Kilpeläinen M, Terho E O, Helenius H, Koskenvuo M
Departments of Pulmonary Diseases and Clinical Allergology, University of Turku, Finland.
Clin Exp Allergy. 2000 Feb;30(2):201-8. doi: 10.1046/j.1365-2222.2000.00800.x.
A protective effect of infections in early life might explain the firmly reported finding of an inverse association between atopic disorders and large sibships.
To study the effect of childhood farm, rural non-farm and urban environment, as well as family size and other factors on the occurrence of asthma, wheezing and atopic disorders up to young adulthood.
Data on lifetime prevalence of physician-diagnosed asthma, allergic rhinitis and/or allergic conjunctivitis, atopic dermatitis, as well as self-reported episodic wheezing from 10 667 Finnish first-year university students aged 18-24 years were collected by a postal questionnaire. Associations of lifetime prevalence of the diseases with living on a farm, in a rural non-farm and urban environment during childhood were estimated by logistic regression analysis. Adjustment was made for potential confounding by gender, parental atopy, parental education, number of older siblings, day care outside the home and passive smoking.
The childhood farm environment independently reduced the risk for physician-diagnosed allergic rhinitis and/or allergic conjunctivitis (adjusted odds ratio 0.63, 95% CI 0.50-0.79, P < 0.001), and for diagnosed asthma and episodic wheezing analysed together (OR 0.71, 95% CI 0.54-0.93, P < 0.05), but not for atopic dermatitis during lifetime. Urban childhood environment did not show independent increased risk when compared with rural non-farm residence. The inverse association of sibship size with the occurrence of allergic rhinitis and/or allergic conjunctivitis was found among subjects with one (OR 0.86, 95% CI 0.77-0.96, P < 0.01) or at least four older siblings (OR 0.47, 95% CI 0.26-0.84, P < 0.05).
Childhood farm environment seems to have a protective effect against allergic rhinitis and/or conjunctivitis, and more weakly against asthma and wheezing irrespective of family size. Environmental exposure to immune modulating agents, such as environmental mycobacteria and actinomycetes, favouring manifestation of a nonatopic phenotype could explain the finding.
早年感染的保护作用可能解释了已确凿报道的特应性疾病与大家庭之间的负相关关系。
研究儿童时期的农场、农村非农业和城市环境，以及家庭规模和其他因素对青年期前哮喘、喘息和特应性疾病发生的影响。
通过邮政问卷收集了10667名年龄在18 - 24岁的芬兰一年级大学生中医生诊断的哮喘、过敏性鼻炎和/或过敏性结膜炎、特应性皮炎的终生患病率数据，以及自我报告的发作性喘息数据。通过逻辑回归分析估计这些疾病的终生患病率与童年时期在农场、农村非农业和城市环境中生活之间的关联。对性别、父母特应性、父母教育程度、哥哥姐姐数量、家庭外日托和被动吸烟等潜在混杂因素进行了调整。
童年时期的农场环境独立降低了医生诊断的过敏性鼻炎和/或过敏性结膜炎的风险（调整后的优势比为0.63，95%可信区间为0.50 - 0.79，P < 0.001），以及综合分析的诊断哮喘和发作性喘息的风险（优势比为0.71，95%可信区间为0.54 - 0.93，P < 0.05），但对终生特应性皮炎无影响。与农村非农业居住相比，城市童年环境未显示出独立增加的风险。在有一个哥哥姐姐（优势比为0.86，95%可信区间为0.77 - 0.96，P < 0.01）或至少四个哥哥姐姐（优势比为0.47，95%可信区间为0.26 - 0.84，P < 0.05）的受试者中发现家庭规模与过敏性鼻炎和/或过敏性结膜炎的发生呈负相关。
童年农场环境似乎对过敏性鼻炎和/或结膜炎有保护作用，对哮喘和喘息的保护作用较弱，且与家庭规模无关。环境暴露于免疫调节剂，如环境分枝杆菌和放线菌，有利于非特应性表型的表现，这可能解释了这一发现。
