| 1. |
- Mucci, Lorelei A., et al.
(författare)
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Circadian dysrhythm and advanced prostate cancer
- 2014
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Ingår i: Journal of Clinical Oncology. - : American Society of Clinical Oncology (ASCO). - 0732-183X .- 1527-7755. ; 32:4
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: The circadian rhythm regulates diverse biologic pathways including tumor oncogenes, metabolism, and cell proliferation. Dysregulation of the circadian rhythm arises from faulty input signals such as exposure to light at night, variability in core circadian rhythm genes, and variation in outputs that regulate circadian behavior including melatonin. There is compelling biologic rationale, but little human data, on circadian dysrhythm and advanced prostate cancer.Methods: We undertook an integrative molecular epidemiology study of circadian dysrhythm and advanced prostate cancer among men in the Icelandic AGES-Reykjavik cohort and the U.S. Health Professionals Follow-up Study, which allowed integration of questionnaire data, biorepositories, and long-term follow-up. We characterized circadian dysrhythm using complimentary approaches: information on sleep problems from questionnaires, prediagnostic melatonin (6-sulfatoxymelatonin) measured on first morning void urine samples, and genetic variation across twelve circadian clock genes. We used multivariable regression models to estimate relative risks (RR) and 95% confidence intervals (CI) of associations with advanced prostate cancer, adjusted for potential confounders.Results: Twenty percent of men reported sleep problems. Men who had trouble falling asleep (RR = 2.1; 95% CI 0.7-6.2) and staying asleep (RR=3.2, 95% CI 1.1-9.7) had an increased risk of developing advanced prostate cancer. Men with sleep problems had significantly lower melatonin levels compared to those without. Low melatonin levels were associated with a statistically significant 4-fold higher risk of advanced prostate cancer compared to those with high levels (95% CI: 1.25-10.0). Variant alleles in two SNPs in cryptochrome (CRY1), involved in generating and maintaining circadian rhythms, were significantly associated with risk of advanced prostate cancer in both cohorts, with a gene-level p-value<0.01.Conclusions: Our results suggest there are multiple nodes in the circadian rhythm that are associated with an increased risk of advanced prostate cancer. As such, there is the potential for complimentary strategies to target circadian disruption and reduce the risk of advanced prostate cancer.
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| 2. |
- Sigurdardottir, Lara G., et al.
(författare)
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Circadian disruption, sleep loss, and prostate cancer risk : a systematic review of epidemiologic studies
- 2012
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Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - Philadelphia, USA : American Association for Cancer Research. - 1055-9965 .- 1538-7755. ; 21:7, s. 1002-1011
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Forskningsöversikt (refereegranskat)abstract
- Disruption of the circadian system has been hypothesized to increase cancer risk, either because of direct disruption of the molecular machinery generating circadian rhythms or because of disruption of parameters controlled by the clock such as melatonin levels or sleep duration. This hypothesis has been studied in hormone-dependent cancers among women, but data are sparse about potential effects of circadian disruption on the risk of prostate cancer. This review systematically examines available data evaluating the effects of light at night, sleep patterns, and night shift work on prostate cancer risk.
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| 3. |
- Sigurdardottir, Lara G., et al.
(författare)
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Pineal Gland Volume Assessed by MRI and Its Correlation with 6-Sulfatoxymelatonin Levels among Older Men
- 2016
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Ingår i: Journal of Biological Rhythms. - Thousand Oaks, USA : Sage Publications. - 0748-7304 .- 1552-4531. ; 31:5, s. 461-469
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Tidskriftsartikel (refereegranskat)abstract
- The pineal gland produces the hormone melatonin, and its volume may influence melatonin levels. We describe an innovative method for estimating pineal volume in humans and present the association of pineal parenchyma volume with levels of the primary melatonin metabolite, 6-sulfatoxymelatonin. We selected a random sample of 122 older Icelandic men nested within the AGES-Reykjavik cohort and measured their total pineal volume, their parenchyma volume, and the extent of calcification and cysts. For volume estimations we used manual segmentation of magnetic resonance images in the axial plane with simultaneous side-by-side view of the sagittal and coronal plane. We used multivariable adjusted linear regression models to estimate the association of pineal parenchyma volume and baseline characteristics, including 6-sulfatoxymelatonin levels. We used logistic regression to test for differences in first morning urinary 6-sulfatoxymelatonin levels among men with or without cystic or calcified glands. The pineal glands varied in volume, shape, and composition. Cysts were present in 59% of the glands and calcifications in 21%. The mean total pineal volume measured 207 mm(3) (range 65-536 mm(3)) and parenchyma volume 178 mm(3) (range 65-503 mm(3)). In multivariable-adjusted models, pineal parenchyma volume was positively correlated with 6-sulfatoxymelatonin levels (β = 0.52, p < 0.001). Levels of 6-sulfatoxymelatonin did not differ significantly by presence of cysts or calcification. By using an innovative method for pineal assessment, we found pineal parenchyma volume to be positively correlated with 6-sulfatoxymelatonin levels, in line with other recent studies.
