Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan; Scientific Research Works Peer Support Group (SRWS-PSG), Osaka, Japan; Division of Epidemiology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, USA.
Scientific Research Works Peer Support Group (SRWS-PSG), Osaka, Japan; Department of Internal Medicine, Kyoto Min-iren Asukai Hospital, Kyoto, Japan; Section of Clinical Epidemiology, Department of Community Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan; Department of Healthcare Epidemiology, Kyoto University Graduate School of Medicine / School of Public Health, Kyoto, Japan.
Environ Pollut. 2024 Dec 15;363(Pt 1):125039. doi: 10.1016/j.envpol.2024.125039. Epub 2024 Oct 3.
The association between environmental greenness and childhood asthma remains unclear. Pollen has been proposed as a potential mechanism of detrimental associations. This study aimed to elucidate the mechanisms underlying the association between environmental greenness during the pre-, peri-, and postnatal periods and childhood persistent asthma. A nationwide retrospective birth cohort study was conducted using data from the Japan Medical Data Center (JMDC). Child-mother dyads between January 2010 and January 2017 were identified, and four subcohorts were developed based on the timing of exposure to the highest greenness season. The exposure of interest was environmental greenness levels between June and September, quantified using the normalized difference vegetation index (NDVI). The primary outcome was persistent asthma in children aged 4-5 years. Causal mediation analysis was conducted to evaluate pollen as a mediator between NDVI and asthma. In these analyses, linear and modified Poisson regression models were used to evaluate the association of NDVI with pollen levels and childhood persistent asthma. The analyses were stratified by metropolitan and non-metropolitan areas. Clinically meaningful confounders and predictors of asthma were adjusted in the statistical models. A total of 100,273 child-mother dyads were included in the entire cohort, with 24.1% of the children having persistent asthma at the ages of 4-5 years. Higher environmental greenness was associated with higher pollen levels. The modified Poisson regression models showed higher environmental greenness was associated with a slightly higher risk of persistent childhood asthma. In metropolitan areas, significant detrimental natural direct effects of NDVI were observed; however, the natural indirect effects were uncertain. A large part of the association between environmental greenness and childhood persistent asthma in metropolitan areas was attributed to mechanisms other than those involving pollen. The associations in non-metropolitan areas remain uncertain. Further studies are required to elucidate the underlying mechanisms.
环境绿化与儿童哮喘之间的关系尚不清楚。花粉已被提出作为有害关联的潜在机制。本研究旨在阐明环境绿化与儿童持续性哮喘之间关联的潜在机制。使用日本医疗数据中心（JMDC）的数据，进行了一项全国性回顾性出生队列研究。确定了 2010 年 1 月至 2017 年 1 月期间的母子对子，并根据暴露于最高绿化季节的时间开发了四个亚组。感兴趣的暴露是 6 月至 9 月之间的环境绿化水平，使用归一化差异植被指数（NDVI）进行量化。主要结局是 4-5 岁儿童持续性哮喘。进行因果中介分析以评估花粉作为 NDVI 和哮喘之间的中介。在这些分析中，使用线性和修正泊松回归模型来评估 NDVI 与花粉水平和儿童持续性哮喘之间的关联。分析按大都市和非大都市地区进行分层。在统计模型中调整了哮喘的临床有意义的混杂因素和预测因素。共有 100273 对母子对子纳入整个队列，其中 24.1%的儿童在 4-5 岁时患有持续性哮喘。较高的环境绿化与较高的花粉水平有关。修正泊松回归模型显示，较高的环境绿化与持续性儿童哮喘的风险略高有关。在大都市地区，观察到 NDVI 的不利自然直接效应具有统计学意义；然而，自然间接效应尚不确定。大都市地区环境绿化与儿童持续性哮喘之间的关联很大程度上归因于除花粉以外的机制。非大都市地区的关联仍不确定。需要进一步研究阐明潜在机制。
