Sleep duration, melatonin and breast cancer among Chinese women in Singapore

Insomnia disorder and cancer mortality in South Korea: a secondary analysis of musculoskeletal disease cohort

PURPOSE

The association between insomnia disorder and cancer-related mortality risk remains controversial. Therefore, this study aimed to investigate the correlation between insomnia disorder and cancer-related mortality.

METHODS

Patients who were diagnosed with musculoskeletal disease (MSD) between 2010 and 2015 were included in this study as a secondary analysis of a patient cohort with MSD in South Korea. Cancer mortality was evaluated between January 1, 2016, and December 31, 2020, using multivariable Cox regression modeling. Patients with and without insomnia disorder constituted the ID and non-ID groups, respectively.

RESULTS

The final analysis incorporated a total of 1,298,314 patients diagnosed with MSDs, of whom 11,714 (0.9%) died due to cancer. In the multivariable Cox regression model, the risk of total cancer-related mortality was 14% (hazard ratio [HR], 1.14; 95% confidence interval [CI], 1.10-1.19; P < 0.001) higher in the ID group than in the non-ID group. Moreover, the ID group had a higher risk of mortality due to esophageal (HR, 1.46; 95% CI, 1.08-1.96; P = 0.015), colorectal (HR, 1.20; 95% CI, 1.05-1.36; P = 0.007), head and neck (HR, 1.39; 95% CI, 1.01-1.94; P = 0.049), lung (HR, 1.17; 95% CI, 1.08-1.27; P < 0.001), and female genital organ (HR: 1.39, 95% CI: 1.09, 1.77; P = 0.008) cancers; leukemia; and lymphoma (HR, 1.30; 95% CI, 1.12-1.49; P < 0.001).

CONCLUSION

Insomnia disorder was associated with elevated overall cancer mortality in patients with MSDs, which was more evident for cancer mortality due to esophageal, colorectal, head and neck, lung, and female genital organ cancers; leukemia; and lymphoma.

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.

A Longitudinal Study of Sleep Habits and Leukemia Incidence Among Postmenopausal Women

We sought to assess the relationship between sleep duration, sleep disturbance, and leukemia incidence among postmenopausal women. This study included 130,343 postmenopausal women aged 50-79 years who were enrolled in the Women's Health Initiative (WHI) during 1993-1998. Information on self-reported typical sleep duration and sleep disturbance was obtained by questionnaire at baseline, and sleep disturbance level was defined according to the Women's Health Initiative Insomnia Rating Scale (WHIIRS). WHIIRS scores of 0-4, 5-8, and 9-20 comprised 37.0%, 32.6%, and 30.4% of all women, respectively. After an average of 16.4 years (2,135,109 cumulative person-years) of follow-up, 930 of the participants were identified as having incident leukemia. Compared with women with the lowest level of sleep disturbance (WHIIRS score 0-4), women with higher sleep disturbance levels (WHIIRS scores of 5-8 and 9-20) had 22% (95% confidence interval (CI): 1.04, 1.43) and 18% (95% CI: 1.00, 1.40) excess risks of leukemia, respectively, after multivariable adjustment. A significant dose-response trend was found for the association between sleep disturbance and leukemia risk (P for trend = 0.048). In addition, women with the highest level of sleep disturbance had a higher risk of myeloid leukemia (for WHIIRS score 9-20 vs. WHIIRS score 0-4, hazard ratio = 1.39, CI: 1.05, 1.83). Higher sleep disturbance level was associated with increased risk of leukemia, especially for myeloid leukemia among postmenopausal women.

Nocturnal sleep duration and bone mineral density: a cross-sectional study of the National Health and Nutrition Examination Survey (NHANES) 2007-2014

BACKGROUND

This study aimed to investigate the association between sleep duration and bone mineral density (BMD) and determine whether vitamin D (VD) status influenced the association between sleep duration and BMD.

METHODS

National Health and Nutrition Examination Survey 2007-2014 participants aged ≥ 40 years were included in this study. BMD testing was conducted with dual-energy X-ray absorptiometry examinations. Moreover, all individuals were divided into four groups according to self-reported nocturnal sleep duration (7-8 h; 6 h; < 6 h; and > 8 h). In addition, the differences in BMD between the normal sleep duration group and other groups were calculated using multiple linear regression models.

RESULTS

Overall, the median age of the overall study population was 55.00 years old, with 46.97% of men distributed. Participants sleeping > 8 h/night had lower BMDs than those sleeping 7-8 h/night. Moreover, the association between unhealthy sleep duration (especially > 8 h/night) and low BMD was more pronounced in older individuals, men, postmenopausal women, and subjects with inadequate VD intakes (< 15.00 µg/day) or deficient/insufficient serum 25-hydroxyvitamin D (< 75.00 nmol/L).

CONCLUSIONS

In conclusion, unhealthy sleep duration, especially long sleep duration, was associated with decreased BMD, particularly among individuals aged > 60 years, men, or postmenopausal women. Moreover, VD status might influence the association between sleep duration and BMD, especially in the context of inadequate VD intake or deficient/insufficient serum 25-hydroxyvitamin D levels. However, given the limitations of the present study, further investigation is warranted to confirm this association and to explore potential mechanisms.

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.

Protective role of melatonin in breast cancer: what we can learn from women with blindness

PURPOSE

This review proposes an overall vision of the protective and therapeutic role of melatonin in breast cancer: from the specific cases of blind women and their reduction of breast cancer incidence to all clinical uses of the sleep hormone in breast cancer.

METHODS

We reviewed studies focused on (1) the correlation between blindness and breast cancer, (2) the correlation between melatonin and breast cancer occurrence in the general population, (3) melatonin therapeutic use in breast cancer, and (4) we discussed the properties of melatonin that could explain an anticancer effect.

