The measurement of exhaled gas nitric oxide (FeNO) has safe, non-invasive, simple, repetitive characteristics which is widely used in the assessment of airway inflammation in asthmatic patients, but the determination of FeNO is affected by a variety of factors, among which living environment factors exposure may have a close relationship to FeNO level, whereas there are few studies on the impact of exposure of living environment factors on the level of FeNO.

To analyze the effect of exposure to living environment factors on the level of exhaled nitric oxide (FeNO) in patients with bronchial asthma in non acute attack period, so as to improve the efficacy of clinicians in using FeNO to manage asthma.

A total of 109 patients with bronchial asthma in non acute attack period who visited the Respiratory Department Outpatient of the Second Affiliated Hospital of Guangzhou Medical University from July 2018 to June 2020 were included as the study subjects, the data were collected through a questionnaire survey, and the questionnaire information mainly included general information (gender, age, height, body mass) , living environment factors (including smoking history, whether family members smoked at home, allergy history, location of residence, the distance between the residence and the main road with large traffic volume, whether there were factories around the residence, floors of residential buildings, length of residence building, frequency of washing and drying bed sheets, quilt covers/pillow cases, curtain materials at home, potted plants at home, whether the trash can in the home was cleaned regularly, whether kept pets at home, whether there were cockroaches at home and whether kitchen waste was disposed of the same day, whether there were plush toys at home) and the inspection data of FeNO collected. Patients with bronchial asthma were divided into 3 groups according to FeNO level: there were 47 cases in the FeNO low level group (FeNO<25 ppb) , 35 cases in the FeNO medium level group (25 ppb≤FeNO≤50 ppb) and 27 cases in the FeNO high level group (FeNO>50 ppb) . Ordinal multiple classification logistic regression analysis was used to explore the environmental factors affecting the FeNO value level measurement.

There was no significant difference in gender, age, height and body mass among the three groups (P>0.05) . There was no significant difference among the three groups in floors of residential buildings, length of residence, frequency of washing and drying bed sheets, quilt covers/pillow cases, curtain materials at home, potted plants at home, whether the trash can in the home was cleaned regularly, whether there were cockroaches at home and whether kitchen waste was disposed of the same day, whether there were plush toys at home (P>0.05) ; There were statistically significant differences in smoking history, whether family members smoked at home, allergy history, location of residence, the distance between the residence and the main road with large traffic volume, whether there were factories around the residence, and whether there were pets at home (P<0.05) . Those with a history of smoking were 0.332 (P=0.022) times more likely to have one grade higher FeNO levels compared to those without; Family member smoking at home was 0.345 (P=0.014) times more likely to have one grade higher FeNO level compared to those not smoking at home; Compared with those without pets at home, those who kept pets at home were 0.327 (P=0.014) times more likely to have one grade higher FeNO level; Those with a history of allergy were 4.076 (P=0.003) times more likely to have one grade higher FeNO levels compared to those without; Those whose place of residence was the center of the city were 3. 908 (P = 0.006) times more likely to have one grade higher FeNO level compared with those whose place of residence was suburban; The probability of having one grade higher FeNO level were 2.689 (P=0.018) times higher in those whose place of residence was near the main tract versus those whose place of residence was far from the main tract; Those with a factory around their place of residence were 2.740 (P=0.032) times more likely to have one grade higher FeNO level compared with those without a factory around their place of residence.

The determination of FeNO value level used in daily management of asthma is obviously affected by exposure factors of living environment, especially tobacco exposure, allergies, keeping pets and place of residence, and needs to be differentiated clinically for relevant patients.

呼出气一氧化氮（FeNO）的测量具有安全、无创、简便、重复性好等特点已经被广泛应用于哮喘患者气道炎症的评估，但FeNO的测定结果受到多种因素的影响，生活环境因素暴露可能与FeNO水平有较为密切的关系，而目前关于生活环境因素暴露对FeNO水平影响的研究较少。

分析生活环境因素暴露对支气管哮喘非急性发作期患者FeNO水平的影响，以提高临床医生利用FeNO管理哮喘的效能。

纳入2018年7月至2020年6月就诊于广州医科大学附属第二医院呼吸内科门诊的109例支气管哮喘非急性发作期患者作为研究对象，通过问卷调查的方法收集资料，问卷信息主要包括一般资料（性别、年龄、身高、体质量）、生活环境因素（包括吸烟史，家人在家是否吸烟，过敏史，居住地位置，居住地离车流量大的主干道位置，居住地周围有无工厂，居住房屋楼层，房屋居住年限，床单、被/枕套清洗晾晒的频率，家中窗帘材料，家中有无盆栽花草，家中垃圾桶有无定期清洗，家中有无饲养宠物，家中有无蟑螂，厨房垃圾有无当天处置，家中是否有毛绒玩具），并收集FeNO的检查资料。根据FeNO水平将支气管哮喘患者分成3组：FeNO低水平组（FeNO<25 ppb）47例，FeNO中水平组（25 ppb≤FeNO≤50 ppb）35例，FeNO高水平组（FeNO>50 ppb）27例，采用有序多因素Logistic回归分析方法探寻影响FeNO水平测定的生活环境因素。

3组患者性别、年龄、身高、体质量比较，差异无统计学意义（P>0.05）。3组患者居住房屋楼层、房屋居住年限、床单、被/枕套清洗晾晒的频率、家中窗帘材料、家中有无盆栽花草、家中垃圾桶有无定期清洗、家中有无蟑螂、厨房垃圾有无当天处置、家中是否有毛绒玩具比较，差异无统计学意义（P>0.05）；吸烟史、家人在家是否吸烟、过敏史、居住地位置、居住地离车流量大的主干道位置、居住地周围有无工厂、家中有无饲养宠物比较，差异有统计学意义（P<0.05）；有吸烟史者与无吸烟史者相比，FeNO水平高一个等级的可能性为0.332（P=0.022）倍；家人在家吸烟者与家人不在家吸烟者相比，FeNO水平高一个等级的可能性为0.345（P=0.014）倍；家中饲养宠物者与家中未饲养宠物者相比，FeNO水平高一个等级的可能性为0.327（P=0.014）倍；有过敏史与无过敏史者相比，FeNO水平高一个等级的可能性为4.076（P=0.003）倍；居住地为位置为城市中心者与居住地位置为郊区者相比，FeNO水平高一个等级的可能性为3.908（P=0.006）倍；居住地位置临近主干道者与居住地位置远离主干道者，FeNO水平高一个等级的可能性为2.689（P=0.018）倍；居住地周围有工厂者与居住地周围无工厂者相比，FeNO水平高一个等级的可能性为2.740（P=0.032）倍。

FeNO水平测定用于哮喘的日常管理明显受生活环境因素暴露的影响，尤其是烟草暴露情况、过敏情况、饲养宠物以及居住地位置影响较大，临床需对相关患者区别对待。