“We found a dose-response relationship between depressive symptoms and the risk of developing heart failure,” said Lise Tuset Gustad, first author of the study and an intensive care nurse at Levanger Hospital in Norway. “That means that the more depressed you feel, the more you are at risk.”
The study used data collected during the second wave of a large epidemiological study in Nord-Trøndelag county, Norway, called the Nord-Trøndelag Health Study (HUNT study). Nearly 63,000 of the 97,000 residents in the county agreed to take part in the study.
When the second wave of the HUNT study began in 1995, information was collected, including body mass index, physical activity, smoking habits, and blood pressure. Depression was assessed and ranked for severity using the Hospital Anxiety and Depression Scale, according to the researchers.
Every Norwegian citizen receives a unique 11-digit number at birth that is used at hospitals and the National Cause of Death Registry. The researchers used this number to track which patients were hospitalized with heart failure or died from heart failure during the 11-year study.
During that time, nearly 1,500 people developed heart failure. Compared to residents with no symptoms of depression, people with mild symptoms had a five percent increased risk of developing heart failure, the researchers found. Those with moderate to severe symptoms had a 40 percent increased risk.
“Depressive symptoms increase the chance of developing heart failure and the more severe the symptoms are, the greater the risk,” Gustad said. “Depressed people have less healthy lifestyles, so our analysis adjusted for factors such as obesity and smoking that could cause both depression and heart failure. This means we can be confident that these factors did not cause the association.”
She noted that there is effective treatment for depression, particularly if people get help early.
“The early symptoms of depression include a loss of interest and loss of pleasure in things that have normally been interesting or given pleasure,” she said.
“If you feel like that, speak to your friends and if it lasts for a month see your doctor or nurse. Depression can be treated easily in the early stages and many people don’t need medication. Talking to a professional may be all you need.”
Depression triggers stress hormones, Gustad noted.
“If you’re stressed, you feel your pulse going up and your breath speeding up, which is the result of hormones being released,” she said. “Those stress hormones also induce inflammation and atherosclerosis, which may accelerate heart diseases. Another mechanism could also be because depressed people find it more difficult to follow advice about how to take medications and improve their lifestyle.”
The researcher noted that depression is disabling.
“It blocks people’s ability to take their medications as prescribed, stop smoking, improve their diet, or exercise more,” she said.
“Patients at all hospitals should be screened for depression to help them recover from existing illnesses, avoid developing new ones, and have a more enjoyable life.”
The study’s findings were presented at EuroHeartCare 2014.
Source: European Society of Cardiology