RESULTS

(1) Seven studies of breast cancer risk in blind women related significant incidence decreases, up to 57%, among totally blind women. The limited number of studies and the absence of adjustment for confounding factors in most studies limit conclusions. None of these studies established melatonin profiles to determine whether blind women with a decreased breast cancer incidence produced higher levels of melatonin. (2) In the general population, 5 meta-analyses and 12 prospective-cohort studies focused on melatonin levels at recruitment and breast cancer occurrence. All reported the absence of correlation in premenopausal women, whereas in postmenopausal women, most studies showed significantly decreased risk for women with highest melatonin levels. (3) The therapeutic interest of melatonin associated with chemotherapy, radiotherapy, and hormonotherapy is poorly documented in breast cancer to conclude on a positive effect. (4) Melatonin effects on mammary carcinogenesis were only reported in in vitro and animal studies that demonstrated antiestrogenic, antioxidant, oncostatic, and immunomodulatory properties.

CONCLUSION

The preventive role of high endogenous melatonin on breast cancer as well as its beneficial therapeutic use remains to be proven.

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.

Sleep pattern and bone mineral density: a cross-sectional study of National Health and Nutrition Examination Survey (NHANES) 2017-2018

This research is a cross-sectional study based on the participants aged 50 years and older from National Health and Nutrition Examination Survey (NHANES) database. Poor sleep patterns were associated with lower bone mineral density (BMD) and a higher risk of osteoporosis, especially among older individuals or females.

INTRODUCTION

Accumulated evidence demonstrates that sleep duration, which is one aspect of sleep pattern, is associated with the risk of osteoporosis. However, the related studies on the association between sleep patterns and the risk of osteoporosis were limited. Therefore, this research aims to investigate the association of sleep patterns with BMD and the risk of osteoporosis among individuals aged 50 years and older.

METHODS

Participants aged ≥ 50 years from the NHANES database were included in the present study. The diagnosis of osteoporosis was based on the results of BMD testing. Moreover, all the participants were divided into different sleep pattern groups according to nocturnal sleep duration and bedtime. In addition, this study used multivariate linear regression models to evaluate the association between sleep patterns and BMD and exploited multiple logistic regression models to investigate the odds ratios (ORs) for osteoporosis.

RESULTS

Finally, 1,865 individuals (non-osteoporosis: N = 1,713; osteoporosis: N = 152) aged over 50 years old with complete data were analyzed. The results of multivariate linear regression models showed that individuals with normal sleep duration/later bedtime or long sleep duration/later bedtime had lower femoral BMD than those with normal sleep duration/usual bedtime. Moreover, subjects with long sleep duration/later bedtime had a higher risk of osteoporosis compared with those with normal sleep duration/usual bedtime. In addition, subgroup analyses revealed the association of sleep patterns with BMD and the risk of osteoporosis appeared to be more pronounced among individuals aged ≥ 65 years or females.

CONCLUSION

This study demonstrated that sleep patterns are associated with BMD and the risk of osteoporosis. Poor sleep patterns contribute to decreased bone mass and the increased risk of osteoporosis. Therefore, a healthy sleep pattern is favorable for the prevention of osteoporosis.

Sleep duration and health outcomes: an umbrella review

PURPOSE

To collect existing evidence on the relationship between sleep duration and health outcomes.

METHODS

A thorough search was conducted in PubMed, Web of Science, Embase, and the Cochrane Database of Systematic Reviews from inception to January, 2021. Meta-analyses of observational and interventional studies were eligible if they examined the associations between sleep duration and human health.

RESULTS

In total, this umbrella review identified 69 meta-analyses with 11 outcomes for cancers and 30 outcomes for non-cancer conditions. Inappropriate sleep durations may significantly elevate the risk for cardiovascular disease (CVD), cognitive decline, coronary heart disease (CHD), depression, falls, frailty, lung cancer, metabolic syndrome (MS), and stroke. Dose-response analysis revealed that a 1-h reduction per 24 hours is associated with an increased risk by 3-11% of all-cause mortality, CHD, osteoporosis, stroke, and T2DM among short sleepers. Conversely, a 1-h increment in long sleepers is associated with a 7-17% higher risk of stroke mortality, CHD, stroke, and T2DM in adults.

CONCLUSION

Inappropriate sleep duration is a risk factor for developing non-cancer conditions. Decreasing and increasing sleep hours towards extreme sleep durations are associated with poor health outcomes.

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.

The association between sleep duration and prostate cancer: A systematic review and meta-analysis

The association between sleep duration and prostate cancer (PCa) risk is still unclear. We performed a systematic review and meta-analysis to explore if sleep duration is associated with PCa in men.A comprehensive literature search was conducted in November 2019 based on the Pubmed, Embase, and Cochrane databases. After extracting the data, the random effects model was used to calculate the pooled Risk Ratio (RR) and it's 95% confidence interval (CI) to represent the correlation between sleep duration and PCa risk.Overall, we included 6 studies in our meta-analysis. Our pooled results showed that neither short sleep (RR = 0.99; 95%CI:0.91-1.07, P = .74) nor long sleep (RR = 0.88; 95%CI:0.75-1.04, P = .15) was associated with the risk of PCa.Sleep duration has no significant effect on PCa risk. Long sleep may have a potential protective effect on PCa incidence.

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.

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.

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.

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.

