Abstract: Objective To discuss the risk factors for recurrent respiratory tract infection (RRTI) in preschool children,and to analyze its correlation with vitamin D (VitD) level,in order to provide reference for preventing RRTI in preschool children. Methods Totally 98 cases children aged 2 to 6 years with RRTI in Shaoxing Central Hospital from August 2015 to August 2017 were selected as the observation group,and 101 healthy children admitted in the same period were selected as control group.Data on maternal pregnancy,preterm birth,birth weight,breastfeeding time,outdoor activities,second-hand smoking and the history of allergic diseases were collected by questionnaire survey.The serum levels of vitamin D,IgA,IgG,IgM,CD4+,CD8+,CD4+/CD8+and other humoral immune indexes in observation group and control group were determined.For children with VitD deficiency (<20 ng/ml),these indexes were tested again in three months after VitD supplementation.Besides,children with VitD deficiency were followed up to 12 months,and the times for respiratory tract infections in children were counted. Results Preterm birth,low birth weight,breastfeeding time,living environment,outdoor activities,VitD,IgA,CD4+,CD4+/CD8+ levels were the risk factors of RRTI.The serum levels of IgA,CD4+,CD4+/CD8+ were higher in children after 3 months of VitD supplementation,and the times for infection in one year was significantly lower than that before VitD supplementation (P<0.05).There were positive correlations among vitamin D level and IgA,CD4+,CD4+/CD8+ before and after treatment (r=0.56,0.73,0.68,P<0.05).There was a negative correlation between VitD level and the times for respiratory tract infection (r=-0.64,P<0.05). Conclusions Preterm birth,low weight,breastfeeding time,living environment and outdoor activities are risk factors for RRTI in children.VitD level and immunological indexes are abnormal in children with RRTI.Increasing VitD level can improve the immunity of children with RRTI and reduce the recurrence of respiratory tract infection.

Key words: recurrent respiratory tract infection, risk factors, children, immunization

摘要： 目的 分析学龄前儿童反复呼吸道感染(RRTI)的危险因素及与维生素D(VitD)水平的相关性,为预防儿童RRTI提供依据。方法 选取2015年8月-2017年8月在绍兴市中心医院就诊的2~6岁患儿98例为观察组,选取同期收治的 101例健康儿童为对照组。完成结构问卷调查,收集母孕期情况、早产、出生体重、母乳喂养时间、户外活动时间、二手烟和过敏性疾病的病史资料。测定观察组非活动感染期及对照组VitD水平、IgA、IgG、 IgM、CD4+、CD8+、CD4+/CD8+水平,对VitD缺乏(＜20 ng/ml)患儿,给予VitD补充3个月后再次测定上述指标,并随访12个月,记录患儿呼吸道感染次数。结果 早产、出生低体重、母乳喂养时间、居住环境、户外活动、VitD水平、IgA水平、CD4+、CD4+/CD8+均为RRTI的危险因素,予补充Vit D 3个月后患儿IgA水平较前升高,统计1年的感染次数较前明显减少,差异有统计学意义(P＜0.05)。观察组治疗前后Vit D水平与IgA、CD4+、CD4+/CD8+呈正相关(r=0.56、0.73、0.68,P<0.05)与呼吸道感染复发次数呈负相关(r=-0.64,P<0.05)。结论 早产、低体重、母乳喂养时间、居住环境、户外活动均为RRTI患儿危险因素,RRTI患儿存在VitD水平及免疫学异常,提高VitD水平可改善RRTI患儿免疫,减少呼吸道感染复发次数。

关键词: 反复呼吸道感染, 危险因素, 儿童, 免疫