"Our findings are novel and therefore it is important that additional studies be performed to confirm these results and determine their therapeutic implications," the researchers comment. "In the meantime, as part of good medical care, patients with psoriasis should be encouraged to aggressively address their modifiable cardiovascular risk factors."

Psoriasis is a "T-helper cell disease" and heart attack has been linked to such diseases, Dr. Joel M. Gelfand, from the University of Pennsylvania in Philadelphia, and colleagues explain in the Journal of the American Medical Association.

Research has, in fact, supported a link between psoriasis and cardiovascular disease, but all of it has come from hospital-based studies that did not control for known cardiovascular risk factors.

To address these issues, Gelfand's group conducted a population-based cohort study to examine the risk of heart attack in patients with and without psoriasis, after adjusting for high blood pressure, diabetes, lipid abnormalities, and other heart risk factors.

The study involved 127,139 patients with mild psoriasis, 3,837 with severe psoriasis, and 556,995 controls. They were follow-up period was 5.4 years.

Over an average of 5.4 years, the heart attack rate in the control group was 2.0 percent, while the rates in the mild and severe psoriasis groups were 1.8 percent and 2.9 percent, respectively. The corresponding incidences per 1000 person-years were 3.58, 4.04, and 5.13.

The association between psoriasis and heart attack risk becomes weaker with age, the report indicates. For example, the presence of mild or severe psoriasis in a 30-year-old patient raised the risk of heart attack by 1.29- and 3.10-fold, respectively. In a 60-year-old patient, by contrast, the corresponding risks were elevated just 1.08- and 1.36-fold.