Objectives Both overall and central obesity have been associated with the risk of psoriasis in a prospective study. Data on the association between obesity and psoriatic arthritis (PsA) have been sparse and no evidence on obesity measures and the risk of incident PsA is available now. This study aimed to evaluate the association between obesity and the risk of incident PsA in a large cohort of women.
Methods 89 049 participants were included from the Nurses Health Study II over a 14-year period (1991–2005). Information on body mass index (BMI), weight change and measures of central obesity (waist circumference, hip circumference and waist–hip ratio) was collected during the follow-up. The incidence of clinician-diagnosed PsA was ascertained and confirmed by supplementary questionnaires.
Results 146 incident PsA cases were identified during 1 231 693 person-years of follow-up. Among all participants, BMI was monotonically associated with an increased risk of incident PsA. Compared with BMI less than 25.0, the RR was 1.83 for BMI 25.0–29.9 (95% CI 1.15 to 2.89), 3.12 for BMI 30.0–34.9 (95% CI 1.90 to 5.11) and 6.46 for BMI over 35.0 (95% CI 4.11 to 10.16). There was a graded positive association between weight change from age 18 years, measures of central obesity and risk of PsA (p for trend <0.001). The analysis among participants developing psoriasis during follow-up revealed a similar association (p for trend <0.01), indicating an increased risk of PsA associated with obesity among patients with psoriasis.
Conclusion This study provides further evidence linking obesity with the risk of incident PsA among US women.
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Funding The work is supported by the Department of Dermatology, Brigham and Women's Hospital, NHS II grant R01 CA50385.
Competing interests AAQ has received a grant from Amgen/Pfizer to evaluate ‘Biomarkers in psoriasis and psoriatic arthritis’. AAQ also serves as a consultant for Abbott, Centocor, Novaritis and the Centers for Disease Control and Prevention. The other authors state no conflict of interest.
Ethics approval The institutional review btoard of Partners Health Care System approved this study.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.