Sleep duration and the risk of breast cancer: the Ohsaki Cohort Study

A narrative review of sleep and breast cancer: from epidemiology to mechanisms

Breast cancer is the leading cause of cancer-related death and the most common cancer among women worldwide. It is crucial to identify potentially modifiable risk factors to intervene and prevent breast cancer effectively. Sleep factors have emerged as a potentially novel risk factor for female breast cancer. Current epidemiologic studies suggest a significant impact of sleep factors on breast cancer. Exposure to abnormal sleep duration, poor sleep quality, sleep disorders, sleep medication use, or night shift work can increase the risk of breast cancer by decreasing melatonin secretion, disrupting circadian rhythm, compromising immune function, or altering hormone levels. However, there are still controversies regarding the epidemiologic association, and the underlying mechanisms have yet to be fully elucidated. This paper summarizes the epidemiologic evidence on the associations between sleep factors, including sleep duration, sleep quality, sleep disorders, sleep medication use, sleep habits, and night shift work, and the development of breast cancer. The potential mechanisms underlying these associations were also reviewed.

Sleep and Cancer

Background/Objectives: Sleep issues are common in the general population, and these problems occur even more frequently for people with cancer. Sleep problems may pre-exist a patient's cancer diagnosis, and there is a growing interest in understanding the impact of sleep on cancer development and progression. Sleep disorders may impact cancer through altered metabolism, impacts on immune response, and alterations in hormones and gene expression. Sleep disorders may also arise after, or be aggravated by, an individual's cancer and cancer treatment. Treating a person with cancer's sleep disorder may help improve their healing, mental health, cognition, and overall resilience. Methods: Studies examining a variety of aspects of the relationship between sleep and cancer were found by searching the National Library of Medicine and characterized by their specific information provided on the relationship between sleep and cancer. Results: This review article summarizes our current understanding of the complex inter-relationship between sleep and cancer, the underlying mechanisms that create these connections, and the methods and impact of treating sleep issues in cancer patients. The article also outlines an approach to sleep complaints for clinicians caring for patients with cancer. Conclusions: Significant research is still needed to understand the full relationship between sleep disorders and cancer. The impact of sleep issues on cancer and of cancer on sleep appears to be specific to the tissue and the molecular type of cancer. The treatment of sleep disorders is multimodal, and offers a promising avenue to improve the health and quality of life of cancer patients.

Neuroscience of cancer: unraveling the complex interplay between the nervous system, the tumor and the tumor immune microenvironment

The study of the multifaceted interactions between neuroscience and cancer is an emerging field with significant implications for understanding tumor biology and the innovation in therapeutic approaches. Increasing evidence suggests that neurological functions are connected with tumorigenesis. In particular, the peripheral and central nervous systems, synapse, neurotransmitters, and neurotrophins affect tumor progression and metastasis through various regulatory approaches and the tumor immune microenvironment. In this review, we summarized the neurological functions that affect tumorigenesis and metastasis, which are controlled by the central and peripheral nervous systems. We also explored the roles of neurotransmitters and neurotrophins in cancer progression. Moreover, we examined the interplay between the nervous system and the tumor immune microenvironment. We have also identified drugs that target the nervous system for cancer treatment. In this review we present the work supporting that therapeutic agent targeting the nervous system could have significant potential to improve cancer therapy.

Dissecting the genetic and causal relationship between sleep-related traits and common brain disorders

BACKGROUND

There is a profound connection between abnormal sleep patterns and brain disorders, suggesting a shared influential association. However, the shared genetic basis and potential causal relationships between sleep-related traits and brain disorders are yet to be fully elucidated.

METHODS

Utilizing linkage disequilibrium score regression (LDSC) and bidirectional two-sample univariable Mendelian Randomization (UVMR) analyses with large-scale GWAS datasets, we investigated the genetic correlations and causal associations across six sleep traits and 24 prevalent brain disorders. Additionally, a multivariable Mendelian Randomization (MVMR) analysis evaluated the cumulative effects of various sleep traits on each brain disorder, complemented by genetic loci characterization to pinpoint pertinent genes and pathways.

RESULTS

LDSC analysis identified significant genetic correlations in 66 out of 144 (45.8 %) pairs between sleep-related traits and brain disorders, with the most pronounced correlations observed in psychiatric disorders (66 %, 48/72). UVMR analysis identified 29 causal relationships (FDR<0.05) between sleep traits and brain disorders, with 19 associations newly discovered according to our knowledge. Notably, major depression, attention-deficit/hyperactivity disorder, bipolar disorder, cannabis use disorder, and anorexia nervosa showed bidirectional causal relations with sleep traits, especially insomnia's marked influence on major depression (IVW beta 0.468, FDR = 5.24E-09). MVMR analysis revealed a nuanced interplay among various sleep traits and their impact on brain disorders. Genetic loci characterization underscored potential genes, such as HOXB2, while further enrichment analyses illuminated the importance of synaptic processes in these relationships.

CONCLUSIONS

This study provides compelling evidence for the causal relationships and shared genetic backgrounds between common sleep-related traits and brain disorders.

The role of circadian clock in regulating cell functions: implications for diseases

The circadian clock system orchestrates daily behavioral and physiological rhythms, facilitating adaptation to environmental and internal oscillations. Disruptions in circadian rhythms have been linked to increased susceptibility to various diseases and can exacerbate existing conditions. This review delves into the intricate regulation of diurnal gene expression and cell function by circadian clocks across diverse tissues. . Specifically, we explore the rhythmicity of gene expressions, behaviors, and functions in both immune and non-immune cells, elucidating the regulatory effects and mechanisms imposed by circadian clocks. A detailed discussion is centered on elucidating the complex functions of circadian clocks in regulating key cellular signaling pathways. We further review the circadian regulation in diverse diseases, with a focus on inflammatory diseases, cancers, and systemic diseases. By highlighting the intimate interplay between circadian clocks and diseases, especially through clock-controlled cell function, this review contributes to the development of novel disease intervention strategies. This enhanced understanding holds significant promise for the design of targeted therapies that can exploit the circadian regulation mechanisms for improved treatment efficacy.

Beneficial impacts of residential greenness on sleep deprivation in adults aged 19 or older living in South Korea: A nationwide community health survey in 2011-2018

BACKGROUND

Evidence of the relationship between greenness and sleep is limited, and, given the worsening sleep insufficiency worldwide, this relationship needs elucidation. In this study, we investigated the association of greenness with sleep deprivation using nationwide survey data.

METHODS

This study included 1,727,273 participants in the Korea Community Health Survey who resided in all 229 districts of South Korea from 2011 to 2018. Sleep deprivation variables were defined as strong deprivation or mild deprivation, based on average daily sleep duration of <5 or 5-6 h, respectively. District-specific annual average of satellite-derived enhanced vegetation index (EVI) was used as a green space exposure. A logistic regression with complex survey weights was used to estimate the association between greenness and sleep deprivation, and it was further examined by sex, age group, educational status, income level, and population density. The regression analysis was performed annually, and the annual estimates were pooled by a combined data analysis.

RESULTS

A higher level of greenness was associated (odds ratio [95 % confidence interval]) with strong and mild sleep deprivation (0.96 [0.93-0.99] and 0.96 [0.95-0.97]), respectively, and males and the younger age group (<65 years) showed a more prominent association with greenness than in females and the elderly group (65 years or older). In addition, only high-population-density areas showed evident associations of greenness with both strong and mild sleep deprivation.

CONCLUSIONS

This large population-based study provides important epidemiological evidence for improving sleep quantity through an increase in greenness exposure and supports policymakers in establishing strategies for urban planning.

Sleep disorders and cancer incidence: examining duration and severity of diagnosis among veterans

Introduction

Sleep disruption affects biological processes that facilitate carcinogenesis. This retrospective cohort study used de-identified data from the Veterans Administration (VA) electronic medical record system to test the hypothesis that patients with diagnosed sleep disorders had an increased risk of prostate, breast, colorectal, or other cancers (1999-2010, N=663,869). This study builds upon existing evidence by examining whether patients with more severe or longer-duration diagnoses were at a greater risk of these cancers relative to those with a less severe or shorter duration sleep disorder.

