Population, Policy and Practice, UCL Great Ormond Street Institute of Child Health, London, UK.
Research Department of Epidemiology and Public Health, University College London, London, UK.
J Epidemiol Community Health. 2018 May;72(5):390-396. doi: 10.1136/jech-2017-209722. Epub 2018 Jan 24.
Despite its high prevalence, early onset and chronic nature, the causes of asthma are not clearly established. The present study examined a plausible but untested relationship in the development of non-allergic asthma; an asthma phenotype closely linked to deprivation and other preventable risk factors. Our aim was to determine the mediating role of adiposity in the relationship between socioeconomic position in infancy and non-allergic asthma emergence in mid-childhood.
To estimate the causal indirect effect of adiposity we applied the parametric g-computational procedure to 6203 singleton children from the UK Millennium Cohort Study. Adiposity was measured at age 7 by body mass index, waist circumference and waist circumference-to-height ratio. Children who developed non-allergic asthma between the age of 7 and 14 were compared with children without allergies or allergic asthma at these ages.
We found no evidence to suggest that adiposity is a mediator in the relationship between socioeconomic position and the development of non-allergic asthma in mid-childhood. After adjustment for risk factors, the direct effect of socioeconomic position remained; children in the lowest tertile of socioeconomic position had a 43% (OR 1.43, 95% CI 1.38 to 1.49) greater odds of developing non-allergic asthma compared with the highest tertile.
Adiposity at age 7 does not mediate the relationship between socioeconomic position and non-allergic asthma. The results suggest that improving socioeconomic conditions and promoting healthy weight are both important in reducing the development of non-allergic asthma in early to mid-childhood.
尽管哮喘的发病率高、发病早且呈慢性特征，但哮喘的病因仍不明确。本研究探讨了一种在非过敏性哮喘发展中可能存在但尚未得到验证的关系；非过敏性哮喘与贫困和其他可预防的危险因素密切相关。我们的目的是确定肥胖在婴儿期社会经济地位与儿童中期非过敏性哮喘发病之间的关系中的中介作用。
为了估计肥胖的因果间接效应，我们应用参数 g 计算程序对来自英国千禧年队列研究的 6203 名单胎儿童进行了分析。肥胖程度在 7 岁时通过体重指数、腰围和腰围身高比进行测量。在 7 至 14 岁期间发展为非过敏性哮喘的儿童与这些年龄时无过敏或过敏性哮喘的儿童进行了比较。
我们没有发现证据表明肥胖是社会经济地位与儿童中期非过敏性哮喘发展之间关系的中介。在调整了危险因素后，社会经济地位的直接效应仍然存在；社会经济地位最低三分位的儿童比最高三分位的儿童发生非过敏性哮喘的几率高 43%（OR 1.43，95%CI 1.38 至 1.49）。
7 岁时的肥胖程度并不能介导社会经济地位与非过敏性哮喘之间的关系。结果表明，改善社会经济条件和促进健康体重都有助于减少儿童早期至中期非过敏性哮喘的发生。
