It’s long been said that a person can die from a broken heart, but now, research suggests that there may be truth behind this timeless expression.

Known as the widowhood effect, social scientists say this phenomenon is one of the best documented examples of relationships on a person’s health, and may be the result of an intense physical response to grief.

In a nine-year study of elderly couples across the U.S., researchers found that the death of a spouse substantially increased the likelihood of death in the surviving half of the pair.

The study, by Nicholas A. Christakis of Harvard and Felix Elwert of the University of Wisconsin-Madison may be the best existing study on the subject, according to New York Magazine.

The researchers collected data from 373,189 elderly married couples, and examined what happened after one of the spouses died.

In men whose wives died first, they found an 18 percent increase in ‘all-cause mortality,’ and a 16 percent increase for women.

‘The death of a spouse, for whatever reason, is a significant threat to health and poses a substantial risk of death by whatever cause,’ the 2008 research says.

A report from quotes the late Dr. Lee Lipsenthal, who said that sudden death and heart disease is the number one cause of death in a grieving spouse.

This condition, called takotsubo cardiomyopathy, is commonly known as ‘broken heart syndrome.’

The condition nearly always follows a traumatic emotional loss, such as death of a spouse, parent, or child and it primarily affects women,’ writes reporter Linda Dahlstrom, who references geriatric specialist Dr. Barbara Messinger-Rapport.

‘It causes chest pain and sudden heart failure, believed to be brought on by a surge of fight or flight hormones.’

Shock may be a significant contributor to broken heart syndrome, Christakis and Elwert found.

In people whose spouses died of long-term illnesses, like Alzheimer’s, Parkinson’s, and certain cancers, the study found little to no increase in chance of death.

The researchers also found that death of a spouse was related to an increase in subsequent deaths from accidents or emergencies, and chronic disease.

These findings suggest that grief and shock may not be the only factors in broken heart syndrome.

The sudden death of spouse may leave a person alone to adjust to the newness of solitude, resulting in vulnerability and lapses in treatment for chronic illnesses.