Abstract
Objective
To investigate the potential association between domestic exposure to light at night (LAN) and the risk of human breast cancer.
Methods
A case–control study of female breast cancer was conducted in Connecticut. A total of 363 incident breast cancer cases and 356 age frequency-matched controls were interviewed using a standardized, structured questionnaire to obtain information on sleeping patterns and bedroom light environment. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by unconditional multivariate logistic regression.
Results
A non-significantly increased risk of breast cancer was observed among postmenopausal women for those keeping lights on while sleeping (OR = 1.4, 95% CI 0.7, 2.7), those who reported mainly sleeping in the daytime (OR = 1.4, 95% CI 0.5, 4.3), and those not drawing the curtains/window shades while sleeping at night (OR = 1.2, 95% CI 0.8, 1.9).
Conclusion
The results from this study suggest a potential increased risk of breast cancer associated with domestic exposure to LAN. Further studies with larger sample size are needed to confirm the results.
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Acknowledgments
Preparation of the manuscript is partly supported by grants: 5D43TW008323 and 5D43TW007864. This study was supported by a grant CA-62986 from National Cancer Institute/National Institute of Environmental Health Science. We also appreciate the support of personnel at the hospitals of Connecticut. The following Connecticut hospitals have participated in the study: Yale-New Haven Hospital, Hospital of St. Raphael, Hartford Hospital, St. Francis Hospital and Medical Center, New Britain General Hospital, Middlesex Hospital, Mt. Sinai Hospital, Manchester Memorial Hospital, UCONN Health Center/John Dempsey Hospital, Windham Community Memorial Hospital, Day Kimball Hospital, Rockville General Hospital, and Johnson Memorial Hospital.
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Li, Q., Zheng, T., Holford, T.R. et al. Light at night and breast cancer risk: results from a population-based case–control study in Connecticut, USA. Cancer Causes Control 21, 2281–2285 (2010). https://doi.org/10.1007/s10552-010-9653-z
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DOI: https://doi.org/10.1007/s10552-010-9653-z