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Vitamin D intake not related to psoriasis in women

There was no association found between vitamin D intake and incident psoriasis among women, according to recent research results.

Joseph F. Merola, MD, instructor at Harvard Medical School and director of clinical trials, dermatology, at Brigham and Women’s Hospital in Boston, and fellow researchers conducted a prospective study of 70,437 US female nurses aged 47 to 74 years enrolled in the Nurses’ Health Study. The nurses did not have psoriasis at baseline in 1994. That year and in 1998, 2002 and 2006, they completed food frequency questionnaires. Self-reported questionnaires were used to validate clinician-diagnosed psoriasis.

 

Joseph F. Merola

During follow-up from 1994 to June 2008, there were 502 cases of incident psoriasis documented across 973,057 person-years. Multivariable-adjusted Cox regression analysis was used to measure associations between vitamin D intake and incident psoriasis.

No significant association was found between dietary, supplementary and total vitamin D intake and incident psoriasis risk after adjustment for age, smoking, BMI, calorie intake, UV flux, exercise and alcohol use. Multivariate relative risks for psoriasis, when compared with women whose dietary vitamin D intake was less than 100 IU daily, were 1.03 (95% CI, 0.76-1.40) for 100-199 IU/day, 1.08 (95% CI, 0.79-1.49) for 200-299 IU/day, 0.95 (95% CI, 0.64-1.41) for 300-399 IU/day and 1.13 (95% CI, 0.66-1.92) for 400 IU/day or more. When compared with women who did not take supplementary vitamin D, the women who took at least 400 IU/day had a multivariate relative risk of 1.18 (95% CI, 0.88-1.58).

“The multivariate risk for women who had total vitamin D intake of 300-399 IU/day was no different than at higher and lower doses of vitamin D intake,” the researchers reported. “We find no evidence to support a preventive role of dietary or supplemental vitamin D for incident psoriasis.”

Disclosure: See the study for a full list of relevant financial disclosures.