Artificial Light at Night of Different Spectral Compositions Differentially Affects Tumor Growth in Mice: Interaction With Melatonin and Epigenetic Pathways

Lighting technology is rapidly advancing toward shorter wavelength illuminations that offer energy-efficient properties. Along with this advantage, the increased use of such illuminations also poses some health challenges, particularly breast cancer progression. Here, we evaluated the effects of artificial light at night (ALAN) of 4 different spectral compositions (500-595 nm) at 350 Lux on melatonin suppression by measuring its urine metabolite 6-sulfatoxymelatonin, global DNA methylation, tumor growth, metastases formation, and urinary corticosterone levels in 4T1 breast cancer cell-inoculated female BALB/c mice. The results revealed an inverse dose-dependent relationship between wavelength and melatonin suppression. Short wavelength increased tumor growth, promoted lung metastases formation, and advanced DNA hypomethylation, while long wavelength lessened these effects. Melatonin treatment counteracted these effects and resulted in reduced cancer burden. The wavelength suppression threshold for melatonin-induced tumor growth was 500 nm. These results suggest that short wavelength increases cancer burden by inducing aberrant DNA methylation mediated by the suppression of melatonin. Additionally, melatonin suppression and global DNA methylation are suggested as promising biomarkers for early diagnosis and therapy of breast cancer. Finally, ALAN may manifest other physiological responses such as stress responses that may challenge the survival fitness of the animal under natural environments.

Joint effects of multiple sleep characteristics on breast cancer progression by menopausal status

OBJECTIVES

Sleep has been closely linked to breast cancer risk. However, the association between sleep and breast cancer prognosis remains unclear. The aim of this study was to evaluate the separate and joint effects of multiple sleep characteristics on breast cancer prognosis among Chinese women.

METHODS

A total of 1580 breast cancer patients were recruited between October 2008 and December 2014 and followed up until December 31, 2017 in Guangzhou. Multivariate Cox models were conducted to estimate the hazard ratios (HR) and 95% confidence intervals (95%CI) for breast cancer prognosis in association with sleep characteristics.

RESULTS

Long sleep duration at night (>9 h) (HR = 2.33, 95%CI: 1.01-5.42), poor sleep quality (HR = 3.08, 95%CI: 1.74-5.47), and impaired daytime function (HR = 2.49, 95%CI: 1.65-3.79) after diagnosis were associated with an increased risk of breast cancer progression. Both short sleep duration (<6 h) (HR = 2.00, 95%CI: 1.06-3.77, P_interaction = 0.011) and long sleep duration (>9 h) (HR = 4.69, 95%CI: 1.31-16.78, P_interaction = 0.187) increased the progression risk only among patients with impaired but not normal daytime function. In addition, daytime napping significantly modified the effect of short sleep duration on the progression (HR = 3.55, 0.59, 95%CI: 1.55-7.97, 0.23-1.53 for patients without and with daytime napping, respectively, P_interaction = 0.005). Stratification results suggested that the associations were more evident among pre-menopausal patients, although no significant interaction was observed.

CONCLUSION

Our findings suggested that inadequate sleep duration to feel one's best and poor sleep quality after diagnosis were associated with an increased risk of breast cancer progression, particularly for pre-menopausal women.

Sleep duration and the risk of cancer: a systematic review and meta-analysis including dose-response relationship

Background

The effect of sleep duration on cancer risk remains controversial. We aimed to quantify the available evidence on this relationship using categorical and dose–response meta-analyses.

Methods

Population-based cohort studies and case-control studies with at least three categories of sleep duration were identified by searching PubMed, EMBASE, and the Cochrane Library database up to July 2017.

Results

Sixty-five studies from 25 articles were included, involving 1,550,524 participants and 86,201 cancer cases. The categorical meta-analysis revealed that neither short nor long sleep duration was associated with increased cancer risk (short: odds ratio [OR] = 1.01, 95% confidence intervals [CI] = 0.97–1.05; long: OR = 1.02, 95% CI = 0.97–1.07). Subgroup analysis revealed that short sleep duration was associated with cancer risk among Asians (OR = 1.36; 95% CI: 1.02–1.80) and long sleep duration significantly increased the risk of colorectal cancer (OR = 1.21; 95% CI: 1.08–1.34). The dose–response meta-analysis showed no significant relationship between sleep duration and cancer risk. When treated as two linear piecewise functions with a cut point of 7 h, similar nonsignificant associations were found (per 1-h reduction: OR = 1.02, 95% CI = 0.98–1.07; per 1-h increment: OR = 1.003, 95% CI = 0.97–1.03).

Conclusion

Categorical meta-analysis indicated that short sleep duration increased cancer risk in Asians and long sleep duration increased the risk of colorectal cancer, but these findings were not consistent in the dose–response meta-analysis. Long-term randomized controlled trials and well-designed prospective studies are needed to establish causality and to elucidate the mechanism underlying the association between sleep duration and cancer risk.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5025-y) contains supplementary material, which is available to authorized users.

Sleep lengthening in late adulthood signals increased risk of mortality

Study Objectives

Epidemiological evidence indicates that both short and long sleep at midlife increase mortality risk, but few studies have examined how change in sleep duration between midlife and later life affects this risk. We examined the association between change in sleep duration and mortality risk.

Methods

The Singapore Chinese Health Study is a prospective cohort of 63257 Chinese in Singapore aged 45-74 years at recruitment (1993-1998). Self-reported sleep duration was collected from 39523 participants who completed both baseline (mean age 54.8 years) and follow-up II (mean age 67.9 years; 2006-2010) interviews, which were on average 12.7 years apart. Mortality data were obtained via linkage with national death registry up to December 31, 2015.

Results

Compared with participants who reported sleeping the recommended duration (7 hr) at both interviews, those with persistently short sleep (≤5 hr) had increased risk of all-cause mortality (hazard ratio [HR] 1.27, 95% confidence interval [CI] 1.06-1.53). Similarly, those with persistently long sleep (≥9 hr) had increased risk of all-cause (HR 1.47, 95% CI 1.24-1.73) and cardiovascular (HR 1.40, 95% CI 1.04-1.89) mortality. The proportion of long-sleepers increased with aging (6%-23.7%). Progression to long sleep from short (HR 1.50, 95% CI 1.24-1.81) or recommended (HR 1.43, 95% CI 1.25-1.64) duration was associated with increased all-cause mortality, especially for cardiovascular mortality. Change in sleep duration was not linked to cancer mortality.

