Johansen Christoffer, Schüz Joachim, Andreasen Anne-Marie Serena, Dalton Susanne Oksbjerg
Oncology Clinic, Finsen Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark.
Unit of Survivorship, Danish Cancer Society Research Center, Strandboulevarden 49, 2100 Copenhagen, Denmark.
Br J Cancer. 2017 Mar 28;116(7):841-848. doi: 10.1038/bjc.2017.46. Epub 2017 Mar 7.
Glioma is a rare brain tumour with a very poor prognosis and the search for modifiable factors is intense. We reviewed the literature concerning risk factors for glioma obtained in case-control designed epidemiological studies in order to discuss the influence of this methodology on the observed results. When reviewing the association between three exposures, medical radiation, exogenous hormone use and allergy, we critically appraised the evidence from both case-control and cohort studies. For medical radiation and hormone replacement therapy (HRT), questionnaire-based case-control studies appeared to show an inverse association, whereas nested case-control and cohort studies showed no association. For allergies, the inverse association was observed irrespective of study design. We recommend that the questionnaire-based case-control design be placed lower in the hierarchy of studies for establishing cause-and-effect for diseases such as glioma. We suggest that a state-of-the-art case-control study should, as a minimum, be accompanied by extensive validation of the exposure assessment methods and the representativeness of the study sample with regard to the exposures of interest. Otherwise, such studies cannot be regarded as 'hypothesis testing' but only 'hypothesis generating'. We consider that this holds true for all questionnaire-based case-control studies on cancer and other chronic diseases, although perhaps not to the same extent for each exposure-outcome combination.
胶质瘤是一种预后极差的罕见脑肿瘤，人们一直在积极寻找可改变的因素。我们回顾了在病例对照设计的流行病学研究中获得的有关胶质瘤危险因素的文献，以讨论这种方法对观察结果的影响。在回顾医疗辐射、外源性激素使用和过敏这三种暴露因素之间的关联时，我们严格评估了病例对照研究和队列研究的证据。对于医疗辐射和激素替代疗法（HRT），基于问卷的病例对照研究似乎显示出负相关，而巢式病例对照研究和队列研究则未显示出相关性。对于过敏，无论研究设计如何，均观察到负相关。我们建议，在确定胶质瘤等疾病的因果关系的研究层次结构中，基于问卷的病例对照设计应处于较低位置。我们建议，一项先进的病例对照研究至少应同时对暴露评估方法进行广泛验证，并确保研究样本在感兴趣的暴露方面具有代表性。否则，此类研究不能被视为“假设检验”，而只能被视为“假设生成”。我们认为，这适用于所有关于癌症和其他慢性病的基于问卷的病例对照研究，尽管每种暴露-结果组合的适用程度可能不尽相同。
