Table 3 Effects of farm childhood and adult farm work/exposure on the risk of asthma/rhinitis/allergic sensitization in adulthood: Studies from 2000
From: Respiratory diseases and allergy in farmers working with livestock: a EAACI position paper
References/country | Populations (n)/design | Farm childhood | Adult exposure | Asthma | Rhinitis | SPT | Specific IgE | Total IgE | Remarks |
|---|---|---|---|---|---|---|---|---|---|
OR (95% CI) unless otherwise stated | |||||||||
Lampi et al. [92]/Finland 2011 | Prospective birth cohort study; atopy at age 31 | 1262+ vs 4247− | Not done | Dd asthma ever: 0.7 (0.5–1.0) | Allergic rhinitis at age 31: 0.9 (0.7–1.03) | Positive SPT: 0.7 (0.6–0.8) | Not done | Not done | / |
Omland et al. [8]/Denmark 2011 (SUS study) | Nested case–control study (107 vs 102) | 77+ vs 132 | Swine farming (n = 94) Dairy farming (n = 59) | New-onset asthma Farm childhood: 0.50 (0.2–0.98) Exposure during FU: Swine 3.4 (1.6–7.0) Dairy 2.5 (1.1–5.3) | Not done | Atopy (positive SPT): not a risk factor for new-onset asthma | Not done | Not done | / |
Varraso et al. [149]/France 2012 | 54,018 female adults/13 years. follow-up | Farmer parents Place of birth Bovine density score 0–3 | Not done | Farmer parents: childhood asthma 0.5 (0.4–0.7) adult-onset asthma 0.7 (0.6–0.8) Rural birth: childhood asthma 0.8 (0.7–0.9) adult-onset asthma 0.9 (0.8–0.96) Highest vs. lowest bovine density score: childhood asthma 0.7 (0.5–0.98) adult-onset asthma 0.8 (0.6–0.98) | Not done | Not done | Not done | Not done | Focus on asthma history and phenotype and on dietary factors Effects on both persistent and adult-onset asthma |
Elholm et al. [11]/Denmark 2013 (SUS study) | 1166/follow-up at age 35 for new sensitization to common allergens | 496+ vs 476− (of 1162) | Farm work during follow-up (age 20–35) | Not stated | Not stated | No-farm childhood 0.6 (0.3–1.3) Farm childhood 0.4 (0.1–1.2) | No-farm childhood 0.2 (0.05–0.7) Farm childhood: too few subjects | Not done | / |
Elholm et al. [42] Denmark 2018 (SUS study) | 884 (of 1166) follow-up at age 35 for new onset sensitization |  |  |  |  | Farm Childhood OR = 0.5 Sensitisation to pollen during follow up vs sensitization in no-farm child | Farm Childhood OR = 0.5 Sensitisation to pollen during follow up vs sensitization in no-farm child | Not done |  |
Elholm et al. Denmark 2018 (SUS study) | 1116 (of 1166)/follow-up at age 35 for new sensitization to Lep D | 558 558 | Farm work during follow-up (age 20–35) | Not done | Not done | Farm Childhood OR = 0.5 Sensitisation to endotoxin during follow up ass to less sensitization in no-farm child | Farm Childhood OR = 0.5 Sensitisation to endotoxin during follow up ass to less sensitization in no-farm child | Not done |  |
Kilpeläinen et al. [85]/Finland 2000 | 10,667 1st year university students/cross-sectional | 1095+ vs 1243- | Not done | Farm childhood: dd asthma 0.7 (0.5–0.9) | Farm childhood: dd rhinitis 0.6 (0.5–0.8) | Not done | Not done | Not done | / |
Ernst &Cormier [86]/Canada 2000 | 1199 secondary school children from rural areas, age 12–19 years/cross-sectional | 802+ vs 397− | Not done | Farm childhood: wheeze 0.7 (0.6–0.99) dd asthma 0.7 (0.4–0.98) | Not done | Farm childhood: 0.6 (0.5–0.8) | Not done | Not done | Farm childhood: BHR 0.8 (0.6–0.9) |
