Link Found Between Working Night Shifts and Increased Risk of Heart Disease

Link Found Between Working Night Shifts and Increased Risk of Heart Disease
Image credit: Janie Airey | Getty Images

Grow Your Business, Not Your Inbox

Stay informed and join our daily newsletter now!
3 min read
This story originally appeared on Reuters

People who occasionally work night shifts may be at a slightly increased risk of heart disease, according to a new study.

Nurses in the study who worked at least three nights per month were more likely to develop heart problems over the next 24 years than nurses who stuck to daytime shifts.

"I think it’s an important message because it’s a potentially modifiable risk factor," said lead author Celine Vetter, of Harvard Medical School andBrigham and Women's Hospital in Boston.

For the new study, Vetter and her colleagues used data from more than 189,000 women. About 40 percent were participating in the Nurses' Health Study (NHS), which began in 1988. The others were in NHS2, which began in 1989.

The women entered the studies between the ages of 25 and 55. At the start, none of them had coronary heart disease, which is when the arteries that carry blood to heart muscle become narrowed or blocked.

NHS participants were only asked once about their history of working night shifts, but NHS2 participants were asked about their night shifts every two years.

During the follow-up period, there were 7,303 cases of coronary heart disease problems -- like heart attacks, chest pain and bypass surgeries -- in the NHS study and 3,519 cases in the NHS2.

Overall, the risk went up with the number of years women spent covering night shifts, the researchers report in JAMA.

Compared to the risk for nurses in NHS2 who didn't work night shifts, the risk of coronary heart disease was 12 percent higher in nurses who worked night shifts for less than five years, 19 percent higher in those who worked night shifts for five to nine years, and 27 percent higher in nurses who worked nights for at least 10 years.

But the risk of coronary heart disease came back down as women quit working night shifts or retired, the researchers found.

For example, women in NHS with at least 10 years of rotating night shifts had a 27 percent increased risk of coronary heart disease during the first half of the follow-up period, but only a 10 percent increased risk during the second half of the follow-up period.

The study can't explain the association, but Vetter said it could be related to increased inflammation in the body and social disruption. She also said the findings may apply to people who work early morning shifts since they have to get up during the night.

Once researchers have more data, Vetter said, they will be able to design healthy work schedules.

"Hopefully we can design schedules that are healthier for the individual," she said.

Source: bit.ly/1T2XrW0 JAMA, online April 26, 2016.

(By Andrew M. Seaman)

More from Entrepreneur
Our Franchise Advisors will guide you through the entire franchising process, for FREE!
  1. Book a one-on-one session with a Franchise Advisor
  2. Take a survey about your needs & goals
  3. Find your ideal franchise
  4. Learn about that franchise
  5. Meet the franchisor
  6. Receive the best business resources
Use code MARKET2021 through 4/24/21 to save on 12 marketing books for entrepreneurs that are recommended by entrepreneurs:
  • Digital Marketing Handbook
  • No B.S. Guide to Direct Response Social Media Marketing
  • Ultimate Guide to Youtube for Business
  • And more
Make sure you’re covered for physical injuries or property damage that occur at work by
  • Providing us with basic information about your business
  • Verifying details about your business with one of our specialists
  • Speaking with an agent who is specifically suited to insure your business

Latest on Entrepreneur