The effects of short-term dietary calorie restriction combined with aerobic exercise on systemic inflammation in overweight or obese individuals with knee osteoarthritis: a randomised controlled trial

PURPOSE: The purpose of this study is to determine the effects of 4-weeks dietary calorie restriction alone (CR) compared to CR with aerobic exercise (CR + E) on systemic inflammation and index knee pain in overweight and obese individuals with knee osteoarthritis (OA). METHODS: Twenty-three individuals with knee OA completed a randomised controlled trial. Participants in the CR group (n = 9, BMI: 30.0 ± 2.4 kg/m², 56 ± 5 years) were asked to reduce their habitual energy intake by 5000 kcal/week for 4 weeks, and those randomised to the CR + E group (n = 14, BMI: 32.3 ± 4.8 kg/m², 57 ± 5 years) were asked to follow the same dietary CR and perform five, 30-min bouts of moderate intensity cycling per week. Blood markers of inflammation, body composition, function, and pain were compared after a 4-week intervention period by ANCOVA, using pre-intervention value as a covariate. RESULTS: There was no difference in CRP between groups at post-intervention (p = 0.517, d = 0.31). IL-6 was lower (p < 0.01; d = 1.69) at post-intervention in the CR + E group (1.36 mg/dL, 0.72 to 2.00) compared to CR group (2.98 mg/dL, 2.22-3.73). Visual analogue scale (VAS) knee pain was lower (p < 0.01; d = 1.29) at post-intervention in the CR + E group (2, 1-3) compared to the CR group (4, 3-5). The time to complete the stair climb test was lower at post-intervention in the CR + E group compared to the CR group (p = 0.016, d = 1.17). CONCLUSIONS: Four weeks of moderate-intensity aerobic exercise training combined with CR led to a greater reduction in IL-6, but not CRP, compared to CR alone. The addition of exercise to CR led to greater reduction in knee pain compared to CR alone. TRIAL REGISTRATION: ClinicalTrials.gov (ID: NCT05518890).