Daily sleep, weekly working hours, and risk of work-related injury: US National Health Interview Survey (2004–2008)

Center for Injury Epidemiology, Liberty Mutual Research Institute for Safety, Hopkinton, Massachusetts 01748, USA.
Chronobiology International (Impact Factor: 3.34). 07/2010; 27(5):1013-30. DOI: 10.3109/07420528.2010.489466
Source: PubMed


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 (< or =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.

Download full-text


Available from: Simon Folkard,
  • Source
    • "According to a chronic sleep restriction study by van Dongen et al. [27], test subjects who were limited to 6 hours of sleep for two weeks had neurobehavioral functioning similar to those who did not sleep at all for two days. Two studies by Lombardi et al. [22, 23] on sleep duration and work-related injury used data from the US National Health Interview Survey to show a decrease in sleep duration (compared to a sleep duration of 7.00 to 7.99 hours) led to an increase in the risk of injury, with less than 5 hours having odds ratios up to 2.65, and, in sleep duration categories greater than 8 hours, the elevated risk was marginally significant. In our study, the injury group reported lower mean sleep durations than the non-injury group. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Objectives The decrease or increase in sleep duration has recently been recognized as a risk factor for several diseases, including hypertension and obesity. Many studies have explored the relationship of decreased sleep durations and injuries, but few have examined the relationship between increased sleep duration and injury. The objective of this research is to identify the risk for injury associated with both decreased and increased sleep durations. Methods Data from the 2010 Community Health Survey were used in this study. We conducted logistic regression with average sleep duration as the independent variable, injury as a dependent variable, and controlling for age, sex, occupation, education, region (cities and provinces), smoking, alcohol use, body mass index, hypertension, diabetes, arthritis, and depression. Seven categories of sleep duration were established: ≤4, 5, 6, 7, 8, 9, and ≥10 hours. Results Using 7 hours of sleep as the reference, the adjusted injury risk (odds ratio) for those sleeping a total of ≤4 h/d was 1.53; 1.28 for 5 hours, for 1.11 for 6 hours, 0.98 for 8 hours, 1.12 for 9 hours, and 1.48 for ≥10 hours. The difference in risk was statistically significant for each category except for the 8 and 9 hours. In this study, risk increased as the sleep duration decreased or increased, except for the 8 and 9 hours. Conclusions This research found that either a decrease or increase in sleep duration was associated with an increased risk for injury. The concept of proper sleep duration can be evaluated by its associated injury risk.
    Journal of Preventive Medicine and Public Health 05/2014; 47(3):150-7. DOI:10.3961/jpmph.2014.47.3.150
  • Source
    • "Sleep problems have a profound negative impact not only for individuals but also for the workplace and society as a whole. Consequences of sleep problems include reduced productivity (Nena et al. 2010; Rosekind et al. 2010), increased injuries at work (Kling et al. 2010; Lombardi et al. 2010; Nakata 2011a; Salminen et al. 2010; Vahtera et al. 2006), absenteeism (Akerstedt et al. 2010; Nakata et al. 2004b; Philip et al. 2001), and medical care expenditures (Leger and Bayon 2010; Metlaine et al. 2005). To date, a number of studies have examined the relationship between work organization factors and sleep problems; these studies have identified overtime work (Dahlgren et al. 2006), job dissatisfaction (Nakata et al. 2004a, 2007; Scott and Judge 2006), overcommitment (Kudielka et al. 2004; Ota et al. 2005), effort-reward imbalance (Fahlen et al. 2006; Ota et al. 2005, 2009), low job control (Runeson et al. 2011), high job demands (Cahill and Landsbergis 1996; Kalimo et al. 2000; Knudsen et al. 2007; Nakata et al. 2007; Pelfrene et al. 2002; Runeson et al. 2011), role conflict (Knudsen et al. 2007), poor interpersonal relationships (Nakata et al. 2004a, 2007) job insecurity (Ferrie et al. 1998; Kim et al. 2011), workaholism (Kubota et al. 2010), and poor social support from colleagues/supervisors (Nakata et al. 2001, 2004a; Ota et al. 2009; Pelfrene et al. 2002; Runeson et al. 2011; Sinokki et al. 2010), as risk factors for sleep problems, although earlier studies have emphasized the negative impact of non-standard work schedules, that is, shift/night work, on sleep (Akerstedt et al. 2002; Estryn-Behar et al. 1990; Niedhammer et al. 1994). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose The purpose of this study was to assess the association of organizational factors with work-related sleep problems (WRSP) among Korean workers. Methods The data were derived from the First Korean Working Conditions Survey conducted in 2006 with a representative sample of the Korean working population (n = 10,039). Results The overall prevalence of WRSP was 5.1 % (95 % confidence interval (CI) 4.7–5.5). Those who experienced sexual harassment at work (adjusted odds ratio (aOR) 3.47: 95 % CI 1.77–6.81), discrimination due to sex (aOR 2.44: 95 % CI 1.36–4.36) or age (aOR 2.22: 95 % CI 1.52–3.23), violence at work (aOR 1.98: 95 % CI 1.06–3.68), threat of violence (aOR 1.96: 95 % CI 1.05–3.66), poor work-life balance (aOR 1.78: 95 % CI 1.44–2.20), low job satisfaction (aOR 1.69: 95 % CI 1.37–2.09), high cognitive (OR 1.64: 95 % CI 1.32–2.03) and emotional (aOR 1.53: 95 % CI 1.22–1.91) demands, job insecurity (aOR 1.32: 95 % CI 1.07–1.63), and high work intensity (aOR 1.55: 95 % CI: 95 % CI 1.25–1.92) had an increased risk of WRSP compared to their respective counterparts (p < 0.01). Low social support was not significantly associated with WRSP (aOR 0.88: 95 % CI 0.67–1.15). Conclusion The results revealed that poor psychosocial working conditions may be related to a high prevalence of WRSP among representative Korean workers.
    International Archives of Occupational and Environmental Health 03/2012; 86(2). DOI:10.1007/s00420-012-0759-3 · 2.20 Impact Factor
  • Source
    • "According to these studies, it is possible to estimate double the risk of accident when working in a12-h shift as compared with an 8-h shift. Also, a recent survey of more than 75,000 US workers over a 4-year period [21] confirmed a higher risk of injury strictly related to a progressive increase of working hours and reduction of sleep duration. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The paper gives an overview of the problems to be tackled nowadays by occupational health with regards to shift work as well as the main guidelines at organizational and medical levels on how to protect workers' health and well-being. Working time organization is becoming a key factor on account of new technologies, market globalization, economic competition, and extension of social services to general populations, all of which involve more and more people in continuous assistance and control of work processes over the 24 hours in a day. The large increase of epidemiological and clinical studies on this issue document the severity of this risk factor on human health and well being, at both social and psychophysical levels, starting from a disruption of biological circadian rhythms and sleep/wake cycle and ending in several psychosomatic troubles and disorders, likely also including cancer, and extending to impairment of performance efficiency as well as family and social life. Appropriate interventions on the organization of shift schedules according to ergonomic criteria and careful health surveillance and social support for shift workers are important preventive and corrective measures that allow people to keep working without significant health impairment.
    Safety and Health at Work 12/2010; 1(2):112-23. DOI:10.5491/SHAW.2010.1.2.112
Show more