Credits: REUTERS/JOHN SUMMERS
The team of international researchers looked at nearly three dozen studies involving two million people.
Shift workers were considered those who have night shifts or irregular and rotating schedules, and were compared to a control group of day workers.
They found shift workers, overall, have a 23% increased risk of heart attacks and a 5% greater risk of stroke.
Night shift employees are the most at risk for coronary events, with a 41% greater risk.
Shift work has already been found to play a role in high blood pressure, high cholesterol and diabetes, the study says.
The authors recommend medical screening programs for employees to help identify and treat symptoms, such as high blood pressure and cholesterol.
The study was published online Thursday in the British Medical Journal.