Adiposity and Physical Activity as Risk Factors for Developing Psoriatic Arthritis: Longitudinal Data From a Population‐Based Study in Norway

Objective Adiposity is prevalent among patients with psoriatic arthritis (PsA). However, the temporal relation unclear. The present study was undertaken to investigate whether adiposity and body fat distribution are related risk of developing PsA, physical activity could modify possible risk. Methods We included 36,626 women men from Norwegian Nord-Trøndelag Health Study without diagnosed PsA at baseline 1995 1997. Cox regression analysis used estimate adjusted hazard ratios (HRs) 95% confidence intervals (95% CIs) incident follow-up 2006 2008. Results During follow-up, 185 new cases were reported. Increases 1 SD in mass index (BMI) (4.2 3.5 kg/m2 for men, respectively) waist circumference (10.8 8.6 cm, associated HRs 1.40 CI 1.24, 1.58) 1.48 1.31, 1.68), respectively. Compared individuals normal weight, obese had an HR 2.46 1.65, 3.68), overweight 1.41 1.00, 1.99). Comparing extreme quartiles yielded 2.63 1.73, 3.99). In analyses combined effects using a BMI <25 high as reference, ≥25 2.06 1.18, 3.58) 1.53 0.80, 2.91) those low levels, Corresponding 2.25 1.40, 1.63) 1.85 0.95, 3.50). Conclusion results suggest that adiposity, particularly central obesity, increased PsA. Although there no clear modifying effect activity, levels reduced regardless BMI.