Methods

Incident cancer cases were identified in the VA Tumor Registry and sleep disorders were defined by International Classification of Sleep Disorder codes. Analyses were performed using extended Cox regression with sleep disorder diagnosis as a time-varying covariate.

Results

Sleep disorders were present among 56,055 eligible patients (8% of the study population); sleep apnea (46%) and insomnia (40%) were the most common diagnoses. There were 18,181 cancer diagnoses (41% prostate, 12% colorectal, 1% female breast, 46% other). The hazard ratio (HR) for a cancer diagnosis was 1.45 (95% confidence interval [CI]: 1.37, 1.54) among those with any sleep disorder, after adjustment for age, sex, state of residence, and marital status. Risks increased with increasing sleep disorder duration (short [<1-2 years] HR: 1.04 [CI: 1.03-1.06], medium [>2-5 years] 1.23 [1.16-1.32]; long [>5-12 years] 1.52 [1.34-1.73]). Risks also increased with increasing sleep disorder severity using cumulative sleep disorder treatments as a surrogate exposure; African Americans with more severe disorders had greater risks relative to those with fewer treatments and other race groups. Results among patients with only sleep apnea, insomnia, or another sleep disorder were similar to those for all sleep disorders combined.

Discussion

The findings are consistent with other studies indicating that sleep disruption is a cancer risk factor. Optimal sleep and appropriate sleep disorder management are modifiable risk factors that may facilitate cancer prevention.

Night shift work, sleep duration and endometrial cancer risk: A pooled analysis from the Epidemiology of Endometrial Cancer Consortium (E2C2)

Data on the role of circadian related factors in the etiology of endometrial cancer are scarce. We collected individual data on night shift work or daily sleep duration from 7,207 cases and 22,027 controls participating in 11 studies from the Epidemiology of Endometrial Cancer Consortium (E2C2). Main analyses were performed among postmenopausal women: 6,335 endometrial cancer cases and 18,453 controls. Using individual data, study-specific odd ratios (ORs) and their corresponding 95% confidence intervals (CIs) were estimated with logistic regression and pooled analyses were conducted using random-effects meta-analyses. A non-significant inverse association was observed between endometrial cancer and night shift work (OR=0.89, 95%CI=0.72-1.09; I2=0.0%, Pheterogeneity=0.676). Associations did not vary by shift type (permanent or rotating), or duration of night work. Categorizations of short (<7h) or long (≥9h) sleep duration were not associated with endometrial cancer risk (ORshort=1.02, 95%CI=0.95-1.10; I2=55.3%, Pheterogeneity=0.022; ORlong=0.93, 95%CI=0.81-1.06; I2=11.5%, Pheterogeneity=0.339). No associations were observed per 1-h increment of sleep (OR=0.98, 95%CI=0.95-1.01; I2=46.1%, Pheterogeneity=0.063), but an inverse association was identified among obese women (OR=0.93, 95%CI=0.89-0.98 per 1-h increment; I2=12.7%, Pheterogeneity=0.329). Overall, these pooled analyses provide evidence that night shift work and sleep duration are not strong risk factors for endometrial cancer in postmenopausal women.

Relationship of sleep-quality and social-anxiety in patients with breast cancer: a network analysis

BACKGROUND

There is a complex relationship between social anxiety and sleep quality. However, network analysis studies of associations between social anxiety and sleep quality are lacking, particularly among patients with breast cancer. The current study aimed to extend this research to a sample of patients with breast cancer and to examine symptom-level associations between social anxiety and sleep quality using network analysis.

METHODS

Network analysis was conducted to explore their associations and identify bridge items of social anxiety and sleep quality.

RESULTS

The network structure revealed 9 important edges between social anxiety and sleep quality. "Subjective sleep quality" had the highest EI value in the network. "Working difficulty under watching" and "Sleep disorders" had the highest BEI values in their own communities.

CONCLUSION

There are complex pathological correlation pathways between social anxiety and sleep quality in breast cancer patients. "Subjective sleep quality", "Working difficulty under watching" and "Sleep disorders" have the potential to be intervention targets for sleep disorder-social anxiety comorbidity. Medical staff can take corresponding interventions according to the the centrality indices and bridge centrality indicators identified in this study, which is likely to effectively reduce the comorbidity of sleep disorders and social anxiety.

Sleep Deprivation and Its Consequences

OBJECTIVE

This article reviews the clinical, cognitive, behavioral, and physiologic consequences of sleep deprivation in relation to general neurology practice.

LATEST DEVELOPMENTS

Despite being one of the most common sleep problems in modern society, the role of sleep deprivation is underrecognized and underestimated in clinical medicine and general neurology practice. The recognition, diagnosis, and management of sleep deprivation in neurologic practice have only recently received close attention. The consequences of sleep deprivation involve all aspects of general neurology practice, including individuals with neurologic disease, neurologists, communities, and health care systems. The identification and timely management of sleep deprivation symptoms may help to improve symptoms of underlying primary neurologic disorders.

ESSENTIAL POINTS

This article emphasizes complexities related to the identification and evaluation of sleep deprivation in general neurology practice and describes the consequences of sleep deprivation. By recognizing sleep deprivation in patients with neurologic conditions, the neurologist can provide comprehensive care and contribute to improved clinical and neurologic outcomes.

Dietary insulinemic potential, sleep quality and quantity in Iranian adults: Yazd health study and TAMYZ study

BACKGROUND & AIMS

To examine the link between dietary insulin index (DII) and load (DIL) and sleep duration/quality for the first time.

METHODS

This cross-sectional study conducted on data from the recruitment phase of Yazd Health Study (YaHS)-Yazd Nutrition Study (TAMYZ), prospective study in Yazd, central Iran. Data on demographic characteristics, dietary intakes, sleep quantity and quality, and potential confounders were gathered by interview. Sleep quality and its components (insufficient sleep, delay in falling asleep, medication use for sleep, and sleep disorder) were assessed by a modified version of Pittsburgh questionnaire. The link between DII/DIL and low sleep quality and short/long sleep duration was studied using multivariable logistic regression.

RESULTS

In total, 5925 individuals aged 20 to 70 were eligible to take part in the current study. After adjustment for all potential confounders, participants in the highest DIL score tertile had a lower chance for sleep disorder (OR = 0.38; 95%CI: 0.17-0.85, Ptrend = 0.02) and delay in falling asleep (OR = 0.66; 95%CI: 0.42-1.03, Ptrend = 0.05) compared to those in the lowest tertile. The DII was also linked to a lower chance for sleep disorder (OR = 0.61; 95% CI: 0.39-0.93, P trend = 0.02). The DIL was inversely associated with sleep medication use and delay in falling sleep in men and women, respectively (P < 0.05). Moreover, DII was linked to a decreased odds of sleep disorder in women (P < 0.05). The associations were observed in those with overweight or obesity but not in those without overweight (P < 0.05).

CONCLUSION

Higher DIL and DII might be associated with sleep quality and its components. Prospective investigations are needed in the future to confirm these findings.

Sleep Deprivation and Gut Microbiota Dysbiosis: Current Understandings and Implications

Gut microbiota comprises the microbial communities inhabiting our gastrointestinal (GI) tracts. Accordingly, these complex communities play a fundamental role in many host processes and are closely implicated in human health and diseases. Sleep deprivation (SD) has become increasingly common in modern society, partly owing to the rising pressure of work and the diversification of entertainment. It is well documented that sleep loss is a significant cause of various adverse outcomes on human health including immune-related and metabolic diseases. Furthermore, accumulating evidence suggests that gut microbiota dysbiosis is associated with these SD-induced human diseases. In this review, we summarize the gut microbiota dysbiosis caused by SD and the succedent diseases ranging from the immune system and metabolic system to various organs and highlight the critical roles of gut microbiota in these diseases. The implications and possible strategies to alleviate SD-related human diseases are also provided.

