(CBS NEWS) -- Married couples vow to stay together in "sickness and in health," and a new nationwide study finds having a spouse can actually improve your health -- lowering your risk of heart disease by five percent. The large-scale study by researchers at NYU Langone Medical Center surveyed 3.5 million men and women at 20,000 centers around the U.S.
Married people had lower risk than singles in every age group, but marriage seemed to do the most good for those under age 50; they had a 12 percent lower risk of heart-related disease than single people their age.
The benefits were found in women as well as men, and regardless of other heart disease risk factors they had such as high cholesterol or diabetes, researchers found.
"Our survey results clearly show that when it comes to cardiovascular disease, marital status does indeed matter," senior study investigator and NYU Langone cardiologist Dr. Jeffrey Berger said in a statement. "If one of my patients is recently widowed or divorced, I'm increasingly vigilant about examining that patient for signs of any type of cardiovascular disease and depression," he added.
CBS News contributor Dr. Tara Narula is a cardiologist at Lenox Hill Hospital in New York. She joined the "CBS This Moring" co-hosts to discuss the study's findings. She said that this study points out that our social relationships play a big role in our health.
"We've known about this concept of a marriage advantage since almost the late 1800s when it was first described to improve your overall survival," she said. "And now we're recognizing that it may be as important as traditional risk factors for cardiovascular disease."
Narula said that there are several reasons why this is the case.
"Married couples help each other to eat better, exercise, avoid smoking and alcohol. They serve as a buffer for stressful life events for each other," she said. "They encourage each other to take their medications. To go to doctor's appointments and they may even recognize symptoms that their partners doesn't."
For example, when someone has sleep apnea, which can indicate higher risk for heart attack and stroke, they may not know they are snoring until their spouse lets them know.
Narula said that doctors should ask their patients about their marriage status as part of every appointment to get a feel for what is happening in their lives, saying "life changes happen throughout your course of time with a patient."
"Every doctor in training, we're taught to get a social history, which means to get a sense of our people," she explained. "Are they single, divorced? Do they live alone? And patients often look at you and wonder why you're asking that, but it's because it plays into what's going on at home in your emotional and family life, and how well you're taking care of yourself."
She said that it's not just being married that counts, but the quality of the union, especially for women.
"We know that if the marriage is not good it can increase stress. It can increase blood pressure. It can cause depression, which can lead to cardiovascular disease," she said.