Sleep duration and risk of cancer in the Mexican American Mano-a-Mano Cohort

The mediating effect of sleep duration on metabolic syndrome severity in adults: a structural equation modeling approach

BACKGROUND

Metabolic syndrome (MetS) is associated to sleep duration. It is crucial to identify factors that disrupt sleep regulation. The study aimed to assess the indirect effect of risk factors related to MetS severity through sleep duration by utilizing a structural equation model (SEM).

METHODS

The study involving 3,935 adults from the baseline data of the Ravansar Non-Communicable Disease (RaNCD) cohort study. MetS severity scores were the outcome variables. SEM was employed to explore the relationships, utilizing IBM SPSS and AMOS version 23.

RESULTS

The mean MetS severity score was higher in women compared to men (0.25 vs. 0.16, P = 0.003). In men, socioeconomic status (SES) has a positive direct effect (β = 0.048) and a negative indirect effect (β=-0.006) on MetS severity. Increased physical activity is directly (β=-0.036) and indirectly (β=-0.093) associated with reducing MetS severity. Nap duration is directly linked to an increase (β = 0.072) but has an indirect effect (β=-0.008) in decreasing MetS severity. In women, SES has a direct (β=-0.020) and indirect (β=-0.001) inverse relationship with MetS severity. Increased physical activity is directly (β=-0.048) and indirectly (β=-0.036) associated with decreasing MetS severity in women. Nap duration is directly associated with an increase in MetS severity (β=-0.018) but indirectly contributes to its reduction (β=-0.002). Sleep duration not only directly affects MetS severity but is also influenced by age, SES, physical activity, obesity and nap duration.

CONCLUSION

Physical activity, SES, and nap duration directly and indirectly effect the MetS severity. Sleep duration was recognized as a mediating variable that supports the indirect effects.

Eyes Wide Open: Sleep as a Potential Contributor to Racial and Ethnic Disparities in Cancer

U.S. racial and ethnic minoritized groups face disproportionate cancer burdens compared to White Americans. Investigating modifiable factors, such as sleep, that are socially patterned and inequitably distributed by race and ethnicity may advance understanding of cancer disparities and provide intervention opportunities. Emerging data suggest poor sleep health is associated with cancer. Yet, its contribution to racial and ethnic cancer disparities is understudied. In this narrative review, we explored the sleep-cancer relation through a disparities lens. We (i) summarized literature reporting on associations between sleep and cancer among racial and ethnic minority populations; (ii) examined potential sleep-cancer mechanisms; and (iii) discussed future directions. We identified five studies reporting on sleep-cancer associations among minoritized groups. Poor sleep health was associated with aggressive breast cancer among Black women, increased breast cancer risk among Asian women, and increased risk of breast and total cancer among Hispanic/Latinx Americans. Sleep and cancer disparities have similar socioeconomic and behavioral determinants, suggesting racial and ethnic minoritized groups may be vulnerable to poor sleep health and its adverse health impacts. Evidence indicates that the sleep-cancer disparities relation is an emerging, but important area of research that warrants further investigation, as sleep may be an avenue for reducing cancer disparities.

Association of habitual sleep duration and its trajectory with the risk of cancer according to sex and body mass index in a population-based cohort

BACKGROUND

The relationship between sleep duration and cancer in China remains inconclusive. The authors investigated the association between sleep duration and cancer from both static and dynamic perspectives.

METHODS

This study was based on the China Health and Retirement Longitudinal Study. We first tested the hazard ratios (HRs) with 95% confidence intervals (CIs) between baseline sleep duration and incident cancer using Cox proportional hazards regression analysis. Sleep duration trajectories from 2011 to 2015 were identified using group-based trajectory modeling to examine the subsequent risk of incident cancer from 2015 to 2018 using Cox proportional hazards regression model.

RESULTS

The risk of incident cancer increased by 69% (HR, 1.69; 95% CI, 1.19-2.39) in individuals who slept for <7 h per day (vs. 7 to ≤8 h), 41% (HR, 1.41; 95% CI, 1.01-1.95) in those who slept for <6 h per night (vs. 6 to ≤8 h), and 60% (HR, 1.60; 95% CI, 1.01-2.55) in those who did not take any naps during the day (vs. >60 min). Stratified by sex and body mass index, the risk of cancer was evident among women with night sleep of <6 h (vs. 6-8 h). However, the duration of <7 h of total sleep among men and overweight individuals was associated with cancer risk. Moreover, individuals with a short night sleep duration but no napping had a higher risk of cancer. Furthermore, cancer risk was only observed in individuals with short stable trajectory of night sleep (HR, 2.01; 95% CI, 1.07-3.80) and among women with short stable trajectory of total sleep (HR, 2.26; 95% CI, 1.13-4.52).

