March 19 (UPI) -- Depression and heart disease are not connected through a common genetic association, but rather unhealthy risk factors that bring about both conditions, a study says.
Researchers found that people who've had at least one parent die of heart disease had a 20 percent increased risk of developing depression compared to those who didn't, according to a study published Tuesday in Molecular Psychiatry. At first glance, these findings suggested that a hereditary connection may exist between depression and heart disease. But the link wasn't conclusive.
"It is possible that heart disease and depression share common underlying biological mechanisms, which manifest as two different conditions in two different organs -- the cardiovascular system and the brain," Golam Khandaker, a researcher at the University of Cambridge and study author, said in a news release. "Our work suggests that inflammation could be a shared mechanism for these conditions."
After digging a little deeper, the researchers found no genetic predisposition that connected the two conditions, noticing instead that inflammation occurred in people who had both depression and heart disease.
Risk factors for heart disease -- like smoking, drinking too much alcohol, not getting enough exercise and obesity -- and the psychological stress normally associated with depression, can all trigger inflammation. Specifically, the risk factors for both conditions produce IL-6 and CRP, two inflammatory markers.
"Taking a holistic view of a person's health -- such as looking at heart disease and depression together --enables us to understand how factors like traumatic experiences and the environmental impact on both our physical and mental health," Khandaker said.
The researchers think this discovery opens the door for patients with depression to be treated with anti-inflammatory drugs.
Khandaker is not testing tocilizumab, an anti-inflammatory drug that blocks IL-6 while treating rheumatoid arthritis.
"This research shows clearly the shared biological changes that are involved," Khandaker said. "This not only opens opportunities for earlier diagnosis, but also create a solid foundation for exploring new treatments or using existing treatments differently.
"We need to stop thinking about mental and physical health in isolation and continue this example of bringing sciences together to create real change," he said.