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Author Grundy, A.; Richardson, H.; Burstyn, I.; Lohrisch, C.; SenGupta, S.K.; Lai, A.S.; Lee, D.; Spinelli, J.J.; Aronson, K.J.
Title Increased risk of breast cancer associated with long-term shift work in Canada Type Journal Article
Year 2013 Publication Occupational and Environmental Medicine Abbreviated Journal Occup Environ Med
Volume (down) 70 Issue 12 Pages 831-838
Keywords Human Health; Adult; Aged; Aged, 80 and over; Breast Neoplasms/epidemiology/*etiology/metabolism; British Columbia/epidemiology; Case-Control Studies; Female; Humans; Menopause; Middle Aged; Occupational Diseases/*epidemiology; Ontario/epidemiology; Receptors, Estrogen/metabolism; Receptors, Progesterone/metabolism; Risk Factors; Tumor Markers, Biological/metabolism; Work Schedule Tolerance/*physiology; Young Adult
Abstract 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.
Address Department of Public Health Sciences and Queen's Cancer Research Institute, Queen's University, Kingston, Ontario, Canada
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1351-0711 ISBN Medium
Area Expedition Conference
Notes PMID:23817841 Approved no
Call Number LoNNe @ kagoburian @ Serial 757
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Author Hansen, J.; Lassen, C.F.
Title Nested case-control study of night shift work and breast cancer risk among women in the Danish military Type Journal Article
Year 2012 Publication Occupational and Environmental Medicine Abbreviated Journal Occup Environ Med
Volume (down) 69 Issue 8 Pages 551-556
Keywords Adult; Aged; Aged, 80 and over; Breast Neoplasms/*etiology; Case-Control Studies; *Circadian Rhythm; Denmark/epidemiology; Female; Humans; Logistic Models; Middle Aged; Military Personnel; *Occupations; Odds Ratio; Risk Factors; *Sunlight; *Work; *Work Schedule Tolerance; oncogenesis
Abstract OBJECTIVES: Growing but limited evidence suggests that night shift work is associated with breast cancer. The authors conducted a nationwide case-control study nested within a cohort of 18,551 female military employees born in 1929-1968 to investigate the risk for breast cancer after night shift work and to explore the role of leisure time sun exposure and diurnal preference. METHODS: The authors documented 218 cases of breast cancer (1990-2003) and selected 899 age-matched controls from the cohort by incidence density sampling. Information on shift work, sun exposure habits, diurnal preference and other potential confounders was obtained from a structured questionnaire. ORs were estimated by multivariate conditional logistic regression. RESULTS: Overall, the authors observed an adjusted OR of 1.4 (95% CI 0.9 to 2.1) among women with ever compared with never night shifts. The RR for breast cancer tended to increase with increasing number of years of night shift work (p=0.03) and with cumulative number of shifts (p=0.02),with a neutral risk for fewer than three night shifts per week. The OR for the group with the highest tertile of cumulative exposure was 2.3 (95% CI 1.2 to 4.6). The most pronounced effect of night shift work on breast cancer risk was observed in women with morning chronotype preference and intense night shifts (OR=3.9, 95% CI 1.6 to 9.5). Night shift workers tended to sunbathe more frequently than day workers. CONCLUSIONS: The results indicate that frequent night shift work increases the risk for breast cancer and suggest a higher risk with longer duration of intense night shifts. Women with morning preference who worked on night shifts tended to have a higher risk than those with evening preference.
Address Institute of Cancer Epidemiology, Danish Cancer Society, Strandboulevarden 49, Copenhagen DK2100, Denmark. johnni@cancer.dk
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1351-0711 ISBN Medium
Area Expedition Conference
Notes PMID:22645325 Approved no
Call Number IDA @ john @ Serial 156
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Author Blask, D.E.; Brainard, G.C.; Dauchy, R.T.; Hanifin, J.P.; Davidson, L.K.; Krause, J.A.; Sauer, L.A.; Rivera-Bermudez, M.A.; Dubocovich, M.L.; Jasser, S.A.; Lynch, D.T.; Rollag, M.D.; Zalatan, F.
Title Melatonin-depleted blood from premenopausal women exposed to light at night stimulates growth of human breast cancer xenografts in nude rats Type Journal Article
Year 2005 Publication Cancer Research Abbreviated Journal Cancer Res
Volume (down) 65 Issue 23 Pages 11174-11184
Keywords Human Health; Animals; Breast Neoplasms/*blood/genetics/pathology; Cell Growth Processes/physiology; Circadian Rhythm/*physiology; Female; Humans; Light; Liver Neoplasms, Experimental/metabolism; Male; Melatonin/blood/*deficiency; Premenopause/blood; RNA, Messenger/biosynthesis/genetics; Rats; Rats, Nude; Receptors, Melatonin/biosynthesis/genetics; Transplantation, Heterologous
Abstract The increased breast cancer risk in female night shift workers has been postulated to result from the suppression of pineal melatonin production by exposure to light at night. Exposure of rats bearing rat hepatomas or human breast cancer xenografts to increasing intensities of white fluorescent light during each 12-hour dark phase (0-345 microW/cm2) resulted in a dose-dependent suppression of nocturnal melatonin blood levels and a stimulation of tumor growth and linoleic acid uptake/metabolism to the mitogenic molecule 13-hydroxyoctadecadienoic acid. Venous blood samples were collected from healthy, premenopausal female volunteers during either the daytime, nighttime, or nighttime following 90 minutes of ocular bright, white fluorescent light exposure at 580 microW/cm2 (i.e., 2,800 lx). Compared with tumors perfused with daytime-collected melatonin-deficient blood, human breast cancer xenografts and rat hepatomas perfused in situ, with nocturnal, physiologically melatonin-rich blood collected during the night, exhibited markedly suppressed proliferative activity and linoleic acid uptake/metabolism. Tumors perfused with melatonin-deficient blood collected following ocular exposure to light at night exhibited the daytime pattern of high tumor proliferative activity. These results are the first to show that the tumor growth response to exposure to light during darkness is intensity dependent and that the human nocturnal, circadian melatonin signal not only inhibits human breast cancer growth but that this effect is extinguished by short-term ocular exposure to bright, white light at night. These mechanistic studies are the first to provide a rational biological explanation for the increased breast cancer risk in female night shift workers.