CONCLUSIONS

Cancer incidence risk was observed in participants with sleep duration of <7 h and among women with short stable sleep trajectory. Short nights and total sleep duration were both associated with a high risk of incident cancer, but varied by sex. Interestingly, cancer risk was restricted to women with short stable sleep trajectory.

PLAIN LANGUAGE SUMMARY

This study showed that short nights and total sleep duration were associated with a high risk of cancer incidence in middle-aged and elderly Chinese population, with implications for early effective cancer prevention. Habitual sleep is a modifiable and dynamic lifestyle behavior, and long-term short sleep trajectories among women can predict cancer outcomes. Future studies should examine the association between the trajectory of sleep parameters based on objective measures and specific cancer types.

Risk-Reducing Measures for Cancer Prevention

Cancer, or malignancy, continues to be one of the most serious health problems in the world, leading to death and disability. Unlike in previous years, where new cases of cancer were predominant in developed nations, the number of cases of cancer and the resultant deaths are increasing in low- and middle-income countries. This is partially attributable to the current trend of adopting a Western lifestyle, substantial urbanization, and the rise in infections, such as the human papillomavirus (HPV) and hepatitis B virus (HBV), which together account for over 30% of cancer cases in underdeveloped and developing nations. The deleterious impact of cancer, as cases multiply worldwide, is multi-dimensional. Cancer exerts serious physical, psychological, and monetary burdens, not only on cancer patients but also on their family members, close friends, health care systems, and society at large. Importantly, over half of all cancer types can be prevented globally by mitigating the risk and causative factors as well as prompt adherence to scientifically recommended prevention measures. This review provides various scientifically based and people-centered strategies that every individual could adopt to reduce their risk of developing cancer in the future. It is recommended that, for these cancer prevention strategies to be effective, there should be a strong political will from the governments of individual countries to enact specific laws and implement policies that will significantly reduce sedentary lifestyles and unhealthy eating among the general public. Likewise, HPV and HBV vaccines, as well as cancer screenings, should be made available, affordable, and accessible on a timely basis for those who are eligible to take them. Finally, intensified campaigns and numerous informative and educational programs that promote cancer prevention should be initiated globally.

Sleep and breast and prostate cancer risk in the MCC-Spain study

Breast and prostate cancers have been associated with circadian disruption. Some previous studies examined associations of sleep duration and breast or prostate cancer risk though findings remain inconsistent. This study examines associations of a range of detailed sleep characteristics and breast and prostate cancer risk in a large-scale population-based case-control study, MCC-Spain. A total of 1738 incident breast cancer cases, 1112 prostate cancer cases and frequency matched controls (n = 1910, and 1493 respectively) were recruited. Detailed data on habitual sleep duration, quality, timing, and daytime napping ("siesta") were collected at recruitment. Additional data on sleep habits during both the previous year and at age 40 years were also subsequently captured. Adjusted odds ratios (ORs) and 95% confidence intervals (CI) were estimated. There were no associations of habitual sleep duration (h), timing of sleep, or any or specific sleep problems, and either breast and prostate cancer risk. There was a significant positive association of ever taking habitual siestas at recruitment and breast cancer risk (OR = 1.22, 95% CI 1.06-1.42), which strengthened with increased frequency or duration. There were also significant positive associations observed for both breast and prostate cancer, among those reporting recent sleep problems, but not sleep problems at age 40 years, in a subsequent circadian questionnaire. Adverse associations with siesta and disturbed sleep during the previous year likely reflect symptoms of developing/diagnosed cancer and comorbidities. Overall, there was no clear association between various sleep characteristics and breast or prostate cancer risk observed.

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.

Sleep Traits, Night Shift Work and Lung Cancer Risk among Women: Results from a Population-Based Case-Control Study in France (The WELCA Study)

Circadian rhythm disruption due to night shift work and/or sleep disorders is associated with negative health outcomes including cancer. There is only scant evidence of an association with lung cancer, unlike breast and prostate cancer. We explore the role of sleep disorders and night shift work in lung cancer risk among women in a population-based case-control study, including 716 lung cancer cases and 758 controls. Multivariable logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) associated with sleep duration per day (<7 h, 7−7.9 h, ≥8 h), a summary index of sleep disorders, chronotype, and night shift work exposure metrics. When compared to women with an average sleep duration of 7−7.9 h per day, the OR was 1.39 (95% CI 1.04−1.86) in long sleepers (≥8 h) and 1.16 (95% CI 0.86−1.56) in short sleepers (<7 h). Overall, lung cancer was not associated with the sleep disorder index, nor with night shift work, regardless of the duration of night work or the frequency of night shifts. However, elevated OR associated with the sleep disorder index were found in the subgroup of current smokers. The U-shaped association of lung cancer with sleep duration was more particularly pronounced among women who worked at night ≥5 years. Our findings suggested that sleep patterns are associated with lung cancer risk in women with a potential modifying effect by night shift work duration or tobacco smoking.

