Psychological factors do not affect inflammation

NEW YORK (Reuters Health) - While psychological factors increase the risk of developing coronary heart disease, they do not affect inflammation, a factor also associated with the development of coronary heart disease, according to findings published in the journal Arteriosclerosis, Thrombosis, and Vascular Biology.

"Although several studies have shown psychological factors to play a role in the development and prognosis of coronary heart disease outcomes, the mechanisms underpinning this association remain poorly understood," Dr. Hermann Nabi, of University College London, and colleagues write.

Markers of inflammation have recently been suggested as a means by which psychological factors influence the outcome of coronary heart disease.

To further investigate, the researchers used data from the Whitehall II Study to see if psychological factors influence the inflammation processes to an extent that increases the risk of coronary heart disease. Included in the study were 6,396 civil servants (4453 men, 1943 women) between the ages of 35 to 55 years who did not have coronary heart disease when the follow-up period began.

Two psychological factors -- negative mood and psychological distress -- were assessed between 1985 and 1988 and between1989 and 1990. The team then measured inflammatory markers between 1991 and 1993, including fibrinogen, high-sensitivity C-reactive protein, interleukin-6, along with coronary heart disease risk factors, sociodemographic factors, and work stress.

The incidence of coronary heart disease was assessed between 1991 and 1993 and between 2003 and 2004. Coronary heart disease included fatal coronary heart disease, first nonfatal myocardial infarction, or definite angina, heart-related chest pain.

After accounting for the potential influence of patient age, sex and ethnicity, the investigators found that higher levels of negative mood and psychological distress were associated with a greater incidence of coronary heart disease.

On the other hand, there was no association between higher levels of negative mood and psychological distress and greater concentrations of inflammatory markers.

The researchers note that the importance of this "null" finding is that it eliminates inflammation as a candidate mechanism for the association between psychological factors and coronary heart disease.

SOURCE: Arteriosclerosis, Thrombosis, and Vascular Biology, July 2008.