History Of Night Shift Work Research Articles

Rotating Night Shift Work and Bladder Cancer Risk in Women: Results of Two Prospective Cohort Studies.

Bladder cancer is the sixth most common cancer in the United States. Night shift work has previously been linked with cancer risk. Whether there is an association between rotating night shift work and bladder cancer in women has not been studied previously. Eligible participants in the Nurses' Health Study (NHS, n = 82,147, 1988-2016) and Nurses' Health Study II (NHSII, n = 113,630, 1989-2015) were prospectively followed and a total of 620 and 122 incident bladder cancer cases were documented during the follow-up of NHS and NHSII, respectively. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) for bladder cancer incidence. We observed a significantly increased risk of bladder cancer among women with >5 years of night shift work history compared with women who never worked rotating night shifts in NHS (HR = 1.24; 95%CI = 1.01-1.54, p for trend = 0.06), but not in the pooled NHS and NHS II (HR = 1.18; 95%CI = 0.97-1.43, p for trend = 0.08). Secondary analyses stratified by smoking status showed no significant interaction (p = 0.89) between the duration of rotating night shift work and smoking status. In conclusion, our results did not provide strong evidence for an association between rotating night shift work and bladder cancer risk.

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

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

Circadian Disruption and Colorectal Cancer Incidence in Black Women.

Animal and experimental studies suggest circadian disruption increases colorectal cancer risk, but evidence in humans is limited. We examined night shift work, chronotype, and residential position within a time zone, proxies for circadian disruption, in relation to colorectal cancer risk. Participants in the Black Women's Health Study, a prospective cohort of 59,000 Black American women established in 1995, reported history of night shift work and chronotype on follow-up questionnaires. Residential position within a time zone was estimated using participant addresses at each questionnaire cycle. Number of colorectal cancer cases and follow-up duration varied by analysis depending on timing of exposure assessment, ranging from 204 over the 2005 to 2018 night shift work study period to 452 over the 1995 to 2018 residential position study period. Cox proportional hazards regression was used to estimate multivariable-adjusted HRs and 95% confidence intervals (CI). Compared with never having worked a night shift, working a night shift for ≥10 years was associated with increased colorectal cancer risk (HR = 1.64; 95% CI, 1.01-2.66). However, shorter duration was not. The HR for evening versus morning chronotype was 0.96 (95% CI, 0.73-1.27). Westward position of residence within a time zone was not associated with colorectal cancer risk (HR per 5-degree longitude increase: 0.92; 95% CI, 0.82-1.03). Our findings suggest a possible increased risk of colorectal cancer associated with long duration night shift work; however, results require confirmation in larger studies. Circadian disruption from long-term night shift work may contribute to colorectal cancer development in Black women.

Rotating night shift work, sleep and thyroid cancer risk in the Nurses’ Health Study 2

Background and aim Thyroid cancer is the most common endocrine malignancy with rising incidence worldwide. We prospectively evaluated whether rotating night shift work and sleep disturbances are associated with incident thyroid cancer risk in the Nurses’ Health Study 2 (NHS2). Methods We assessed rotating night shift work (≥3 nights/month) history (cumulative number of years) at baseline and throughout follow-up (1989-2015) and sleep duration and sleep difficulty in 2001. Cox proportional hazard models, adjusted for potential confounders were used to calculate thyroid cancer hazard ratios (HR) and 95% confidence intervals (CI) for shift work history (0.1-4.9yrs, 5-9.9yrs, 10+yrs), sleep duration (≤5, 6, 7, 8, ≥9hours) and difficulty falling or staying asleep (little or none of the time, sometimes, most or all of the time). We further stratified the analyses of night shift work by sleep characteristics. Results We identified 588 incident cases among 114,534 women. We observed no association between night shift work history and thyroid cáncer risk (1-4.9 years: HR 1.19, 95% CI 0.98, 1.44; 5-9.9 years: HR 1.13 95% CI 0.86, 1.48; ≥10 years: HR 1.10, 95% CI 0.78, 1.54; Ptrend=0.55). Sleep difficulty was suggestively associated with higher incidence of thyroid cancer when reported sometimes (HR 1.26, 95% CI 0.95, 1.67) and most or all the time (HR 1.35, 95% CI 1.00, 1.81; Ptrend=0.03), compared to little or none of the time. Participants with >10 years of night shift work and ≤6 hours of sleep had a 2-fold increase in thyroid cancer risk (HR 2.23; 95%CI, 1.08-4.06). Shift workers with <5 years of shift work and frequent sleep difficulty had an increased risk of thyroid cancer (HR 1.95; 95% CI 1.03, 3.67). Conclusion We found evidence that rotating night workers with frequent sleep difficulty or short sleep had an increased risk of thyroid cáncer. Keywords night work, thyroid cancer

