A Historical cohort study of cancer mortality and offspring sex ratio among municipal solid waste incinerator workers

城市固体垃圾焚烧厂工人癌症死亡率和后代性别比的历史队列研究

• 批准号: 14207018
• 负责人: MORI Ippei
• 金额: $ 18.97万
• 依托单位: National Institute of Occupational Safety and Health, Japan
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14207018/
• 关键词: municipal solid waste incinerator; dioxins; risk of cancer; reproductive toxicity; sex ratio; cohort study; 男女比

1. Construction of the cohortWith the collaboration of the trade union, we asked municipal solid waste workers to join the cohort study. Finally, 2,866 workers having a work history at municipal solid waste incinerators (exposed group) and 6,239 waste collection workers (reference group) answered to the baseline survey questionnaire. To make rapid evaluation of cancer mortality, we tried to construct a retired workers cohort but it was not possible mainly due to strong social concern on privacy protection.2. Assessment of exposure to dioxins among incinerator workersIt is not feasible to measure blood dioxin levels for all cohort members. Therefore, we generated several surrogate exposure indices from baseline data such as duration / frequency of exposure to fly ash obtained by self-administrated questionnaire. Those indices were validated by comparing with blood dioxin levels in the subgroup of 58 waste incinerator workers. A correlation was observed between duration of exposure (sum of the period of work exposed to fly ash) and HpDF (one of the PCDD/F congeners) concentration.3. Evaluation of cancer mortalitySince the cohort consists of active workers only, the population is too yang to evaluate risks of cancer mortality. We need further follow-up for more than 10 years to reach conclusions.4. Effects on offspring sex ratioWe examined offspring sex ratio as an index of effect on reproductive system. Analysis using surrogate exposure indices showed association between longer period of exposure and lower sex ratio (fewer male offspring), though it was not statistically significant. The association did not change after adjusting maternal parity, paternal age at birth and the year of birth. However, the sex ratio was higher in the shortest exposure group than in the control group. The evidence is not strong enough to discuss relationship between fly ash exposure and offspring sex ratio. Further research is necessary.

1.队列建设在工会的配合下，我们邀请城市固废工人加入队列研究。最后，2,866 名有城市固体垃圾焚烧厂工作经历的工人（暴露组）和 6,239 名垃圾收集工人（参照组）回答了基线调查问卷。为了快速评估癌症死亡率，我们试图构建一个退休工人队列，但未能成功，主要是由于社会对隐私保护的强烈关注。2．焚烧厂工人二恶英暴露评估 测量所有队列成员的血液二恶英水平是不可行的。因此，我们根据基线数据生成了几个替代暴露指数，例如通过自填问卷获得的暴露于飞灰的持续时间/频率。这些指数通过与 58 名垃圾焚烧厂工人的血液二恶英水平进行比较得到验证。观察到暴露时间（暴露于飞灰的工作时间之和）与 HpDF（PCDD/F 同系物之一）浓度之间存在相关性。3．癌症死亡率的评估由于该队列仅由活跃工人组成，因此人群过于阳刚，无法评估癌症死亡率的风险。需要进一步跟踪10多年才能得出结论。4．对后代性别比的影响我们检查了后代性别比作为对生殖系统影响的指标。使用替代暴露指数的分析表明，较长的暴露时间与较低的性别比（较少的男性后代）之间存在关联，尽管这种关联并不具有统计学意义。调整母亲胎次、父亲出生年龄和出生年份后，这种关联没有改变。然而，最短暴露组的性别比高于对照组。证据不足以讨论飞灰暴露与后代性别比之间的关系。进一步的研究是必要的。