0076 Long-term nightshift work and breast cancer risk in Hong Kong women: results update
该研究更新了香港女性长期夜班工作与乳腺癌风险的关系，发现从未就业女性风险显著升高，夜班工作≥15年风险增加但统计不显著。
<h3>Objectives</h3> To report updated results on long-term nightshift work and breast cancer risk in Hong Kong women. <h3>Method</h3> This ongoing case-control study involves three hospitals in Hong Kong. By 31/03/2013, we’ve consecutively recruited 443 newly diagnosed breast cancer cases and 335 age-matched controls from the hospital that the cases came from, with a response rate of 90%. We expect to collect 1000 cases and 1000 controls by 31/12/2013. We obtained each participant’s lifetime occupational history and shift work, exposure to light-at-night and other important risk factors including family cancer history. We performed unconditional logistic regression analyses to calculate odds ratio (OR) after adjusting for potential confounders. <h3>Results</h3> The age at diagnosis (interview) between cases and controls is comparable (55.1 ± 11.9 vs. 54.2 ± 14.6 years). More cases than controls were non-parity and non-breast feeding, but gave first birth slightly late. A significantly elevated (adjusted OR=1.90, 95% CI: 1.24–2.89) breast cancer risk was observed in never employed women. Among those ever employed, 19.8% of breast cancers had ever worked at nightshift at least once per month for ≥1 year and it was 21.7% for the controls. Further analyses revealed that nightshift work for ≥15 years resulted in an adjusted OR of 1.55 (95% CI: 0.76–3.14) but power is limited. There is no excess breast cancer risk for women with nightshift work for <15 years. <h3>Conclusions</h3> This ongoing study provides supportive evidence on a positive association between long-term nightshift work and breast cancer risk. [Research Grants Council (Project no.: 474811) and Direct Grant (Project no.: 2041788), shelly@cuhk.edu.hk].