Shift Work Patterns

Shift working

According to the European Union (EU) Survey on Working Conditions , carried out in 2000 in the 15 EU countries, only 24% of the working population (27% of employed and 8% of self-employed workers) are now engaged in the so-called ‘normal’ or ‘standard’ day work, that is between 7.30-8.00 and 17.00 – 18.00 Monday to Friday and 18.8% of workers are involved in shift work that includes night work (Costa 2003). This means that the majority of the working population is engaged in shift work, night work, part time work, varying working hours, weekend work. These trends are likely to continue as economic demands, market globalization and societal changes push us into a 24 hour society.
Most studies and reports that refer to shift

Sleep disturbance is a major complaint among shift workers. Fatigue, poor sleep, difficulty falling asleep, insomnia, wakefulness when trying to sleep, irritability, poor concentration are all symptoms of shift lag syndrome or shift worker syndrome. There has been much research done on the effects of sleep, performance and accidents comparing shift workers with day workers. Shift workers invariably report more sleep disturbance than day workers (Åkerstedt 2003)
There is some evidence to suggest that rotating shifts clockwise every 2 weeks are better tolerated.
Employees rotating between morning and afternoon shifts have greater sleep difficulties than daytime workers, more difficulties initiating sleep and night or shift workers also have a shorter duration sleep. Also there is more daytime sleepiness in rotating shift workers and night workers. (Ohayon et al. 2002)

Gastrointestinal Disorders are more common in shift workers than day workers. They often complain of abdominal pain and alterations in bowel habit such as diarrhoea and constipation. (Saberi and Moravveji

A Japanese study has shown an increased prevalence of peptic and duodenal ulcers in shift workers compared to day workers (Segawa et al. 1987). Also the ulcerogenic potential of H pylori infection increases in shift work and should be considered a risk factor for duodenal ulcer disease in infected shift workers. Treating infected workers in the this high risk group may reduce the risk of ulcer disease (Pietroiusti et al. 2006)

Cardiovascular disease:
There is strong evidence linking cardiovascular disease and shift work (Knutsson 2003). Many studies have been conducted and an important review of 17 studies looking at shift work and cardiovascular disease in 1999 found that there is a 40% increased risk of cardiovascular disease in shift workers compared to day workers (Bøggild and Knutsson 1999). Some studies suggest an increase in cardiovascular risk factors in shift workers such as raised cholesterol and triglyceride levels (Romon et al. 1992), however the exact causal link or mechanism are still under investigation.