WASHINGTON, Oct. 10 (UPI) -- Researchers have discovered that psoriasis, a chronic inflammatory skin condition, is an independent risk factor for heart attacks.
Previous research had suggested the skin condition is associated with a higher prevalence of cardiovascular disease, but it was not clear if other risk factors, such as obesity or smoking, were the real cause.
"The fact there is this relationship is striking -- it's a novel finding," said lead author Dr. Joel Gelfand, an assistant professor of dermatology at the University of Pennsylvania in Philadelphia.
Gelfand and colleagues used records from a population-based study of British patients, aged 20 to 90, between 1987 to 2002. The team noted how many heart attacks occurred in two groups: 130,976 people with psoriasis and 556,995 people without the disease. Of those with psoriasis, 127,139 had a mild form of the disease, and 3,837 had a severe form.
There were 11,194 heart attacks in the control group, and 2,319 and 112 heart attacks within the mild and severe psoriasis groups, respectively.
In their analysis, the researchers corrected for hypertension; diabetes; history of heart attack; age; gender; smoking; body mass index; and hyperlipidemia, an excess of fats or lipids in the blood.
The results showed younger patients with severe psoriasis were most at risk for having a heart attack. For instance, the relative risk of a 30-year-old with severe psoriasis having a heart attack is 3.10, compared to a relative risk of 1.36 for a 60-year-old with severe psoriasis. (Relative risks greater than 1 always indicate a stronger association.)
A 40-year-old patient with severe psoriasis had a 1-in-600 risk of having a heart attack, Gelfand said. The effects were generally the same for men and women.
It's possible psoriasis contributes between 2,000 to 3,000 extra heart attacks each year in the United States, Gelfand says.
However, this was a cohort study that observed an association; more research is needed to pinpoint psoriasis as a cause of heart attacks. The study was also limited by the fact researchers could not measure stress, and smoking was not analyzed in detail.
Likewise, there's always the possibility an unexplained, third factor could be influencing the research, Gelfand said. But the fact severe psoriasis was linked to more heart attacks than mild forms of the disease -- or, the dose-response effect -- makes Gelfand think the connection is real.
Psoriasis affects about 2 percent to 3 percent of the adult U.S. population, or between 5.8 million and 7.5 million Americans, according to the National Institutes of Health. Between 10 percent and 30 percent of this group also develop psoriatic arthritis, which causes pain, stiffness and swelling in and around the joints, according to the National Psoriasis Foundation.
Scientists believe psoriasis is sparked by an overproduction of T-cells or T-helper cells in the immune system, which cause inflammation. These cells also play a role in diseases such as multiple sclerosis and Crohn's disease. Although the outward signs of psoriasis -- the thick, scaly red lesions -- are most obvious, several studies have shown the disease also degrades quality of life.
In a 2006 NPF survey of 405 people, about 48 percent of psoriasis sufferers reported strong feelings of anger and frustration due to their disease. Around 40 percent said they felt helpless and self-conscious.
"Psoriasis is misunderstood as a disease in the general public," said Liz Horn, a molecular biologist and director of research for the National Psoriasis Foundation.
"This is an important study (because) it generates awareness of psoriasis as a serious disease."
It's not entirely known how psoriasis could lead to heart attacks. Since psoriasis is likely an immune system abnormality, Gelfand speculates the same immune pathways active in psoriasis spur inflammation in other parts of the body. For instance, inflammation may cause thickening of the blood vessels, which in turn hardens the arteries, a major precursor of heart attacks.
It's reasonable, then, to wonder if a person with psoriasis may be at risk for other diseases. Gelfand has done similar research showing psoriasis sufferers may be at higher risk of obesity and diabetes. One theory is the same immune processes involved in psoriasis can activate insulin resistance, and thus diabetes.
While more research is needed to reinforce Gelfand's findings, he still recommends psoriasis patients get screened for cardiovascular risk factors, such as cholesterol and blood sugar. The study should also be a reminder to dermatologists, who see psoriasis patients frequently, to be aware of the possible link to heart troubles.
Horn agrees.
"We don't want to alarm patients," she said, "but they may want to consider healthy lifestyle changes."
Quitting smoking, managing stress and staying at a healthy weight are all actions that can stave off cardiovascular disease, she said.