Rotating Night Shift Work and Healthy Aging After 24 Years of Follow-up in the Nurses' Health Study

Rotating night shift work is associated with higher mortality. Whether it is also associated with overall health among those who survive to older ages remains unclear. To examine whether rotating night shift work is associated with healthy aging after 24 years of follow-up in the Nurses' Health Study, a cohort study among registered female nurses. For this cohort study, a composite healthy aging phenotype was ascertained among 46 318 participants who were aged 46 to 68 years and free of major chronic diseases in 1988 when the history of night shift work was assessed. In a secondary analysis in which cognitive function decline was considered in the healthy aging definition, 14 273 nurses were involved. Data were analyzed from March 1 to September 30, 2021. Duration of rotating night shift work. Healthy aging was defined as reaching at least 70 years of age and being free of 11 major chronic diseases, memory impairment, physical limitation, or deteriorated mental health. Of 46 318 female nurses (mean [SD] age at baseline, 55.4 [6.1] years), 3695 (8.0%) achieved healthy aging after 24 years of follow-up. After adjusting for established and potential confounders, compared with women who never worked rotating night shifts, the odds of achieving healthy aging decreased significantly with increasing duration of night shift work. The odds ratios were 0.96 (95% CI, 0.89-1.03) for 1 to 5 years, 0.92 (95% CI, 0.79-1.07) for 6 to 9 years, and 0.79 (95% CI, 0.69-0.91) for 10 or more years of night shift work (P = .001 for trend). This association did not differ substantially by age and lifestyles and was consistent for 4 individual dimensions of healthy aging. Results were similar in a secondary analysis, with an odds ratio of 0.73 (95% CI, 0.60-0.89; P < .001 for trend) comparing 10 or more years of night shift work vs no night shift work. In this cohort study, rotating night shift work was associated with decreased probability of healthy aging among US female nurses. These data support the notion that excess night shift work is a significant health concern that may also lead to deteriorated overall health among older individuals.

Occupational risk factors and breast cancer in Beijing, China: a hospital-based case–control study

IntroductionStudies on the association between breast cancer and occupational hazards are limited, especially in China. This is the first study to explore the relationship between breast cancer and occupational hazards...

Night Shift Work Accelerates Menopausal Age in Health Workers

Introduction: Earlier menopause has been associated with increased risk of cardiovascular disease, osteoporosis, shorter life expectancy and even cognitive decline. There are many factors that cause differences in the age of menopause in women, one of these environmental factors is a history of night shift work as a consequence of a job. It is not yet known whether female medical workers, with a history of night shifts, get earlier menopause.Methods: This case control study was conducted among 57 female night workers of the Dr. Soetomo General Academic Hospital. Data collection was conducted from December 2019 - March 2020. The study sample was postmenopausal health workers (nurse and midwife) and administrators. The instrument used in this study was a list of interview questions. The data was processed using SPSS software release 23.Results: The results show that from 45 children diagnosed with ALL, 53% are of the age ≤ 5 years old, with 58% males and 42% females. 13% of the patients are in the high risk group and 87% are in the standard risk group. Nutritional statuses of patients are 2% of them obese experienced remission after induction phase therapy, 56% normal with 80% of them experienced remission. 40% underweight with 89% of them experienced remission and 11% not experienced remission, 2% malnutrition and experienced remission. There is no correlation between the nutritional status of children with acute lymphoblastic leukemia with the outcome of induction phase (p = 0.798).Conclusion: In conclusion, there is no correlation between nutritional status and remission outcome of patients with ALL in the induction phase of therapy. However, high percentage of underweight patients shows nutrition needs special attention to improve therapy outcomes.

