"Many of the known risk factors for heart disease and stroke – high blood pressure and cholesterol, obesity, diabetes, smoking and lack of exercise – can, to some extent, be controlled by our lifestyle choices," said Matthew F. Muldoon, M.D., M.P.H., associate professor of medicine, University of Pittsburgh School of Medicine. "Until now, no one had studied the possibility that brain abnormalities could explain why some people make these poor lifestyle choices and have multiple risk factors for heart disease."
In the study being presented today, which included 244 adult volunteers between the ages of 30 and 55 years, researchers measured serotonergic activity using a pharmacological approach and carotid artery thickness using ultrasonography. At the time of testing, participants were free of clinically evident vascular disease. Yet, those with low levels of serotonergic function were more likely to have thickening of the carotid artery than those with higher levels.
"If, through further studies, we can establish that risk factors for heart disease and stroke are, in part, controlled by the serotonin systems in the brain, it could open a whole new avenue for preventing heart disease and stroke," said Dr. Muldoon.
Serotonin is a type of neurotransmitter, a chemical that sends messages between neurons in the brain. It is thought to play an important role in the regulation of mood, appetite and blood pressure. Previous studies by Dr. Muldoon and colleagues have found that people who get little exercise, are overweight, have high blood pressure, blood sugar and cholesterol have low levels of serotonergic function. A number of research studies have established a link between serotonin and mood. However, until now, the relationship between the serotonin system and atherosclerosis had remained unstudied.
This study was funded by a grant from the National Heart, Lung and Blood Institute of the National Institutes of Health.
Also contributing to the study were Rachel H. Mackey, Ph.D., M.P.H., and Kim Sutton-Tyrell, Dr.P.H., department of epidemiology, University of Pittsburgh Graduate School of Public Health; Stephen B. Manuck, Ph.D., department of psychology, University of Pittsburgh; Janine D. Flory, Ph.D., department of psychiatry, Mt. Sinai School of Medicine; and Bruce G. Pollock, M.D., Ph.D., department of psychiatry, University of Toronto.