高中生PPD反应程度与结核病发病危险的队列研究

Relationship between PPD reaction extent and tuberculosis risk among senior high school students

目的探讨高中生PPD反应程度与结核病发病危险的关系,为选择合适的预防性治疗对象提供科学依据。方法对两所高中的1664名学生进行随访。研究开始时采用PPD做皮内试验,开始和结束时作X线胸部透视,对有异常阴影者摄X线胸片。PPD试验阴性反应为对照组,阳性反应(≥5mm)为暴露组。按阳性反应强度的不同分为5～、10～、15～、≥20mm、水泡5个亚组,分别有274、339、108、33、55例。采用Mantel-Haenszel卡方检验(卡方MH)和Cox回归模型,分析暴露组与对照组人年发病率的差异,以P<0.05为差异有统计学意义。结果Cox回归多因素分析显示,PPD阳性反应15～mm、≥20mm、水泡组的人年发病率分别是10.14%(14/138)、21.21%(7/33)、52.00%(26/50),为结核病发病的危险因素(Waldχ2值分别为53.366、54.851、124.829,P值均为0.000),RR值分别为35.55、63.43、161.84。结论高中生PPD反应≥15mm或有水泡者为结核病的高发人群,应作为结核病预防性治疗对象。

Objective To explore the relationship between the extent of PPD reaction and risk of tuberculosis（TB） among senior high school students,and to provide scientific evidence for prophylactic treatment object selection.Methods 1664 students from 2 senior high schools were the target of prospective cohort study.At the beginning of cohort study,the intracutaneous test of PPD and chest fluoroscopy were applied.Chest X-ray was conducted for those with abnormal chest fluoroscopy.People with PPD negative reaction were control group and with PPD positive reaction（diameter of induration in PPD skin test≥5mm） were exposure group.The exposure group were divided into 5 subgroups according to the extent of PPD positive reaction（5-,10-,15-,≥20mm and with blister）.The Mantel-Haenszel chi-square statistics and Cox regression were applied to analyze the difference of incidence rates between exposure group and control group.Results Coxregression model multivariate analysis showed the incidence rates of three subgroups（15-,≥20mm and with blister） were 10.14%（14/138）,21.21%（7/33） and 52.00%（26/50）,so the diameter of induration ≥15mm and 20mm,≥20mm and with blaster were risk factors of tuberculosis（Wald χ2=53.366,54.851,124.829,P values were 0.000）,RR（relative risk） values were 35.55,63.43 and 161.84,respectively.Conclusion The senior high school students of whom diameter of induration in PPD skin test ≥15mm and with blister were high risk population of tuberculosis and should be the target of prophylactic treatment.