A recent clinical review has concluded that shift workers who regularly work night shifts have a 23% increased risk of coronary heart disease compared to day workers. Workers who worked evening shifts had similar risk for coronary heart disease to day workers.
The authors of the paper, published in the BMJ, reviewed the results of several systematic reviews and meta-analyses that included more than 2 million people and 34 observational studies.
While the findings indicate that the health effects of night shifts are moderate compared to day or evening shifts, night shifts appear to induce larger risks to cardiovascular health.
Shift work forcefully disrupts the normal sleep-wake cycle, leading to short sleep and excessive fatigue. Shift work is associated with irregular eating, eating at the wrong circadian phase, and poorer quality of food, increased alcohol intake and smoking.
In addition, shift work can lead to a disruption to normal social activities which can lead to poorer work-life balance and subjective health. Psychosocial work stress is correlated with CHD.
Shift work is associated with lower socioeconomic status, a further risk factor for poorer health status.
The authors concluded that while there is an apparent link with night shift work and increased risk for coronary heart disease, there is insufficient evidence to state that shift work is a causal factor for chronic disease.