CHANGES IN WORKING TIME ARRANGEMENTS OVER TIME AS A CONSEQUENCE OF WORK-FAMILY CONFLICT

Existing longitudinal studies on the relationship between working time arrangements (WTA) and work-family conflict have mainly focused on the normal causal relationship, that is, the impact of WTA on work-family conflict over time. So far, however, the reversed relationship, that is, the effect of work-family conflict on adjustments in WTA over time, has hardly been studied. Because work-family conflict is highly prevalent in the working population, further insight in this reverse relationship is invaluable to gain insight into secondary selection processes. The aim of this study is to investigate whether work-family conflict is prospectively related to adjustments in work schedules, working hours, and overtime work, and to explore sex differences and different time lags in this relation. Data of the prospective Maastricht Cohort Study were used. To study the effect of work-family conflict on a change from shift- to day work over 32 months of follow-up, male three-shift (n?=?727), five-shift (n?=?932), and irregular-shift (n?=?451) workers were selected. To study effects of work-family conflict on reduction of working hours over 12 and 24 months of follow-up, respectively, only day workers (males and females) were selected, capturing 5809 full-time workers (≥36?h/wk) and 1387 part-time workers (<36?h/wk) at baseline. To examine effects of work-family conflict on refraining from overtime work over 12 months of follow-up, only day workers reporting frequent overtime work at baseline were selected (3145 full-time and 492 part-time workers). Cox regression analyses were performed with adjustments for age, educational level, and presence of a long-term illness. Work-family conflict was associated with a significantly increased risk of changing from shift- to day work over 32 months of follow-up in three-shift workers (relative risk [RR]?=?1.77, 95% confidence interval [CI] 1.19–2.63) but not in five-shift workers (RR?=?1.32, 95% CI 0.78–2.24) and irregular-shift workers (RR?=?0.81, 95% CI 0.50–1.31). Within day workers, work-family conflict among full-time workers was associated with a significantly increased risk of reducing working hours during 1 yr of follow-up in women (RR?=?2.80, 95% CI 1.42–5.54) but not men (RR?=?1.34, 95% CI 0.81–2.22). In part-time workers, work-family conflict was associated with a significantly increased risk of reducing working hours during 1 yr of follow-up both in women (RR?=?1.99, 95% CI 1.04–3.82) and men (RR?=?4.03, 95% CI 1.28–12.68). Whereas the effects of work-family conflict on a reduction of working hours somewhat decreased among female full-time workers after 2 yr of follow-up (RR?=?2.13, 95% CI 1.24–3.66), among male full-time workers the effects increased and reached statistical significance (RR?=?1.53, 95% CI 1.05–2.21). Work-family conflict was not significantly associated with refraining from overtime work over 1 yr of follow-up. This study shows that work-family conflict has important consequences in terms of adjustments in work schedules and working hours over time, with considerable sex differences. The study thereby clearly illustrates secondary selection processes both in shift- and day workers, with significant implications for labor force participation, emphasizing the need for prevention of work-family conflict (Author correspondence: Nicole.Jansen@epid.unimaas.nl).     

Alcohol Consumption Patterns of Shiftworkers Compared With Dayworkers

The detrimental effects of excessive alcohol consumption are well documented. There is some evidence that shiftworkers consume more alcohol than dayworkers as a sleep aid to compensate for sleep difficulties associated with work schedules. This study investigated drinking patterns between shiftworkers and dayworkers using the 2006 and 2007 waves from the Household Income and Labour Dynamics Survey. A subset of workers who were not in full-time study and had a single job were selected; participants who did not drink alcohol (n?=?2090) were excluded. Using the 2001 Australian Government alcohol guidelines, alcohol consumption for risk of short-term harm (7+ standard drinks for men, 5+ for women) was investigated. The number of workers who drank alcohol “nearly every day” or “every day” was also examined. Some 13% of shiftworkers and 10% of those on standard schedules reported consuming alcohol at levels risky for short-term harm. Having a child less than 17 yrs (odds ratio [OR]?=?.39, 95% confidence interval [CI]?=?.22–.69), higher job demands (OR?=?.71, 95% CI?=?.58–.86), being female (OR?=?.45, 95% CI=. 26–.79), and being older (OR?=?.89, 95% CI?=?.87–.92) significantly reduced, whereas being a shiftworker (OR?=?2.10, 95% CI?=?1.08–4.12) significantly increased, the odds of drinking alcohol in short-term risky levels. Nearly 10% of shiftworkers and 8% of those on standard schedules reported consuming alcohol in short-term risky levels at least weekly. Having a child less than 17 yrs (OR?=?.40, 95% CI?=?.22–.74), higher job demands (OR?=?.69, 95% CI?=?.56–.86), being female (OR?=?.28, 95% CI?=?.15–.53), and being older (OR?=?.92, 95% CI?=?.89–.94) were associated with a significant reduction in the odds of consuming alcohol at risky levels at least weekly. Being a shiftworker was not associated with a significant increase in the odds of consuming alcohol at such risky levels at least weekly, but a trend was evident (OR?=?1.47, 95% CI?=?.73–3.00). Some 13.5% of shiftworkers and 21% of those on standard schedules reported consuming alcohol in any amount “near daily” or “daily.” Working more hours than preferred (OR?=?1.80, 95% CI?=?1.12–2.89) and being older (OR?=?1.10, 95% CI?=?1.07–1.13) were associated with a significant increase, and being female (OR?=?.18, 95% CI?=?.10–.33), and being a shiftworker (OR?=?.20, 95% CI?=?.09–.45) were associated with a significant decrease in the odds of consuming alcohol “daily” or “near daily.” Overall, the results suggest that shiftworkers may be more likely to consume alcohol at levels considered to be risky for health in the short term. In contrast, they appear less likely to drink alcohol daily. This pattern is suggestive of “binge drinking” behavior. (Author correspondence: jill.dorrian@unisa.edu.au)     