The neural addiction of cancer

The recently uncovered key role of the peripheral and central nervous systems in controlling tumorigenesis and metastasis has opened a new area of research to identify innovative approaches against cancer. Although the 'neural addiction' of cancer is only partially understood, in this Perspective we discuss the current knowledge and perspectives on peripheral and central nerve circuitries and brain areas that can support tumorigenesis and metastasis and the possible reciprocal influence that the brain and peripheral tumours exert on one another. Tumours can build up local autonomic and sensory nerve networks and are able to develop a long-distance relationship with the brain through circulating adipokines, inflammatory cytokines, neurotrophic factors or afferent nerve inputs, to promote cancer initiation, growth and dissemination. In turn, the central nervous system can affect tumour development and metastasis through the activation or dysregulation of specific central neural areas or circuits, as well as neuroendocrine, neuroimmune or neurovascular systems. Studying neural circuitries in the brain and tumours, as well as understanding how the brain communicates with the tumour or how intratumour nerves interplay with the tumour microenvironment, can reveal unrecognized mechanisms that promote cancer development and progression and open up opportunities for the development of novel therapeutic strategies. Targeting the dysregulated peripheral and central nervous systems might represent a novel strategy for next-generation cancer treatment that could, in part, be achieved through the repurposing of neuropsychiatric drugs in oncology.

Sleep duration and the onset of menopause in Japanese women

OBJECTIVE

Sleep characteristics may potentially affect the hormonal environment related to follicular degeneration. The present study aimed to examine the association between sleep duration and the onset of menopause in Japanese women.

METHODS

We conducted a prospective study among 3,090 premenopausal Japanese women aged 35 to 56 years derived from participants in the Takayama Study. Habitual sleep duration was determined by a self-administered questionnaire at the baseline. Menopausal status was defined as the absence of menstruation for 12 months or more. The Cox proportional hazard model was used to estimate the hazard ratio of the occurrence of menopause for each category of sleep duration (≤6, 8, and ≥9 h) as compared with 7 hours of sleep after controlling for age, parity, body mass index, smoking status, years of education, and lifelong irregular menstrual cycle.

RESULTS

During the 10 follow-up years, 1,776 women experienced natural menopause. Sleep duration of ≤6 hours was significantly associated with decreased hazard ratio of menopause (0.88; 95% confidence interval, 0.78-0.99).

CONCLUSIONS

The data suggest that short sleep duration is associated with later onset of menopause.

Sleep-related factors and circulating levels of sex hormones in premenopausal Japanese women

Sleep disruption and circadian disruption have been proposed to be risk factors of breast cancer. The present study examined the associations of sleep-related factors, referring to night shift work, sleep habits, and sleep disturbances, with the plasma levels of sex hormones in premenopausal Japanese women. Study participants were 432 women who had regular menstrual cycles less than 40 days long. Information on their history of night shift work and sleep disturbances was obtained using a self-administered questionnaire. Information on their sleep habits, such as usual wake-up times, bedtimes, and ambient light level while sleeping, was obtained in an interview. The participants' height and weight were measured. Plasma concentrations of estradiol, testosterone, dehydroepiandrosterone sulfate, sex hormone-binding globulin (SHBG), FSH, and LH were also measured. After controlling for the phase of the menstrual cycle and other covariates, more years of night shift work ≥ once a week during the past 10 years was significantly associated with a lower SHBG and a higher free estradiol level. Shorter sleep duration was significantly associated with the higher total, bioavailable, and free testosterone levels. Sleep disturbance by awaking after sleep onset was significantly associated with a high free estradiol level. The data suggest that long-term night shift work, short sleep duration, and arousal during sleep are associated with higher estradiol or testosterone levels in premenopausal women.

Circadian Disruption and Breast Cancer Risk: Evidence from a Case-Control Study in China

Studies had suggested an association between circadian disruptors (including night shift work, domestic light exposure at night, sleep duration, and circadian gene polymorphism) and breast cancer, while rare studies had been conducted in the Chinese population. This study was a case-control study conducted to explore the impact of circadian disruptors on the risk of breast cancer in China. Four hundred and sixty-four cases and 464 controls, admitted from the Department of Breast Surgery, Cancer Hospital, Chinese Academy of Medical Sciences, were included in this study. Adjusting age, BMI group, smoking, alcohol consumption, menopausal status, family history of breast cancer, duration of breastfeeding, age at menarche, number of pregnancies, age at first full-term pregnancy, use of estrogen and use of oral contraceptive, multivariate logistic regression analysis showed that the risk of breast cancer was higher in short sleep duration group (OR = 4.86, 95%CI: 1.73-17.33). Meanwhile, rs2292912 in CRY2, rs2253820 in PER1, rs2289591 in PER1 and rs3027188 in PER1 were positively associated with the risk of breast cancer. This study supported that the short duration of sleep and four SNPs in crucial circadian genes played a role in the development of breast cancer.

Association between working hours and cancer risk in Japan: The Japan public health center-based prospective study

OBJECTIVES

In this study, we evaluated the association between working hours and cancer risk in the Japanese population, which has not been evaluated.

METHODS

Using a cohort database from a Japan Public Health Center-based Prospective Study, we evaluated 26 738 participants (16 351 men and 10 387 women), who responded to a questionnaire about working hours and followed these participants from 1993-1994 to 2013. Participants were divided into four groups according to working hours (≤6, 7-8, 9-10, ≥11 h/day). The hazard ratio (HR) and 95% confidence interval (CI) of each cancer incidence were calculated using a multivariable-adjusted Cox proportional hazard model.

RESULTS

During 488 383 person-years of follow-up, 481 patients with newly diagnosed cancers were identified. There was no clear association between long working hours and overall cancer, lung cancer, and stomach cancer risks. Long working hours tended to increase prostate cancer risk in men and breast cancer risk in women, although the difference was not statistically significant. Increased liver cancer risk with short working hours (HR [95% CI]; 3.15 [1.44-6.88] in the ≤6 h/day group vs. 7-8 h/day) was observed. Colorectal cancer also tended to increase risk in short working hours, however, there were not statistically significance.

CONCLUSIONS

In this population, long working hours were not associated with cancer risk with statistically significance. The association between short working hours and liver cancer risk was observed, probably due to the reverse causation of liver cancer.

Cancer sleep symptom-related phenotypic clustering differs across three cancer specific patient cohorts

Specific sleep disorders have been linked to disease progression in different cancers. We hypothesised sleep symptom clusters would differ between cancer types. The aim of this study was to compare sleep symptom clusters in post-treatment melanoma, breast and endometrial cancer patients. Data were collected from 124 breast cancer patients (1 male, 60 ± 15 years, 28.1 ± 6.6 kg/m2 ), 82 endometrial cancer patients (64.0 ± 12.5 years, 33.5 ± 10.4 kg/m2 ) and 112 melanoma patients (59 male, 65.0 ± 18.0 years, 29.1 ± 6.6 kg/m2 ). All patients completed validated questionnaires to assess sleep symptoms, including the Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and Functional Outcomes of Sleep Questionnaire-10 (FOSQ-10). Snoring, tiredness, observed apneas, age, BMI, and gender data were also collected. Binary values (PSQI, ISI, FOSQ), or continuous variables for sleepiness (ESS) and perceived sleep quality (PSQI), were created and sleep symptom clusters were identified and compared across cancer cohorts. Four distinct sleep symptom clusters were identified: minimally symptomatic (n = 152, 47.7%); insomnia-predominant (n = 87, 24.9%); very sleepy with upper airway symptoms (n = 51, 16.3%), and severely symptomatic with severe dysfunction (n = 34, 11.1%). Breast cancer patients were significantly more likely to be in the insomnia predominant or severely symptomatic with severe dysfunction clusters, whereas melanoma patients were more likely to be minimally symptomatic or sleepy with upper airway symptoms (p <0.0001). Endometrial cancer patients were equally distributed across symptom clusters. Sleep symptom clusters vary across cancer patients. A more personalised approach to the management of sleep-related symptoms in these patients may improve the long term quality of life and survival.

