Beer Drinking Increases Risk for Psoriasis in Women

From Medscape Medical News
Fran Lowry

August 17, 2010 — Consumption of regular, but not light, beer is associated with an increased risk for the development of psoriasis among women, but other alcoholic beverages do not increase this risk, according to new research published Online First August 16 in the Archives of Dermatology.

"Psoriasis is a common immune-mediated skin disease. The association between alcohol consumption and increased risk of psoriasis onset and psoriasis worsening has long been suspected," write Abrar A. Qureshi, MD, MPH, from Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, and colleagues.
"Risk for psoriasis may vary by type of alcoholic beverage, given previous evidence that different types of alcoholic beverages have conferred deleterious effects in other inflammatory diseases."

If this were so, then it would have practical implications for psoriasis prevention and management, the study authors write. The aim of this study, therefore, was to evaluate the independent association between alcohol consumption and the risk for the development of psoriasis. The study authors also sought to determine if there was an association between the type of alcoholic beverage and the risk for psoriasis.

Dr. Qureshi and colleagues assessed data from 82,869 women who were aged 27 to 44 years in 1991. The women were participants in the Nurses' Health Study II, an ongoing longitudinal study of 116,430 registered nurses from 15 states in the United States. Responding to biennial questionnaires, the women reported the amount and type of alcohol they consumed. They also reported whether they had received a diagnosis of psoriasis. The period of follow-up was from 1991 to 2005.

During this time, there were 1150 cases of incident psoriasis, 1069 of which were used for analysis. Compared with women who did not drink alcohol, the risk for psoriasis was 72% greater among women who had an average of 2.3 drinks per week or more (multivariate relative risk [RR], 1.72; 95% confidence interval [CI], 1.15 - 2.57). When this risk was examined by type of alcoholic beverage, the researchers found that women who drank 5 or more regular beers per week had a 1.8-fold greater risk for the development of psoriasis (multivariate RR for ≥ 5 drinks per week, 1.76; 95% CI, 1.15 - 2.69), but that consumption of light beer, red or white wine, and liquor was not associated with this risk.

The association between psoriasis and regular beer intake became stronger in a subset of women with a confirmed diagnosis, who had provided more details about their condition on a 7-item self-assessment questionnaire. In this subset, the risk for psoriasis was 2.3 times higher for women who drank 5 or more beers per week than women who did not drink beer (multivariate RR for ≥ 5 drinks per week, 2.29; 95% CI, 1.36 - 3.85).

"Nonlight 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 study authors write. "One of these components may be the starch source used in making beer. Beer is one of the few nondistilled alcoholic beverages that use a starch source for fermentation, which is commonly barley...Starch sources such as barley contain gluten, which has been shown to be associated with psoriasis."

Noting the limitations of their study, the authors state that the retrospective recall of psoriasis onset may have led to misclassifications of psoriasis onset. They were also unable to examine whether the risk for psoriasis differed regarding early-onset vs later-onset psoriasis given the age of the study cohort. Finally, the study was observational, and the cohort consisted of well-educated women and does not represent a random sample of US women, they write.

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

This study was supported by grants from the National Institutes of Health and the National Cancer Institute. Dr. Qureshi has disclosed various financial relationships with Amgen and Genentech.

Arch Dermatol. Published online August 16, 2010.