RT Journal Article
SR Electronic
T1 Increased risk of breast cancer associated with long-term shift work in Canada
JF Occupational and Environmental Medicine
JO Occup Environ Med
FD BMJ Publishing Group Ltd
SP 831
OP 838
DO 10.1136/oemed-2013-101482
VO 70
IS 12
A1 Anne Grundy
A1 Harriet Richardson
A1 Igor Burstyn
A1 Caroline Lohrisch
A1 Sandip K SenGupta
A1 Agnes S Lai
A1 Derrick Lee
A1 John J Spinelli
A1 Kristan J Aronson
YR 2013
UL http://oem.bmj.com/content/70/12/831.abstract
AB Objectives Long-term night work has been suggested as a risk factor for breast cancer; however, additional studies with more comprehensive methods of exposure assessment to capture the diversity of shift patterns are needed. As well, few previous studies have considered the role of hormone receptor subtype. Methods Relationships between night shift work and breast cancer were examined among 1134 breast cancer cases and 1179 controls, frequency-matched by age in Vancouver, British Columbia, and Kingston, Ontario. Self-reported lifetime occupational histories were assessed for night shift work, and hormone receptor status obtained from tumour pathology records. Results With approximately one-third of cases and controls ever employed in night shift work, associations with duration demonstrated no relationship between either 0–14 or 15–29 years, while an association was apparent for ≥30 years (OR=2.21, 95% CI 1.14 to 4.31). This association with long-term night shift work is robust to alternative definitions of prolonged shift work, with similar results for both health and non-health care workers. Conclusions Long-term night shift work in a diverse mix of occupations is associated with increased breast cancer risk and not limited to nurses, as in most previous studies.