Cigarette Smoking Identified as Risk Factor for Postmenopausal Psoriasis

Among postmenopausal women, cigarette smoking was found to be associated with increased risk for psoriasis, according to study findings published in the American Journal of Clinical Dermatology. Smoking cessation was found to be associated with a decreased risk for psoriasis for moderate smokers in this population. Alcohol consumption was not found to be an independent risk factor for psoriasis in postmenopausal women.

Investigators sought to evaluate whether alcohol consumption (by status, frequency, and alcohol subtype) modifies smoking-related psoriasis risk in postmenopausal women and to determine the effect of smoking cessation on psoriasis risk in this population.

They conducted a review that included 118,097 postmenopausal women linked to Medicare data who were enrolled in the Women’s Health Initiative (WHI) between 1993 and 1998. They used fee-for-service Medicare International Classification of Diseases, Ninth Revision (ICD-9), Clinical Modification codes assigned by dermatologists or rheumatologists to identify patients diagnosed with psoriasis. Self-administered questionnaires provided information on smoking and alcohol habits, as well as medical history and demographic data.

WHI eligibility criteria included age from 50 to 79 years, postmenopausal status (no menstrual period for at least 6 months if 55 years of age and older and 12 months if aged 50 to 54 years), and intention to reside in the same area for at least 3 years. Women were recruited from 24 states and the District of Columbia through a mass mailing. Women with diagnosed psoriasis prior to WHI enrollment (2-year look-back period) were excluded, as were those missing smoking or alcohol habit data, leaving a final analytical cohort of 106,844 study participants.

Baseline enrollment characteristics revealed that women who were White, had higher education, held managerial/technical jobs, and earned a higher income consumed more alcohol. Women who were nondrinkers or past drinkers were more likely to hold jobs in the service/labor industry, engage in less physical activity, and have a higher body mass index. A greater proportion of nondrinkers or past drinkers had comorbidities.

During 21 years of follow-up (mean 12.6 years), the investigators found 2837 (2.7%) new diagnoses of psoriasis. The initial statistical model revealed that past and current alcohol drinkers were at higher risk of psoriasis vs never-drinkers (P-trend <.001). After adjusting for cigarette smoking, there was no association between alcohol consumption and psoriasis risk (P-trend =.478). There was also no association with psoriasis for the effect of alcohol by status, frequency, or alcohol subtype (wine, beer, or liquor).

Investigators noted an increasing risk for psoriasis with greater pack-years vs never-smokers (P-trend <.001). Past smokers had a lower risk of developing psoriasis compared with current moderate (5-14 cigarettes per day) smokers (hazard ratio [HR], 0.67; 95% CI, 0.51-0.88) and current smokers (for 5-24 years; HR, 0.65; 95% CI, 0.46-0.90).

Study limitations include an incidence of psoriasis (2.7%) based on ICD-9 codes that was higher than the US population prevalence of 2.2%, which could affect generalizability; the relatively short look-back period of 2 years; limitation of enrollment to postmenopausal women with available Medicare claims data; ICD-9 codes (not available before 1991) that may have missed undiagnosed psoriasis prior to ICD-9; self-reported data that may include response bias; and the unconfirmed assumption that alcohol and smoking habits remained unchanged during the observation period.

Investigators conclude, “Cigarette smoking, but not alcohol consumption, is an independent risk factor for psoriasis in postmenopausal women.” They added that cigarette smoking is associated with worse disease severity and lack of response to therapy. They urge a greater emphasis on smoking abstinence and cessation counseling, which may help patients who already face other risk factors for psoriasis.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

This article originally appeared on Dermatology Advisor