Conclusions

Persistent short or long sleep or increasing sleep duration in late adulthood was associated with increased risk of all-cause mortality, especially from cardiovascular causes.

Melatonin and health: an umbrella review of health outcomes and biological mechanisms of action

BACKGROUND

Our aims were to evaluate critically the evidence from systematic reviews as well as narrative reviews of the effects of melatonin (MLT) on health and to identify the potential mechanisms of action involved.

METHODS

An umbrella review of the evidence across systematic reviews and narrative reviews of endogenous and exogenous (supplementation) MLT was undertaken. The Oxman checklist for assessing the methodological quality of the included systematic reviews was utilised. The following databases were searched: MEDLINE, EMBASE, Web of Science, CENTRAL, PsycINFO and CINAHL. In addition, reference lists were screened. We included reviews of the effects of MLT on any type of health-related outcome measure.

RESULTS

Altogether, 195 reviews met the inclusion criteria. Most were of low methodological quality (mean -4.5, standard deviation 6.7). Of those, 164 did not pool the data and were synthesised narratively (qualitatively) whereas the remaining 31 used meta-analytic techniques and were synthesised quantitatively. Seven meta-analyses were significant with P values less than 0.001 under the random-effects model. These pertained to sleep latency, pre-operative anxiety, prevention of agitation and risk of breast cancer.

CONCLUSIONS

There is an abundance of reviews evaluating the effects of exogenous and endogenous MLT on health. In general, MLT has been shown to be associated with a wide variety of health outcomes in clinically and methodologically heterogeneous populations. Many reviews stressed the need for more high-quality randomised clinical trials to reduce the existing uncertainties.

Sleep and Breast Cancer in the Western New York Exposures and Breast Cancer (WEB) Study

STUDY OBJECTIVES

Night shift work is associated with increased breast cancer risk, possibly from altered sleep. Epidemiologic evidence is sparse regarding sleep disturbances and breast cancer tumor markers. We examined sleep disturbance in association with breast tumor aggressiveness and mortality following diagnosis.

METHODS

We analyzed associations of measures of sleep disturbance in a sample of 1,122 incident breast cancer cases from the Western New York Exposures and Breast Cancer (WEB) Study. Sleep disturbance was assessed using self-administered questionnaires; responses about difficulty falling asleep, waking up frequently, having trouble staying asleep, and waking up feeling tired and worn out were used to create a summary sleep disturbance score. We used general linear models to examine associations of sleep disturbance with markers of tumor aggressiveness among cases: estrogen receptor (ER) status, progesterone receptor (PR) status, and human epidermal growth factor receptor-2 (HER2) status; tumor size, stage, grade, lymph node involvement, and presence of metastasis. In addition, we examined the association between sleep disturbance and survival using Cox regression.

RESULTS

Among breast cancer cases, sleep disturbance was higher for women with ER- / PR- tumors compared to women with ER+ / PR+ tumors, even after adjusting for potential covariates (P for trend = .02). Results suggest that the association of sleep quality differs by menopausal status, where mild sleep disturbance is associated with higher breast cancer mortality in premenopausal women; however, we had a relatively small sample size.

CONCLUSIONS

Sleep disturbance may be associated with aggressive subtypes of breast cancer; however, further studies are needed.

Determinants of prolactin in postmenopausal Chinese women in Singapore

PURPOSE

Mechanistic and observational data together support a role for prolactin in breast cancer development. Determinants of prolactin in Asian populations have not been meaningfully explored, despite the lower risk of breast cancer in Asian populations.

METHODS

Determinants of plasma prolactin were evaluated in 442 postmenopausal women enrolled in the Singapore Chinese Health Study, a population-based prospective cohort study. At baseline all cohort members completed an in-person interview that elicited information on diet, menstrual and reproductive history, and lifestyle factors. One year after cohort initiation we began collecting blood samples. Quantified were plasma concentrations of prolactin, estrone, estradiol, testosterone, androstenedione, and sex hormone-binding globulin (SHBG). Analysis of covariance method was used for statistical analyses with age at blood draw, time since last meal, and time at blood draw as covariates.

RESULTS

Mean prolactin levels were 25.1% lower with older age at menarche (p value = 0.001), and 27.6% higher with greater years between menarche and menopause (p value = 0.009). Prolactin levels were also positively associated with increased sleep duration (p value = 0.005). The independent determinants of prolactin were years from menarche to menopause, hours of sleep, and the plasma hormones estrone and SHBG (all p values < 0.01).

CONCLUSION

The role of prolactin in breast cancer development may involve reproductive and lifestyle factors, such as a longer duration of menstrual cycling and sleep patterns.

Sleep and circadian disruption and incident breast cancer risk: An evidence-based and theoretical review

Opportunities for restorative sleep and optimal sleep-wake schedules are becoming luxuries in industrialized cultures, yet accumulating research has revealed multiple adverse health effects of disruptions in sleep and circadian rhythms, including increased risk of breast cancer. The literature on breast cancer risk has focused largely on adverse effects of night shift work and exposure to light at night (LAN), without considering potential effects of associated sleep disruptions. As it stands, studies on breast cancer risk have not considered the impact of both sleep and circadian disruption, and the possible interaction of the two through bidirectional pathways, on breast cancer risk in the population at large. We review and synthesize this literature, including: 1) studies of circadian disruption and incident breast cancer; 2) evidence for bidirectional interactions between sleep and circadian systems; 3) studies of sleep and incident breast cancer; and 4) potential mechanistic pathways by which interrelated sleep and circadian disruption may contribute to the etiology of breast cancer.

