Depression was linked with an increased risk of peripheral artery disease (PAD) in a study of more than 1,000 men and women with heart disease conducted by researchers at the San Francisco VA Medical Center and the University of California, San Francisco.

PAD is a circulatory problem in which narrowed arteries reduce blood flow to the limbs -- usually the legs and feet -- resulting in pain, reduced mobility and, in extreme cases, gangrene and amputation.

The study was published electronically on July 26 in the Journal of the American Heart Association.

Marlene Grenon, MD, CM, a vascular surgeon at SFVAMC and an assistant professor of Surgery at UCSF, led the analysis of data from 1,024 participants in the Heart and Soul Study, a prospective study of men and women with coronary artery disease who were followed for an average of approximately seven years.

"We discovered that there was an association between depression and PAD at baseline, and also found that the patients who were depressed at the beginning of the study had a higher likelihood of developing PAD during follow-up at seven years," said Grenon.

"These findings add to the growing body of research showing the importance of depression in both the development and progression of PAD," said senior author Beth Cohen, MD, MAS, a physician at SFVAMC and an assistant professor of medicine at UCSF. "This also emphasizes the need for medical providers to be attentive to the mental health of their patients who have developed, or who are at risk for, PAD."

The authors found that some of the risk for PAD was partly explained by modifiable risk factors such as smoking and reduced physical activity.

"We still don't know which comes first," said Grenon. "Is it that patients with PAD become depressed because their mobility is impaired, or that people who are depressed engage in unhealthy behaviors such as smoking and lack of exercise, and are thus more at risk of developing PAD? Or might it be a vicious cycle, where one leads to the other?"

Further research is needed to tease out cause and effect, she said.

The study authors suggest that whatever the initial cause, lifestyle modifications such as being more physically active, eating better, quitting smoking and managing stress more effectively might reduce the risk for the association, as well as potentially address symptoms of both PAD and depression.

"These lifestyle changes would be considered healthy for anyone, and would also help overall cardiovascular health," said Grenon.

"As providers, we can help patients recognize the connections between mental and physical health," added Cohen. "This may help reduce the stigma of mental health diagnosis and encourage patients to seek treatment for problems such as depression."

Co-authors of the study are Jade Hiramoto, MD, of UCSF; Kim J. Smolderen, PhD, of Saint Luke's Mid America Heart Institute, Kansas City, MO and Tilburg University, Netherlands; Eric Vittinghof, PhD, of UCSF; and Mary A. Whooley, MD, of SFVAMC and UCSF and Principal Investigator of the Heart and Soul Study.