Outdoor light at night and risk of endometrial cancer in the NIH-AARP diet and health study

Menée auprès d'une cohorte de 97 677 femmes ménopausées, cette étude analyse l'association entre la lumière extérieure nocturne et le risque de cancer de l'endomètre (991 cas)

Résumé en anglais

Purpose: Outdoor light at night (LAN) can result in circadian disruption and hormone dysregulation and is a suspected risk factor for some cancers. Our study is the first to evaluate the association between LAN and risk of endometrial cancer, a malignancy with known relationship to circulating estrogen levels.

Methods: We linked enrollment addresses (1996) for 97,677 postmenopausal women in the prospective NIH-AARP cohort to satellite imagery of nighttime radiance to estimate LAN exposure. Multivariable Cox models estimated hazard ratios (HR) and 95% confidence intervals (95% CI) for LAN quintiles and incident endometrial cancer overall (1,669 cases) and endometrioid adenocarcinomas (991 cases) through follow-up (2011). We tested for interaction with established endometrial cancer risk factors.

Results: We observed no association for endometrial cancer overall (HRQ1vsQ5 0.92; 95% CI 0.78–1.08; p trend = 0.67) or endometrioid adenocarcinoma (HRQ1vsQ5 1.01; 95% CI 0.82–1.24; p trend = 0.36). Although body mass index and menopause hormone therapy were both associated with risk, there was no evidence of interaction with LAN (p interactions = 0.52 and 0.50, respectively).

Conclusion: Our study did not find an association between outdoor LAN and endometrial cancer risk, but was limited by the inability to account for individual-level exposure determinants. Future studies should consider approaches to improve characterization of personal exposures to light.