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

1.在工会的配合下，我们邀请城市固体废物工人参加队列研究。最后，2，866名在城市固体废物焚烧厂工作过的工人（接触组）和6，239名废物收集工人（参照组）回答了基线调查问卷。为了快速评估癌症死亡率，我们尝试建立一个退休工人队列，但由于社会对隐私保护的强烈关注，这是不可能的.评估焚化炉工人的二恶英暴露量测量所有队列成员的血液二恶英水平是不可行的。因此，我们从基线数据中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。通过与58名垃圾焚烧厂工人的血液二恶英水平进行比较，这些指标得到了验证。暴露持续时间（暴露于飞灰的工作时间总和）与HpDF（PCDD/F同系物之一）浓度之间存在相关性。癌症死亡率的评估由于队列仅由活跃的工人组成，人口太阳，无法评估癌症死亡率的风险。我们需要进一步随访10年以上才能得出结论。对子代性比的影响我们研究了子代性比对生殖系统的影响。使用替代接触指数进行的分析表明，接触时间较长与性别比例较低（雄性后代较少）之间存在关联，但在统计学上并不显著。在调整了母亲的产次、父亲的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。证据不足以讨论粉煤灰暴露与后代性别比的关系。需要进一步研究。

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.