DAILY SLEEP,WEEKLY WORKING HOURS,AND RISK OF WORK-RELATED INJURY: US NATIONAL HEALTH INTERVIEW SURVEY (2004–2008)

The impact on health and safety of the combination of chronic sleep deficits and extended working hours has received worldwide attention. Using the National Health Interview Survey (NHIS), an in-person household survey using a multistage, stratified, clustered sample design representing the US civilian, non-institutionalized population, the authors estimated the effect of total daily self-reported sleep time and weekly working hours on the risk of a work-related injury. During the survey period 2004–2008, 177,576 persons (ages 18–74) sampled within households reported that they worked at a paid job the previous week and reported their total weekly work hours. A randomly selected adult in each household (n?=?75,718) was asked to report his/her usual (average) total daily sleep hours the prior week; complete responses were obtained for 74,415 (98.3%) workers. Weighted annualized work-related injury rates were then estimated across a priori defined categories of both average total daily sleep hours and weekly working hours. To account for the complex sampling design, weighted multiple logistic regression was used to independently estimate the risk of a work-related injury for categories of usual daily sleep duration and weekly working hours, controlling for important covariates and potential confounders of age, sex, race/ethnicity, education, type of pay, industry, occupation (proxy for job risk), body mass index, and the interaction between sleep duration and work hours. Based on the inclusion criteria, there were an estimated 129,950,376 workers annually at risk and 3,634,446 work-related medically treated injury episodes (overall injury rate 2.80/100 workers). Unadjusted annualized injury rates/100 workers across weekly work hours were 2.03 (≤20 h), 3.01 (20–30 h), 2.45 (31–40 h), 3.45 (40–50 h), 3.71 (50–60 h), and 4.34 (>60 h). With regards to self-reported daily sleep time, the estimated annualized injury rates/100 workers were 7.89 (<5 h sleep), 5.21 (5–5.9 h), 3.62 (6–6.9 h), 2.27 (7–7.9 h), 2.50 (8–8.9 h), 2.22 (9–9.9 h), and 4.72 (>10 h). After controlling for weekly work hours, and aforementioned covariates, significant increases in risk/1 h decrease were observed for several sleep categories. Using 7–7.9 h sleep as reference, the adjusted injury risk (odds ratio [OR] for a worker sleeping a total of <5 h/day was 2.65 (95% confidence interval [CI]: 1.57–4.47), for 5–5.9 h 1.79 (95% CI: 1.22–2.62), and for 6–6.9 h 1.40 (95% CI: 1.10–1.79). No other usual sleep duration categories were significantly different than the reference; however, for >10 h of usual daily sleep, the OR was marginally significantly elevated, 1.82 (95% CI: 0.96–3.47). These results suggest significant increases in work-related injury risk with decreasing usual daily self-reported sleep hours and increasing weekly work hours, independent of industry, occupation, type of pay, sex, age, education, and body mass (Author correspondence: david.lombardi@libertymutual.com)     

Working on Sundays–Effects on Safety,Health, and Work-life Balance

Several attributes of the work schedule can increase the risk of occupational injuries and accidents, health impairments, and reduced social participation. Although previous studies mainly focused on the effects of shiftwork and long working hours on employee health and safety, there is little evidence of a potential negative impact of working Sundays on the incidence of occupational accidents, health impairments, and work-life balance. A representative sample of employed workers in 31 member and associated states of the European Union (n?=?23,934) served as the database for a cross-sectional analysis. The sample was collected via face-to-face interviews in the year 2005. The association of the risks of occupational accidents, health impairments, and decreases in work-life balance with working Sundays was calculated using logistic regression models, controlling for potential confounders, such as shiftwork, workload, and demographic characteristics. The results indicated that working one or more Sundays/month was associated with increase both in the risk of reporting one or more health impairments (odds ratio [OR]: 1.17, 95% confidence interval [CI]: 1.06–1.29) and poorer work-life balance (OR: 1.15, 95% CI: 1.02–1.28). These effects remained after controlling for potentially confounding factors, such as other work schedule attributes, intensity of physical and mental workload, and individual characteristics. Furthermore, working Sundays was also related to increased risk of occupational accidents within the last year (OR: 1.34, 95% CI: 1.03–1.73). Controlling again for individual, workload, and working-time characteristics, a significant association with accident risk, however, remained only in work sectors with low a priori risk of occupational accidents (OR: 1.40, 95% CI: 1.02–1.91), although the increased risk could be observed for both medium and high a priori risk sectors working Sundays (without controlling for additional confounders). The results thus indicate that the detrimental effects of working Sundays on safety, health, and social well-being should be taken into account when designing work schedules. The potential hazards to employees' safety, health, and work-life balance, in particular, should be considered in discussions concerning extending work on Sundays in certain sectors, e.g., retail. (Author correspondence: awirtz@hsph.harvard.edu)     