Sleep Quality and Dietary Patterns in an Occupational Cohort of Police Officers

We examined the association between self-reported sleep quality, sleep duration, and dietary patterns among police officers in the Buffalo Cardio-Metabolic Occupational Stress (BCOPS) study.422 police officers aged 21-74 (2004-2009).We used a cross-sectional study design and obtained sleep quality and duration from responses to the 19-item Pittsburgh Sleep Quality Index. Using 46 energy-adjusted food groups derived from a 125-item food frequency questionnaire, we identified dietary patterns using exploratory factor analysis. Multiple linear regression analysis was used to examine the associations of sleep quality and duration with the derived dietary patterns.We identified major dietary patterns: fruits and vegetables (FV), dairy products, starches and fried foods, and meat and eggs. Individuals with poor sleep quality had a lower average FV score than those with optimal sleep (β [SE] = -0.32 [0.13]; p = .01). Significant interactions were observed between sex and the FV and dairy products dietary patterns, where women with poor sleep quality had a lower mean FV score compared to women with optimal sleep quality (β [SE] = -0.81 [0.29]; p = .01). Women with < 6 hours sleep duration had a lower mean dairy score compared to women with ≥ 7 hours sleep duration (β [SE] = -0.69 [0.29]; p = .02). We did not observe these associations among men.Among women, good sleep quality and long sleep duration were associated with a dietary pattern high in consumption of both fruits and vegetables and dairy products.Abbreviations: BCOPS: Buffalo Cardio-Metabolic Occupational Stress study; BMI: body mass index; FFQ: food frequency questionnaire; FV: fruits and vegetables; KMO: Kaiser-Meyer-Olkin test; MET: metabolic equivalent of task score; PSQI: Pittsburgh Sleep Quality Index questionnaire.

Association of sleep duration, sleep apnea, and shift work with risk of colorectal neoplasms: a systematic review and meta-analysis

Background

Although studies have reported that certain sleep characteristics, such as sleep duration and sleep apnea, are linked to the risk of colorectal cancer (CRC), this link remains contentious because of the limited evidence from individual studies. Furthermore, evidence indicated that shift work involving circadian disruption as a probable human carcinogen. This systematic review and meta-analysis aimed to examine the associations between sleep duration, sleep apnea, and shift work with the risk of colorectal neoplasms, including CRC and colorectal adenoma (CRA).

Methods

We conducted a comprehensive literature search in PubMed, Embase, and Web of Science databases. The inclusion criteria were determined using PICOS principles. Observational studies reporting associations of sleep duration, sleep apnea, or shift work with risk of CRC or CRA were included. We assessed the risk of bias on the basis of the Newcastle-Ottawa Scale.

Results

A total of 18 observational studies were included. Of these studies, nine studies reported the effect of sleep duration on risk of colorectal neoplasms, five reported the effect of sleep apnea, and six reported the effect of shift work. The relative risk (RR) for colorectal neoplasms was 1.06 [95% confidence interval (CI): 0.94, 1.20] in the short sleep duration group compared with the moderate sleep duration group. Long sleep duration was associated with an increased risk of colorectal neoplasms (RR: 1.33, 95% CI: 1.07, 1.65). The pooled results showed that sleep apnea was associated with an increased risk of colorectal neoplasms (RR: 1.75, 95% CI: 1.56, 1.97). Furthermore, results showed that the association between shift work and the risk of colorectal neoplasms was not significant (RR: 1.06, 95% CI: 0.95, 1.17). No publication bias was observed in all the analyses (all P>0.05). The sensitivity analysis showed that no individual study substantially influenced the pooled RRs for colorectal neoplasms and CRC.

Conclusions

Our findings suggest the significant positive association of long sleep duration and sleep apnea with risk of colorectal neoplasms and CRC. Given that sleep characteristics may be a potentially modifiable risk factor for colorectal neoplasms, further understanding of its role in carcinogenesis will provide valuable insight for cancer prevention.

Sleep duration and risk of cancer incidence and mortality: a pooled analysis of six population-based cohorts in Japan

Sleep duration is emerging as an important modifiable risk factor for morbidity and mortality. We assessed the association between sleep duration and cancer incidence and mortality among Japanese adults using data from six population-based cohorts with 271 694 participants. During a total follow-up period of about 5.9 million person-years, we identified 40 751 incident cancer cases and 18 323 cancer deaths. We computed study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional hazards regression models and pooled the estimates using random-effects meta-analysis. Sleep duration of ≥ 10 h (vs. 7 h) was associated with increased risk of cancer incidence among women (HR 1.19, 95% CI 1.02-1.38), but not men, and increased risk of cancer mortality among men (HR 1.18, 95% CI 1.00-1.39) and women (HR 1.44, 95% CI 1.20-1.73). Sleep duration of ≤ 5 h (vs. 7 h) was not associated with cancer incidence and mortality. However, among post-menopausal women, sleep durations of both ≤ 5 h and ≥ 10 h (vs. 7 h) were associated with an increased risk of cancer mortality. Among Japanese adults, sleep duration of ≥ 10 h is associated with increased risk of cancer incidence and mortality among women and cancer mortality among men. This article is protected by copyright. All rights reserved.

Sleep Disruption and Cancer: Chicken or the Egg?

Sleep is a nearly ubiquitous phenomenon across the phylogenetic tree, highlighting its essential role in ensuring fitness across evolutionary time. Consequently, chronic disruption of the duration, timing, or structure of sleep can cause widespread problems in multiple physiological systems, including those that regulate energy balance, immune function, and cognitive capacity, among others. Many, if not all these systems, become altered throughout the course of cancer initiation, growth, metastatic spread, treatment, and recurrence. Recent work has demonstrated how changes in sleep influence the development of chronic diseases, including cancer, in both humans and animal models. A common finding is that for some cancers (e.g., breast), chronic disruption of sleep/wake states prior to disease onset is associated with an increased risk for cancer development. Additionally, sleep disruption after cancer initiation is often associated with worse outcomes. Recently, evidence suggesting that cancer itself can affect neuronal circuits controlling sleep and wakefulness has accumulated. Patients with cancer often report difficulty falling asleep, difficulty staying asleep, and severe fatigue, during and even years after treatment. In addition to the psychological stress associated with cancer, cancer itself may alter sleep homeostasis through changes to host physiology and via currently undefined mechanisms. Moreover, cancer treatments (e.g., chemotherapy, radiation, hormonal, and surgical) may further worsen sleep problems through complex biological processes yet to be fully understood. This results in a "chicken or the egg" phenomenon, where it is unclear whether sleep disruption promotes cancer or cancer reciprocally disrupts sleep. This review will discuss existing evidence for both hypotheses and present a framework through which the interactions between sleep and cancer can be dissociated and causally investigated.

Identification of Smartwatch-Collected Lifelog Variables Affecting Body Mass Index in Middle-Aged People Using Regression Machine Learning Algorithms and SHapley Additive Explanations

Body mass index (BMI) plays a vital role in determining the health of middle-aged people, and a high BMI is associated with various chronic diseases. This study aims to identify important lifelog factors related to BMI. The sleep, gait, and body data of 47 middle-aged women and 71 middle-aged men were collected using smartwatches. Variables were derived to examine the relationships between these factors and BMI. The data were divided into groups according to height based on the definition of BMI as the most influential variable. The data were analyzed using regression and tree-based models: Ridge Regression, eXtreme Gradient Boosting (XGBoost), and Category Boosting (CatBoost). Moreover, the importance of the BMI variables was visualized and examined using the SHapley Additive Explanations Technique (SHAP). The results showed that total sleep time, average morning gait speed, and sleep efficiency significantly affected BMI. However, the variables with the most substantial effects differed among the height groups. This indicates that the factors most profoundly affecting BMI differ according to body characteristics, suggesting the possibility of developing efficient methods for personalized healthcare.