Leynaert et al. [87]/4 EU and NZ (ECRHS) 2001 | 6251 subjects 20–44 years of age/cross-sectional study in the general population | 548+ vs 5703− | Not done | Farm childhood: current asthma 0.8 (0.5–1.39) wheeze 1.1 (0.8–1.5) | Farm childhood: pollen-related nasal sx 0.8 (0.6–1.02) animal/feather/dust-related sx 0.97 (0.8–1.2) | Not done | Farm childhood: 0.8 (0.6–0.97) cat sensitization 0.6 (0.4–0.96) grass s. 0.7 (0.5–0.9) hdm s. 0.8 (0.6–1.1) Cladosporium s. 0.9 (0.4–1.9) | Not stated | Between-country heterogeneity |
Portengen et al. [88]/Denmark 2002 | 999 farming students age 19 years/cross-sectional | 505+ vs 494− | Farming vs non-farming | Farm childhood: asthma 0.8 (0.5–1.3) wheeze 0.7 (0.4–1.1) Farmers: wheeze less often than controls (p < 0.05) | Farm childhood: rhino-conjunctivitis 0.7 (0.5–0.99) | Farm childhood: 0.5 (0.4–0.8) Farmers: + SPT lower than controls (p < 0.05) | Not stated | Farm childhood: 0.7 (0.5–1.1) | Farm childhood: BHR 0.6 (0.4–0.95) |
Eduard et al. [104]/Norway 2004 | 1614 farmers/cross-sectional | Not done | JEM, farmers with livestock vs farmers without livestock | Asthma: cattle farmers 1.8 (1.1–2.8) pig farmers: 1.6 (1.0–2.5) Non-atopic asthma: pig farmers 2.0 (1.2–3.3) 2 + livestock 1.9 (1.1–3.3) Atopic asthma: 2 + livestock 0.3 (0.1–0.97) | Not done | Not done | Not stated | Not done | Atopic vs. non-atopic asthma |
Radon et al. [102]/Germany 2004 | 3112 rural subjects, age 18–44 years/cross-sectional | 1268+ vs 1807− | Presently living on farm | Presently living on a farm: atopic asthma sx 0.7 (0.4–1.4) non-atopic asthma 0.9 (0.6–1.4) Regular visits to stables started at age 4–6: atopic asthma sx 0.4 (0.2–0.95) | Presently living on a farm: nasal allergies 0.6 (0.4–0.9) Regular visits to stables started at age 4–6: nasal allergies 0.4 (0.2–0.6) | Not done | Not done | Not done | / |
Koskela et al. [150]/Finland 2005 | 231 women living on a farm, 202 women not living on a farm/cross-sectional | 119+ vs 314− | Presently living on farm | Not done | Not done | + SPT: living in a dairy farm 35%, not living on a dairy farm 37% (NS) Sensitization to pollens: living in a dairy farm 4.4%, not living on a dairy farm 17.3% (p = 0.01) S. to cat: living in a dairy farm 3.5%, not living on a dairy farm 10.4% (p < 0.05) | Not done | Not done | Protection by living on a dairy farm only |
Portengen et al. [151]/The Netherlands 2005 | 162 pig farmers/case- control study | Not done | Modelled airborne endotoxin | Not done | Not done | + SPT: endotoxin exp. < 75 ng m−3 0.03 (0.0–0.3) endotoxin exp. > 75 ng m−3 1.2 (0.4–3.6) | Endotoxin exposure: 0.9 (0.3–2.3) | Endotoxin exposure: 1.2 (0.5–2.3) | Endotoxin exposure associated with BHR in sensitized pig farmers: 17 (1.3–227) |
Radon et al. [103]/Germany 2006 | 2678 rural adults, age 18–44 years/cross-sectional | Only in childhood: 877+ 1118− | Childhood and adulthood: 421+ 876− Only in adulthood: 75+ vs 1043− | Not done | Allergic rhinitis and farm animal exposure: only in childhood 0.7 (0.5–0.9) In childhood and adulthood 0.2 (0.1–0.4) Only in adulthood 1.0 (0.4–2.6) | Not done | + specific IgE and farm animal exp: only in childhood 0.7 (0.5–0.9) in childhood and adulthood 0.4 (0.3–0.6) Only in adulthood 2.4 (1.1–5.2) | Not done | Adult protection = effect of self-selection? |