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| 4. |
- Sigurdardottir, Lara G., et al.
(författare)
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Sleep disruption among older men and risk of prostate cancer
- 2013
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Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - 1055-9965 .- 1538-7755. ; 22:5, s. 872-879
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Tidskriftsartikel (refereegranskat)abstract
- Background: Although positive associations have consistently been reported between sleep disruption and breast cancer, less is known about its potential role in prostate cancer.Methods: Within the prospective AGES-Reykjavik cohort study, we followed 2,102 men recruited in 20022006 until the end of 2009. Participants answered questions on sleep disruption. Information on the occurrence of prostate cancer was obtained through record linkages across the Icelandic Cancer Registry. We used Cox regression models with 95% confidence intervals (CI) to estimate HRs of prostate cancer by symptoms of sleep disruption.Results: During follow-up, 135 men (6.4%) were diagnosed with prostate cancer. Compared with men without sleep disruption, those with problems falling and staying asleep were at significantly increased risk of prostate cancer [HR, 1.7 (95% CI, 1.0-2.9) and 2.1 (95% CI, 1.2-3.7)], respectively, with increasing sleep disruption severity. When restricted to advanced prostate cancer (>= stage T3 or lethal disease), these associations became even stronger [HR 2.1 (95% CI, 0.7-6.2) and 3.2 (95% CI, 1.1-9.7)]. The results did not change after excluding from the analyses men who woke up during the night, indicative of nocturia, suggesting limited risk of reverse association.Conclusions: Our data suggest that certain aspects of sleep disruption may confer an increased risk of prostate cancer and call for additional, larger studies with longer follow-up times.Impact: Prostate cancer is one of the leading public health concerns in men; if confirmed in future studies, the association between sleep disruption and prostate cancer risk may open new avenues for prevention.
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| 5. |
- Sigurdardottir, Lara G., et al.
(författare)
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Urinary melatonin levels, sleep disruption, and risk of prostate cancer in elderly men
- 2015
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Ingår i: European Urology. - : Elsevier. - 0302-2838 .- 1873-7560. ; 67:2, s. 191-194
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Tidskriftsartikel (refereegranskat)abstract
- Melatonin has anticarcinogenic properties in experimental models. We undertook a case-cohort study of 928 Icelandic men without prostate cancer (PCa) nested within the Age, Gene/Environment Susceptibility (AGES)-Reykjavik cohort to investigate the prospective association between first morning-void urinary 6-sulfatoxymelatonin (aMT6s) levels and the subsequent risk for PCa, under the hypothesis that men with lower aMT6s levels have an increased risk for advanced PCa. We used weighted Cox proportional hazards models to assess the association between first morning-void aMT6s levels and PCa risk, adjusting for potential confounders. A total of 111 men were diagnosed with incident PCa, including 24 with advanced disease. Men who reported sleep problems at baseline had lower morning aMT6s levels compared with those who reported no sleep problems. Men with morning aMT6s levels below the median had a fourfold statistically significant increased risk for advanced disease compared with men with levels above the median (hazard ratio: 4.04; 95% confidence interval, 1.26-12.98). These results require replication in larger prospective studies with longer follow-up.Patient summary: In this report, we evaluated the prospective association between urinary aMT6s levels and risk of PCa in an Icelandic population. We found that lower levels of aMT6s were associated with an increased risk for advanced PCa.
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