Night shift work, chronotype and prostate cancer risk in the MCC‐Spain case‐control study
TL;DR: Overall risk was higher among subjects with an evening chronotype, but also increased in morning chronotypes after long‐term night work, particularly for tumors with worse prognosis.
Abstract: Night shift work has been classified as a probable human carcinogen based on experimental studies and limited human evidence on breast cancer. Evidence on other common cancers, such as prostate cancer, is scarce. Chronotype is an individual characteristic that may relate to night work adaptation. We evaluated night shift work with relation to prostate cancer, taking into account chronotype and disease severity in a population based case-control study in Spain. We included 1,095 prostate cancer cases and 1,388 randomly selected population controls. We collected detailed information on shift schedules (permanent vs. rotating, time schedules, duration, frequency), using lifetime occupational history. Sociodemographic and lifestyle factors were assessed by face-to-face interviews and chronotype through a validated questionnaire. We used unconditional logistic regression analysis adjusting for potential confounders. Subjects who had worked at least for one year in night shift work had a slightly higher prostate cancer risk [Odds Ratio (OR) 1.14; 95%CI 0.94, 1.37] compared with never night workers; this risk increased with longer duration of exposure (≥28 years: OR 1.37; 95%CI 1.05, 1.81; p-trend = 0.047). Risks were more pronounced for high risk tumors [D'Amico classification, Relative Risk Ratio (RRR) 1.40; 95%CI 1.05, 1.86], particularly among subjects with longer duration of exposure (≥28 years: RRR 1.63; 95%CI 1.08, 2.45; p-trend = 0.027). Overall risk was higher among subjects with an evening chronotype, but also increased in morning chronotypes after long-term night work. In this large population based study, we found an association between night shift work and prostate cancer particularly for tumors with worse prognosis.
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TL;DR: The authors explore the recent advancements in the field of metastasis and highlight the latest insights that contribute to shaping this hallmark of cancer.
Abstract: Metastasis is the hallmark of cancer that is responsible for the greatest number of cancer-related deaths. Yet, it remains poorly understood. The continuous evolution of cancer biology research and the emergence of new paradigms in the study of metastasis have revealed some of the molecular underpinnings of this dissemination process. The invading tumor cell, on its way to the target site, interacts with other proteins and cells. Recognition of these interactions improved the understanding of some of the biological principles of the metastatic cell that govern its mobility and plasticity. Communication with the tumor microenvironment allows invading cancer cells to overcome stromal challenges, settle, and colonize. These characteristics of cancer cells are driven by genetic and epigenetic modifications within the tumor cell itself and its microenvironment. Establishing the biological mechanisms of the metastatic process is crucial in finding open therapeutic windows for successful interventions. In this review, the authors explore the recent advancements in the field of metastasis and highlight the latest insights that contribute to shaping this hallmark of cancer.
807 citations
TL;DR: Melatonin exhibits several unique features which differ from the classic antioxidants, including its cascade reaction with free radicals and its capacity to be induced under moderate oxidative stress, which make melatonin a potent endogenously-occurring antioxidant that protects organisms from catastrophic oxidative stress.
Abstract: Melatonin is a tryptophan-derived molecule with pleiotropic activities. It is present in almost all or all organisms. Its synthetic pathway depends on the species in which it is measured. For example, the tryptophan to melatonin pathway differs in plants and animals. It is speculated that the melatonin synthetic machinery in eukaryotes was inherited from bacteria as a result of endosymbiosis. However, melatonin's synthetic mechanisms in microorganisms are currently unknown. Melatonin metabolism is highly complex with these enzymatic processes having evolved from cytochrome C. In addition to its enzymatic degradation, melatonin is metabolized via pseudoenzymatic and free radical interactive processes. The metabolic products of these processes overlap and it is often difficult to determine which process is dominant. However, under oxidative stress, the free radical interactive pathway may be featured over the others. Because of the complexity of the melatonin degradative processes, it is expected that additional novel melatonin metabolites will be identified in future investigations. The original and primary function of melatonin in early life forms such as in unicellular organisms was as a free radical scavenger and antioxidant. During evolution, melatonin was selected as a signaling molecule to transduce the environmental photoperiodic information into an endocrine message in multicellular organisms and for other purposes as well. As an antioxidant, melatonin exhibits several unique features which differ from the classic antioxidants. These include its cascade reaction with free radicals and its capacity to be induced under moderate oxidative stress. These features make melatonin a potent endogenously-occurring antioxidant that protects organisms from catastrophic oxidative stress.
416 citations
Cites background from "Night shift work, chronotype and pr..."
...For example, shift workers, particularly including nurses, air plane crews and miners have a higher prevalence of breast and prostate cancers [21–23]....
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TL;DR: Countermeasures to the effects of ALAN, such as melatonin, bright light, or psychotropic drugs, have been proposed as a means to combat circadian clock disruption and improve adaptation to shift and night work.
405 citations
TL;DR: The circadian clock is a complex cellular mechanism that, through the control of diverse metabolic and gene expression pathways, governs a large array of cyclic physiological processes as mentioned in this paper, which has implications for therapeutic approaches, and discuss the possible design of chronopharmacological strategies.
