High exposure to endotoxin in farming is associated with less new-onset pollen sensitisation

Elholm, Grethe; Schlünssen, Vivi; Doekes, Gert; Basinas, Ioannis; Bolund, Anneli Clea; Hjort, Charlotte; Grønager, Pernille Milvang; Omland, Øyvind; Sigsgaard, Torben

doi:10.1136/oemed-2017-104384

Cited by 12 publications

(16 citation statements)

References 39 publications

(22 reference statements)

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“…Analyses were based on exposure quartiles, the 4th quartile representing the highest exposure. 8,9 Changes in Table 1 show less newonset sensitization to Lep d among participants with a rural or farm childhood and a greater loss of sensitization consistent with findings for other aeroallergens. 8 In contrary, farming exposure during adulthood appeared to be consistently associated with increased new- Figure S1 shows the results of the adjusted SPT analyses).…”

Section: Adult Farming Exposure Does Not Protect Against Sensitizatiosupporting

confidence: 69%

“…This protective effect was, however, not seen for HDM, but neither was an increased risk of new HDM sensitization among current farmers, 7 show high homology and mutual cross-reactivity but share only approximately 40% amino acid identity with Der p 2, and cross-reactivity with HDM does not appear as often as previously suspected. 10,11 In this study, we could determine both the HDM and 8 We speculate that this effect is due to a high occupational exposure to storage mites in general when working on a farm. While for the common allergens, exposure levels presumably remain relatively constant in adulthood as in childhood and adolescence, it is probable that the levels of general storage mite exposure increase considerably for young adults who start working as farmers.…”

Section: Adult Farming Exposure Does Not Protect Against Sensitizatiomentioning

confidence: 90%

“…5,6 Working as a farmer in young adulthood may also provide protection against incident sensitization and persistence of existing sensitization, especially to pollen allergens. 7,8 As storage mites are most abundant in barns and stables, we assume that adults working in farming are exposed to much higher levels of storage mite allergens than children growing up in farm homes, with an at highest intermittent presence in barns and stables. However, it is so known to be high.…”

Section: Adult Farming Exposure Does Not Protect Against Sensitizatiomentioning

confidence: 99%

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Adult farming exposure does not protect against sensitization to the storage mite Lepidoglyphus destructor

Elholm

Schlünssen

Doekes

et al. 2018

Allergy

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Section: Adult Farming Exposure Does Not Protect Against Sensitizatiosupporting

confidence: 69%

Section: Adult Farming Exposure Does Not Protect Against Sensitizatiomentioning

confidence: 90%

Section: Adult Farming Exposure Does Not Protect Against Sensitizatiomentioning

confidence: 99%

See 1 more Smart Citation

Adult farming exposure does not protect against sensitization to the storage mite Lepidoglyphus destructor

Elholm

Schlünssen

Doekes

et al. 2018

Allergy

Self Cite

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“…The effects of exposure to endotoxin are predominantly respiratory, including decline in lung function and increased prevalence of chronic bronchitis and asthma-like syndrome [ 5 , 14 , 15 ]. In addition to adverse health effects, occupational endotoxin exposure in agricultural workers has also been implicated in protective effects on allergic sensitisation and hay fever [ 16 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

Respiratory health effects of exposure to low levels of airborne endotoxin – a systematic review

2018

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BackgroundElevated endotoxin levels have been measured in ambient air around livestock farms, which is a cause of concern for neighbouring residents. There is clear evidence that occupational exposure to high concentrations of airborne endotoxin causes respiratory inflammation, respiratory symptoms and lung function decline. However, health effects of exposure to low levels of endotoxin are less well described. The aim of this systematic review is to summarize published associations between exposure to relatively low levels of airborne endotoxin and respiratory health endpoints.MethodsStudies investigating respiratory effects of measured or modelled exposure to low levels of airborne endotoxin (average < 100 EU/m3) were eligible for inclusion. In total, 1362 articles were identified through a Pubmed database search, of which 31 articles were included in this review. Studies were included up to February 2017. Overview tables and forest plots were created, and study quality was assessed.ResultsTwenty-two included studies had a cross-sectional design, others were designed as longitudinal observational (n = 7) or experimental (n = 2) studies. Most studies (n = 23) were conducted in an occupational setting, some involved domestic or experimental exposure. Several studies reported statistically significant effects of exposure to low levels of endotoxin on respiratory symptoms and lung function. However, considerable heterogeneity existed in the outcomes of the included studies and no overall estimate could be provided by meta-analysis to quantify the possible relationship. Instead, a best evidence synthesis was performed among studies examining the exposure-response relationship between endotoxin and respiratory outcomes. Significant exposure-response relationships between endotoxin and symptoms and FEV1 were shown in several studies, with no conflicting findings in the studies included in the best evidence synthesis. Significantly different effects of endotoxin exposure were also seen in vulnerable subgroups (atopics and patients with broncho-obstructive disease) and smokers.ConclusionsRespiratory health effects of exposure to low levels of airborne endotoxin (< 100 EU/m3) seem plausible. Future studies are needed to investigate ambient exposure to endotoxin and potential respiratory health effects, especially in vulnerable subgroups of the population.Electronic supplementary materialThe online version of this article (10.1186/s12940-018-0360-7) contains supplementary material, which is available to authorized users.

