饮水型地方性砷中毒影响因素的流行病学研究

Epidemiological study on the effect of drinking water endemic arsenism

目的探讨饮水型地方性砷中毒的影响因素。方法选择甘肃省甘南藏族自治州夏河县萨索玛村为调查点。依据《地方性砷中毒诊断标准》（WS／T211-2001），对在村的全部人员进行了地方性砷中毒病情和流行病学问卷调查，内容包括性别、年龄、民族、居住年限、饮水量、饮茶情况、奶类摄入量、豆类摄入量、肉类摄入量、鱼类摄入量、蛋类摄入量、蔬菜类摄入量、水果类摄入量13项指标。根据地方性砷中毒临床诊断结果，将凋查对象分为非中毒（对照）组、轻度中毒组、中度中毒组、重度中毒组，进行相关影响因素的多因素Logistic回归分析：采集调查村集中饮用水水样，利用氢化物发生原子荧光法测定含砷量；采集调查对象尿样66份，按病情分为对照组和砷中毒组，用氢化物发生原子荧光法测定尿中3价无机砷（iAsⅢ）、一甲基砷酸（MMA）、二甲基砷化物（DMA）和5价无机砷（iAsⅤ）4种形态砷的量，以所测4种砷形态量之和为近似总砷（TAs）值，以iAsⅢ和iAsⅤ之和为总无机砷（iAs）。结果调查村水砷为0．97mg／L；共调查155人，检出地方性砷中毒病例90人，检出率为58．1％；砷中毒组与对照组比较，MMA（300．85、177．48μg／L）明显升高（X2=6．1823，P〈0．05），DMA（417．18、586．93μg／L）明显降低（xz=4．1726，P〈0．05）；多因素Logistic回归分析表明，居住年限和蛋氨酸摄入量与饮水型地方性砷中毒病情显著相关，居住年限长是饮水型地方性砷中毒病情的主要危险因素（OR=1．513，P〈0．05），蛋氨酸摄入量增加是饮水型地方性砷中毒病情的保护因素（OR=0．591，P〈0．05）。结论地方性砷中毒病情主要与高砷暴露年限有关，增加蛋氨酸的摄入量是可能的保护因素。

Objective To investigate the influence factors of patients of chronically endemic arsenism. Methods Samples were taken from Sasuoma village in Gansu province. According to Standard of Dagnosis for Endemic Arsenism （WS/T 211-2001 ）, questionnaire investigation on 13 indexes was conducted among all persons in village, such as general condition, time of residence, drinking amount, intake of different nutriment, etc. All subjects were divided into 4 groups： normal group, three patient groups of mild, moderate and severe conditions. Multiple Logistic regression analysis was performed. Using hydride generation atomic fluorescence spectrometry, arsenic content in water and the content of iAsⅢ, MMA, DMA, and iAsv was respectively determined in 66 urine samples, taking 4 kinds of arsenic contents as TAs, the sum of iAsⅢ and iAsv as total inorganic arsenic （iAs）. Results The arsenic concentration of drinking water in this village was 0.97 mg/L; 90 patients were detected among 155 investigation objects, and the detective rate of endemic arsenism was 58.1%. Compared with normal group, the content of MMA （300.85,177.48 μg/L） of patients was higher（x2 = 6.1823,P 〈 0.05）, the DMA（417.18,586.93 μg/L）of patients lowered significantly. The result of multiple regression analysis indicated the longer length of residencewas a risky factor of drinking water endemic arsenism（OR = 1.513, P〈 0.05）, on the contrary, the more intake of methionine（ OR = 0.591, P 〈 0.05） was a protecting factor. Conclusion The condition of endemic arsenism is mainly affected by the time of high arsenic exposure. The intake of methionine may be a protective factor for endemic arsenism.