Sleep characteristics, light at night and breast cancer risk in a prospective cohort

Increasing numbers of women in the US are getting too little sleep. Inadequate sleep has been associated with impaired metabolic function and endocrine disruption. Sister Study cohort participants (n = 50,884), completed baseline and follow-up questionnaires on sleep patterns. Incident breast cancers estrogen receptor (ER) status of the tumor were ascertained from questionnaires and medical records. Cox regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs). Analyses of sleep characteristics reported at the first follow-up interview included only participants who were breast cancer-free at time of follow-up interview. Over ∼7 years of follow-up, 2,736 breast cancer cases (invasive and ductal carcinoma in situ) were diagnosed. There was little evidence that usual sleep duration or other sleep characteristics were associated with breast cancer. However, relative to those with no difficulty sleeping, women who reported having difficulty sleeping ≥ 4 nights a week were at an increased risk of overall (HR = 1.32, 95% CI: 1.09-1.61) and postmenopausal breast cancer (HR = 1.51, 95% CI 1.24-1.85). Risk of ER+ invasive cancer was elevated for women who reported having a light or television on in the room while sleeping (HR = 1.20, 95% CI: 0.97-1.47) or who typically got less sleep than they needed to feel their best (HR = 1.21, 95% CI: 0.98-1.50). In our study, most sleep characteristics, including sleep duration, were not associated with an increased risk although higher risk was observed for some markers of inadequate or poor quality sleep.

Sleep Duration across the Adult Lifecourse and Risk of Lung Cancer Mortality: A Cohort Study in Xuanwei, China

Sufficient sleep duration is crucial for maintaining normal physiological function and has been linked to cancer risk; however, its contribution to lung cancer mortality is unclear. Therefore, we evaluated the relationship between average sleep duration in various age-periods across the adult lifecourse, and risk of lung cancer mortality in Xuanwei, China. An ambidirectional cohort study was conducted in 42,422 farmers from Xuanwei, China. Participants or their surrogates were interviewed in 1992 to assess average sleep hours in the age periods of 21-30, 31-40, 41-50, 51-60, 61-70, and ≥71 years, which were categorized as ≤7, 8 (reference), 9, and ≥10 hours/day. Vital status was followed until 2011. Sex-specific Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for lung cancer mortality in 1994-2011, adjusted for demographic, anthropometric, medical, and household characteristics. J-shaped relationships were found between average sleep duration and lung cancer mortality. The patterns were consistent across sex, age periods, and fuel usage. Compared with sleeping 8 hours/day on average, ≤7 hours/day was associated with significantly increased HRs ranging from 1.39 to 1.58 in ages ≥41 years in men, and 1.29 to 2.47 in ages ≥51 years in women. Furthermore, sleeping ≥10 hours/day was associated with significantly increased HRs ranging from 2.44 to 3.27 in ages ≥41 year in men, and 1.31 to 2.45 in ages ≤60 years in women. Greater and less than 8 hours/day of sleep in various age-periods may be associated with elevated risk of lung cancer mortality in Xuanwei, China. Cancer Prev Res; 10(6); 327-35. ©2017 AACR.

Circadian Disruption and Prostate Cancer Risk: An Updated Review of Epidemiological Evidences

Since the publication of the International Agency for Research on Cancer Monograph in 2007 classifying night shift work leading to a disruption of circadian rhythm as probably carcinogenic to humans, there is an increasingly growing interest in understanding how circadian disruption may play a role in cancer development.This systematic review provides a comprehensive update on epidemiologic evidences on circadian disruption and prostate cancer since the last review published in 2012. We identified 12 new studies evaluating the effects of several circadian disruptors such as night shift work, sleep patterns, and circadian genes in prostate cancer risk. In contrast, no new studies have focused on exposure to light at night.Several convincing and biologically plausible hypotheses have been proposed to understand how circadian disruption may be related to cancer. However, the current difficulty of concluding on the role of circadian disruption on prostate cancer risk requires further studies including a better characterization of the different night shift systems, data on sleep patterns and chronotype, measurement of biomarkers, and investigations of polymorphisms in the genes regulating the biological clock. Cancer Epidemiol Biomarkers Prev; 26(7); 985-91. ©2017 AACR.

Nighttime eating and breast cancer among Chinese women in Hong Kong

BACKGROUND

A novel line of research suggests that eating at nighttime may have several metabolic consequences that are highly relevant to breast cancer. We investigated the association between nighttime eating habits after 10 p.m. and breast cancer in Hong Kong women.

METHODS

A hospital-based case-control study was conducted during 2012-2015. A total of 922 patients with incident breast cancer (cases) and 913 hospital controls were recruited and interviewed using a standard questionnaire including information on eating behavior during both daytime and nighttime. We collected the timing, duration, types and frequencies of food intake of eating at nighttime. Odds ratios (ORs) for the risk of breast cancer in relation to nighttime eating-related variables were calculated by unconditional multivariable logistic regression.

RESULTS

Eating at night after 10 pm was significantly associated with breast cancer with an adjusted OR of 1.50 (95% confidence interval (CI) 1.06-2.12, P = 0.02), and the associations were stronger in women who had the longest duration of nighttime eating (≥20 years) (adjusted OR = 2.28 (95% CI 1.13-4.61, P = 0.02) and who ate late (midnight to 2 a.m.) (adjusted OR = 2.73, 95% CI 1.01-6.99, P = 0.04). Interestingly, nighttime eating was only associated with breast cancer among women who consumed staple foods (OR = 2.16, 95% CI 1.42-3.29, P < 0.001) but not those who ate vegetables or fruits as nighttime meals. The significant association between nighttime eating and breast cancer was observed among women with body mass index (BMI) <25 (OR = 2.29, 95% CI 1.48-3.52, P < 0.001) but not among women with BMI ≥25.

CONCLUSIONS

Results from this study suggest a possible association between nighttime eating behavior and breast cancer. These findings need to be confirmed by independent large studies.

Protective Effect of Aerobic Physical Activity on Sleep Behavior in Breast Cancer Survivors

HYPOTHESES

Sleep disorders are associated with an increased risk of cancer, including breast cancer (BC). Physical activity (PA) can produce beneficial effects on sleep.