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“…For children, an inverse association between livestock exposure and allergic diseases has been firmly established, this protective association is believed to be mediated by exposure to microbes (Campbell et al, 2015). Recent studies also identified this inverse association in adult populations (adjusted for childhood farm exposure) suggesting continuous exposure to be the most effective to prevent development of allergic diseases (Elholm et al, 2013(Elholm et al, , 2018Smit et al, 2010;Spierenburg et al, 2017). For both atopic sensitization as asthma, the prevalence ratio observed in our study was substantial (0.75, 0.80; respectively) suggesting the size of the effect of livestock-related environmental exposure in a nonfarming population to be considerable.…”

Section: Endotoxin and Healthmentioning

confidence: 98%

Endotoxin and particulate matter emitted by livestock farms and respiratory health effects in neighboring residents

Rooij¹,

Smit²,

Erbrink³

et al. 2019

Occupational and Environmental Health

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Background: Living in livestock-dense areas has been associated with health effects, suggesting airborne exposures to livestock farm emissions to be relevant for public health. Livestock farm emissions involve complex mixtures of various gases and particles. Endotoxin, a pro-inflammatory agent of microbial origin, is a constituent of livestock farm emitted particulate matter (PM) that is potentially related to the observed health effects. Quantification of livestock associated endotoxin exposure at residential addresses in relation to health outcomes has not been performed earlier. Objectives: We aimed to assess exposure-response relations for a range of respiratory endpoints and atopic sensitization in relation to livestock farm associated PM 10 and endotoxin levels. Methods: Self-reported respiratory symptoms of 12,117 persons participating in a population-based cross-sectional study were analyzed. For 2494 persons, data on lung function (spirometry) and serologically assessed atopic sensitization was additionally available. Annual-average PM 10 and endotoxin concentrations at home addresses were predicted by dispersion modelling and land-use regression (LUR) modelling. Exposure-response relations were analyzed with generalized additive models. Results: Health outcomes were generally more strongly associated with exposure to livestock farm emitted endotoxin compared to PM 10. An inverse association was observed for dispersion modelled exposure with atopic sensitization (endotoxin: p = .004, PM 10 : p = .07) and asthma (endotoxin: p = .029, PM 10 : p = .022). Prevalence of respiratory symptoms decreased with increasing endotoxin concentration at the lower range, while at the higher range prevalence increased with increasing concentration (p < .05). Associations between lung function parameters with exposure to PM 10 and endotoxin were not statistically significant (p > .05). Conclusions: Exposure to livestock farm emitted particulate matter is associated with respiratory health effects and atopic sensitization in non-farming residents. Results indicate endotoxin to be a potentially plausible etiologic agent, suggesting non-infectious aspects of microbial emissions from livestock farms to be important with respect to public health.

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High exposure to endotoxin in farming is associated with less new-onset pollen sensitisation

Abstract: High exposure to endotoxin during young adulthood appears to protect against new onset of pollen sensitisation, independent of childhood farm exposure.

Cited by 12 publications

References 39 publications

Adult farming exposure does not protect against sensitization to the storage mite Lepidoglyphus destructor

Adult farming exposure does not protect against sensitization to the storage mite Lepidoglyphus destructor

Respiratory health effects of exposure to low levels of airborne endotoxin – a systematic review

Endotoxin and particulate matter emitted by livestock farms and respiratory health effects in neighboring residents

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