Overtime

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Overtime Extended Work Shifts

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

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Authors

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

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Acknowledgments

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

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Introduction

• Annual number of hours worked in the United
  States surpasses Japan and most of Western
  Europe.
• International Labour Office 2002

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

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Selection Criteria

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

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Outcome Measures

• Illnesses
• Injuries
• health behaviors
• Performance

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Number of Studies

• 51 studies
• 1 meta-analysis

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Process

• Classified each study into 1 of 4 categories

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1. Overtime Definition

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

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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.

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3. Extended Work Shift gt 40-H Per Week Definition

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

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4. Very Long Shift Definition

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

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Two Classification Problems

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

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Description of the Studies
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Country of Origin

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

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Type of Work

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

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Age and Gender

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

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Summary of Findings
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1. Overtime

• 16 of 22 studies reported either
• ? perceived general health
• ? injury rates
• ? illnesses
• ? mortality
• see pages 5 12 of report

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• 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

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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

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8-H versus 12-H Shifts
2. Extended Shifts

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

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• 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

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3. Extended Shift gt 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

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Shift Work with Overtime

• 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

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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

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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

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Research Gaps
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Work Schedules

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

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Other Work Factors

• compensation
• vacation Time
• commute Time

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Worker Factors

• women
• older workers
• preexisting chronic health problems

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Occupational Exposures

• chemical
• heat
• noise
• lifting

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Summary

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

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

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Previous Research

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

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Future Research

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

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To Obtain Document

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