Computing sleep deficiency

Circadian epidemiology: Structuring circadian causes of disease and practical implications

That disruptions of the body's internal clockwork can lead to negative health consequences, including cancer, is a plausible hypothesis. Yet, despite strong mechanistic and animal support, the International Agency for Research on Cancer (IARC) experts considered epidemiological evidence as limited regarding the carcinogenicity of "shift-work involving circadian disruption" (2007) and "night shift work" (2019). We use directed acyclic graphs (DAGs) to outline a concept of circadian causes that discloses challenges when choosing appropriate exposure variables. On this basis, we propose to move beyond shift-work alone as a direct cause of disease. Instead, quantifying chronodisruption as individual doses can lead to interpretable circadian epidemiology. The hypothesis is that doses of chronodisruption cause disrupted circadian organisation by leading to desynchronization of circadian rhythms. Chronodisruption can be conceptualized as the split physiological nexus of internal and external times. Biological (or internal) night - an individual's intrinsically favoured sleep time window - could be the backbone of circadian epidemiology. In practice, individual doses that cause disrupted circadian organisation are derived from the intersection of time intervals of being awake and an individual's biological night. After numerous studies counted work shifts, chronobiology may now advance circadian epidemiology with more specific dose estimation - albeit with greater challenges in measurement (time-dependent individual data) and analysis (time-dependent confounding).

Chronodisruption: Origin, Roots, and Developments of an 18-Year-Old Concept. Comment on Desmet et al. Time-Restricted Feeding in Mice Prevents the Disruption of the Peripheral Circadian Clocks and Its Metabolic Impact during Chronic Jetlag. Nutrients 2021, 13, 3846

We read with interest the article by Desmet and colleagues entitled "Time-Restricted Feeding in Mice Prevents the Disruption of the Peripheral Circadian Clocks and Its Metabolic Impact during Chronic Jetlag" [...].

Are sleep continuity disturbance and fatigue prodromal symptoms of cancer development?

Sleep continuity disturbance (also known as insomnia) and fatigue are common complaints of individuals diagnosed with cancer. Traditionally, many have believed that sleep continuity disturbance and fatigue are caused, in large measure, by the impact of the cancer diagnosis and treatment. Recent prospective research suggests however, that sleep continuity disturbance and fatigue may actually precede a cancer diagnosis. We suggest that sleep continuity disturbance and fatigue may in fact represent prodromal symptoms of cancer. We review the current perspectives of this sequence of events and present a revised schematic that accounts for the role of biological, behavioural, and cognitive factors that contribute to the development and maintenance of sleep continuity disturbances in cancer patients. Monitoring emergent and unexplained patient-reported fatigue, sleepiness, and insomnia may serve as early warning signs of new onset cancer, providing opportunity for early detection and early intervention.