Caffeine for the prevention of injuries and errors in shift workers

Area of Science:

• Occupational Health
• Sleep Medicine
• Pharmacology

Background:

• Sleepiness impairs performance and increases injury risk, particularly in shift work disorder and jet lag.
• Circadian rhythm disruptions necessitate interventions for safe operation during altered wakefulness periods.
• Caffeine's role in promoting alertness for these conditions is explored, but its effect on injury and error remains unclear.

Purpose of the Study:

• To evaluate the efficacy of caffeine in preventing injuries associated with impaired alertness in individuals experiencing jet lag or shift work disorder.

Main Methods:

• Searched multiple databases (Cochrane, MEDLINE, EMBASE, PsycINFO, CINAHL, TRANSPORT, PubMed) and reference lists for relevant studies.
• Included randomized controlled trials examining caffeine's effects on injury, error, or cognitive performance in individuals with jet lag or shift work disorder.
• Extracted data, assessed risk of bias, and pooled results using a fixed-effect model to calculate odds ratios and standardized mean differences (SMD).

Main Results:

• Thirteen trials were included; none measured injury outcomes.
• Caffeine significantly reduced errors compared to placebo and was associated with fewer errors than a nap in one trial.
• Cognitive performance improvements were noted in concept formation, reasoning, memory, orientation, and attention, but not in verbal functioning.

Conclusions:

• Caffeine may enhance performance in shift workers, but its effect on injury prevention is unevaluated.
• Findings are primarily from simulated conditions with young participants, limiting generalizability to real-world scenarios and older workers.
• Current evidence suggests healthy individuals can continue recommended caffeine use for alertness without concern, and future research should compare caffeine with other countermeasures.