Prevalence of sleep disruption and determinants of sleepiness in a cohort of Italian hospital physicians: The PRESOMO study.

Nightshift work can cause daytime somnolence and decreased alertness, and can increase risk of medical errors, occupational injuries and car accidents. We used a structured questionnaire, including the Epworth Sleepiness Scale (ESS), to assess the prevalence and the determinants of sleep disruption in 268 Italian University hospital physicians from Cagliari (N = 57), Milan (N = 180) and Pisa (N = 31), who participated in the multicentre study on the prevalence of sleep disturbance among hospital physicians (PRESOMO); 198 of them (74%) were engaged in nightshift work. We explored the association between history of nightshift work and poor sleep quality and daytime somnolence with multivariate logistic regression, adjusting by personal and lifestyle covariates. Age, female gender, taking medication interfering with sleep and an elevated ESS score were significant predictors of poor sleep quality and daytime somnolence. Nightshift work was associated with a higher prevalence of unrestful sleep (84% versus 70%; odds ratio [OR] = 2.4, 95% confidence interval [CI] 1.18–5.05) and daytime dozing (57% versus 35%; OR = 1.9, 95% CI 1.03–3.64), with an upward trend by years of engagement in nightshift work for both conditions (p = .043 and 0.017, respectively), and by number of nightshifts/year for unrestful sleep (p = .024). Such an association was not detected with the ESS scale. Our results suggest that nightshift work significantly affects sleep quality and daytime somnolence in hospital physicians, who might underestimate their daytime dozing problem, when asked to subjectively scale it.

Sleep duration and napping in relation to colorectal and gastric cancer in the MCC-Spain study

Sleep duration is a novel and potentially modifiable risk factor for cancer. We evaluated the association of self-reported sleep duration and daytime napping with odds of colorectal and gastric cancer. We included 2008 incident colorectal cancer cases, 542 gastric cancer cases and 3622 frequency-matched population controls, recruited in the MCC-Spain case–control study (2008–2013). Sleep information, socio-demographic and lifestyle characteristics were obtained through personal interviews. Multivariable adjusted logistic regression models were used to estimate odds ratios (OR) with 95% confidence intervals (CI) for cancer, across categories of sleep duration (≤ 5, 6, 7, 8, ≥ 9 hours/day), daytime napping frequency (naps/week) and duration (minutes/nap). Compared to 7 hours of sleep, long sleep was associated with increased odds of colorectal (OR≥9 hours: 1.59; 95%CI 1.30–1.94) and gastric cancer (OR≥9 hours: 1.95; 1.37–2.76); short sleep was associated with increased odds of gastric cancer (OR≤5 hours: 1.32; 0.93–1.88). Frequent and long daytime naps increased the odds of colorectal (OR6–7 naps/week, ≥30 min: 1.32; 1.14–1.54) and gastric cancer (OR6–7 naps/week, ≥30 min: 1.56; 1.21–2.02). Effects of short sleep and frequent long naps were stronger among participants with night shift-work history. Sleep and circadian disruption may jointly play a role in the etiology of colorectal and gastric cancer.

