Department of Family and Preventive Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, Maryland.
Cancer. 2021 May 1;127(9):1448-1458. doi: 10.1002/cncr.33392. Epub 2021 Feb 8.
Light at night (LAN) inhibits nighttime secretion of melatonin and may cause circadian disruption, which may be a risk factor for cancer. Recent studies have linked high LAN exposure with elevated breast cancer risk. Given that breast cancer may share a common hormone-dependent etiology with thyroid cancer and that circadian rhythms play a role in regulating thyroid function, the authors hypothesized that exposure to LAN is positively associated with thyroid cancer incidence.
This study examined the association between LAN and thyroid cancer incidence in the National Institutes of Health-American Association of Retired Persons Diet and Health Study. LAN exposure was estimated from satellite data and was linked to residential addresses at the baseline. Incident thyroid cancer cases were ascertained via linkage to state cancer registries. Cox regression was used to determine the relationship between LAN and thyroid cancer risk, with adjustments made for sociodemographic, lifestyle, and other environmental factors.
Among 464,371 participants, a positive association was found between LAN and thyroid cancer risk. Specifically, in comparison with the lowest quintile of LAN, the highest quintile was associated with a 55% increase in risk (hazard ratio [HR], 1.55; 95% confidence interval [CI], 1.18-2.02). The association was primarily driven by papillary thyroid cancer and was stronger in women (HR, 1.81; 95% CI, 1.26-2.60) than men (HR, 1.29; 95% CI, 0.86-1.94). In women, the association was stronger for localized cancer, whereas in men, the association was stronger for a more advanced stage. Results were consistent across different tumor sizes.
LAN was positively associated with thyroid cancer risk. Future studies are needed to confirm this association and identify underlying biological mechanisms.
夜间光线（LAN）抑制褪黑素在夜间的分泌，可能会导致昼夜节律紊乱，而这可能是癌症的一个风险因素。最近的研究将高 LAN 暴露与乳腺癌风险升高联系起来。鉴于乳腺癌可能与甲状腺癌有共同的激素依赖性病因，且昼夜节律在调节甲状腺功能方面发挥作用，作者假设 LAN 暴露与甲状腺癌发病率呈正相关。
本研究在美国国立卫生研究院-美国退休人员协会饮食与健康研究中，研究了 LAN 与甲状腺癌发病率之间的关系。LAN 暴露量是根据卫星数据估算的，并与基线时的居住地址相关联。通过与州癌症登记处的链接确定甲状腺癌病例。使用 Cox 回归来确定 LAN 与甲状腺癌风险之间的关系，并对社会人口统计学、生活方式和其他环境因素进行了调整。
在 464371 名参与者中，LAN 与甲状腺癌风险之间存在正相关关系。具体而言，与 LAN 最低五分位相比，最高五分位与风险增加 55%相关（风险比 [HR]，1.55；95%置信区间 [CI]，1.18-2.02）。这种关联主要是由乳头状甲状腺癌驱动的，在女性（HR，1.81；95% CI，1.26-2.60）中比男性（HR，1.29；95% CI，0.86-1.94）更强。在女性中，局部癌症的关联更强，而在男性中，更晚期癌症的关联更强。结果在不同的肿瘤大小中是一致的。
LAN 与甲状腺癌风险呈正相关。需要进一步的研究来证实这一关联并确定潜在的生物学机制。