Systematic review: sleep health in the US Latinx population

Sleep disturbances are a common and unmet health problem in Latinx. While Latinx report similar sleep disturbances as non-Hispanic Whites [NHW], Latinx suffer from these disturbances to a greater degree than their NHW counterparts. Sleep disturbances are associated with increased risk of chronic health conditions, which Latinx experience at high rates. Research also points to significant sleep differences within Latinx. Given that Latinx are a rapidly growing population in the United States, sleep disparities between Latinx and NHWs and sleep differences within Latinx warrant further investigation. While research on Latinx sleep is growing, the last narrative review on US Latinx sleep health was published by Loredo and colleagues in 2010. Our narrative review expands on Loredo et al.'s work, adding the literature on Latinx sleep published since 2010 (N = 70). A total of 78 peer-reviewed articles related to young to middle-aged (i.e., 18-65 years) healthy Latinx adult sleep were identified in three databases-PsycInfo, PubMed/Medline, and Web of Science. With the socioecological model as framework, this review (1) summarizes current evidence pertaining to sleep health in healthy, community dwelling, urban Latinx adults; (2) discusses measurement challenges related to investigating Latinx sleep disparities and differences; and (3) discusses potential contributors to Latinx sleep. The prevalence of short sleep duration, long sleep duration, and poor sleep quality is high among Latinx; there are differences by Latinx subgroup. Our review identifies several multi-level influences associated with poor sleep: SES, sexual minority status, racial discrimination, access to care, neighborhood environment, and shift work. N = 250/250.

Both increased and decreased sleep duration over time are associated with subsequent cancer development

PURPOSE

Changes in sleep duration have been reported to correlate with lifestyle-related diseases in humans. However, equivalent studies regarding the effects of sleep on cancer progression are lacking. This study aimed to determine whether or not increase or decrease in sleep duration over time is associated with subsequent cancer development.

METHODS

A large-scale, retrospective cohort study was conducted at a preventive medicine health center at a general community hospital in Tokyo, Japan. All participants who underwent health checkups at the hospital between January 2005 and December 2018 were included. The primary study outcome was development of any type of cancer according to the slope of sleep duration over the study period. The Cox proportional hazard model was used to adjust the outcomes based on potential covariates.

RESULTS

Of 15,025 participants, 7,692 (51.2%) were men. The mean age (standard deviation) was 66.0 (7.5) years. During a median follow-up of 2,588 (interquartile range: 1,583-3,695) days, 1,396 (9.3%) participants developed cancer of any type. Compared to hazard ratio in the stable sleep duration group (- 0.1 to + 0.1 h/day in 1 year), both greatly decreased (less than - 0.2 h/day in 1 year; hazard ratio (HR), 2.13; 95% confidence interval (CI), 1.72-2.62) and increased (more than + 0.2 h/day in 1 year; HR, 2.55; 95% CI 2.14-3.04) groups showed significantly higher hazard ratio for the development of any type of cancer.

CONCLUSION

Both increased and decreased sleep duration over time are associated with subsequent cancer development.

The association of sleep duration and metabolic syndrome in the Bandare-Kong cohort study, a cross-sectional survey (finding from PERSIAN cohort study)

BACKGROUND

A variety of health problems, such as metabolic syndrome (MetS), have been linked to sleep disorders. While numerous epidemiological studies have shown a U-shaped relationship between sleep duration and poor health outcomes, the results were limited and inconsistent. This study was designed to evaluate the relationship between sleep duration and MetS.

METHODS

This population-based study was conducted on the participants aged 35-70 of Bandare-Kong Non-Communicable Diseases (BKNCD) Cohort Study, a part of Prospective Epidemiological Research Studies in IrAN (PERSIAN). MetS was diagnosed according to the National Cholesterol Education Program (NCEP) criteria and the Iranian-specific cut-off for waist circumference (≥ 95 cm). Sleep information was extracted through a standard questionnaire based on self-reported information. Data were analyzed by R software using generalized additive models (GAMs). A statistically significant level was considered as P < 0.05.