Sleep complaints in former and current night shift workers: findings from two cross-sectional studies in Austria

ABSTRACT Sleep impairment is highly prevalent in night shift workers, but evidence on the association of former night shift work (NSW) and its metrics (duration and frequency) in relation to sleep complaints is lacking. We evaluated the association of former and current NSW with chronic insomnia or circadian rhythm sleep disorder in a sample of the general worker (GW) population and in hospital workers (HW) in Austria. Information on sleep, NSW history, sociodemographic, and lifestyle factors was collected through an online cross-sectional survey in a representative sample of GW (N= 1,004) and a sample of HW (N= 799) between 2017 and 2019. Multi-variable adjusted logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for various measures of sleep (including chronic insomnia, daytime sleepiness, sleep duration, napping habits) and doctor-diagnosed chronic insomnia across NSW exposure (never night shift work; ever; ever/former; ever/current) and related metrics (cumulative duration, average frequency), compared to never NSW. Effect modification by chronotype and daytime napping was investigated. Former NSW was associated with higher odds of chronic insomnia in both samples (GW: OR = 2.28, 95% CI = 1.07–4.83; HW: OR = 1.17, 95% CI = 0.60–2.27). Chronic insomnia odds tended to increase among current night shift workers (HW: OR = 1.50, 95% CI = 0.79–2.83), compared to day workers. Higher NSW frequency (shifts/month) was associated with higher chronic insomnia odds in former night shift workers in both samples (GW: ORper shift/month = 1.06, 95% CI = 1.00–1.12; HW: ORper shift/month = 1.12, 95% CI = 1.00–1.25). Former NSW was also associated with increased daytime sleepiness among GW (OR = 2.26, 95% CI 1.28–3.99). Associations were more pronounced among early chronotypes and participants who reported no daytime naps. Our results suggest that NSW is associated with chronic insomnia even in the years after cessation of involvement in working it.

Night Shift Work and Fecundability in Late Reproductive-Aged African American Women.

Background: We estimated the association between night shift work and fecundability among African American women. Methods: Black Women's Health Study participants (n = 560) aged 30-45 years reported their history of night shift work in 2005. Time to pregnancy for all pregnancies resulting in a livebirth was reported in 2011. We estimated the fecundability ratio (FR) and 95% confidence interval (CI) using proportional probabilities regression, accounting for multiple observations of individual women using generalized estimating equations. Results: We observed 4,417 months of pregnancy attempt time resulting in 390 births. After adjustment for covariates, women who reported ever working night shifts had 20% lower fecundability compared with those who never reported night shift work (FR = 0.80, 95% CI: 0.59-1.04). The FR for women reporting night shift work with a frequency of ≥1 time per month and a duration of ≥2 years was 0.65 (95% CI: 0.47-0.94) relative to women reporting no shift work. We observed a decrease in fecundability associated with ever working night shifts (FR = 0.74, 95% CI: 0.56-0.96) among women aged ≥35 years, but not among younger women (FR = 1.33, 95% CI: 0.78-2.28). Conclusion: A history of working night shifts was associated with reduced fecundability among older reproductive-aged African American women attempting pregnancy.

Rotating night shift work and risk of multiple sclerosis in the Nurses’ Health Studies

ObjectivesNight shift work has been suggested as a possible risk factor for multiple sclerosis (MS). The objective of the present analysis was to prospectively evaluate the association of rotating night...

Night shift work before and during pregnancy in relation to depression and anxiety in adolescent and young adult offspring