Molecular regulations of circadian rhythm and implications for physiology and diseases

The term “circadian rhythms” describes endogenous oscillations with ca. 24-h period associated with the earth’s daily rotation and light/dark cycle. Such rhythms reflect the existence of an intrinsic circadian clock that temporally orchestrates physiological processes to adapt the internal environment with the external cues. At the molecular level, the circadian clock consists of multiple sets of transcription factors resulting in autoregulatory transcription-translation feedback loops. Notably, in addition to their primary role as generator of circadian rhythm, the biological clock plays a key role in controlling physiological functions of almost all tissues and organs. It regulates several intracellular signaling pathways, ranging from cell proliferation, DNA damage repair and response, angiogenesis, metabolic and redox homeostasis, to inflammatory and immune response. In this review, we summarize findings showing the crosstalk between the circadian molecular clock and some key intracellular pathways, describing a scenario wherein their reciprocal regulation impinges upon several aspects of mammalian physiology. Moreover, based on evidence indicating that circadian rhythms can be challenged by environmental factors, social behaviors, as well as pre-existing pathological conditions, we discuss implications of circadian misalignment in human pathologies, such as cancer and inflammatory diseases. Accordingly, disruption of circadian rhythm has been reported to affect several physiological processes that are relevant to human diseases. Expanding our understanding of this field represents an intriguing and transversal medicine challenge in order to establish a circadian precision medicine.

Genetic Liability to Insomnia and Lung Cancer Risk: A Mendelian Randomization Analysis

Lung cancer is the second most frequently diagnosed cancer and the leading cause of cancer death worldwide, making its prevention an urgent issue. Meanwhile, the estimated prevalence of insomnia was as high as 30% globally. Research on the causal effect of insomnia on lung cancer incidence is still lacking. In this study, we aimed to assess the causality between the genetic liability to insomnia and lung cancer. We performed a two-sample Mendelian randomization analysis (inverse variance weighted) to determine the causality between the genetic liability to insomnia and lung cancer. Subgroup analysis was conducted, which included lung adenocarcinoma and lung squamous cell carcinoma. In the sensitivity analysis, we conducted heterogeneity test, MR Egger, single SNP analysis, leave-one-out analysis, and MR PRESSO. There were causalities between the genetic susceptibility to insomnia and increased incidence of lung cancer [odds ratio (95% confidence interval), 1.35 (1.14-1.59); P, < 0.001], lung adenocarcinoma [odds ratio (95% confidence interval), 1.35 (1.07-1.70); P, 0.01], and lung squamous cell carcinoma [odds ratio (95% confidence interval), 1.35 (1.06-1.72), P, 0.02]. No violation of Mendelian randomization assumptions was observed in the sensitivity analysis. There was a causal relationship between the genetic susceptibility to insomnia and the lung cancer, which was also observed in lung adenocarcinoma and lung squamous cell carcinoma. The underlying mechanism remains unknown. Effective intervention and management for insomnia were recommended to improve the sleep quality and to prevent lung cancer. Moreover, regular screening for lung cancer may be beneficial for patients with insomnia.

Perceptions of Work-Related Health and Cancer Risks Among Women Firefighters: A Qualitative Study

OBJECTIVES

We use a qualitative method to gain further insight into women firefighters' experiences, perceptions of cancer, health, and safety risks in the fire service.

METHODS

We conducted six focus groups with U.S. women firefighters. Participants engaged in a 60 to 75-minute, semi-structured discussion and completed a sociodemographic questionnaire. A qualitative descriptive approach was used to inductively create themes. Data collection concluded when saturation was met.

RESULTS

Forty-nine women firefighters participated. Qualitative results indicated the main health concerns include: occupational cancer risks including, risks related to hazardous exposures, sleep disruption and stress; and women's health concerns including, cancer, pregnancy and breastfeeding, and lack of resources.

CONCLUSIONS

Women firefighters are concerned about their risk for cancer due to their occupation and identify a lack of resources specific to health and safety needs of women firefighters.

Effects of poor sleep on the immune cell landscape as assessed by single-cell analysis

Poor sleep has become an important public health issue. With loss of sleep durations, poor sleep has been linked to the increased risks for diseases. Here we employed mass cytometry and single-cell RNA sequencing to obtain a comprehensive human immune cells landscape in the context of poor sleep, which was analyzed in the context of subset composition, gene signatures, enriched pathways, transcriptional regulatory networks, and intercellular interactions. Participants subjected to staying up had increased T and plasma cell frequency, along with upregulated autoimmune-related markers and pathways in CD4⁺ T and B cells. Additionally, staying up reduced the differentiation and immune activity of cytotoxic cells, indicative of a predisposition to infection and tumor development. Finally, staying up influenced myeloid subsets distribution and induced inflammation development and cellular senescence. These findings could potentially give high-dimensional and advanced insights for understanding the cellular and molecular mechanisms of pathologic conditions related to poor sleep.

Role of sleep deprivation in immune-related disease risk and outcomes

Modern societies are experiencing an increasing trend of reduced sleep duration, with nocturnal sleeping time below the recommended ranges for health. Epidemiological and laboratory studies have demonstrated detrimental effects of sleep deprivation on health. Sleep exerts an immune-supportive function, promoting host defense against infection and inflammatory insults. Sleep deprivation has been associated with alterations of innate and adaptive immune parameters, leading to a chronic inflammatory state and an increased risk for infectious/inflammatory pathologies, including cardiometabolic, neoplastic, autoimmune and neurodegenerative diseases. Here, we review recent advancements on the immune responses to sleep deprivation as evidenced by experimental and epidemiological studies, the pathophysiology, and the role for the sleep deprivation-induced immune changes in increasing the risk for chronic diseases. Gaps in knowledge and methodological pitfalls still remain. Further understanding of the causal relationship between sleep deprivation and immune deregulation would help to identify individuals at risk for disease and to prevent adverse health outcomes.

Genetically predicted insomnia and lung cancer risk: a Mendelian randomization study

BACKGROUND

The relationship between insomnia and lung cancer is scanty. The Mendelian randomization approach provides the rationale for evaluating the potential causality between genetically-predicted insomnia and lung cancer risk.

METHODS

We extracted 148 insomnia-related single-nucleotide polymorphisms (SNPs) as instrumental variables (IVs) from published genome-wide association studies (GWASs). Summary data of individual-level genetic information of participants were obtained from the International Lung Cancer Consortium (ILCCO) (29,266 cases and 56,450 controls). MR analyses were performed using the inverse-variance-weighted approach, MR pleiotropy residual sum and outlier (MR-PRESSO) test, weighted median estimator, and MR-Egger regression. Sensitivity analyses were further performed using Egger intercept analysis, leave-one-out analysis, MR-PRESSO global test, and Cochran's Q test to verify the robustness of our findings.

RESULTS

The results of the MR analysis indicated an increased risk of lung cancer in insomnia patients (OR = 1.1671; 95% CI 1.0754-1.2666, p = 0.0002). The subgroup analyses showed increased risks of lung adenocarcinoma (OR = 1.1878; 95% CI 1.0594-1.3317, p = 0.0032) and squamous cell lung cancer (OR = 1.1595; 95% CI 1.0248-1.3119, p = 0.0188).

CONCLUSION

Our study indicated that insomnia is a causal risk factor in the development of lung cancer. Due to the lack of evidence on both the epidemiology and the mechanism level, more studies are needed to better elucidate the results of the study.

Sleep duration and severe periodontitis in middle-aged Japanese workers

AIM

To evaluate the association between sleep duration and severe periodontitis in Japanese workers.

MATERIALS AND METHODS

This cross-sectional study included 1130 workers (mean age 43.0 years) who underwent full-mouth periodontal examinations and health check-ups and completed a self-administered questionnaire that included questions on sleep duration. Logistic regression and a restricted cubic spline model were used to analyse the data.

RESULTS

Severe periodontitis was identified in 6.3% of the study population. Those with <5, 5-5.9, 6-6.9, 7-7.9, and ≥8 hr of sleep were 6.7%, 17.4%, 40.3%, 26.3%, and 8.9%, respectively. After adjusting for potential confounders, study participants who slept <5 hr were more likely to have severe periodontitis (adjusted odds ratio = 2.64; 95% confidence interval = 1.06-6.60) than those who slept 7-7.9 hr. The spline model, with a reference value of 399 min (the median sleep duration), showed a non-linear association between sleep duration and severe periodontitis, where an increased prevalence of severe periodontitis was observed only among those with a shorter sleep duration. The prevalence of severe periodontitis did not increase with longer sleep duration.