RESULTS

A total of 3695 participants were included in the analyses. The mean age was 48.05 years (SD 9.36), and 2067 (55.9%) were female. The estimated Prevalence of MetS was 35.9%, and women appeared to be more likely to have MetS than men (P < 0.001). There was a non-linear and linear association between sleep duration and the risk of MetS in women and men, respectively. The lowest risk was observed among those with 7-7.5 h of sleep duration per night.

CONCLUSION

Long sleep duration was associated with increased risk of MetS and higher MetS severity score in both genders, while the short sleep duration increased the risk of Mets as well as MetS severity score just in women. The longitudinal studies would be suggested to assess the relationship between sleep quality and quantity components and MetS.

The association of sleep duration and feeling rested with health in U.S. Hispanic women

This study aims to understand the health correlates of sleep deficiencies in non-elderly U.S. Hispanic¹ women. Data from a sample of U.S. Hispanic women (n = 1531; ages 18-65 [M = 39.98; SD = 12.85]) who completed the 2017 National Health Interview Survey were analyzed to understand (1) sleep duration and quality; (2) the association of sleep patterns with key health indicators; and (3) whether these relationships are mediated by health behaviors (ie, healthy eating and physical activity). Shorter sleep duration was associated with a higher likelihood of often feeling anxious and having hypertension. Worse sleep quality was associated with a higher likelihood of being overweight, having fair or poor health status, often feeling depressed, often feeling anxious, having high cholesterol, and having asthma. Doctor's recommendation to engage in physical activity and to decrease calorie intake served as mediators in some of these relationships. Results indicate that among Hispanic women: (1) sleep is an important determinant of a variety of health outcomes and (2) the association of sleep and many health outcomes are mediated by healthy eating and physical activity. Further research on the association of sleep and risk of chronic disease among Hispanic women is needed.

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.

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.

Night Shift Work, Chronotype, Sleep Duration, and Prostate Cancer Risk: CAPLIFE Study

To analyze the association between prostate cancer (PCa) risk and night shift work, chronotype, and sleep duration in the context of a population-based case-control study of incident prostate cancer in Spain, a total of 465 PCa cases and 410 controls were analyzed. Selection criteria were: (i) age 40-80 years, and (ii) residence in the coverage area of the reference hospitals for ≥6 months before recruitment. Exposure variables were: (i) night shift work (permanent or rotating); (ii) chronotype: morning, neither, or evening (Munich ChronoType Questionnaire) and (iii) sleep duration according to the recommendations of the American National Sleep Foundation. PCa aggressiveness was determined according to the International Society of Urology Pathology classification. Adjusted odds ratios (aOR) and 95% confidence intervals (95% CI) were estimated using logistic regression models. Night shift work was associated with PCa, aOR = 1.47 (95% CI 1.02-2.11), especially for rotating night shifts, aOR = 1.73 (95% CI 1.09-2.75). The magnitude of the association between ever night work and PCa was higher in evening subjects with aOR = 3.14 (95% CI 0.91-10.76) than in morning chronotypes with an aOR = 1.25 (95% CI 0.78-2.00). Working night shifts, especially rotating night shifts, could increase PCa risk. This risk may be higher in people with an evening chronotype.

Non-linear relationship between sleep duration and metabolic syndrome: A population-based study

The aims of this study were to evaluate the prevalence of metabolic syndrome (MetS) and explore the association between sleep duration and MetS. This study enrolled 8 272 adults aged 18 years and older from 6 urban and 8 rural areas during 2013 to 2014in Henan China. Participants were interviewed about demographic characteristics, lifestyle factors and medical history, and physical measurements were performed. The relationships between sleep duration and MetS were evaluated and plotted by Restricted Cubic Spline Regression. The mean age was 51.5 years (SD 14.2) and 4 916 (59.4%) were female. The crude prevalence of MetS was 30.3% and the age-standardized rate was 23.6%. Men were more likely to have MetS than women (P = .01). MetS was positively associated with age, education, smoking, drinking, BMI and sleep duration, and seemed irrelevant to occupation and sedentary behavior. In terms of individual component of MetS, high blood pressure was the most prevalent component for both men and women, while the lowest prevalent was high triglycerides in men and for women was low high-density lipoprotein cholesterol (HDL-C). There was a U-shaped relationship between sleep duration and MetS and its components. Sleep duration <6 hours or >9 hours were associated with higher risk of MetS (OR from 1.10 to 2.15). The MetS was prevalent, and more than half of total adult population was suffering from high blood pressure. Sleep duration may be a determinant of metabolic health. Both short (<6 hours) and long sleep duration (>9 hours) was linked to an increased risk of MetS.