We investigated the relationship between maternal history of nightshift work before and shift work during pregnancy and offspring risk of depression and anxiety, among mothers participating in the Nurses Health Study II and in their offspring enrolled in the Growing Up Today Study 2 between 2004 and 2013. Case definitions were based on offspring self-reports of physician/clinician-diagnosed depression and/or anxiety, regular antidepressant use and depressive symptoms assessed using the Center for Epidemiologic Studies Depression Scale. Multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using generalized estimating equation models. We found no associations between maternal nightshift work before pregnancy or during pregnancy and offspring mental health disorders (e.g., nightshift work before pregnancy: depression (based on physician/clinician diagnosis): ORever nightwork = 1.14; 95% CI, 0.88–1.47; either depression or anxiety: ORever nightwork = 0.93; 95% CI, 0.81–1.08; nightshift work during pregnancy: depression: ORever nightwork = 1.14; 95% CI, 0.68–1.94; depression or anxiety: ORever nightwork =1.17; 95% CI, 0.70–1.98) and no dose-response relationship with longer history of nightshift work (all PTrend >0.10). Stratifying by maternal chronotype revealed a higher risk of depression for offspring whose mothers worked nightshifts before pregnancy and reported being definite morning chronotypes (a proxy for circadian strain) (ORever nightwork = 1.95; 95% CI, 1.17, 3.24 vs. ORever nightwork = 0.93; 95% CI, 0.68, 1.28 for any other chronotype; PInteraction = 0.03). Further studies replicating our findings and refined understanding regarding the interplay of nightshift work and chronotype and its potential influences on offspring mental health are needed.

Sleep duration, nightshift work, and the timing of meals and urinary levels of 8-isoprostane and 6-sulfatoxymelatonin in Japanese women

ABSTRACTIt has been hypothesized that disruption of circadian rhythms affects human health. Shift work and sleep deprivation are thought to disrupt the normal light–dark cycle, although the disruption due to shiftwork may be dependent on sleep deprivation. Both conditions have been suggested to be associated with an increased risk of cardiometabolic disorders. Non-photic environmental factors, such as the timing of eating, are also thought to regulate circadian rhythm and thus, may have effects on health, but the evidence from human studies is scarce. Oxidative stress is a risk factor of cardiometabolic disorders. Some laboratory studies suggest an involvement of circadian clock genes in the regulation of the redox system. The present study aimed to examine the association of sleeping habits, nightshift work, and the timing of meals with urinary levels of 8-isoprostane, a marker of oxidative stress, and 6-sulfatoxymelatonin, the principal metabolite of melatonin. Study subjects were 542 women who had previously attended a breast cancer mass screening in a community in Japan. Information on bedtimes and wake-up times, history of nightshift work, and the timing of meals was obtained by a self-administered questionnaire. The 8-isoprostane and 6-sulfatoxymelatonin were measured using the first morning void of urine and expressed per mg of creatinine. The geometric mean of 8-isoprostane levels was 12.1% higher in women with ≤6 hours of sleep than that in those with >8 hours of sleep on weekdays, and longer sleep duration on weekdays was significantly associated with lower urinary levels of 8-isoprostane after controlling for covariates (p for trend = 0.04). Women who were currently working the nightshift had a 33.3% higher geometric mean of 8-isoprostane levels than those who were not working nightshift (p = 0.03). Urinary 6-sulfatoxymelatonin levels were unrelated to sleep habits or nightshift work. Women who ate breakfast at irregular times had a 19.8% higher geometric mean of 8-isoprostane levels than those who ate breakfast at a regular time or who did not eat (p = 0.02). Women who ate nighttime snacks at irregular times had a 16.2% higher geometric mean of 8-isoprostane levels than those who did not eat nighttime snacks or who ate nighttime snacks at a regular time (p = 0.003). Among women who ate dinner at a regular time, earlier times for dinner were associated with higher 8-isoprostane and 6-sulfatoxymelatonin levels (p values for trends were 0.01 and 0.02, respectively). However, the times of dinner and nighttime snack are overlapping, and the time of last meal of the day was not associated with 8-isoprostane and 6-sulfatoxymelatonin levels. The time of breakfast or lunch was not associated with these biomarkers among women who ate the meal at regular times. Disturbing the rhythmicity of daily life may be associated with oxidative stress.

High Mammographic Density in Long-Term Night-Shift Workers: DDM-Spain/Var-DDM.