Address Laboratory of Chrono-Neuroendocrine Oncology, Bassett Research Institute, The Mary Imogene Bassett Hospital, Cooperstown, New York 13326, USA. david.blask@bassett.org
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0008-5472 ISBN Medium
Area Expedition Conference
Notes PMID:16322268 Approved no
Call Number LoNNe @ kagoburian @ Serial 721
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Author Dickerman, B.; Liu, J.
Title Does current scientific evidence support a link between light at night and breast cancer among female night-shift nurses? Review of evidence and implications for occupational and environmental health nurses Type Journal Article
Year 2012 Publication Workplace Health & Safety Abbreviated Journal Workplace Health Saf
Volume (down) 60 Issue 6 Pages 273-81; quiz 282
Keywords Human Health; Breast Neoplasms/*epidemiology/nursing; Chronobiology Disorders/*epidemiology/nursing; Education, Nursing, Continuing; Environmental Health; Evidence-Based Nursing; Female; Humans; Light; Night Care/*statistics & numerical data; *Occupational Health Nursing; Risk Factors; *Work Schedule Tolerance
Abstract Breast cancer is increasingly prevalent in industrialized regions of the world, and exposure to light at night (LAN) has been proposed as a potential risk factor. Epidemiological observations have documented an increased breast cancer risk among female night-shift workers, and strong experimental evidence for this relationship has also been found in rodent models. Indirect support for the LAN hypothesis comes from studies involving blind women, sleep duration, bedroom light levels, and community nighttime light levels. This article reviews the literature, discusses possible mechanisms of action, and provides recommendations for occupational health nursing research, practice, and education. Research is needed to further explore the relationship between exposure to LAN and breast cancer risk and elucidate the mechanisms underlying this relationship before interventions can be designed for prevention and mitigation of breast cancer.
Address MultiCare Good Samaritan Hospital, Puyallup, WA, USA. barbra.dickerman@gmail.com
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2165-0799 ISBN Medium
Area Expedition Conference
Notes PMID:22658734 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 512
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Author Kujanik, S.; Mikulecky, M.
Title Circadian and ultradian extrasystole rhythms in healthy individuals at elevated versus lowland altitudes Type Journal Article
Year 2010 Publication International Journal of Biometeorology Abbreviated Journal Int J Biometeorol
Volume (down) 54 Issue 5 Pages 531-538
Keywords Human Health; Acclimatization/physiology; Aged; *Altitude; Anoxia/etiology; Cardiac Complexes, Premature/*physiopathology; Circadian Rhythm/*physiology; Electrocardiography, Ambulatory; Heart Rate/*physiology; Humans; Male; Middle Aged; Reference Values; Time Factors
Abstract We defined chronobiologic norms for supraventricular and ventricular single extrasystoles (SV and VE, respectively) in healthy older males in lowland areas. The study was extended to higher altitudes, where hypobaric hypoxia was expected to increase extrasystole frequency, while perhaps not changing rhythmicity. In healthy men (lowland n = 37, altitude n = 22), aged 49-72 years, mean numbers of SVs and VEs were counted over a 24-h period. Cosinor regression was used to test the 24-h rhythm and its 2nd-10th harmonics. The resulting approximating function for either extrasystole type includes its point, 95% confidence interval of the mean, and 95% tolerance for single measurement estimates. Separate hourly differences (delta) between altitude and lowland (n = 59) were also analysed. Hourly means were significantly higher in the mountains versus lowland, by +0.8 beats/h on average for SVs, and by +0.9 beats/h for VEs. A relatively rich chronogram for VEs in mountains versus lowland exists. Delta VEs clearly display a 24-h component and its 2nd, 3rd, 4th and 7th harmonics. This results in significantly higher accumulation of VEs around 8.00 a.m., 11.00 a.m. and 3.00 p.m. in the mountains. The increase in extrasystole occurrence in the mountains is probably caused by higher hypobaric hypoxia and resulting sympathetic drive. Healthy men at elevated altitudes show circadian and several ultradian rhythms of single VEs dependent on the hypoxia level. This new methodological approach--evaluating the differences between two locations using delta values--promises to provide deeper insight into the occurrence of premature beats.
Address Dept of Physiology, Faculty of Medicine, Pavol Jozef Safarik University, Trieda SNP 1, 040 66 Kosice, Slovak Republic. stefan.kujanik@upjs.sk
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-7128 ISBN Medium
Area Expedition Conference
Notes PMID:20195873 Approved no
Call Number LoNNe @ kagoburian @ Serial 774
Permanent link to this record