Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA; Epidemiology Branch, National Institute of Environmental Health Sciences, Durham, NC, USA.
Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA.
Environ Int. 2022 Nov;169:107495. doi: 10.1016/j.envint.2022.107495. Epub 2022 Sep 2.
Light at night (LAN) may alter estrogen regulation through circadian disruption. High levels of outdoor LAN may increase breast cancer risk, but studies have largely not considered possible residual confounding from correlated environmental exposures. We evaluated the association between indoor and outdoor LAN and incident breast cancer.
In 47,145 participants in the prospective Sister Study cohort living in the contiguous U.S., exposure to outdoor LAN was determined using satellite-measured residential data and indoor LAN was self-reported (light/TV on, light from outside the room, nightlight, no light). We used Cox proportional hazards models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between outdoor and indoor LAN and breast cancer risk. Models were adjusted for age, race/ethnicity, educational attainment, annual household income, neighborhood disadvantage, latitude, and population density as a proxy for urbanicity. To evaluate the potential for residual confounding of the outdoor LAN and breast cancer relationship by factors associated with urbanicity, we considered further adjustment for exposures correlated with outdoor LAN including NO [Spearman correlation coefficient, rho (ρ) = 0.78], PM (ρ = 0.36), green space (ρ = - 0.41), and noise (ρ = 0.81).
During 11 years of follow-up, 3,734 breast cancer cases were identified. Outdoor LAN was modestly, but non-monotonically, associated with a higher risk of breast cancer (Quintile 4 vs 1: HR = 1.10, 95% CI: 0.99-1.22; Quintile 5 vs 1: HR = 1.04, 95% CI: 0.93-1.16); however, no association was evident after adjustment for correlated ambient exposures (Quintile 4 vs 1: HR = 0.99, 95% CI: 0.86-1.14; Quintile 5 vs 1: HR = 0.89, 95% CI: 0.74-1.06). Compared to those with no indoor LAN exposure, sleeping with a light or TV on was associated with a HR = 1.09 (95% CI: 0.97-1.23) in the adjusted model.
Outdoor LAN does not appear to increase the risk of breast cancer after adjustment for correlated environmental exposures.
夜间光（LAN）可能通过扰乱昼夜节律来改变雌激素的调节。高水平的室外 LAN 可能会增加乳腺癌的风险，但这些研究大多没有考虑到相关环境暴露的可能残留混杂。我们评估了室内和室外 LAN 与乳腺癌发病的关系。
在居住在美国大陆的前瞻性姐妹研究队列的 47145 名参与者中，使用卫星测量的住宅数据确定了室外 LAN 的暴露情况，室内 LAN 通过自我报告（灯/电视开着、房间外的灯光、夜灯、无灯光）来确定。我们使用 Cox 比例风险模型计算了室外和室内 LAN 与乳腺癌风险之间的风险比（HR）和 95%置信区间（CI）。模型调整了年龄、种族/民族、教育程度、家庭年收入、邻里劣势、纬度和人口密度（代表城市化程度）。为了评估与城市化程度相关的因素对室外 LAN 和乳腺癌关系的潜在残余混杂作用，我们考虑了与室外 LAN 相关的其他暴露因素的进一步调整，包括 NO [Spearman 相关系数，rho（ρ）= 0.78]、PM（ρ= 0.36）、绿地（ρ= -0.41）和噪音（ρ= 0.81）。
在 11 年的随访期间，发现了 3734 例乳腺癌病例。室外 LAN 与乳腺癌风险呈适度但非单调增加相关（第 4 五分位与第 1 五分位相比：HR=1.10，95%CI：0.99-1.22；第 5 五分位与第 1 五分位相比：HR=1.04，95%CI：0.93-1.16）；然而，在调整了相关环境暴露因素后，没有明显的关联（第 4 五分位与第 1 五分位相比：HR=0.99，95%CI：0.86-1.14；第 5 五分位与第 1 五分位相比：HR=0.89，95%CI：0.74-1.06）。与没有室内 LAN 暴露的人相比，睡觉时开着灯或电视与 HR=1.09（95%CI：0.97-1.23）相关。
在调整了相关环境暴露因素后，室外 LAN 似乎不会增加乳腺癌的风险。
