Raaschou-Nielsen Ole, Hertel Ole, Thomsen Birthe L, Olsen Jørgen H
Institut for Epidemiologisk Kraeftforskning, Kraeftens Bekaempelse, DK-2100 København.
Ugeskr Laeger. 2002 Apr 22;164(17):2283-7.
The hypothesis that exposure to traffic-related air pollution increases the risk of cancer developing during childhood was investigated.
We enrolled 1,989 children notified to the Danish Cancer Registry with a diagnosis of leukaemia, tumour of the central nervous system (CNS), or malignant lymphoma during 1968-1991, and 5,506 control children selected at random from the entire childhood population. The residential histories of the children were traced from nine months before birth up to the time of diagnosis, as was a similar period for the controls. Information on traffic and the configuration of streets and buildings was collected for each of the 18,440 identified addresses. Concentrations of benzene and nitrogen dioxide (indicators of traffic-related air pollution) were calculated for the relevant residential periods, and combined into exposures to air pollution during pregnancy and childhood, respectively.
The risks of leukaemia, CNS tumours, and all selected cancers combined were not related to exposure to benzene or nitrogen dioxide during either period. The risk of lymphomas increased by 25% (p for trend = 0.06) and 51% (p for trend = 0.05) for a doubling of the concentration of benzene and nitrogen dioxide, respectively, during the pregnancy. The association was restricted to Hodgkin's disease.
On the basis of a low potential for selection bias, information bias, and confounding factors, we conclude that traffic-related air pollution at the residence of children is not linked to the risk of leukaemia or CNS tumour, which are the two major types of childhood cancer. The results indicated a possible association between air pollution and the risk of Hodgkin's disease, but the evidence allows of no firm conclusion at present.
对暴露于交通相关空气污染会增加儿童患癌风险这一假说进行了调查。
我们纳入了1968年至1991年间被丹麦癌症登记处通知诊断为白血病、中枢神经系统（CNS）肿瘤或恶性淋巴瘤的1989名儿童，以及从整个儿童群体中随机选取的5506名对照儿童。追溯了这些儿童从出生前九个月到诊断时的居住史，对照儿童也追溯了类似的时间段。为18440个已确定地址中的每一个收集了交通以及街道和建筑物布局的信息。计算了相关居住期间苯和二氧化氮（交通相关空气污染指标）的浓度，并分别合并为孕期和儿童期的空气污染暴露量。
白血病、CNS肿瘤以及所有选定癌症综合起来的风险与两个时期内苯或二氧化氮的暴露均无关。孕期苯浓度翻倍时，淋巴瘤风险增加25%（趋势p值 = 0.06），二氧化氮浓度翻倍时，淋巴瘤风险增加51%（趋势p值 = 0.05）。该关联仅限于霍奇金病。
基于选择偏倚、信息偏倚和混杂因素的可能性较低，我们得出结论，儿童居住地的交通相关空气污染与白血病或CNS肿瘤（儿童癌症的两种主要类型）的风险无关。结果表明空气污染与霍奇金病风险之间可能存在关联，但目前证据尚不能得出确凿结论。