Background: Night-shift work (NSW) has been suggested as a possible cause of breast cancer, and its association with mammographic density (MD), one of the strongest risk factors for breast cancer, has been scarcely addressed. This study examined NSW and MD in Spanish women.Methods: The study covered 2,752 women aged 45-68 years recruited in 2007-2008 in 7 population-based public breast cancer screening centers, which included 243 women who had performed NSW for at least one year. Occupational data and information on potential confounders were collected by personal interview. Two trained radiologist estimated the percentage of MD assisted by a validated semiautomatic computer tool (DM-scan). Multivariable mixed linear regression models with random screening center-specific intercepts were fitted using log-transformed percentage of MD as the dependent variable and adjusting by known confounding variables.Results: Having ever worked in NSW was not associated with MD [Formula: see text]:0.96; 95% confidence interval (CI), 0.86-1.06]. However, the adjusted geometric mean of the percentage of MD in women with NSW for more than 15 years was 25% higher than that of those without NSW history (MD>15 years:20.7% vs. MDnever:16.5%;[Formula: see text]:1.25; 95% CI,1.01-1.54). This association was mainly observed in postmenopausal participants ([Formula: see text]:1.28; 95% CI, 1.00-1.64). Among NSW-exposed women, those with ≤2 night-shifts per week had higher MD than those with 5 to 7 nightshifts per week ([Formula: see text]:1.42; 95% CI, 1.10-1.84).Conclusions: Performing NSW was associated with higher MD only in women with more than 15 years of cumulated exposure. These findings warrant replication in futures studies.Impact: Our findings suggest that MD could play a role in the pathway between long-term NSW and breast cancer. Cancer Epidemiol Biomarkers Prev; 26(6); 905-13. ©2017 AACR.

Rotating night shift work, sleep, and colorectal adenoma in women.

This study aims to investigate the associations of rotating night shift work history and sleep duration with risk of colorectal adenoma. We evaluated 56,275 cancer-free participants of the Nurses' Health Study II, who had their first colonoscopy or sigmoidoscopy between 1991 and 2011; rotating night shift work and sleep duration were reported by mailed questionnaire. Multivariable-adjusted logistic regression was used to estimate relative risks (RR) of colorectal adenoma, with 95% confidence intervals (CI), across categories of rotating night shift work history (none, 1-4, 5-9, and ≥10years) and sleep duration (≤5, 6, 7, 8, and ≥9h/day). We found no association between duration of rotating night shift work and occurrence of colorectal adenoma (p-trend across shift work categories=0.5). Women with the longest durations of rotating night shift work (≥10years) had a similar risk of adenoma compared to women without a history of rotating night shift work (multivariable-adjusted RR=0.96, 95% CI=0.83-1.11). Similarly, there were no associations of shorter or longer sleep durations with adenoma risk (p-trend=0.2 across sleep durations of ≤5 through 7h/day and p-trend=0.5 across sleep durations of 7 through ≥9h/day). Results were similar when we examined associations according to adenoma location and subtype. Our results do not support an association between rotating night shift work or sleep duration and risk of colorectal adenoma in women.

Association of shift-work, daytime napping, and nighttime sleep with cancer incidence and cancer-caused mortality in Dongfeng-tongji cohort study

Background: Few studies investigated the combined effects of night-shift work, daytime napping, and nighttime sleep on cancer incidence and mortality.Methods: A total of 25,377 participants were included in this study. Information on sleep habits, cancer incidences, and mortalities were collected. Cox proportional hazards models were used to calculate the adjusted hazard ratios and 95% confidence intervals (HRs, 95%CIs).Results: Male subjects experienced ≥20 years of night-shift work, or without daytime napping had an increased risk of cancer, when compared with males who did not have night-shift work or napped for 1–30 min [HR (95%CI) = 1.27 (1.01–1.59) and 2.03 (1.01–4.13), respectively]. Nighttime sleep for ≥10 h was associated with a separate 40% and 59% increased risk of cancer [HR (95%CI) = 1.40 (1.04–1.88)] and cancer-caused mortality [HR (95%CI) = 1.59 (1.01–2.49)] than sleep for 7–8 h/night. Combined effects of three sleep habits were further identified. Male participants with at least two above risk sleep habits had a 43% increased risk of cancer [HR (95%CI) = 1.43 (1.07–2.01)] and a 2.07-fold increased cancer-caused mortality [HR (95%CI) = 2.07 (1.25–3.29)] than those who did not have any above risk sleep habits. However, no significant associations were observed among women.Conclusions: Long night-shift work history, without daytime napping, and long nighttime sleep duration were independently and jointly associated with higher cancer incidence among males.KEY MESSAGESNight-shift work of ≥20 years, without napping, and nighttime sleep of ≥10 h were associated with increased cancer incidence.Nighttime sleep ≥10 h was associated with a 2.07-fold increased cancer-caused mortality among males.Combined effects of night-shift work ≥20 years, without napping, and nighttime sleep ≥10 h on increasing cancer incidence were existed among males.