CONCLUSIONS

Short sleep duration was associated with severe periodontitis in this cohort of Japanese adults.

Relation of repeated exposures to air emissions from swine industrial livestock operations to sleep duration and awakenings in nearby residential communities

OBJECTIVES

Since waste from swine industrial livestock operations (ILOs) produces air pollutants associated with negative health outcomes among nearby residents, we assessed the impact of odorant emissions on sleep duration and awakenings.

DESIGN

A repeated-measures design.

SETTING

Sixteen residential communities in eastern North Carolina hosting swine ILOs.

PARTICIPANTS

Eighty participants residing in eastern North Carolina from 2003 to 2005.

INTERVENTION (IF ANY)

Not applicable.

MEASUREMENTS

Study participants completed twice-daily diaries in which they rated the strength of hog odors and indicated whether they were asleep or awake per hour for 2 weeks. Simultaneously, a monitoring trailer placed in a central location in each community measured the atmospheric concentration of hydrogen sulfide (H₂S). Subject-conditional fixed-effects regression models were used to estimate associations between 2 markers of swine ILO pollutant exposures (H₂S and swine odor) and 2 self-reported sleep outcomes (nightly sleep duration and awakening from sleep).

RESULTS

Among 80 participants, nightly (across a 12-hour period) swine odor was associated with lower nightly sleep duration (mean difference = -14.3 minutes, 95% confidence interval -25.0 to -3.3 minutes) compared to odor-free nights and detection of nightly hydrogen sulfide was associated with an increased risk of awakening (hazard ratio = 1.23, 95% confidence interval 0.98 to 1.55) compared to nights with no detection of hydrogen sulfide.

CONCLUSIONS

These results suggest that environmental odorants are important considerations for sleep health and highlight the importance of sleep as a potential mediator between environmental air pollution and health outcomes impacted by poor sleep.

Sleep duration and breast cancer incidence: results from the Million Women Study and meta-analysis of published prospective studies

STUDY OBJECTIVES

To investigate the association between sleep duration and breast cancer incidence, we examined the association in a large UK prospective study and conducted a meta-analysis of prospective studies.

METHODS

In the Million Women Study, usual sleep duration over a 24-h period was collected in 2001 for 713,150 participants without prior cancer, heart problems, stroke, or diabetes (mean age = 60 years). Follow-up for breast cancer was by record linkage to national cancer registry data for 14.3 years on average from the 3-year resurvey. Cox regression models yielded multivariable-adjusted breast cancer relative risks (RR) and 95% confidence intervals (CIs) for sleep duration categories. Published prospective studies of sleep duration and breast cancer risk were included in a meta-analysis, which estimated the inverse-variance weighted average of study-specific log RRs for short and for long versus average duration sleep.

RESULTS

After excluding the first 5 years to minimize reverse causation bias in the Million Women Study, 24,476 women developed breast cancer. Compared with 7-8 h of sleep, the RRs for <6, 6, 9, and >9 h of sleep were 1.01 (95% CI, 0.95-1.07), 0.99 (0.96-1.03), 1.01 (0.96-1.06), and 1.03 (0.95-1.12), respectively. In a meta-analysis of 14 prospective studies plus the Million Women Study, including 65,410 breast cancer cases, neither short (RR < 7 h = 0.99 [0.98-1.01]) nor long (RR > 8 h = 1.01 [0.98-1.04]) versus average duration sleep was associated with breast cancer risk.

CONCLUSIONS

The totality of the prospective evidence does not support an association between sleep duration and breast cancer risk.

Sleep deficiency and breast cancer risk among postmenopausal women in the California teachers study (CTS)

PURPOSE

There is provocative, yet inconsistent, evidence that sleep deficiency may influence the development of breast cancer. The purpose of this study was to evaluate the risk of breast cancer associated with sleep deficiency among postmenopausal women in the California Teachers Study (CTS).

METHODS

We conducted a case-control study of 2,856 invasive breast cancer cases and 38,649 cancer-free controls, nested within the CTS. Self-administered questionnaires were used to ascertain several components of sleep deficiency, including quality, latency, duration, disturbance and use of sleep medications. Additionally, a Global Sleep Index (GSI) was created by summing the individual sleep components and categorizing into quartiles. Multivariable logistic regression analyses were used to estimate odds ratios and 95% confidence intervals (OR, 95% CI).

RESULTS

Increased breast cancer risks were associated with sleep deficiency. With the exception of duration, linear increases in risk were associated with all the other individual components of sleep deficiency (p-trend ≤ 0.002). The OR for the highest GSI quartile vs. lowest was 1.24, 95% CI 1.12-1.38; p-trend < 0.001).

CONCLUSIONS

Sleep deficiency may be a risk factor for breast cancer. Additional prospective studies and those aimed at elucidating underlying mechanism are warranted.

Do malignant cells sleep at night?

Biological rhythms regulate the biology of most, if not all living creatures, from whole organisms to their constitutive cells, their microbiota, and also parasites. Here, we present the hypothesis that internal and external ecological variations induced by biological cycles also influence or are exploited by cancer cells, especially by circulating tumor cells, the key players in the metastatic cascade. We then discuss the possible clinical implications of the effect of biological cycles on cancer progression, and how they could be exploited to improve and standardize methods used in the liquid biopsy field.

Dopamine Receptor D2 Gene (DRD2) Polymorphisms, Job Stress, and Their Interaction on Sleep Dysfunction

Recent studies have shown that incessant job stress could eventually result in sleep dysfunction (SD), and most importantly, the essential role dopamine receptor D2 (DRD2) gene polymorphisms play in the psychopathological mechanism of SD. The Effort-Reward Imbalance scale and the Pittsburgh Sleep Quality Index were both used to access SD and job stress (JS). A significant negative correlation was observed between the sDA levels and SD subscale scores (sleep efficiency, daytime dysfunction). The findings revealed that high levels of JS were linked to a higher SD score (OR = 2.13, 95% CI: 1.46–3.12). Likewise, the homozygous A1A1 genotype of DRD2 rs1800497 was more likely to be associated with SD (OR = 2.90, 95% CI: 1.75–4.82). Compared to participants with low JS and heterozygous A1A2/A2A2 genotype, those with both high JS and homozygous A1A1 genotype had a higher SD score (OR = 5.40, 95% CI: 2.89–10.11). The A1 allele of the DRD2 rs1800497 polymorphism also enhances the likelihood of SD when undergoing JS. Besides, subjects with low JS and the homozygous A1A1 genotype also showed an increased possibility for sleep dysfunction (OR = 2.05, 95% CI: 1.03–4.11). Our results suggest that the DA system may interrelate with JS to affect sleep.

Effects of probiotics and paraprobiotics on subjective and objective sleep metrics: a systematic review and meta-analysis

Inadequate sleep (i.e., duration and/or quality) is becoming increasingly recognized as a global public health issue. Interaction via the gut-brain axis suggests that modification of the gut microbial environment via supplementation with live microorganisms (probiotics) or nonviable microorganisms/microbial cell fractions (paraprobiotics) may improve sleep health. This systematic review and meta-analysis aimed to clarify the effect of consuming probiotics/paraprobiotics on subjective and objective sleep metrics. Online databases were searched from 1980 to October 2019 for studies involving adults who consumed probiotics or paraprobiotics in controlled trials, during which, changes in subjective and/or objective sleep parameters were examined. A total of 14 studies (20 trials) were included in meta-analysis. Random effects meta-analyses indicated that probiotics/paraprobiotics supplementation significantly reduced Pittsburgh Sleep Quality Index (PSQI) score (i.e., improved sleep quality) relative to baseline (-0.78-points, 95% confidence interval: 0.395-1.166; p < 0.001). No significant effect was found for changes on other subjective sleep scales, nor objective parameters of sleep (efficiency/latency) measured using polysomnography or actigraphy. Subgroup analysis for PSQI data suggested that the magnitude of the effect was greater (although not statistically) in healthy participants than those with a medical condition, when treatment contained a single (rather than multiple) strain of probiotic bacteria, and when the duration of treatment was ≥8 weeks. Probiotics/paraprobiotics supplementation may have some efficacy in improving perceived sleep health, measured using the PSQI. While current evidence does not support a benefit of consuming probiotics/paraprobiotics when measured by other subjective sleep scales, nor objective measures of sleep; more studies using well-controlled, within-subject experimental designs are needed.

