Effects of N-acetyl glucosamine and chondroitin sulfate supplementation on knee pain and self-reported knee function in middle-aged and older Japanese adults: a randomized, double-blind, placebo-controlled trial

Abstract

Background: There was no evidence of satisfying the standard to decide the efficacies of glucosamine and chondroitin in middle-aged and older Japanese adults with knee pain and/or stiffness.

Aim: To investigate the effects of 24 week oral N-acetyl glucosamine and chondroitin sulfate supplementation on knee pain, self-reported knee function, physical activity, and physical performance.

Methods: We randomly assigned 11 men and 39 women (aged 52-87 years) to receive 100 mg of N-acetyl glucosamine and 180 mg of chondroitin sulfate daily (Glu/Cho group) or a placebo (control, C group) for 24 weeks. The primary outcomes were a 100 mm visual analog pain scale (VAS) and the Japanese Knee Osteoarthritis Measure (JKOM) score. The secondary outcomes were physical activity and physical performance.

Results: We observed a significant group × time interaction on the JKOM score. According to the post hoc test, it significantly decreased (i.e., improved knee function) from the 4- to 12-week follow-up in the Glu/Cho group and the Glu/Cho group score was significantly lower than the C group at the 12-week follow-up. We found a significant interaction on household physical activity. There was no significant interaction on VAS or physical performance tests.

Discussion: The results of the present study were consistent with previous studies mainly conducted in European and American countries.

Conclusion: These results suggest that consumption of N-acetyl glucosamine and chondroitin sulfate for 12 weeks or longer has a positive effect on self-reported knee function and household physical activity in middle-aged and older Japanese adults with knee pain and/or stiffness.

Keywords: Japanese knee osteoarthritis measure; Knee osteoarthritis; Physical activity; Physical performance.