Douwes et al. [89]/New Zealand 2007 | 4262 farmers vs 1314 non-farmers/cross-sectional | 3081+ vs 2495− | Not done | Current and childhood exp.: asthma ever 0.6 (0.5–0.7) Wheeze 0.6 (0.5–0.7) Current exp. only: asthma ever 0.7 (0.6–0.8) wheeze 0.8 (0.6–0.99) Childhood exp. only: asthma ever 0.9 (0.6–1.2) wheeze 1.01 (0.7–1.3) | Current farming exp.: self-reported nasal sx 0.97 (0.8–1.1) Childhood exp. only: self-reported nasal sx 0.8 (0.7–0.9) | Not done | Not done | Not done | / |
Chen et al. [91]/Canada 2007 | 579 farmers/cross-sectional study in the general population | Not done | Grain or livestock farming (85% both) | Dd asthma OR = 0.8 (0.5–1.1) | Self-reported nasal sx OR = 0.95 (0.8–1.2) | hdm, grass pollen, cat, Alternaria 0.7 (0.6–0.9) | Not done | Not done | / |
Schulze et al. [152]/Germany 2007 | 1595, age 18–44 years/cross-sectional | 677+ vs 918− | Not done |  | Farmers: dd 0.7 (0.4–1.1) | Farmers: allergic rhinitis, 0.5 (0.4–0.8) | Farmers: + SPT 0.7 (0.6–0.9) | Not done | Dd asthma in sensitized farmers: 0.5 (0.3–1.0) BHR in sensitized farmers: 0.8 (0.5–1.1) |
Smit et al. [100]/The Netherlands 2007 | 593 organic farmers vs 1205 conventional farmers, mean age 44–45/cross-sectional | 1370+ vs 428− | 911 livestock only 629 crops only 258 livestock and crops | Livestock farmers 1.0 (0.5–2.2) Livestock farmers with childhood farm exp.: 0.6 (0.4–1.2) | Livestock farmers 0,5 (0.3–0.9) Livestock farmers with childhood farm exp.: 0.4 (0.3–0.7) | Not done | Not done | Not done | No clear effect organic farming |
Smit et al. [10]/The Netherlands 2008 | 877 farmers and agri-industry workers, mean age 40–46/cross-sectional | 511+ vs 366− | Endotoxin exposure (modelled) | Farm childhood: dd 0.9 (0.3–2.8) No farm childhood: dd 0.9 (0.4–2.3) Endotoxin exp.: wheezing 1.4 (1.2–1.7) dd 0.99 (0.5–2.0) | Farm childhood: self-reported 0.6 (0.4–0.9) No farm childhood: self-reported 0.6 (0.4–0.8) Endotoxin exp.: self-reported 0.6 (0.5–0.8) |  |  |  | No effect modification by farm childhood |
Eriksson et al. [153]/Sweden 2010 | 18,087 rural population/cross-sectional | 2557+ vs 15,238– | Urbanization | Not done | Raised on a farm: self-reported 0.8 (0.7–0.9) | Not done | Not done | Not done | / |
Smit et al. [101]/The Netherlands 2010 | 427 farmers | 193+ vs 234− | Endotoxin exposure (modelled) | Endotoxin exposure: wheezing 1.3 (1.01–1.7) | Endotoxin exposure: self-reported 0.6 (0.4–0.7) | Not done | Endotoxin exp.: specific IgE to common allergens 0.7 (0.5–0.8) | Endotoxin exposure: total IgE 0.9 (0.7–1.05) | Effects on sensitization mainly in non-FC Endotoxin exposure: BHR 1.5 (1.03–2.3) |
Basinas et al. [7]/Denmark and The Netherlands 2012 | 3883 farmers, veterinary students and power plants workers/cross-sectional | + (adjusted) | JEM-estimated airborne endotoxin: four levels; reference ≤ 50 EU m−3 | High vs low occup. endotoxin exposure: wheezing 1.7 (1.1–2.6) asthma 1.5 (1.1–2.1) | High vs low occupational endotoxin exposure: hay fever 0.6 (0.4–0.9) | High vs low occup. endotoxin exposure: positive SPT and/or IgE to pollen, hdm, and pets 0.7 (0.4–0.99) |  | Not done | / |
Galli et al. [93]/Italy 2015 | 78 Italian swine farmers vs 82 non-swine farmers/cross-sectional | Not stated | Swine farming vs non-swine farmers | 6.4% vs 15.8%, p < 0.06 | 16.7% vs 51.2%, p < 0.01 | + SPT to grass: 7.7% vs 25.6%, p < 0.02 | Not done | Not done | / |
Rennie et al. [154]/Canada 2015 | 1599 rural adults | 1068+ vs 531– | 766+ vs 833− | Not done | Not done | Women living on a farm in the 1st yr. of life: atopy (positive SPT) 0.6 (0.4–0.9) | Not done | Not done | / |