The Association Between Smartphone Use and Breast Cancer Risk Among Taiwanese Women: A Case-Control Study

Introduction

Breast cancer is a common malignancy worldwide. Smartphones have gradually become indispensable to our modern lives and have already changed lifestyles of human beings. To our best knowledge, no study has investigated the relationship between smartphone use and breast cancer. This case-control study purposely investigated the relationship between smartphone use and breast cancer risk.

Materials and Methods

This was a case-control study comprising 894 healthy controls and 211 patients with breast cancer. All participants were asked to respond to standard questionnaires to collect information on sleep quality, smartphone addiction, and smartphone use.

Results

Participants with smartphone addiction had a significantly higher 1.43-fold risk of breast cancer. Individuals with the habitual behavior of smartphone use >4.5 minutes before bedtime had a significantly increased 5.27-fold risk of breast cancer compared to those who used a smartphone for ≤4.5 minutes before bedtime. Additionally, a closer distance between the smartphone and the breasts when using the smartphone exhibited a significantly increased 1.59-fold risk. Participants who carried their smartphone near their chest or waist-abdomen area had significantly increased 5.03-fold and 4.06-fold risks of breast cancer, respectively, compared to those who carried the smartphone below the waist. Moreover, there was a synergistic effect of smartphone addiction and smartphone use of >4.5 minutes before bedtime which increased the breast cancer risk.

Conclusion

Excessive smartphone use significantly increased the risk of breast cancer, particularly for participants with smartphone addiction, a close distance between the breasts and smartphone, and the habit of smartphone use before bedtime.

The Association of Sleep Disorders, Obesity and Sleep-Related Hypoxia with Cancer

BACKGROUND

Sleep disorders have emerged as potential cancer risk factors.

OBJECTIVE

This review discusses the relationships between sleep, obesity, and breathing disorders with concomitant risks of developing cancer.

RESULTS

Sleep disorders result in abnormal expression of clock genes, decreased immunity, and melatonin release disruption. Therefore, these disorders may contribute to cancer development. Moreover, in sleep breathing disorder, which is frequently experienced by obese persons, the sufferer experiences intermittent hypoxia that may stimulate cancer cell proliferation.

DISCUSSION

During short- or long- duration sleep, sleep-wake rhythm disruption may occur. Insomnia and obstructive sleep apnea increase cancer risks. In short sleepers, an increased risk of stomach cancer, esophageal squamous cell cancer, and breast cancer was observed. Among long sleepers (>9 hours), the risk of some hematologic malignancies is elevated.

CONCLUSION

Several factors including insomnia, circadian disruption, obesity, and intermittent hypoxia in obstructive sleep apnea are contributing risk factors for increased risk of several types of cancers. However, further studies are needed to determine the more significant of these risk factors and their interactions.

Sleep deprivation and its association with diseases- a review

Sleep deprivation, a consequence of multiple health problems or a cause of many major health risks, is a significant public health concern in this era. In the recent years, numerous reports have been added to the literature to provide explanation and to answer previously unanswered questions on this important topic but comprehensive updates and reviews in this aspect remain scarce. The present study identified 135 papers that investigated the association between sleep deprivation and health risks, including cardiovascular, respiratory, neurological, gastrointestinal, immunology, dermatology, endocrine, and reproductive health. In this review, we aimed to provide insight into the association between sleep deprivation and the development of diseases. We reviewed the latest updates available in the literature and particular attention was paid to reports that detailed all possible causal relationships involving both extrinsic and intrinsic factors that may be relevant to this topic. Various mechanisms by which sleep deprivation may affect health were presented and discussed, and this review hopes to serve as a platform for ideas generation for future research.

Sleep problems in advanced cancer patients and their caregivers: Who is disturbing whom?

Background The aims of the study were to understand sleep problems and their effects in advanced cancer patients and spousal and intimate partner caregivers and to examine the directionality of the link between patients' and caregivers' sleep problems. Methods Fifty-four advanced cancer patients and their spousal and intimate partners were administered a battery of questionnaires that included the Pittsburgh Sleep Quality Index and the Center for Epidemiological Studies at the patients' cancer diagnosis and at 2, 4, and 6 months after diagnosis. Results Patients' and caregivers' sleep duration was significantly related. Using cross-lagged panel analyses, caregivers' sleep quality significantly predicted patients' sleep quality and patients' sleep quality subsequently predicted caregivers' sleep quality. Patients' sleep latency significantly was found to significantly predict caregivers' sleep latency. Conclusion Patients diagnosed with cancer and their intimate partners have poor sleep quality and sleep patterns are related.

Long-term sleep habits and the risk of breast cancer among Chinese women: a case-control study

Previous observational studies have inconsistently suggested that poor sleep is a novel risk factor for breast cancer (BC). However, these studies mainly focused on sleep duration; other sleep domains were rarely reported. The aim of this study was to evaluate the association of a broad range of sleep domains with the risk of BC incidence. We used a community-based 1 : 1 individual matched case-control design that included 401 female patients with incident BC and 401 age-matched and area-matched female controls in Jiujiang, China. Long-term sleep habits were assessed comprehensively using a validated 17-item Sleep Factors Questionnaire. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression. Light exposure at night (highest vs. lowest level, aOR=1.19, 95% CI: 1.06-2.68), habitual timing of sleep (after 12 a.m. midnight vs. before 22 p.m., aOR=1.12, 95% CI: 1.03-2.62), night/shift work (yes vs. no, aOR=1.38, 95% CI: 1.04-2.71), and frequency of night-time wakings (>2 per night vs. never, aOR=1.21, 95% CI: 1.10-2.96) were associated with an increased risk of BC after mutually adjusting for other sleep parameters. These positive associations remained irrespective of menopausal status and tumor estrogen receptor status. There was no association between sleep duration, sleep quality, sleep medication use, insomnia frequency, daytime nap, and the risk of BC. Our results indicate that sleep problems including light exposure at night, night/shift work, late sleeping, and frequent night waking could increase the risk of BC development, independent of other sleep factors.

Sleep, circadian rhythms and health

At the core of human thought, for the majority of individuals in the developed nations at least, there is the tacit assumption that as a species we are unfettered by the demands imposed by our biology and that we can do what we want, at whatever time we choose, whereas in reality every aspect of our physiology and behaviour is constrained by a 24 h beat arising from deep within our evolution. Our daily circadian rhythms and sleep/wake cycle allow us to function optimally in a dynamic world, adjusting our biology to the demands imposed by the day/night cycle. The themes developed in this review focus upon the growing realization that we ignore the circadian and sleep systems at our peril, and this paper considers the mechanisms that generate and regulate circadian and sleep systems; what happens mechanistically when these systems collapse as a result of societal pressures and disease; how sleep disruption and stress are linked; why sleep disruption and mental illness invariably occur together; and how individuals and employers can attempt to mitigate some of the problems associated with working against our internal temporal biology. While some of the health costs of sleep disruption can be reduced, in the short-term at least, there will always be significant negative consequences associated with shift work and sleep loss. With this in mind, society needs to address this issue and decide when the consequences of sleep disruption are justified in the workplace.

Evaluation and management of insomnia in women with breast cancer

PURPOSE

Insomnia is a common issue among patients with breast cancer with a potentially devastating impact on quality of life. It can be caused or exacerbated by multiple disease and treatment-related factors. Despite the prevalence and impact of insomnia, it is rarely addressed systematically in the oncology clinic. We conducted a comprehensive review of insomnia to guide clinical care of patient's with breast cancer and insomnia.

