Additive effects of active vitamin D3 or vitamin E administration on therapeutic lower-limb home exercise for knee osteoarthritis: A pilot prospective randomized controlled trial

Quadriceps weakness, inflammation, and reduced physical function are common in knee osteoarthritis (OA), and lower limb exercise therapy is an established non-pharmacological treatment. Vitamin D3 (vit D3) and vitamin E (vit E) have been proposed as adjunctive therapies; however, clinical findings are inconsistent. We aimed to examine whether combining lower limb home exercises with oral active vit D3 or vit E supplementation provides additive benefits compared with home exercise alone in women with symptomatic knee OA.

Eighty-eight postmenopausal women with knee OA (Kellgren-Lawrence grade 2-4; 71.9 ± 5.6 years) were randomly assigned to receive therapeutic lower limb home exercise only, home exercise with active vit D3 administration, or home exercise with vit E administration. Participants performed isometric lower limb exercises twice daily for 24 weeks. Subsequently, they were assessed using the Japanese knee osteoarthritis measure (JKOM) as the primary outcome. Secondary outcomes were short-form health survey, grip strength, quadriceps muscle strength, 10-m walk test, inflammatory markers, bone mineral density, and body composition. For data analyses, we used paired and independent t tests, analysis of variance, and analysis of covariance, adjusting for age, body mass index, and Kellgren-Lawrence grade.