SLEEP AND SLEEPINESS: IMPACT OF ENTERING OR LEAVING SHIFTWORK—A PROSPECTIVE STUDY

Very little is known about the effects on sleep and sleepiness of entering or exiting shiftwork. The present study used a longitudinal database (n?=?3637). Participants completed a questionnaire on work hours, sleep, and work environment at the start and end of a 5-yr period. Changes in shift/day work status were related to change in a number of subjective sleep variables using logistic regression analysis. The analyses were adjusted for age, sex, and differences in socioeconomic status, work demands, work control, physical workload, marriage status, and number of children. In comparison with constant day work, entering shiftwork (with or without night shifts) from day work increased the risk of difficulties in falling asleep, and leaving shiftwork reduced this risk (odds ratio [OR]?=?2.8 [confidence interval, CI?=?1.8–4.5]). Also falling asleep at work showed a consistent pattern; an increased risk of falling asleep for those with shiftwork on both occasions, and for those with night work on both occasions. Also entering night work was associated with a strongly increased risk of falling asleep at work (OR?=?2.9 [CI?=?1.3–6.7]). These results suggest that entering and leaving shiftwork has a considerable impact on sleep and alertness. However, there is a need for large and more extended longitudinal studies to support our findings. (Author correspondence: Torbjorn.akerstedt@ki.se)     

OBESITY AND HIGH BLOOD PRESSURE OF 12-HOUR NIGHT SHIFT FEMALE CLEAN-ROOM WORKERS

The 12?h shift schedule is widely used in clean rooms for electronic semiconductor production in Taiwan. This study investigated the associations of obesity and metabolic syndrome (MetS) components among women working in a semiconductor manufacturing factory in North Taiwan. Workers were divided into four groups according to their work schedules and duties (i.e., office workers, day workers, fixed 12?h day shift, and fixed 12?h night shiftworkers). The subjects comprised 1838 women who voluntarily attended a health examination between August 2006 and November 2006. Their mean (±SD) age was 33.6 (±7.1) yrs and their mean duration of work was 7.4 (±5.2) yrs. Each subject's health-related behaviors, body mass index, and MetS components were measured and analyzed using multivariate logistic regression. Obesity and MetS were defined according to World Health Organization criteria for Asian populations and the National Cholesterol Educational Program and Adult Treatment Panel III Guidelines, respectively. The results showed that women working in the clean room on fixed 12?h night shifts had significantly elevated odds ratios for obesity (OR, 2.7; 95% CI, 1.6–4.5), central obesity (OR, 2.9; 95% CI, 1.7–5.1), and high blood pressure (OR, 2.3; 95% CI, 1.2–4.4) compared to female office workers; these results persisted after adjusting for age, smoking, drinking, education, and duration of work. We did not find any significant differences in triglyceride and high-density lipoprotein cholesterol among women working different schedules. We conclude that working fixed 12?h night shifts was associated with an increased odds ratio for obesity, central obesity, and high blood pressure among clean-room women workers. Weight reduction and blood pressure control programs should be implemented in the workplace for women working fixed 12?h night shifts. (Author correspondence: m006671@ms.skh.org.tw)     

Objective working hour characteristics and work–life conflict among hospital employees in the Finnish public sector study

This epidemiological cohort study, based on Finnish public sector data, investigated the associations between objective working hour characteristics and work–life conflict in day and shift work. The comprehensive data of hospital workers (n = 8 931, 92% women, average age 45 years), consisted of survey responses from 2012, linked with the payroll data of working hour characteristics from 91 days preceding the survey. Logistic regression analysis was used to investigate the associations between working hour characteristics and experiencing work–life conflict often/very often. The analyses were adjusted for age (< 39, 40–49 and >50 years), sex, level of education, marital status, number of small (0–6 years) and school-aged (7–18 years) children, and the overall stressfulness of the life situation. We also conducted stratified analyses of age and sex on the basis of significant interactions. Difficulties in combining work and life were more often associated with shift work without night shifts and shift work with night shifts than with day work (41% and 34 versus 27%; OR for shift work with night shifts 1.78, 95% CI 1.59–2.00, OR for shift work without night shifts 1.42, 95% CI 1.26–1.60). A high proportion (> 25%) of long (> 40h, (OR 1.26, 95% 1.14–1.39) and very long (> 48h, OR 1.31, 95% CI 1.15–1.49) weekly working hours were associated with work–life conflict, and in the stratified analysis, the latter was also true among women (OR 1.54, 95% CI 1.25–1.89). Of the unsocial working hour characteristics, a relatively large amount (> 10% of all shifts) of evening (OR 1.56, 95% CI 1.41–1.72) and night shifts (OR 1.46, 95%CI 1.32–1.61), a high proportion (> 25% of all shifts) of quick returns (< 11h) (OR 1.46, 95% CI 1.31–1.63), and weekend work (OR 1.44, 95% CI 1.31–1.58) were associated with work–life conflict. A large amount of single days off (> 25% of all days off) was associated with work–life conflict among men (OR 1.90, 95% CI 1.11–3.25), but not in the whole sample. When the two types of shift work were analyzed separately, shift work without night shifts and very long work weeks had higher odds (OR 1.47, 95% CI 1.20–1.80) of work–life conflict than shift work with night shifts. Conversely, weekend work and evening shifts had higher odds of work–life conflict among shift workers with night shifts (OR 1.74, 95% 1.55–1.96; (OR 1.57, 95% CI 1.40–1.77) than among those without night shifts. To conclude, this study shows that shift workers with and without night shifts more often have difficulties combining work and life than day workers. Several unsocial working hour characteristics, including long work weeks, evening and night shifts, weekend work, and quick returns, are associated with work–life conflict.     

New Zealanders working non-standard hours also have greater exposure to other workplace hazards

Exposure to workplace hazards, such as dust, solvents, and fumes, has the potential to adversely affect the health of people. However, the effects of workplace hazards on health may differ when exposure occurs at different times in the circadian cycle, and among people who work longer hours or who do not obtain adequate sleep. The aim of the present study was to document exposures to workplace hazards across a national sample of New Zealanders, comparing people who work a standard 08:00 ?17:00 h Monday-to-Friday working week (Std hours) and those who do not (N-Std hours). New Zealanders (n = 10 000) aged 20–64 yrs were randomly selected from the Electoral Roll to take part in a nationwide survey of workplace exposures. Telephone interviews were conducted between 2004 and 2006, using a six-part questionnaire addressing demographics, detailed information on the current or most recent job (including exposures to a range of workplace hazards), sleep, sleepiness, and health status. N-Std hours were categorised on the basis of: being required to start work prior to 07:00 h or finish work after 21:00 h and/or; having a regular on-call commitment (at least once per week) and/or; working rotating shifts and/or; working night shift(s) in the last month. The response rate was 37% (n = 3003), with 22.2% of participants (n = 656) categorised as working N-Std hours. Industry sectors with the highest numbers of participants working N-Std hours were manufacturing, health and community services, and agriculture, fishing, and forestry. Response rate was 37% (n = 3003) with 22.2% (n = 656) categorised as working N-Std hours. Participants working N-Std hours were more likely to be exposed to all identified hazards, including multiple hazards (OR = 2.45, 95% CI = 2.01–3.0) compared to those working Std hours. Participants working N-Std hours were also more likely to report ‘never/rarely’ getting enough sleep (OR = 1.38, 95% CI = 1.15–1.65), ‘never/rarely’ waking refreshed (OR = 1.23, 95% CI = 1.04–1.47), and excessive sleepiness (OR = 1.77, 95% CI = 1.29–2.42). New Zealanders working N-Std hours are more likely to be exposed to hazards in the workplace, to be exposed to multiple hazards, and to report inadequate sleep and excessive sleepiness than their colleagues working a standard 08:00?17:00 h Monday-to-Friday working week. More research is needed on the effects of exposure to hazardous substances outside the usual waking day, on the effects of exposure to multiple hazards, and on the combination of hazard exposure and sleep restriction as a result of shift work.     

Impact of Nightshift Work on Overweight and Abdominal Obesity Among Workers of a Poultry Processing Plant in Southern Brazil

The authors examined the associations of shiftwork with overweight and abdominal obesity through a cross-sectional study of 1206 employees 18 to 50 yrs of age who were working on a production line in a poultry processing plant. Night-shift workers (n?=?800) were considered exposed, whereas day shiftworkers (n?=?406) were considered nonexposed. Overweight was defined as a body mass index ≥25?kg/m² and abdominal obesity as a waist circumference ≥88?cm in women and ≥102?cm in men. The mean age of the workers was 30.5 yrs (standard deviation?=?8.7 yrs), and 65.2% were women. Nightshift workers compared to dayshift workers showed higher prevalences of overweight (42.2% vs. 34.3%; p?=?.020) and abdominal obesity (24.9% vs. 19.5%; p?=?.037). After adjusting for sociodemographics, parental overweight status, behavioral characteristics, and sleep characteristics, including hours of sleep, the prevalence ratios for overweight and abdominal obesity were 1.27 (95% confidence interval [ CI]: 1.00–1.61) and 1.45 (95% CI: 1.10–1.92), respectively, for the nightshift workers compared to the dayshift workers. A consistent finding in our study was the independent contribution of night shiftwork to overweight and abdominal obesity among Brazilian workers. Further studies are needed to understand the biological mechanisms involved and the complex behavioral and social adaptations experienced by night-shift workers. (Author correspondence: mtolinto@gmail.com)     

Relationship between shift work schedule and self-reported sleep quality in Chinese employees

Few studies have reported on the effects of fixed and rotating shift systems on the prevalence of sleep disturbance. Thus, in this study, the relationships between different work schedules and sleep disturbance in Chinese workers were investigated. A total of 2180 workers aged 19–65 years responded to the self-report questionnaire on shift work schedule (fixed day-shift, fixed night-shift, two-shift or three-shift system), working hours a day, and working days a week, physical effort, subjective sleep quality and subjective mental state. It was found that the rotating shift workers, namely, two- and three-shift workers, exhibited higher risks of sleep disturbance than with the fixed day-shift workers did (OR 1.37; 95% CI 1.07to 1.74; and OR 2.19; 95% CI 1.52 to 3.15, respectively). The risk was particularly high among two- or three-shift workers who worked more than 8 hours a day or more than 5 days a week and among three-shift workers who reported both light and heavy physical effort at work. Moreover, the two- and three-shift workers (rotating shift workers) suffered from poorer sleep quality than the fixed night shift workers did (OR 1.84; 95% CI 1.01 to 3.32; and OR 2.94; 95% CI 1.53 to 5.64, respectively). Consequently, rotating shift work (two- and three-shift work) is a risk factor for sleep disturbance, and the fixed work rhythm may contribute to the quality of sleep.     

Cardiovascular risk factors and cognitive function in middle aged and elderly Lithuanian urban population: results from the HAPIEE study

Background

The purpose of this study was to examine associations between cardiovascular risk factors and cognitive ability in middle aged and elderly Lithuanian urban population.

Methods

Data from the survey performed in the framework of the HAPIEE (Health, Alcohol, Psychosocial Factors in Eastern Europe) study were presented. A random sample of 7,087 individuals aged 45–72 years was screened in 2006–2008.

Results

The scores of immediate recall and delayed verbal recall, cognitive speed and attention were significantly lower in men than in women; yet numerical ability scores were higher in men. Significant associations between lowered cognitive functions and previous stroke (in male OR?=?2.52; 95% CI?=?1.75-3.64; in female OR?=?2.45; 95% CI?=?1.75, 3.64) as well as ischemic heart disease history (among male OR?=?1.28; 95% CI?=?1.03-1.60) have been determined. Higher level of physical activity in leisure time (among female OR?=?1.32; 95% CI?=?1.03-1.69), poor self-rated health (among male OR?=?1.57; 95% CI?=?1.15-2.14) and poor quality of life (in male OR?=?1.67; 95% CI?=?1.07-2.61; in female OR?=?2.81; 95% CI?=?1.92-4.11) were related to lowered cognitive function.

Conclusions

The findings of the study suggest that associations between cardiovascular risk factors and lowered cognitive function among healthy middle-aged and elderly adults strongly depend on gender.

     

Night Work and Mortality: Prospective Study Among Finnish Employees Over the Time Span 1984 to 2008

There is considerable evidence showing that night work is associated with increased morbidity, but only a few studies have focused on its relation to mortality. This study investigates the relationship between the type of working-time arrangement (weekly night work/daytime work) and total and cause-specific mortality among men and women. The data consist of a representative working conditions survey of Finnish employees conducted in 1984 (2286 men/2216 women), which has been combined with register-based follow-up data from Statistics Finland covering the years 1985–2008. In the 1984 survey, the employees were asked if they worked during the night (23:00–06:00?h) and if so, how often. In this study, the authors compare employees who worked at night (121 men/89 women) to daytime employees who did not do night work (1325 men/1560 women). The relative risk of death was examined by Cox proportional hazards analyses adjusted for background (age, level of education, family situation, and county), health (longstanding illness, pain symptoms, smoking status, and psychological symptoms), and work-related factors (weekly working hours, physical and psychological demands, demands of learning at work, and perceived job insecurity). Female employees working at night had a 2.25-fold higher risk of mortality than female dayworkers (95% confidence interval [CI] 1.20–4.20) after adjustment for background and health- and work-related factors. In addition to total mortality, night work was also associated with tumor mortality. Female night workers had a 2.82-fold higher risk of tumor mortality than female dayworkers (95% CI 1.20–6.65) in the adjusted model. Among men, no such significant association was observed. The present study indicated that female night workers had a higher risk of both total and tumor mortality compared to female daytime employees. Additional research on the potential factors and mechanisms behind the association between night work and mortality is required. (Author correspondence: jouko.natti@uta.fi)     

WORKING THE NIGHT SHIFT CAUSES INCREASED VASCULAR STRESS AND DELAYED RECOVERY IN YOUNG WOMEN

Shiftwork has been associated with elevated blood pressure (BP) and decreased heart-rate variability (HRV), factors that may increase the long-term risk of cardiovascular-related mortality and morbidity. This study explored the effect of shiftwork on dynamic changes in autonomic control of HRV (cardiac stress), systolic BP and diastolic BP, i.e., SBP and DBP (vascular stress), and recovery in the same subjects working different shifts. By studying the same subjects, the authors could reduce the effect of possible contribution of between-subject variation from genetic predisposition and environmental factors. The authors recruited 16 young female nurses working rotating shifts—day (08:00–16:00 h), evening (16:00–00:00 h), and night (00:00–08:00 h)—and 6 others working the regular day shift. Each nurse received simultaneous and repeated 48-h ambulatory electrocardiography and BP monitoring during their work day and the following off-duty day. Using a linear mixed-effect model to adjust for day shift, the results of the repeated-measurements and self-comparisons found significant shift differences in vascular stress. While working the night shift, the nurses showed significant increases in vascular stress, with increased SBP of 9.7 mm Hg. The changes of SBP and DBP seemed to peak during waking time at the same time on the day off as they did on the working day. Whereas HRV profiles usually returned to baseline level after each shift, the SBP and DBP of night-shift workers did not completely return to baseline levels the following off-duty day (p?<?.001). The authors concluded that although the nurses may recover from cardiac stress the first day off following a night shift, they do not completely recover from increases in vascular stress on that day. (Author correspondence: jdwang@ntu.edu.tw)     

Independent Effects of Sleep Duration and Body Mass Index on the Risk of a Work-Related Injury: Evidence From the US National Health Interview Survey (2004–2010)

Fatigue has been linked to adverse safety outcomes, and poor quality or decreased sleep has been associated with obesity (higher body mass index, BMI). Additionally, higher BMI is related to an increased risk for injury; however, it is unclear whether BMI modifies the effect of short sleep or has an independent effect on work-related injury risk. To answer this question, the authors examined the risk of a work-related injury as a function of total daily sleep time and BMI using the US National Health Interview Survey (NHIS). The NHIS is an in-person household survey using a multistage, stratified, clustered sample design representing the US civilian population. Data were pooled for the 7-yr survey period from 2004 to 2010 for 101 891 “employed” adult subjects (51.7%; 41.1?±?yrs of age [mean?±?SEM]) with data on both sleep and BMI. Weighted annualized work-related injury rates were estimated across a priori defined categories of BMI: healthy weight (BMI: <25), overweight (BMI: 25–29.99), and obese (BMI: ≥30) and also categories of usual daily sleep duration: <6, 6–6.99, 7–7.99, 8–8.99, and ≥9?h. To account for the complex sampling design, including stratification, clustering, and unequal weighting, weighted multiple logistic regression was used to estimate the risk of a work-related injury. The initial model examined the interaction among daily sleep duration and BMI, controlling for weekly working hours, age, sex, race/ethnicity, education, type of pay, industry, and occupation. No significant interaction was found between usual daily sleep duration and BMI (p?=?.72); thus, the interaction term of the final logistic model included these two variables as independent predictors of injury, along with the aforementioned covariates. Statistically significant covariates (p?≤?.05) included age, sex, weekly work hours, occupation, and if the worker was paid hourly. The lowest categories of usual sleep duration (<6 and 6–6.9?h) showed significantly (p?≤?.05) elevated injury risks than the referent category (7–8?h sleep), whereas sleeping >7–8?h did not significantly elevate risk. The adjusted injury risk odds ratio (OR) for a worker with a usual daily sleep of <6?h was 1.86 (95% confidence interval [CI]: 1.37–2.52), and for 6–6.9?h it was 1.46 (95% CI: 1.18–1.80). With regards to BMI, the adjusted injury risk OR comparing workers who were obese (BMI: ≥30) to healthy weight workers (BMI: <25) was 1.34 (95% CI: 1.09–1.66), whereas the risk in comparing overweight workers (BMI: 25–29.99) to healthy weight risk was elevated, but not statistically significant (OR?=?1.08; 95% CI: .88–1.33). These results from a large representative sample of US workers suggest increase in work-related injury risk for reduced sleep regardless of worker's body mass. However, being an overweight worker also increases work-injury risk regardless of usual daily sleep duration. The independent additive risk of these factors on work-related injury suggests a substantial, but at least partially preventable, risk. (Author correspondence: david.lombardi@libertymutual.com)     

When Work Calls—Associations Between Being Contacted Outside of Regular Working Hours for Work-Related Matters and Health

Boundaries between work and private life are diminishing, but little is known on how this influences worker health. Therefore, we examined the association between work-related contacts outside of regular working hours by e-mail or phone and self-reported health in a representative sample of European employees (n?=?23 760). The risk of reporting ≥1 health problem(s) was increased in workers contacted sometimes (odds ratio [OR]: 1.16, 95% confidence interval [CI]: 1.06–1.27) or often (OR: 1.23, 95% CI: 1.12–1.34) as compared with never, controlling for several demographic and workplace characteristics. Further research is needed to quantify work and nonwork patterns and their health effects.     