STUDY DESIGN

We designed a randomized controlled trial to test the effect of 3 months of physical activity on sleep and circadian rhythm activity level evaluated by actigraphy.

METHODS

40 BC women, aged 35-70 years, were randomized into an intervention (IG) and a control group (CG). IG performed a 3 month of aerobic exercise. At baseline and after 3 months, the following parameters were evaluated both for IG and CG: anthropometric and body composition measurements, energy expenditure and motion level; sleep parameters (Actual Sleep Time-AST, Actual Wake Time-AWT, Sleep Efficiency-SE, Sleep Latency-SL, Mean Activity Score-MAS, Movement and Fragmentation Index-MFI and Immobility Time-IT) and activity level circadian rhythm using the Actigraph Actiwatch.

RESULTS

The CG showed a deterioration of sleep, whereas the IG showed a stable pattern. In the CG the SE, AST and IT decreased and the AWT, SL, MAS and MFI increased. In the IG, the SE, IT, AWT, SL, and MAS showed no changes and AST and MFI showed a less pronounced change in the IG than in the CG. The rhythmometric analysis revealed a significant circadian rhythm in two groups. After 3 months of PA, IG showed reduced fat mass %, while CG had improved weight and BMI.

CONCLUSION

Physical activity may be beneficial against sleep disruption. Indeed, PA prevented sleep worsening in IG. PA can represent an integrative intervention therapy able to modify sleep behaviour.

Pre-diagnostic Sleep Duration and Sleep Quality in Relation to Subsequent Cancer Survival

STUDY OBJECTIVES

Poor sleep quality and short sleep duration have been associated with elevated risk for several cancer types; however, the relationship between sleep and cancer outcomes has not been well characterized. We assessed the association between pre-diagnostic sleep attributes and subsequent cancer survival within the Women's Health Initiative (WHI).

METHODS

We identified WHI participants in whom a first primary invasive cancer had been diagnosed during follow-up (n = 21,230). Participants provided information on sleep characteristics at enrollment. Cox regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between these pre-diagnostic sleep characteristics and cancer-specific survival for all cancers combined and separately for common cancers. Analyses were adjusted for age, study arm, cancer site, marital status, income, smoking, physical activity, and time to diagnosis.

RESULTS

No individual pre-diagnostic sleep characteristics were found to be significantly associated with cancer survival in analyses of all cancer sites combined; however, women who reported short sleep duration (≤ 6 h sleep/night) combined with frequent snoring (≥ 5 nights/w experienced significantly poorer cancer-specific survival than those who reported 7-8 h of sleep/night and no snoring (HR = 1.32, 95% CI: 1.14-1.54). Short sleep duration (HR = 1.46, 95% CI: 1.07-1.99) and frequent snoring (HR = 1.34, 95% CI: 0.98-1.85) were each associated with poorer breast cancer survival; those reporting short sleep combined with frequent snoring combined had substantially poorer breast cancer survival than those reporting neither (HR = 2.14, 95% CI: 1.47-3.13).

CONCLUSIONS

Short sleep duration combined with frequent snoring reported prior to cancer diagnosis may influence subsequent cancer survival, particularly breast cancer survival.

Sleep Duration and Disruption and Prostate Cancer Risk: a 23-Year Prospective Study

BACKGROUND

Sleep deficiency is a major public health problem. There are limited human data on whether sleep duration or disruption are risk factors for prostate cancer.

METHODS

We prospectively followed 32,141 men in the Health Professionals Follow-Up Study who reported their typical sleep duration in 1987, 2000, and 2008. We identified 4,261 incident prostate cancer cases, including 563 lethal cases through 2010. Sleep disruption was assessed in 2004 among 19,639 men, with 930 prostate cancer cases (50 lethal) identified from 2004 to 2010. Cox proportional hazards models were used to evaluate the association between sleep insufficiency and risk of overall and lethal prostate cancer.

RESULTS

In 1987, 2% of men reported sleeping ≤5 hours per night. We found no association between habitual sleep duration or change in sleep duration with the risk of advanced or lethal prostate cancer. We also found no association between waking up during the night, difficulty falling asleep, or waking up too early, and risk of prostate cancer. In 2004, 6% of men reported never feeling rested when they woke up; these men had an increased risk of developing lethal prostate cancer compared with those who reported always feeling rested when they woke up (RR, 3.05; 95% CI, 1.15-8.10).

CONCLUSIONS

We found no consistent association between self-reported sleep duration or sleep disruption and any of our prostate cancer outcomes.

IMPACT

We did not find support for a consistent association between self-reported sleep and risk of advanced or lethal prostate cancer in this large cohort of men.

Sleep duration and breast cancer risk among black and white women

BACKGROUND

Sleep has been suggested to influence breast cancer risk; however, the evidence is mixed. Black women have a higher prevalence of both short (<6 h) and long (≥9 h) sleep duration and are more likely to develop more aggressive, hormone receptor-negative breast cancer. No study has examined the relationship between sleep and breast cancer in blacks. We focused on race-specific associations among the blacks.

METHODS

In the Southern Community Cohort Study (SCCS), a prospective study of which two-thirds of the population were black, we prospectively investigated self-reported sleep duration in relation to overall breast cancer risk by estrogen (ER) and progesterone receptor (PR) status in all women and in black women alone.

RESULTS

Sleep duration was not associated with risk of total or hormone receptor-positive breast cancer. However, we found an inverse relationship between sleep duration and risk of ER- and PR- breast cancer among all women and in black women alone. Compared to the reference group (8 h), black women who reported shorter sleep duration had an increased risk of ER- PR- breast cancer (odds ratios; ORs (95% confidence intervals; CIs): 2.13 (1.15, 3.93), 1.66 (0.92, 3.02), and 2.22 (1.19, 4.12) for <6, 6, and 7 h, respectively, (p for trend, 0.04).

