure was developed by undertaking measurement campaigns across the LU network. The association between exposure and SA was evaluated using zero-inflated mixed-effects negative binomial models.
Staff PM2.5 exposure varied by job grade and tasks undertaken. Drivers had the highest exposure over a work shift (mean: 261 µg/m3), but concentrations varied significantly by LU line and time the train spent subway.
Office staff work in office buildings separate to the LU network and are unexposed to occupational subway PM2.5. They were found to have lower rates of all-cause and respiratory infection SA compared to non-office staff, those who work across the LU network and are occupational exposed to subway PM2.5. Train drivers on five out of eight lines showed higher rates of all-cause SA, but no dose–response relationship was seen. Only drivers from one line showed higher rates of SAs from respiratory infections (incidence rate ratio: 1.24, 95% confidence interval 1.10–1.39). Lower-grade customer service (CS) staff showed higher rates of all-cause and respiratory infection SA compared to higher grade CS staff. Doctor-certified chronic respiratory and cardiovascular SAs were associated with occupational PM2.5 exposure in CS staff and drivers.
While some groups with higher occupational exposure to subway PM reported higher rates of SA, no evidence suggests that subway PM is the main contributing factor to SA. This is the largest subway study on health effects of occupational PM2.5 exposure and may have wider implications for subway workers, contributing to safer working environments.
The relationship between eczema, wheeze or asthma, and rhinitis is complex, and epidemiology and mechanisms of their comorbidities is unclear.
To investigate within-individual patterns of morbidity ...of eczema, wheeze, and rhinitis from birth to adolescence/early adulthood.
We investigated onset, progression, and resolution of eczema, wheeze, and rhinitis using descriptive statistics, sequence mining, and latent Markov modeling in four population-based birth cohorts. We used logistic regression to ascertain if early-life eczema or wheeze, or genetic factors (
mutations and 17q21 variants), increase the risk of multimorbidity.
Single conditions, although the most prevalent, were observed significantly less frequently than by chance. There was considerable variation in the timing of onset/remission/persistence/intermittence. Multimorbidity of eczema+wheeze+rhinitis was rare but significantly overrepresented (three to six times more often than by chance). Although infantile eczema was associated with subsequent multimorbidity, most children with eczema (75.4%) did not progress to any multimorbidity pattern.
mutations and rs7216389 were not associated with persistence of eczema/wheeze as single conditions, but both increased the risk of multimorbidity (
by 2- to 3-fold, rs7216389 risk variant by 1.4- to 1.7-fold). Latent Markov modeling revealed five latent states (no disease/low risk, mainly eczema, mainly wheeze, mainly rhinitis, multimorbidity). The most likely transition to multimorbidity was from eczema state (0.21). However, although this was one of the highest transition probabilities, only one-fifth of those with eczema transitioned to multimorbidity.
Atopic diseases fit a multimorbidity framework, with no evidence for sequential atopic march progression. The highest transition to multimorbidity was from eczema, but most children with eczema (more than three-quarters) had no comorbidities.
Background Seasonal allergic rhinitis is common globally, and symptoms have been shown to impair learning ability in children in laboratory conditions. Critical examinations in children are often ...held in the summer during the peak grass pollen season. Objective To investigate whether seasonal allergic rhinitis adversely impacts examination performance in United Kingdom teenagers. Methods Case-control analysis of 1834 students (age 15-17 years; 50% girls) sitting for national examinations. Cases were those who dropped 1 or more grades in any of 3 core subjects (mathematics, English, and science) between practice (winter) and final (summer) examinations; controls were those whose grades were either unchanged or improved. Associations between allergic rhinitis symptoms, clinician-diagnosed allergic rhinitis, and allergic rhinitis–related medication use, recorded on examination days immediately before the examination, were assessed using multilevel regression models. Results Between 38% and 43% of students reported symptoms of seasonal allergic rhinitis on any 1 of the examination days. There were 662 cases (36% of students) and 1172 controls. After adjustment, cases were significantly more likely than controls to have had allergic rhinitis symptoms during the examination period (odds ratio OR, 1.4; 95% CI, 1.1-1.8; P = .002), to have taken any allergic rhinitis medication (OR, 1.4; 95% CI, 1.1-1.7; P = .01), or to have taken sedating antihistamines (OR, 1.7; 95% CI, 1.1-2.8; P = .03). Conclusion Current symptomatic allergic rhinitis and rhinitis medication use are associated with a significantly increased risk of unexpectedly dropping a grade in summer examinations. Clinical implications This is the first time the relationship between symptomatic allergic rhinitis and poor examination performance has been demonstrated, which has significant implications for clinical practice.
Background In 2003, we recorded a striking difference in the prevalence of atopy between village and small-town populations in southwest Poland. Nine years later, we undertook a second survey of the ...same area. Objective We sought to assess whether rapid changes in farming practices, driven by accession to the European Union in 2004, were accompanied by an increase in atopy, asthma, and hay fever in these villages. Methods In 2012, we surveyed 1730 inhabitants older than 5 years (response rate, 85%); 560 villagers and 348 town inhabitants who had taken part in the earlier survey. Participants completed a questionnaire on farm-related exposures and symptoms of asthma and hay fever. Atopy was assessed by using skin prick tests. Results In 2012, far fewer villagers had contact with cows (4% vs 24.3% in 2003) or pigs (14% vs 33.5%), milked cows (2.7% vs 12.7%), or drank unpasteurized milk (9% vs 35%). Among the villagers, there was a significant increase at all ages in the prevalence of atopy between 2003 and 2012 both in the total population (7.3% vs 19.6%, P < .0001) and among those who took part in both surveys (7.9% vs 17.8%, P < .0001). Among the townspeople, the prevalence of atopy did not change substantially (20% vs 19.9% and 21.7% vs 18.5%, respectively). Hay fever increased 2-fold in the villages (3.0% vs 7.7%) but not in the town (7.1% vs 7.2%); there was little or no change in asthma prevalence in the villages (5.0% vs 4.3%) or town (4.3% vs 5.0%). Conclusions We report a substantial increase in atopy at all ages and in a remarkably short period of time in a Polish population whose farm-related exposures were dramatically reduced after their country's accession to the European Union.
