Regular beer--but not light beer or other types of alcohol--appears to be associated with an increased risk of developing psoriasis, according to a report posted online today that will be published in the December print issue of Archives of Dermatology, one of the JAMA/Archives journals.

"Psoriasis is a common immune-mediated skin disease," the authors write as background information in the article. "The association between alcohol consumption and increased risk of psoriasis onset and psoriasis worsening has long been suspected. For example, individuals with psoriasis drink more alcohol than individuals without psoriasis, and alcohol intake may exacerbate psoriasis severity."

For other diseases, type of alcoholic beverage has been shown to influence risk--for instance, beer confers a larger risk for gout than wine or spirits. To evaluate the association between different types of alcohol and psoriasis risk, Abrar A. Qureshi, M.D., M.P.H., of Brigham and Women's Hospital and Harvard Medical School, Boston, assessed data from 82,869 women who were age 27 to 44 years in 1991. The women, participants in the Nurses' Health Study II, reported the amount and type of alcohol they consumed on biennial questionnaires. They also reported whether they had received a diagnosis of psoriasis.

Through 2005, 1,150 cases of psoriasis developed, 1,069 of which were used for analysis. Compared with women who did not drink alcohol, the risk of psoriasis was 72 percent greater among women who had an average of 2.3 drinks per week or more. When beverages were assessed by type, there was an association between non-light beer drinking and psoriasis, such that women who drank five or more beers per week had a risk for the condition that was 1.8 times higher. Light beer, red wine, white wine and liquor were not associated with psoriasis risk.

When only confirmed psoriasis cases--those in which women provided more details about their condition on a seven-item self-assessment--were considered, the risk for psoriasis was 2.3 times higher for women who drank five or more beers per week than women who did not drink beer.

"Non-light beer was the only alcoholic beverage that increased the risk for psoriasis, suggesting that certain non-alcoholic components of beer, which are not found in wine or liquor, may play an important role in new-onset psoriasis," the authors write. "One of these components may be the starch source used in making beer. Beer is one of the few non-distilled alcoholic beverages that use a starch source for fermentation, which is commonly barley." Barley and other starches contain gluten, to which some individuals with psoriasis show a sensitivity. Lower amounts of grain are used to make light beer as compared with non-light beer, potentially explaining why light beer was not associated with psoriasis risk, they note.

"Women with a high risk of psoriasis may consider avoiding higher intake of non-light beer," the authors conclude. "We suggest conducting further investigations into the potential mechanisms of non-light beer inducing new-onset psoriasis."

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(Arch Dermatol. Published online August 16, 2010. doi:10.1001/archdermatol.2010.204. Available pre-embargo to the media at www.jamamedia.org.)

Editor's Note: This study was supported by grants from the National Institutes of Health/National Cancer Institute. Dr. Qureshi has served as a consultant to Amgen and Genentech. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.