CONCLUSIONS

Short sleep duration may be a risk factor for hormone receptor-negative breast cancer among black women.

Nocturnal light pollution and underexposure to daytime sunlight: Complementary mechanisms of circadian disruption and related diseases

Routine exposure to artificial light at night (ALAN) in work, home, and community settings is linked with increased risk of breast and prostate cancer (BC, PC) in normally sighted women and men, the hypothesized biological rhythm mechanisms being frequent nocturnal melatonin synthesis suppression, circadian time structure (CTS) desynchronization, and sleep/wake cycle disruption with sleep deprivation. ALAN-induced perturbation of the CTS melatonin synchronizer signal is communicated maternally at the very onset of life and after birth via breast or artificial formula feedings. Nighttime use of personal computers, mobile phones, electronic tablets, televisions, and the like--now epidemic in adolescents and adults and highly prevalent in pre-school and school-aged children--is a new source of ALAN. However, ALAN exposure occurs concomitantly with almost complete absence of daytime sunlight, whose blue-violet (446-484 nm λ) spectrum synchronizes the CTS and whose UV-B (290-315 nm λ) spectrum stimulates vitamin D synthesis. Under natural conditions and clear skies, day/night and annual cycles of UV-B irradiation drive corresponding periodicities in vitamin D synthesis and numerous bioprocesses regulated by active metabolites augment and strengthen the biological time structure. Vitamin D insufficiency and deficiency are widespread in children and adults in developed and developing countries as a consequence of inadequate sunlight exposure. Past epidemiologic studies have focused either on exposure to too little daytime UV-B or too much ALAN, respectively, on vitamin D deficiency/insufficiency or melatonin suppression in relation to risk of cancer and other, e.g., psychiatric, hypertensive, cardiac, and vascular, so-called, diseases of civilization. The observed elevated incidence of medical conditions the two are alleged to influence through many complementary bioprocesses of cells, tissues, and organs led us to examine effects of the totality of the artificial light environment in which humans reside today. Never have chronobiologic or epidemiologic investigations comprehensively researched the potentially deleterious consequences of the combination of suppressed vitamin D plus melatonin synthesis due to life in today's man-made artificial light environment, which in our opinion is long overdue.

Risk of Cancer in Patients with Insomnia, Parasomnia, and Obstructive Sleep Apnea: A Nationwide Nested Case-Control Study

Purpose: Insomnia, parasomnia, and obstructive sleep apnea have been associated with a number of disease pathologies, but little is known about the relationship of these sleep disorders and cancer. The study explored the risk of sleep disorder (SD)-induced cancer using nationwide population data. Two million data from the National Health Insurance system of Taiwan was used to assess for the relationship.

Patients and Methods: Patients with cancer as our cases and patients without cancer as our control group in 2001-20011. The study patients were traced back to seek the exposure risk factor of sleep disorders, which was divided into three categories: insomnia, obstructive sleep apnea (OSA) and parasomnia. Patients were selected excluding patients who had cancer prior to presenting with the sleep disorder and the person-year is less than 2 years. Each case was randomly matched with two cases with the same age, gender, and index year.

Results: There were significantly increased risks of breast cancer in the patients with insomnia (AHR=1.73; 95% CI: 1.57-1.90), patients with parasomnia (AHR=2.76; 95% CI: 1.53-5.00), and patients with OSA (AHR=2.10; 95% CI: 1.16-3.80). Moreover, patients with parasomnia had significantly higher risk of developing oral cancer (AHR=2.71; 95% CI: 1.02-7.24) compared with patients without parasomnia. The risk of suffering from nasal cancer (AHR=5.96, 95% CI: 2.96-11.99) and prostate cancer (AHR=3.69, 95% CI: 1.98- 6.89) in patients with OSA was significantly higher than that of patients without OSA.

Conclusions: Our findings provided the evidence that people diagnosed with insomnia, parasomnia and OSA are at a higher risk of developing cancers to remind people to improve sleep quality.

Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society on the Recommended Amount of Sleep for a Healthy Adult: Methodology and Discussion

The American Academy of Sleep Medicine and Sleep Research Society recently released a Consensus Statement regarding the recommended amount of sleep to promote optimal health in adults. This paper describes the methodology, background literature, voting process, and voting results for the consensus statement. In addition, we address important assumptions and challenges encountered during the consensus process. Finally, we outline future directions that will advance our understanding of sleep need and place sleep duration in the broader context of sleep health.

The association between sleep duration and dry eye syndrome among Korean adults

OBJECTIVE

The aim of the present study was to investigate the association between sleep duration and dry eye syndrome (DES) symptoms.

METHODS

We investigated 15,878 subjects (male = 6684; female = 9194) aged 20 years and older who underwent physical examinations and completed a self-report questionnaire and other anthropometric variables from the fifth Korean National Health and Nutrition Examination Survey (KNHANES) 2010-2012. Odds ratios (OR) and 95% confidence intervals (95% CI) for DES according to sleep duration were calculated using multiple logistic regression models.

RESULTS

Compared to that in an optimal sleep group (6-8 h/day), OR (95% CI) DES prevalence after adjusting for age, gender, sociodemographic factors (educational level, occupation, household income, and residence), and health behaviors (smoking habit, alcohol consumption, and level of exercise) was 1.20 (1.05-1.36) for a mild short sleep group (5 h/day) and 1.29 (1.08-1.55) for a severe short sleep group (≤4 h/day).

CONCLUSION

Our results revealed that DES increased at shorter sleep durations.

Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society on the Recommended Amount of Sleep for a Healthy Adult: Methodology and Discussion

The American Academy of Sleep Medicine and Sleep Research Society recently released a Consensus Statement regarding the recommended amount of sleep to promote optimal health in adults. This paper describes the methodology, background literature, voting process, and voting results for the consensus statement. In addition, we address important assumptions and challenges encountered during the consensus process. Finally, we outline future directions that will advance our understanding of sleep need and place sleep duration in the broader context of sleep health.