Irregular 24-hour activity rhythms and the metabolic syndrome in older adults

Circadian rhythms – near 24?h intrinsic biological rhythms – modulate many aspects of human physiology and hence disruption of circadian rhythms may have an important impact on human health. Experimental work supports a potential link between irregular circadian rhythms and several key risk factors for cardiovascular disease including hypertension, obesity, diabetes and dyslipidemia, collectively termed the metabolic syndrome. While several epidemiological studies have demonstrated an association between shift-work and the components of the metabolic syndrome in working-age adults, there is a relative paucity of data concerning the impact of non-occupational circadian irregularity in older women and men. To address this question, we studied 7 days of actigraphic data from 1137 older woman and men participating in the Rush Memory and Aging Project, a community-based cohort study of the chronic conditions of aging. The regularity of activity rhythms was quantified using the nonparametric interdaily stability metric, and was related to the metabolic syndrome and its components obesity, hypertension, diabetes and dyslipidemia. More regular activity rhythms were associated with a lower odds of having the metabolic syndrome (OR?=?0.69, 95% CI?=?0.60–0.80, p?=?5.8?×?10^?7), being obese (OR?=?0.73, 95% CI?=?0.63–0.85, p?=?2.5?×?10^?5), diabetic (OR?=?0.76, 95% CI?=?0.65–0.90, p?=?9.3?×?10^?4), hypertensive (OR?=?0.78, 95% CI?=?0.66–0.91, p?=?2.0?×?10^?3) or dyslipidemic (OR?=?0.82, 95% CI?=?0.72–0.92, p?=?1.2?×?10^?3). These associations were independent of differences in objectively measured total daily physical activity or rest, and were not accounted for by prevalent coronary artery disease, stroke or peripheral artery disease. Moreover, more regular activity rhythms were associated with lower odds of having cardiovascular disease (OR?=?0.83; 95% CI?=?0.73–0.95, p?=?5.7?×?10^?3), an effect that was statistically mediated by the metabolic syndrome. We conclude that irregular activity rhythms are associated with several key components of the metabolic syndrome in older community-dwelling adults, and that the metabolic syndrome statistically partially mediates the association between activity rhythms and prevalent cardiovascular disease. Although additional longitudinal and experimental studies are needed to conclusively delineate the causal relationships underlying these associations, these findings are consistent with preclinical data, and add further support for investigations of the irregularity of activity rhythms as a potential therapeutic target to decrease the burden of cardiovascular disease in older adults.     

MTHFR polymorphisms and ovarian cancer risk: a meta-analysis

The C677T and A1298C polymorphisms of methylenetetrahydrofolate reductase (MTHFR) have been reported to alter the risk of ovarian cancer. However, the results are still inconclusive. For better understanding of the effect of these two polymorphisms on ovarian cancer risk, a meta-analysis was performed. An extensive search was performed to identify all case–control studies investigating such association. The strength of association between these two polymorphisms and ovarian cancer risk was assessed by odds ratio (OR) with the corresponding 95?% confidence interval (95?% CI). 3,496 cases and 3,631 controls for C677T polymorphism and 3,280 cases and 3,346 controls for A1298C polymorphism were included in this meta-analysis. The results suggested that there were no significant associations between C677T and A1298C polymorphisms and ovarian cancer risk in overall comparisons in all genetic models (For C677T: TT vs. CC: OR?=?0.94, 95?% CI?=?0.71–1.24, P?=?0.65; CT vs. CC: OR?=?1.03, 95?% CI?=?0.93–1.14, P?=?0.57; TT/CT vs. CC: OR?=?1.01, 95?% CI?=?0.88–1.16, P?=?0.87; TT vs. CC/CT: OR?=?0.93, 95?% CI?=?0.72–1.20, P?=?0.58. For A1298C: CC vs. AA: OR?=?1.05, 95?% CI?=?0.88–1.25, P?=?0.65; CA vs. AA: OR?=?0.98, 95?% CI?=?0.88–1.08, P?=?0.66; CC/CA vs. AA: OR?=?0.99, 95?% CI?=?0.90–1.09, P?=?0.85; CC vs. AA/CA: OR?=?1.06, 95?% CI?=?0.90–1.26, P?=?0.46). Subgroup analysis based on ethnicities and influence analysis did not perturb the results. In conclusion, the results of this meta-analysis indicate that the MTHFR C677T and A1298C polymorphisms are not associated with ovarian cancer risk, especially in Caucasians.     

The social network around influenza vaccination in health care workers: a cross-sectional study

Background

Influenza vaccination coverage remains low among health care workers (HCWs) in many health facilities. This study describes the social network defined by HCWs’ conversations around an influenza vaccination campaign in order to describe the role played by vaccination behavior and other HCW characteristics in the configuration of the links among subjects.

Methods

This study used cross-sectional data from 235 HCWs interviewed after the 2010/2011 influenza vaccination campaign at the Hospital Clinic of Barcelona (HCB), Spain. The study asked: “Who did you talk to or share some activity with respect to the seasonal vaccination campaign?” Variables studied included sociodemographic characteristics and reported conversations among HCWs during the influenza campaign. Exponential random graph models (ERGM) were used to assess the role of shared characteristics (homophily) and individual characteristics in the social network around the influenza vaccination campaign.

Results

Links were more likely between HCWs who shared the same professional category (OR 3.13, 95% CI?=?2.61–3.75), sex (OR 1.34, 95% CI?=?1.09–1.62), age (OR 0.7, 95% CI?=?0.63–0.78 per decade of difference), and department (OR 11.35, 95% CI?=?8.17–15.64), but not between HCWs who shared the same vaccination behavior (OR 1.02, 95% CI?=?0.86–1.22). Older (OR 1.26, 95% CI?=?1.14–1.39 per extra decade of HCW) and vaccinated (OR 1.32, 95% CI?=?1.09–1.62) HCWs were more likely to be named.

