• 
• 

Three Part Question

For [adult workers] is [night shift working worse than normal hour working] for [prolonged life and good health].

Clinical Scenario

You work in the emergency department as a consultant and your rota currently does not include night working. Nationally it has been recognised that there is a deficit of senior decision makers in emergency departments at night and inevitably it is suggested that care would be safer and more effective if (work-shy) senior emergency physicians stepped off the golf course and into the gap to work shifts. You have heard that this will increase your chances of a heart attack and shorten your life but wonder whether this is just union propaganda or hard actuarial fact.

Search Strategy

Medline 1946-05/13 using OVID interface:
Embase using NHS Evidence 1980–13 July 2013
Medline:[(stroke/epidemiology or myocardial infarction/epidemiology or vascular diseases/epidemiology) AND (exp work schedule tolerance or work) AND (exp risk Factors or exp risk reduction behaviour or exp risk assessment)] LIMIT to publication years 2011 to present.

Embase: (exp HEART INFARCTION/ep [ep=Epidemiology OR exp CEREBROVASCULAR ACCIDENT/ep [ep=Epidemiology] OR exp VASCULAR DISEASE/ep [ep=Epidemiology]) AND exp WORK SCHEDULE TOLERANCE/ OR work.ti,ab) AND (exp RISK FACTOR OR exp RISK REDUCTION/ OR exp RISK ASSESSMENT/) Limit to human, English language and publication years 2011 to present.

Search Outcome

One hundred and twenty-seven papers were identified of which one, a recent meta-analysis, answered the clinical question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Vyas et al, 2012, Canada	Shift workers described as working evening, night, rotating, mixed, and irregular or unspecified work schedules.	Observational studies	Myocardial infarction	RR 1.23, CI 1.15 to 1.31	Variations in outcome definitions between studies make it difficult to compare across studies. Wide variation in which risk factors each study adjusted for. Variability in defining cardiovascular events may have caused omission of otherwise relevant studies.
			Ischemic stroke	RR 1.05, CI 1.01 to 1.09
			Coronary events	RR 1.24, CI 1.10 to 1.39

Comment(s)

This meta-analysis included 2 011 935 people in a total of 34 studies identified. The meta-analysis found that shift work was associated with myocardial infarction, ischaemic strokes and coronary events (although results showed significant heterogeneity in this final outcome).

Clinical Bottom Line

Shift work is associated with an increased risk of vascular events but does not appear to have an effect on mortality.

References

1. Vyas MV, Garg AX, Iansavichus AV et al. Shift work and vascular events: systematic review and meta-analysis. BMJ 2012;345:e4800