Association of breast cancer with sleep pattern--a pilot case control study in a regional cancer centre in South Asia

The rising trend of breast cancer both in developed and developing countries is a real threat challenging all efforts to screening, prevention and treatment aspects to reduce its impact. In spite of modern preventive strategies, the upward trend of breast cancer has become a matter of great concern in both developed and developing countries. Chittaranjan National Cancer Institute is a premier regional cancer institute in eastern region of India catering to a large number of cancer patients every year. A pilot case control study of fifty breast cancer patients and 100 matched controls was conducted during 2013 to evaluate the effects of habitual factors like working in night shift, not having adequate sleep, and not sleeping in total darkness on breast cancer of women. The study revealed that not sleeping in total darkness was associated with higher odds of outcome of breast cancer of women. This positive correlation can play a vital role in formulation of preventive strategies through life style modification.

Sleep duration and cancer risk in women

PURPOSE

The objective was to conduct an analysis of sleep duration and risk of selected site-specific and groups of cancer among a large prospective cohort of California women.

METHODS

The study population was comprised of 101,609 adult females participating in the California Teachers Study. All sites of invasive cancer prospectively diagnosed from baseline (1995-1996) through 2011 were identified through linkage to the California Cancer Registry (n = 12,322). Site-specific analyses focused on the following cancers: breast (n = 5,053), colorectal (n = 983), lung (n = 820), melanoma (n = 749), and endometrial (n = 957). Additionally, we evaluated a group of estrogen-mediated cancers consisting of breast, endometrial, and ovarian cancer (n = 6,458). Sleep duration was based on self-report of average time sleeping in the year prior to baseline. Cox proportional hazard models were used to calculate adjusted hazard ratios and 95 % confidence intervals (HRs, 95 % CI).

RESULTS

Point estimates for all sites and site-specific cancers generally were near or below one for short sleepers (<6 h/night) and above one for long sleepers (10+ h/night); confidence intervals, however, were wide and included unity. Compared to average sleepers (7-9 h/night), long sleepers had an increased risk of the group of estrogen-mediated cancers (HR 1.22, 95 % CI 0.97-1.54, p (trend) = 0.04).

CONCLUSIONS

These analyses suggest that longer sleep may be associated with increased risks of estrogen-mediated cancers. Further studies with more refined measures of sleep duration and quality are warranted.

Obstructive sleep apnea and cancer: Epidemiologic links and theoretical biological constructs

Sleep disorders have emerged as highly prevalent conditions in the last 50-75 y. Along with improved understanding of such disorders, the realization that perturbations in sleep architecture and continuity may initiate, exacerbate or modulate the phenotypic expression of multiple diseases including cancer has gained increased attention. Furthermore, the intermittent hypoxia that is attendant to sleep disordered breathing, has recently been implicated in increased incidence and more adverse prognosis of cancer. The unifying conceptual framework linking these associations proposes that increased sympathetic activity and/or alterations in immune function, particularly affecting innate immune cellular populations, underlie the deleterious effects of sleep disorders on tumor biology. In this review, the epidemiological evidence linking disrupted sleep and intermittent hypoxia to oncological outcomes, and the potential biological underpinnings of such associations as illustrated by experimental murine models will be critically appraised. The overarching conclusion appears supportive in the formulation of an hypothetical framework, in which fragmented sleep and intermittent hypoxia may promote changes in multiple signalosomes and transcription factors that can not only initiate malignant transformation, but will also alter the tumor microenvironment, disrupt immunosurveillance, and thus hasten tumor proliferation and increase local and metastatic invasion. Future bench-based experimental studies as well as carefully conducted and controlled clinical epidemiological studies appear justified for further exploration of these hypotheses.

Night-shift work increases morbidity of breast cancer and all-cause mortality: a meta-analysis of 16 prospective cohort studies

Night-shift work (NSW) has previously been related to incidents of breast cancer and all-cause mortality, but many published studies have reported inconclusive results. The aim of the present study was to quantify a potential dose-effect relationship between NSW and morbidity of breast cancer, and to evaluate the association between NSW and risk of all-cause mortality. The outcomes included NSW, morbidity of breast cancer, cardiovascular mortality, cancer-related mortality, and all-cause mortality. Sixteen investigations were included, involving 2,020,641 participants, 10,004 incident breast cancer cases, 7185 cancer-related deaths, 4820 cardiovascular end points, and 2480 all-cause mortalities. The summary risk ratio (RR) of incident breast cancer for an increase of NSW was 1.057 [95% confidence interval (CI) 1.014-1.102; test for heterogeneity p = 0.358, I(2) = 9.2%]. The combined RR (95% CI) of breast cancer risk for NSW vs daytime work was: 1.029 (0.969-1.093) in the <5-year subgroup, 1.019 (1.001-1.038) for 5-year incremental risk, 1.025 (1.006-1.044) for 5- to 10-year exposure times, 1.074 (1.010-1.142) in the 10- to 20-year subgroup, and 1.088 (1.012-1.169) for >20-year exposure lengths. The overall RR was 1.089 (95% CI 1.016-1.166) in a fixed-effects model (test for heterogeneity p = 0.838, I(2) = 0%) comparing rotating NSW and day work. Night-shift work was associated with an increased risk of cardiovascular death (RR 1.027, 95% CI 1.001-1.053), and all-cause death 1.253 (95% CI 0.786-1.997). In summary, NSW increased the risk of breast cancer morbidity by: 1.9% for 5 years, 2.5% for 5-10 years, 7.4% for 10-20 years, and 8.8% for >20-years of NSW. Additionally, rotating NSW enhanced the morbidity of breast cancer by 8.9%. Moreover, NSW was associated with a 2.7% increase in cardiovascular death.