We address here the importance of epidemiological evidence in risk assessment and decision-making in Europe. To illustrate this, titanium dioxide (TiO2) was used as a model compound. TiO2 is widely used as an odorless white pigment and opacifying agent. A recent systematic review assessing the weight of evidence on the relationship between exposure to TiO2 (all forms) and cancer in humans questions the assumptions that TiO2 is an inert material of low toxicity. Based on this new data, France submitted a proposal to classify TiO2 as a possible human carcinogen under the European regulation. The European Chemicals Agency Risk assessment committee concluded that TiO2 (all forms) warrants a classification as a suspected human carcinogen via inhalation (Category-2) under the CLP regulation (for Classification, Labeling and Packaging of chemicals). No considerations was given to TiO2 particle size, which may affect human health effects. Consequently, further epidemiological studies are needed to assess possible associations between different physical-chemical characteristics of TiO2 exposures and their impact on human health. This would allow strengthening the evidence on which to build the most appropriate regulation and to guaranty safe use given any exposure route of any TiO2 particle shape or size.

中文翻译：

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二氧化钛风险评估的流行病学证据权重：现状和进一步需求。

我们在这里讨论流行病学证据在欧洲风险评估和决策中的重要性。为了说明这一点，二氧化钛 (TiO2) 被用作模型化合物。二氧化钛被广泛用作无味的白色颜料和遮光剂。最近的一项系统评价评估了暴露于 TiO2（所有形式）与人类癌症之间关系的证据权重，质疑 TiO2 是一种低毒性惰性材料的假设。基于这一新数据，法国提交了一份提案，将二氧化钛根据欧洲法规列为可能的人类致癌物。欧洲化学品管理局风险评估委员会得出结论，根据 CLP 法规（化学品的分类、标签和包装），二氧化钛（所有形式）应被归类为通过吸入的可疑人类致癌物（类别 2）。未考虑可能影响人体健康的 TiO2 粒径。因此，需要进一步的流行病学研究来评估 TiO2 暴露的不同物理化学特性之间可能存在的关联及其对人类健康的影响。鉴于任何 TiO2 颗粒形状或尺寸的任何暴露途径，这将允许加强建立最适当法规和保证安全使用的证据。