Effects of glucosamine and chondroitan supplementation in women with knee osteoarthritis participating in the Curves fitness and weight loss program: a randomized, placebo controlled, double blind clinical trial.

The purpose of this study was to determine whether participation in the Curves fitness and weight loss program and/or ingesting a commercially available glucosamine and chondroitan joint support dietary supplement improved functional status and/or health outcomes in women with knee osteoarthritis (OA). Thirty sedentary women with OA participated in a 14-week exercise and diet program and ingested either a glucosamine and chondroitan supplement or placebo. Participants were assigned to follow an isoenergenic high protein/carbohydrate restricted diet (HPD) or high carbohydrate/low protein diet (HCHO). Subjects participated in a supervised 30-minute resistance training circuit program that was interspersed with calisthenic exercises and performed 3-d per week. At 0, 2, 10, and 14 weeks, subjects completed a battery of assessments. Data were analyzed by repeated measures analysis and are presented as means ± SD from baseline. Results indicated that women with knee OA experienced significant training adaptations including decreased body mass (3±4%), decreased fat mass (6%±8), decreased body fat (4%±3), increased 1 repetition maximal muscular strength (11%±12), increased muscular endurance (13%±12), increased isokinetic strength (ranging from 10-25%±4), decreased knee pain (112%±317), stiffness (70%±234), limitations in physical function (96%±1,356), improved quality of life variables of physical functioning (37%±52), energy/fatigue (55%±69), social functioning (40%±76), and mental health (22%±84). Perceptions of appetite (13%±36), hunger (17%±34), energy (24%±35), and quality of diet (19%±38) were also improved. Glucosamine chondroitan supplementation tended to decrease perceptions of pain, with no statistically significant improvement in strength, or functional status. However, a strong effect size (d=1.1) was observed in VAS knee pain and moderate effect sizes were observed in WOMACTM pain (d=0.4), left knee flexion (d=0.53), 1 repetition max (d=0.53), total work (d=0.72), and maximal systolic blood pressure (d=0.69). These findings suggest that glucosamine and chondroitan supplementation during a weight loss and fitness program may have therapeutic benefits for women with OA.