People who worked long hours had a higher risk of stroke, especially if they worked those hours for 10 years or more, according to new research in the American Heart Association's journal Stroke.

Researchers reviewed data from CONSTANCES, a French population-based study group started in 2012, for information on age (18–69), sex, smoking, and work hours derived from questionnaires from 143,592 participants. Cardiovascular risk factors and previous stroke occurrences were noted from separate medical interviews. Researchers found:

• Overall, 1,224 of the participants suffered strokes
• 29%, or 42,542, reported working long hours
• 10%, or 14,481, reported working long hours for 10 years or more
• Participants working long hours had a 29% greater risk of stroke, and those working long hours for 10 years or more had a 45% greater risk of stroke

Long work hours were defined as working more than 10 hours for at least 50 days per year. Part-time workers and those who suffered strokes before working long hours were excluded from the study.

"The association between 10 years of long work hours and stroke seemed stronger for people under the age of 50," said study author Alexis Descatha, MD, PhD, a researcher at Paris Hospital, Versailles and Angers University, and at the French National Institute of Health and Medical Research (Inserm). "This was unexpected. Further research is needed to explore this finding. I would also emphasize that many health-care providers work much more than the definition of long working hours and may also be at higher risk of stroke," Dr. Descatha said. "As a clinician, I will advise my patients to work more efficiently and plan to follow my own advice."

Previous studies noted a smaller effect of long work hours among business owners, CEOs, farmers, professionals, and managers. Researchers noted that this might be because those groups generally have greater decision latitude than other workers. In addition, other studies have suggested that irregular shifts, night work, and job strain may be responsible for unhealthy work conditions.