Occupational exposure is an important, global cause of respiratory disease. Unlike many other non-communicable lung diseases, the proximal causes of many occupational lung diseases are well ...understood and they should be amenable to control with use of established and effective approaches. Therefore, the risks arising from exposure to silica and asbestos are well known, as are the means of their prevention. Although the incidence of occupational lung disease has decreased in many countries, in parts of the world undergoing rapid economic transition and population growth-often with large informal and unregulated workforces-occupational exposures continue to impose a heavy burden of disease. The incidence of interstitial and malignant lung diseases remains unacceptably high because control measures are not implemented or exposures arise in novel ways. With the advent of innovative technologies, new threats are continually introduced to the workplace (eg, indium compounds and vicinal diketones). In developed countries, work-related asthma is the commonest occupational lung disease of short latency. Although generic control measures to reduce the risk of developing or exacerbating asthma are well recognised, there is still uncertainty, for example, with regards to the management of workers who develop asthma but remain in the same job. In this Review, we provide recommendations for research, surveillance, and other action for reducing the burden of occupational lung diseases.
Occupational lung diseases are an important public health issue and are avoidable through preventive interventions in the workplace. Up-to-date knowledge about changes in exposure to occupational ...hazards as a result of technological and industrial developments is essential to the design and implementation of efficient and effective workplace preventive measures. New occupational agents with unknown respiratory health effects are constantly introduced to the market and require periodic health surveillance among exposed workers to detect early signs of adverse respiratory effects. In addition, the ageing workforce, many of whom have pre-existing respiratory conditions, poses new challenges in terms of the diagnosis and management of occupational lung diseases. Primary preventive interventions aimed to reduce exposure levels in the workplace remain pivotal for elimination of the occupational lung disease burden. To achieve this goal there is still a clear need for setting standard occupational exposure limits based on transparent evidence-based methodology, in particular for carcinogens and sensitising agents that expose large working populations to risk. The present overview, focused on the occupational lung disease burden in Europe, proposes directions for all parties involved in the prevention of occupational lung disease, from researchers and occupational and respiratory health professionals to workers and employers.
Exposure to traffic-related air pollution (TRAP) has been associated with adverse health outcomes but underlying biological mechanisms remain poorly understood. Two randomized crossover trials were ...used here, the Oxford Street II (London) and the TAPAS II (Barcelona) studies, where volunteers were allocated to high or low air pollution exposures. The two locations represent different exposure scenarios, with Oxford Street characterized by diesel vehicles and Barcelona by normal mixed urban traffic. Levels of five and four pollutants were measured, respectively, using personal exposure monitoring devices. Serum samples were used for metabolomic profiling. The association between TRAP and levels of each metabolic feature was assessed. All pollutant levels were significantly higher at the high pollution sites. 29 and 77 metabolic features were associated with at least one pollutant in the Oxford Street II and TAPAS II studies, respectively, which related to 17 and 30 metabolic compounds. Little overlap was observed across pollutants for metabolic features, suggesting that different pollutants may affect levels of different metabolic features. After observing the annotated compounds, the main pathway suggested in Oxford Street II in association with NO2 was the acyl-carnitine pathway, previously found to be associated with cardio-respiratory disease. No overlap was found between the metabolic features identified in the two studies.
•Two randomized crossover trials were used to assess the relationship between TRAP and metabolic features with MS-based metabolomics (MWAS)•The locations represent different exposure scenarios, with London characterized by diesel vehicles and Barcelona by normal mixed urban traffic•Levels of 17 and 30 metabolic compounds associated with different air pollutants in the studies, with little overlap in features across pollutants•No overlap found between metabolomic features identified in the two studies, possibly due to different levels of single pollutants•The acyl-carnitine pathway, involved in cardio-respiratory disease, was suggested as a potential pathway in association with NO2 in one study
ABSTRACT
It is widely accepted that air pollution can exacerbate asthma in those who already have the condition. What is less clear is whether air pollution can contribute to the initiation of new ...cases of asthma. Mechanistic evidence from toxicological studies, together with recent information on genes that predispose towards the development of asthma, suggests that this is biologically plausible, particularly in the light of the current understanding of asthma as a complex disease with a variety of phenotypes. The epidemiological evidence for associations between ambient levels of air pollutants and asthma prevalence at a whole community level is unconvincing; meta‐analysis confirms a lack of association. In contrast, a meta‐analysis of cohort studies found an association between asthma incidence and within‐community variations in air pollution (largely traffic dominated). Similarly, a systematic review suggests an association of asthma prevalence with exposure to traffic, although only in those living very close to heavily trafficked roads carrying a lot of trucks. Based on this evidence, the UK's Committee on the Medical Effects of Air Pollutants recently concluded that, overall, the evidence is consistent with the possibility that outdoor air pollution might play a role in causing asthma in susceptible individuals living very close to busy roads carrying a lot of truck traffic. Nonetheless, the effect on public health is unlikely to be large: air pollutants are likely to make only a small contribution, compared with other factors, in the development of asthma, and in only a small proportion of the population.
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