Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
JAMA Pediatr. 2015 Nov;169(11):e153219. doi: 10.1001/jamapediatrics.2015.3219. Epub 2015 Nov 2.
The association between early exposure to animals and childhood asthma is not clear, and previous studies have yielded contradictory results.
To determine whether exposure to dogs and farm animals confers a risk of asthma.
DESIGN, SETTING AND PARTICIPANTS: In a nationwide cohort study, the association between early exposure to dogs and farm animals and the risk of asthma was evaluated and included all children born in Sweden from January 1, 2001, to December 31, 2010 (N = 1,011,051), using registry data on dog and farm registration, asthma medication, diagnosis, and confounders for parents and their children. The association was assessed as the odds ratio (OR) for a current diagnosis of asthma at age 6 years for school-aged children and as the hazard ratio (HR) for incident asthma at ages 1 to 5 years for preschool-aged children. Data were analyzed from January 1, 2007, to September 30, 2012.
Living with a dog or farm animal.
Childhood asthma diagnosis and medication used.
Of the 1,011,051 children born during the study period, 376,638 preschool-aged (53,460 [14.2%] exposed to dogs and 1729 [0.5%] exposed to farm animals) and 276,298 school-aged children (22,629 [8.2%] exposed to dogs and 958 [0.3%] exposed to farm animals) were included in the analyses. Of these, 18,799 children (5.0%) in the preschool-aged children's cohort experienced an asthmatic event before baseline, and 28,511 cases of asthma and 906,071 years at risk were recorded during follow-up (incidence rate, 3.1 cases per 1000 years at risk). In the school-aged children's cohort, 11,585 children (4.2%) experienced an asthmatic event during the seventh year of life. Dog exposure during the first year of life was associated with a decreased risk of asthma in school-aged children (OR, 0.87; 95% CI, 0.81-0.93) and in preschool-aged children 3 years or older (HR, 0.90; 95% CI, 0.83-0.99) but not in children younger than 3 years (HR, 1.03; 95% CI, 1.00-1.07). Results were comparable when analyzing only first-born children. Farm animal exposure was associated with a reduced risk of asthma in both school-aged children and preschool-aged children (OR, 0.48; 95% CI, 0.31-0.76, and HR, 0.69; 95% CI, 0.56-0.84), respectively.
In this study, the data support the hypothesis that exposure to dogs and farm animals during the first year of life reduces the risk of asthma in children at age 6 years. This information might be helpful in decision making for families and physicians on the appropriateness and timing of early animal exposure.
早期接触动物与儿童哮喘之间的关联尚不清楚，并且先前的研究结果存在矛盾。
确定接触狗和农场动物是否会增加哮喘风险。
设计、设置和参与者：在一项全国性队列研究中，评估了儿童早期接触狗和农场动物与哮喘风险之间的关联，该研究纳入了 2001 年 1 月 1 日至 2010 年 12 月 31 日期间在瑞典出生的所有儿童（n=1011051），使用有关狗和农场登记、哮喘药物、诊断以及父母及其子女混杂因素的登记数据。通过评估 6 岁时的当前哮喘诊断（对于学龄儿童）以及 1 至 5 岁时的新发哮喘（对于学龄前儿童）的比值比（OR）来评估相关性。数据于 2007 年 1 月 1 日至 2012 年 9 月 30 日进行分析。
与狗或农场动物一起生活。
儿童哮喘诊断和使用的药物。
在研究期间出生的 1011051 名儿童中，有 376638 名学龄前儿童（53460 名[14.2%]接触狗，1729 名[0.5%]接触农场动物）和 276298 名学龄儿童（22629 名[8.2%]接触狗，958 名[0.3%]接触农场动物）被纳入分析。其中，学龄前儿童队列中有 18799 名儿童（5.0%）在基线前发生哮喘事件，在随访期间记录了 28511 例哮喘和 906071 年的发病风险（发病率为每 1000 年发病风险 3.1 例）。在学龄儿童队列中，有 11585 名儿童（4.2%）在生命的第七年发生哮喘事件。生命第一年接触狗与学龄儿童（OR，0.87；95%CI，0.81-0.93）和 3 岁或以上的学龄前儿童（HR，0.90；95%CI，0.83-0.99）的哮喘风险降低相关，但与小于 3 岁的儿童（HR，1.03；95%CI，1.00-1.07）无关。仅分析第一胎儿童时，结果具有可比性。农场动物暴露与学龄儿童和学龄前儿童哮喘风险降低相关（OR，0.48；95%CI，0.31-0.76，HR，0.69；95%CI，0.56-0.84）。
本研究支持以下假设，即儿童生命第一年接触狗和农场动物可降低其在 6 岁时患哮喘的风险。这些信息可能有助于家庭和医生在适当性和早期动物接触的时机方面做出决策。
