THURSDAY, Sept. 16 (HealthDay News) -- People with both heart disease and depression are much more likely to die than those with just one of the conditions or neither illness, a new study shows.

Researchers analyzed data from nearly 6,000 middle-aged adults in Britain whose mental and physical health were monitored for an average of five-and-a-half years as part of a study looking at how social and economic factors affect long-term health.

Overall, about 15 percent of the participants had depression. Twenty percent of those with heart disease had depression, compared to 14 percent of those without heart problems.

Of the 170 deaths during the monitoring period, 47 were caused by heart attack or stroke. Compared to people with neither condition, those with coronary heart disease alone were 67 percent more likely to die of all causes, while those with depression alone were twice as likely to die.

People with both heart disease and depression were nearly five times more likely to die than those in good physical and mental health.

After accounting for a number of factors, the researchers concluded that the combination of depression and heart disease triples the risk of death from all causes and quadruples the risk of death from heart attack or stroke.

The study was published online Sept. 16 in the journal Heart.

More information

The U.S. Centers for Disease Control and Prevention has more about heart disease.