Abstract
The associations of physical activity (PA) with body composition among persons with psoriatic arthritis (PsA) are not well described. The objective was to investigate associations of PA with visceral fat mass and percentage body fat in persons with PsA of different age groups. Persons with PsA (CASPAR criteria, n = 356), and controls (n = 47,470) from the Trøndelag Health Study (HUNT4, 2017-2019) were included. Visceral fat mass and percentage body fat measured using bioelectrical impedance were primary outcomes in multivariable linear regression analysis. PsA, PA (questionnaire data), and age were explanatory variables, with adjustment for sex, smoking, heart disease, lung disease, and height. An interaction term between PsA and age was included in both models. Persons with PsA had altered body composition, including higher visceral fat mass and percentage body fat, especially those < 40 years of age (p ≤ 0.01). Moderate or high PA was associated with significantly lower values of the primary outcomes. Differences were Moderate compared to low PA: 1.4 kg (95% CI 1.3, 1.5 kg) lower visceral fat mass, and 2.0% (95% CI 1.8, 2.1) lower percentage body fat. Differences were High compared to low PA: 3.2 kg (95% CI 3.1, 3.3) lower visceral fat mass and 5.0% (95% CI 4.8, 5.1%) lower percentage body fat. Persons with PsA had higher visceral fat mass and percentage body fat, especially if < 40 years, and PA was associated with lower values of both endpoints. Changes of body composition in persons with PsA may influence important health outcomes and should be addressed in clinical practice.