Conclusions

This study finds that there is no homophily by vaccination status in whom HCWs speak to or interact with about a workplace vaccination promotion campaign. This result highlights the relevance of social network analysis in the planning of health promotion interventions.

     

REST/ACTIVITY RHYTHMS AND MORTALITY RATES IN OLDER MEN: MROS SLEEP STUDY

An association between increased risk of mortality and disruptions in rest/activity circadian rhythms (RAR) has been shown among adults with dementia and with metastatic colorectal cancer. However, the association among a more general population of older adults has not been studied. Our study population consisted of 2964 men aged?≥?67 yrs of age enrolled in the Outcomes of Sleep Disorders in Older Men (MrOS Sleep) Study. Rest/activity patterns were measured with wrist actigraphy. RAR parameters were computed and expressed as quintiles, and included acrophase (time of peak activity level), amplitude (peak-to-nadir difference), mesor (middle of the peak), pseudo F-value (overall circadian rhythmicity), beta (steepness), and alpha (peak-to-trough width). After adjustment for multiple potential confounders, men in the lowest quintile of pseudo F-value had a 57% higher mortality rate (hazard ratio [HR]?=?1.57, 95% CI, 1.03–2.39) than men in the highest quintile. This association was even stronger with increased risk of cardiovascular disease-related mortality (CVD) (HR?=?2.32, 95% CI, 1.04–5.22). Additionally, men in the lowest quintile of acrophase had a 2.8-fold higher rate of CVD-related mortality (HR?=?2.84, 95% CI, 1.29–6.24). There was no evidence of independent associations with amplitude, mesor, alpha, beta, and mortality risk. Older men with less robust RAR and earlier acrophase timing have modestly higher all-cause and CVD-related mortality rates. Further research should examine potential biological mechanisms underlying this association. (Author correspondence: ames0047@umn.edu)     

Association between the OGG1 Ser326Cys and APEX1 Asp148Glu polymorphisms and lung cancer risk: a meta-analysis

The previous published data on the association between the 8-oxo-guanine glycosylase-1 (OGG1) and apurinic/apyrimidinic-endonuclease-1 (APEX1/APE1) polymorphisms and lung cancer risk remained controversial. Several polymorphisms in the OGG1 and APEX1 gene have been described, including the commonly occurring Ser326Cys in OGG1 and Asp148Glu in APEX1. This meta-analysis of literatures was performed to derive a more precise estimation of the relationship. A total of 37 studies were identified to the meta-analysis, including 9,203 cases and 10,994 controls for OGG1 Ser326Cys (from 25 studies) and 3,491 cases and 4,708 controls for APEX1 Asp148Glu (from 12 studies). When all the eligible studies were pooled into the meta-analysis of OGG1 Ser326Cys polymorphism, significantly increased lung cancer risk was observed in recessive model (OR?=?1.17, 95?% CI?=?1.03–1.33) and in additive model (OR?=?1.21, 95?% CI?=?1.03–1.42). In the stratified analysis, significantly increased risk of lung cancer was also observed on the population-based studies (recessive model: OR?=?1.26, 95?% CI?=?1.08–1.46, additive model: OR?=?1.42, 95?% CI?=?1.06–1.73) and non-smokers (dominant model: OR?=?1.20, 95?% CI?=?1.02–1.42, recessive model: OR?=?1.20, 95?% CI?=?1.02–1.40, additive model: OR?=?1.35, 95?% CI?=?1.08–1.68). Additionally, when one study was deleted in the sensitive analysis, the results of OGG1 Ser326Cys were changed in Asians (recessive model: OR?=?1.16, 95?% CI?=?1.06–1.27, additive model: OR?=?1.23, 95?% CI?=?1.09–1.38). When all the eligible studies were pooled into the meta-analysis of APEX1 Asp148Glu polymorphism, there was no evidence of significant association between lung cancer risk and APEX1 Asp148Glu polymorphism in any genetic model. In the stratified analysis, significantly decreased lung adenocarcinoma risk was observed in recessive model (OR?=?0.68, 95?% CI?=?0.48–0.97, P _h?=?0.475, I²?=?0.0?%). Additionally, when one study was deleted in the sensitive analysis, the results of APEX1 Asp148Glu were changed in Asians (recessive model: OR?=?1.21, 95?% CI?=?1.03–1.43) and smokers (dominant model: OR?=?1.62, 95?% CI?=?1.08–2.44, additive model: OR?=?1.37, 95?% CI?=?1.02–1.84). In summary, this meta-analysis indicates that OGG1 Ser326Cys show an increased lung cancer risk in Asians and non-smokers, APEX1 Asp148Glu polymorphism may be associated with decreased lung adenocarcinoma risk, and APEX1 Asp148Glu polymorphism show an increased lung cancer risk in Asians and smokers. However, a study with the larger sample size is needed to further evaluated gene-environment interaction on OGG1 Ser326Cys and APEX1 Asp148Glu polymorphisms and lung cancer risk.