Department of Surgery, Dentistry, Paediatrics and Gynaecology, University of Verona, 37126 Verona, Italy.
Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, 90127 Palermo, Italy.
Int J Environ Res Public Health. 2021 Jan 17;18(2):747. doi: 10.3390/ijerph18020747.
Seasonal variations in UV-B radiation may influence vitamin D status, and this, in turn, may influence the risk of bronchiolitis hospitalization. The aim of this study was using a causal inference approach to investigate, simultaneously, the interrelationships between personal and environmental risk factors at birth/hospital admission (RFBH), serum vitamin D levels and bronchiolitis hospitalization. A total of 63 children (<2 years old) hospitalized for bronchiolitis (34 RSV-positive) and 63 controls were consecutively enrolled (2014-2016). Vitamin D levels and some RFBH (birth season, birth weight, gestational age, gender, age, weight, hospitalization season) were recorded. The discovered RFBH effects on the risk ok bronchiolitis hospitalization were decomposed into direct and vitamin-D mediated ones through Mediation Analysis. Winter-spring season (vs. summer-autumn) was significantly associated with lower vitamin D levels (mean difference -11.14 nmol/L). Increasing serum vitamin D levels were significantly associated with a lower risk of bronchiolitis hospitalization (OR = 0.84 for a 10-nmol/L increase). Winter-spring season and gestational age (one-week increase) were significantly and directly associated with bronchiolitis hospitalization (OR = 6.37 and OR = 0.78 respectively), while vitamin D-mediated effects were negligible (1.21 and 1.02 respectively). Using a comprehensive causal approach may enhance the understanding of the complex interrelationships among RFBH, vitamin D and bronchiolitis hospitalization.
UV-B 辐射的季节性变化可能会影响维生素 D 水平，进而影响细支气管炎住院的风险。本研究旨在采用因果推理方法，同时研究出生/住院时（RFBH）的个体和环境危险因素、血清维生素 D 水平和细支气管炎住院之间的相互关系。共有 63 名因细支气管炎住院的儿童（34 例 RSV 阳性）和 63 名对照（2014-2016 年）连续入选。记录了维生素 D 水平和一些 RFBH（出生季节、出生体重、胎龄、性别、年龄、体重、住院季节）。通过中介分析，将发现的 RFBH 对细支气管炎住院风险的影响分解为直接影响和维生素 D 介导的影响。冬春季（与夏秋季相比）与较低的维生素 D 水平显著相关（平均差异为-11.14 nmol/L）。血清维生素 D 水平升高与细支气管炎住院风险降低显著相关（每增加 10 nmol/L，OR=0.84）。冬春季和胎龄（每周增加一周）与细支气管炎住院显著且直接相关（OR=6.37 和 OR=0.78），而维生素 D 介导的影响可忽略不计（OR=1.21 和 OR=1.02）。使用综合因果方法可以增强对 RFBH、维生素 D 和细支气管炎住院之间复杂相互关系的理解。
