# Presentation: 679890

## Overtime & Extended Work Shifts

- Recent Findings on Illnesses, Injuries and Health Behaviors
- DHHS (NIOSH) Publication No. 2004-143

## Claire C Caruso PhD, RN
Edward M Hitchcock, PhD
Robert B Dick, PhD
John Russo, PhD
Jennifer M Schmit, BA

- Edward M Hitchcock, PhD
- Robert B Dick, PhD
- John Russo, PhD
- Jennifer M Schmit, BA

**Authors**

## Acknowledgments

- Roger R Rosa, PhD
- Steven L Sauter, PhD
- Thomas R Waters, PhD
- BK Nelson, PhD

## Annual number of hours worked in the United States surpasses Japan and most of Western Europe.

[International Labour Office 2002]

- [International Labour Office 2002]

**Introduction**

## Conducted an integrative review of  research papers that examined associations with long work hours. 

## Selection Criteria

- 1. Focused on overtime or extended work shifts
- 2. Published from 1995 to 2002
- 3. Peer-reviewed publication
- 4. English language

## 
		Illnesses 
		Injuries 
		health behaviors 
		Performance

- 		Illnesses
- 		Injuries
- 		health behaviors
- 		Performance

**Outcome Measures**

## Number of Studies

- 51 studies
- 1 meta-analysis

## Process

- Classified each study into 1 of 4 categories

## 1. Overtime Definition

-    40-h work weeks compared with greater than 40-h work weeks.

## 2. Extended Work Shift   Definition

-    10- or 12-h shifts were compared to 8-h shifts in most studies and used a standard 40-h work week.

## 3. Extended Work Shift  > 40-H Per Week Definition

-    12-h shifts compared to 8-h shifts in most studies.

## 4. Very Long Shift Definition

- Examples
- Resident physician 32-h call
- 48-h taxi driver schedule

## Two Classification Problems

- did not provide a clear, complete description of work schedule
- wide variety of work schedules studied

## Description of the Studies

## Country of Origin

- Europe
- United States
- Asia
- Australia
- Canada
- South America

## Type of Work

- Manufacturing
- Health Care
- White Collar Work
- Public Administration Services
- Utilities
- Transportation
- Construction
- Mining

## Age and Gender

- 40% of studies included only men
- 10% included only women
- 2 studies compared younger and older workers

## Summary of Findings

## 1. Overtime

- 16 of 22 studies reported either
-  perceived general health
-   injury rates
-   illnesses
-   mortality
-     [see pages 5 – 12 of report]

## Meta-analysis: Preterm Birth & Long Hours

	10 studies – not significant

	6 higher quality studies suggested a possible weak relationship 
			(OR 1.24; CI 1.04 – 1.48)

			[Mozurkewich et al. 2000]

- 	10 studies – not significant
- 	6 higher quality studies suggested a possible weak relationship
- 			(OR 1.24; CI 1.04 – 1.48)
- 			[Mozurkewich et al. 2000]

## Overtime & Health Behaviors

- unhealthy weight gain [Nakamura et al. 1998; Shields 1999]
- alcohol use
- 		U-shaped relationship [Shields]
- 		higher use [Trinkoff et al. 1998]
- 		NS [Park et al. 2001b]
- smoking [ Shields 1999; NS  Park et al 2001]
- exercise [ Mizoue et al. 2001; NS Shields 1999;
- 	NS Kageyame et al. 1998]

## 8-H versus 12-H Shifts

- Difficult to draw conclusions due to the inconsistency in the types of work schedules examined.

_**2. Extended Shifts**_

## 4 studies – the 9th to 12th hours of work were associated with either:

 alertness 
 cognitive function
  fatigue 
 injuries

    [Fischer et al. 2000; Hanecke et al. 1998; Macias et al. 1996; Mitchell et al 2000] 

-  alertness
-  cognitive function
-   fatigue
-  injuries
-     [Fischer et al. 2000; Hanecke et al. 1998; Macias et al. 1996; Mitchell et al 2000]

## 3. Extended Shift & > 40-h

-  health complaints [Lipscomb et al. 2002; Tucker et al. 1998]
-  performance [Fischer et al. 2000; Mitchell & Williamson 2000; Novak & Auvil-Novak 1996]
-  pace of work [Duchon et al. 1997]

## Trinkoff et al. [1998]       Nurses
longer rotating or night shifts  odds for higher alcohol use
extended night shifts  odds for smoking

Rosa et al. [1998]      Laboratory study
12-h night associated with  upper-extremity fatigue

- longer rotating or night shifts  odds for higher alcohol use
- extended night shifts  odds for smoking
- Rosa et al. [1998]      Laboratory study
- 12-h night associated with  upper-extremity fatigue

**Shift Work with Overtime**

## Other Work-Related Demands

- Early start times  alertness or
- 	 health complaints [Smith et al. 1998; Tucker et al. 1998]
- Hot work environments  pace of work [Brake & Bates 2001]
- High workloads  discomfort [Macdonald & Bendak 2000]

## 4. Very Long Shifts

- Nakano et al. [1998] reported better immune function in drivers allowed to work overtime.
- Leonard et al. [1998] reported  in mental processing and psychomotor performance in medical personnel after working a 32-h on-call shift.
- Gander et al. [2000] reported  clinical errors

## Research Gaps

## Work Schedules

- effects after the 12th hour of work
- shift work and overtime together
- flexible work hours
- mandatory overtime

## Other Work Factors

- compensation
- vacation Time
- commute Time

## Worker Factors

- women
- older workers
- preexisting chronic health problems

## Occupational Exposures

- chemical
- heat
- noise
- lifting

## Summary

- The number of published studies examining overtime and extended work shifts appears to be increasing.

##    Many research questions remain about the way overtime and extended work shifts influence health and safety.

## Previous Research

- The influence of overtime and extended work shifts may involve a complex interaction of several work organization and individual worker factors.

## Future Research

- Clear, complete description of work schedules and workers would facilitate cross study comparisons.

## To Obtain Document

- DHHS (NIOSH) Publication No. 2004-143
- NIOSH web site:  www.cdc.gov/niosh
- Phone:                 1-800-35-niosh
- email:                    pubstaft@cdc.gov