METHODS

This manuscript reviews the prevalence, etiology, emerging science and both non-pharmacologic and pharmacologic options for treatment of insomnia among patients with breast cancer.

RESULTS

Multiple factors contribute to insomnia among patients with breast cancer including endocrine therapy and hotflashes, pain and discomfort from local therapy, and fear of recurrence. If we do identify insomnia, there are treatment options and strategies available to help patients. In particular, there is now a considerable body of evidence supporting the use of psychosocial interventions and behavioral treatments, such as cognitive behavioral therapy for insomnia (CBT-I), yoga, and mind-body programs. It is also important for oncology providers to be educated regarding available pharmacologic therapies and emerging data for cannabis-based therapy.

CONCLUSION

This manuscript provides an up-to-date and comprehensive review of the prevalence, etiology, and treatment approaches available for insomnia for clinicians treating patients with breast cancer. We also address strategies and goals for cancer care delivery and future research.

Association between sleep duration and breast cancer incidence: The multiethnic cohort

Breast cancer is the most common cancer and the second-leading cause of cancer-related death among women. Inconsistent findings for the relationship between melatonin levels, sleep duration and breast cancer have been reported. We investigated the association of sleep duration at cohort entry and its interaction with body mass index (BMI) with risk of developing breast cancer in the large population-based Multiethnic Cohort study. Among the 74,481 at-risk participants, 5,790 breast cancer cases were identified during the study period. Although we detected no significant association between sleep duration and breast cancer incidence, higher risk estimates for short (HR = 1.03; 95% CI: 0.97-1.09) and long sleep (HR = 1.05; 95% CI: 0.95-1.15) compared to normal sleep (7-8 hr) were found. The patterns for models stratified by age, BMI, ethnicity and hormone receptor status were similar but did not indicate significant interaction effects. When examining the combined sleep duration and BMI interaction effect, in comparison to the normal BMI-normal sleep group, risk estimates for underweight, overweight and obesity were similar across categories of sleep duration (≤6, 7-8, and ≥9 hr). The underweight-normal sleep group had lower breast cancer incidence (HR = 0.66, 95% CI: 0.50-0.86), whereas the overweight-short sleep, overweight-normal sleep group and all obese women experienced elevated breast cancer incidence. The respective HRs for short, normal and long sleep among obese women were 1.35 (95% CI: 1.20-1.53), 1.27 (95% CI: 1.15-1.42) and 1.46 (95% CI: 1.21-1.76). Future perspectives need to examine the possibility that sleep quality, variations in circadian rhythm and melatonin are involved in breast cancer etiology.

Contributions of the Women's Health Initiative to understanding associations between sleep duration, insomnia symptoms, and sleep-disordered breathing across a range of health outcomes in postmenopausal women

The Women's Health Initiative (WHI), a longitudinal study of more than 161,000 postmenopausal women across the United States, provides an opportunity to investigate the link between sleep health and healthy aging. The purpose of this paper was to systematically review all published WHI articles examining sleep as a predictor of health outcomes and health behaviors/quality of life outcomes. A strength of the WHI is that for most participants, sleep measures were completed before a major health diagnosis, with a significant portion of participants also providing sleep measures after diagnosis. Twenty-three WHI articles were identified and examined for this review. The combination of sleep duration and insomnia symptoms was the most commonly investigated sleep measure. The results indicated that both short (≤6 hours) and long (≥9 hours) sleep duration were associated with a higher risk of cardiovascular disease, colorectal cancer, mortality, cognitive decline, and poor diet. Insomnia symptoms, frequent snoring, and risk of sleep-disordered breathing (SDB) were also associated with increased risk for ischemic stroke and cardiovascular disease. However, many significant results were attenuated after multivariable adjustment. Limitations of these WHI examinations include the use of different categories for sleep measures across studies and a lack of examination by race/ethnicity. Owing to the longitudinal study design, large sample size, and long-term follow-up for health outcomes, the WHI serves as a rich resource for examining associations between sleep characteristics, demographics, and health in postmenopausal women.

Gut microbiome diversity is associated with sleep physiology in humans

The human gut microbiome can influence health through the brain-gut-microbiome axis. Growing evidence suggests that the gut microbiome can influence sleep quality. Previous studies that have examined sleep deprivation and the human gut microbiome have yielded conflicting results. A recent study found that sleep deprivation leads to changes in gut microbiome composition while a different study found that sleep deprivation does not lead to changes in gut microbiome. Accordingly, the relationship between sleep physiology and the gut microbiome remains unclear. To address this uncertainty, we used actigraphy to quantify sleep measures coupled with gut microbiome sampling to determine how the gut microbiome correlates with various measures of sleep physiology. We measured immune system biomarkers and carried out a neurobehavioral assessment as these variables might modify the relationship between sleep and gut microbiome composition. We found that total microbiome diversity was positively correlated with increased sleep efficiency and total sleep time, and was negatively correlated with wake after sleep onset. We found positive correlations between total microbiome diversity and interleukin-6, a cytokine previously noted for its effects on sleep. Analysis of microbiome composition revealed that within phyla richness of Bacteroidetes and Firmicutes were positively correlated with sleep efficiency, interleukin-6 concentrations and abstract thinking. Finally, we found that several taxa (Lachnospiraceae, Corynebacterium, and Blautia) were negatively correlated with sleep measures. Our findings initiate linkages between gut microbiome composition, sleep physiology, the immune system and cognition. They may lead to mechanisms to improve sleep through the manipulation of the gut microbiome.

Impact of sleep health on self-perceived health status

Although sleep habits have long been recognized as a promoter of health, the World Health Organization 2014 report on non-communicable diseases (NCDs) only listed smoking, alcohol intake, diet and physical activity (PA) as key modifiable risk factors that could enhance health and prevent NCDs. Cross-sectional data on 4385 surveys from the 2015 Catalan Health Survey, representative of the 2015 non-institutionalized Catalan population over age 14, were used to assess and compare the independent associations of low PA (International Physical Activity Questionnaire (IPAQ): low activity); poor diet (PREvención con DIeta MEDiterránea questionnaire (PREDIMED): low-adherent); poor sleep health (Satisfaction, Alertness, Timing, Efficiency and Duration scale (SATED): <8); smoking status; and, alcohol intake (high-risk drinker based on standard drink units) with having a poor self-perceived health status. Logistic regression models adjusted by age, gender, education level and number of comorbidities showed that poor sleep health had the strongest independent association with poor self-perceived health status (OR = 1.70; 95%CI: 1.37–2.12), followed by poor diet (OR = 1.37; 95%CI: 1.10–1.72) and low PA (OR = 1.31; 95%CI: 1.01–1.69). This suggests that sleep habits should be included among the important modifiable health risk factors and be considered a key component of a healthy lifestyle.

Impacts of Sleep Duration and Snoring on The Risk of Esophageal Squamous Cell Carcinoma

Background Sleep duration and snoring are correlated with tumorigenesis while their associations with esophageal squamous cell carcinoma (ESCC) are unclear. The purpose of this study is to investigate the impacts of night sleep duration and snoring on ESCC risk.

Methods This study included a total of 527 esophageal squamous cell carcinoma patients and 505 gender- and age- matched healthy controls from five hospitals in China. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by conditional logistic regression models.

Results Subjects with sleep duration <7 h (adjusted OR 3.18, 95%CI 1.55-6.53) and regular snoring (adjusted OR 2.56, 95%CI 1.82-3.59) were exposed to high esophageal squamous cell carcinoma risk. After the multivariate models adjusted for body mass index (BMI), the results changed slightly. In the stratified analysis regarding gender, the similar trends occurred in both men and women, and BMI ≥25.0 kg/m² (adjusted OR 0.68, 95%CI 0.48-0.96) was associated with decreased esophageal squamous cell carcinoma risk in men. Additionally, the esophageal squamous cell carcinoma risk attributable to sleep duration <7 h and regular snoring could be completely or partially diminished in subjects with BMI ≥25.0 kg/m².

Conclusion In both genders, short sleep duration (<7h) and regular snoring were significantly related to increased risk of esophageal squamous cell carcinoma independently.