Obesity, waist circumference, weight change, and the risk of psoriasis in women: Nurses' Health Study II.
BACKGROUND
Psoriasis is a common, chronic, inflammatory skin disorder. Higher adiposity may increase the risk of psoriasis, but, to our knowledge, no prospective data are available on this relationship.


METHODS
We prospectively examined the relationships between body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]), weight change, waist circumference, hip circumference, waist-hip ratio, and incident psoriasis in 78 626 women over a 14-year period (1991-2005) in the Nurses' Health Study II. The primary outcome was incident, self-reported, physician-diagnosed psoriasis.


RESULTS
During the 14 years of follow-up, there were 892 self-reported incident cases of psoriasis. There was a graded positive association between BMI measured at multiple time points and the risk of incident psoriasis. When we analyzed BMI updated every 2 years, compared with a BMI of 21.0 through 22.9, the multivariate relative risks of psoriasis were 1.40 (95% confidence interval [CI], 1.13-1.73) for a BMI of 25.0 through 29.9; 1.48 (95% CI, 1.15-1.91) for a BMI of 30.0 through 34.9; and 2.69 (95% CI, 2.12-3.40) for a BMI of 35.0 or greater (P for trend, < .001). For BMI at the age of 18 years, the multivariate relative risk for the top BMI category (> or = 30.0) was 1.73 (95% CI, 1.24-2.41) and that for a lower BMI category (< 21.0) was 0.76 (95% CI, 0.65-0.90) (P for trend, < .001). Weight gain from the age of 18 years, higher waist circumference, hip circumference, and waist-hip ratio were all associated with a higher risk of incident psoriasis (all P values for trend, < .001).


CONCLUSIONS
This large prospective study indicates that increased adiposity and weight gain are strong risk factors for incident psoriasis in women.
Setty
Arathi R
AR
Department of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, Harvard Medical School, Boston, USA.
Curhan
Gary
G
Choi
Hyon K
HK
D000328:Adult; D001835:Body Weight; D001837:Body Weights and Measures; D005260:Female; D006801:Humans; D015994:Incidence; D009765:Obesity / Q000150:complications*; D011446:Prospective Studies; D011565:Psoriasis / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors