輪班工作與攝護腺癌風險：系統性回顧與統合分析

Abstract

背景 雖然目前許多觀察性研究文獻顯示輪班工作與攝護腺癌風險相關，但不同研究結論仍不一致。本研究旨在針對過往無論有無針對輪班工作進行直接暴露評估之相關流行病學研究結果，進行系統性回顧及統合分析（meta-analysis），以釐清暴露輪班工作與攝護腺癌發生之相關性。 方法 於三個電子文獻資料庫搜尋並回顧2016年7月前發表之相關研究文獻及其參考資料。篩選研究結果以風險估計值（含95%信賴區間）呈現輪班工作及攝護腺癌相關性之文獻，並以隨機效應模式（random-effects model）計算統合風險估計值。 結果 統合分析總共納入26篇研究文獻，2785457名樣本，其中包含15655名攝護腺癌個案。針對輪班工作有直接進行暴露評估之研究，其攝護腺癌風險顯著上升（勝算比1.22，95%信賴區間1.08-1.36），以職業別間接進行輪班工作暴露評估之研究，攝護腺癌風險也顯著上升（勝算比1.17，95%信賴區間1.10-1.24），但皆存在顯著異質性。此相關性在多數次群組及敏感性分析下仍顯著存在。累積輪班工作暴露年數與攝護腺癌風險在非線性趨勢預測下未存在顯著劑量反應關係。在美國及歐洲總計可歸因於暴露輪班工作所造成之攝護腺癌死亡人數推估每年約達4906人。 結論 統合分析顯示輪班工作與攝護腺癌風險可能相關。未來流行病學研究宜針對輪班工作進行更細緻之暴露評估，以確認本研究結果並釐清可能之病生理機轉。

Background Increasing numbers of observational studies suggest that shift work is associated with prostate cancer. However, the results remain controversial. We performed meta-analyses both of studies directly assessing shift work and those assessing shift work-related occupations, to clarify the suggested associations. Methods Relevant studies were identified by searching three databases to July 2016; the reference lists of the retrieved articles were also reviewed. We included observational studies that reported risk estimates with 95% confidence intervals (CIs) for the associations between shift work and the risk of prostate cancer. Random-effects models were used to calculate pooled risk estimates. Results A total of 26 studies with 2,785,457 participants involving 15,655 prostate cancer cases were included. A significantly increased risk of prostate cancer was evident in studies directly assessing shift work exposure (OR = 1.22, 95% CI 1.08–1.36) and those assessing shift work-related employment (OR = 1.17, 95% CI 1.10–1.24); however, substantial heterogeneities were apparent. The associations remained significant upon most subgroup and sensitivity analyses. Non-linear trend estimation revealed no significant dose-response relationship between cumulative exposure year of shift work and prostate cancer risk. The total number of prostate cancer deaths attributable to shift work is approximately 4,906 per year in the United States and Europe. Conclusion Our meta-analysis showed that shift work may be associated with an increased risk of prostate cancer. Further studies assessing different domains of shift work are warranted to confirm our findings and to clarify the biological mechanisms involved.