Abstract: The circadian clock is a complex cellular mechanism that, through the control of diverse metabolic and gene expression pathways, governs a large array of cyclic physiological processes. Epidemiological and clinical data reveal a connection between the disruption of circadian rhythms and cancer that is supported by recent preclinical data. In addition, results from animal models and molecular studies underscore emerging links between cancer metabolism and the circadian clock. This has implications for therapeutic approaches, and we discuss the possible design of chronopharmacological strategies.
233 citations
References
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TL;DR: Overall cancer death rates have declined 20% from their peak in 1991 to 2009 and can be accelerated by applying existing cancer control knowledge across all segments of the population, with an emphasis on those groups in the lowest socioeconomic bracket and other underserved populations.
Abstract: Each year, the American Cancer Society estimates the numbers of new cancer cases and deaths expected in the United States in the current year and compiles the most recent data on cancer incidence, mortality, and survival based on incidence data from the National Cancer Institute, the Centers for Disease Control and Prevention, and the North American Association of Central Cancer Registries and mortality data from the National Center for Health Statistics. A total of 1,660,290 new cancer cases and 580,350 cancer deaths are projected to occur in the United States in 2013. During the most recent 5 years for which there are data (2005-2009), delay-adjusted cancer incidence rates declined slightly in men (by 0.6% per year) and were stable in women, while cancer death rates decreased by 1.8% per year in men and by 1.5% per year in women. Overall, cancer death rates have declined 20% from their peak in 1991 (215.1 per 100,000 population) to 2009 (173.1 per 100,000 population). Death rates continue to decline for all 4 major cancer sites (lung, colorectum, breast, and prostate). Over the past 10 years of data (2000-2009), the largest annual declines in death rates were for chronic myeloid leukemia (8.4%), cancers of the stomach (3.1%) and colorectum (3.0%), and non-Hodgkin lymphoma (3.0%). The reduction in overall cancer death rates since 1990 in men and 1991 in women translates to the avoidance of approximately 1.18 million deaths from cancer, with 152,900 of these deaths averted in 2009 alone. Further progress can be accelerated by applying existing cancer control knowledge across all segments of the population, with an emphasis on those groups in the lowest socioeconomic bracket and other underserved populations.
11,556 citations
TL;DR: The principles of the method and how to impute categorical and quantitative variables, including skewed variables, are described and shown and the practical analysis of multiply imputed data is described, including model building and model checking.
Abstract: Multiple imputation by chained equations is a flexible and practical approach to handling missing data. We describe the principles of the method and show how to impute categorical and quantitative variables, including skewed variables. We give guidance on how to specify the imputation model and how many imputations are needed. We describe the practical analysis of multiply imputed data, including model building and model checking. We stress the limitations of the method and discuss the possible pitfalls. We illustrate the ideas using a data set in mental health, giving Stata code fragments. Copyright © 2010 John Wiley & Sons, Ltd.
6,349 citations
"Night shift work, chronotype and pr..." refers methods in this paper
...To increase efficiency and minimize selection bias, we performed multiple imputation of missing values using chained equations.(30) Multiple imputations were done separately for cases and controls....
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TL;DR: Up-to-date estimates of the cancer burden in Europe alongside the description of the varying distribution of common cancers at both the regional and country level provide a basis for establishing priorities to cancer control actions in Europe.
4,722 citations
TL;DR: It is predicted that the timing of sleep has changed during industrialization and that a majority of humans are sleep deprived during the workweek, and the implications are far ranging concerning learning, memory, vigilance, performance, and quality of life.
Abstract: Human behavior shows large interindividual variation in temporal organization. Extreme "larks" wake up when extreme "owls" fall asleep. These chronotypes are attributed to differences in the circadian clock, and in animals, the genetic basis of similar phenotypic differences is well established. To better understand the genetic basis of temporal organization in humans, the authors developed a questionnaire to document individual sleep times, self-reported light exposure, and self-assessed chronotype, considering work and free days separately. This report summarizes the results of 500 questionnaires completed inapilotstudy.Individualsleeptimesshowlargedifferencesbetweenworkand freedays,exceptforextremeearlytypes.Duringtheworkweek,latechronotypes
1,900 citations
"Night shift work, chronotype and pr..." refers methods in this paper
...Participants were contacted again and a phone interview was performed to collect missing information on jobs with rotating night shift work (exact time schedules for each shift, nights performed per month) and assess individual chronotype with the use of the Munich Chronotype Questionnaire (MCTQ).(29) In total, 2,104 subjects (1,208 controls and 896 cases) agreed to participate in this follow-up and completed the chronotype questionnaire....
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TL;DR: An algorithm is established which optimises chronotype assessment by incorporating the information on timing of sleep and wakefulness for both work and free days, because sleep duration strongly depends on chronotype.
1,199 citations
"Night shift work, chronotype and pr..." refers background in this paper
...Chronotype is an individual characteristic that describes the circadian phase and correlates with diurnal preference, the individual preference for morning or evening activity.(23,24) It has been suggested that chronotype may modify the risk for cancer since it has been associated to the capacity of night workers to adapt to nonday work schedules....
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...Chronotype and sleep habits depend on age, although there is evidence that chronotype tracks through life and current chronotype highly correlates with self-reported chronotype at adolescence and early adulthood.(23) We examined lifetime occupational history with detailed shift work characteristics for each job and used metrics such as cumulative duration and frequency....
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