Occupational history of night shift work and Parkinson's disease in Denmark.

We investigated whether working night shifts was associated with the risk of Parkinson's disease (PD). Between January 2008 and December 2010, we recruited 1808 patients with a confirmed diagnosis of idiopathic PD from Denmark and 1876 population controls matched by year of birth and gender. Information on lifelong occupational history, including information on night work, smoking, caffeine and alcohol consumption habits, and family history of PD was collected through structured telephone interviews. Overall, there was no association between a history of night shift work and PD [odds ratio (OR) for any type of night work (ie, either permanent or rotating night work) 1.01, 95% confidence interval (95% CI) 0.86-1.21]. Compared with persons who never worked night shifts, risks of those with longer durations of night work did not appear to differ (OR <10 years=0.95, 95% CI 0.75-1.19, OR 10-19 years= 1.09, 95% CI 0.77-1.53, OR ≥20 years=1.05, 95% CI 0.81-1.37, P for trend=0.23). Associations were similar among men and women. These data suggest that working night shifts is not associated with PD or that low tolerance for night shift work is an early marker of PD. Due to the novel and exploratory nature of these findings, confirmation is needed.

Night shift work at specific age ranges and chronic disease risk factors

ObjectivesWe examined the association of night shift work history and age when night shift work was performed with cancer and cardiovascular disease risk factors among 54 724 women in the...

Sleep duration and its correlates in middle-aged and elderly Chinese women: The Shanghai Women’s Health Study

Abnormal sleep duration, either long or short, is associated with disease risk and mortality. Little information is available on sleep duration and its correlates among Chinese women. Using information collected from 68,832 women who participated in the Shanghai Women's Health Study (SWHS), we evaluated sleep duration and its correlations with sociodemographic and lifestyle factors, health status, and anthropometric measurements and their indexes using polynomial logistic regression. The mean age of the study population was 59.6 years (SD=9.0; range: 44.6-79.9 years) at time of sleep duration assessment. Approximately 80% of women reported sleeping 6-8 h/day, 11.5% slept 5h or less, and 8.7% slept 9h or more. As expected, age was the strongest predictor for sleep duration and was negatively correlated with sleep duration. In general, sleep duration was positively associated with energy intake, intakes of total meat and fruits, body mass index (BMI), waist-hip ratio (WHR), and waist circumference (WC) after adjustment for age and other factors. Both short and long sleep duration were negatively associated with education level, family income, and leisure-time physical activity and positively associated with number of live births, history of night shift work, and certain chronic diseases, compared to sleep duration around 7 h/day (6.5-7.4h/day). Short sleep duration was related to tea consumption and passive smoking. Long sleep duration was related to menopausal status and marital status. In this large, population-based study, we found that sleep duration among middle-aged and elderly Chinese women was associated with several sociodemographic and lifestyle factors and with disease status. The main limitation of the study is the cross-sectional design that does not allow us to draw any causal inference. However, this study provides information for future investigation into the nature of these associations so that recommendations can be developed to reduce sleep problems in middle-aged and elderly Chinese women. It also provides important information on potential confounders for investigation of sleep duration on health outcomes in this population.