The effects of a 6-month weight loss intervention on physical function and serum biomarkers in older adults with and without osteoarthritis

Abstract

Objective: To examine the effects of a 6-month weight loss intervention on physical function, inflammatory biomarkers, and metabolic biomarkers in both those with and without osteoarthritis (OA).

Design: 59 individuals ≥60 years old with obesity and a functional impairment were enrolled into this IRB approved clinical trial and randomized into one of two 6-month weight loss arms: a higher protein hypocaloric diet or a standard protein hypocaloric diet. All participants were prescribed individualized 500-kcal daily-deficit diets, with a goal of 10% weight loss. Additionally, participants participated in three, low-intensity, exercise sessions per week. Physical function, serum biomarkers and body composition data were assessed at the baseline and 6-month timepoints. Statistical analyses assessed the relationships between biomarkers, physical function, body composition, and OA status as a result of the intervention.

Results: No group effects of dietary intervention were detected on any outcome measures (multiple p ​> ​0.05). During the 6-month trial, participants lost 6.2 ​± ​4.0% of their bodyweight (p ​< ​0.0001) and experienced improved physical function on the Short-Performance-Physical-Battery (p ​< ​0.0001), 8-foot-up-and-go (p ​< ​0.0001), and time to complete 10-chair-stands (p ​< ​0.0001). Adiponectin concentrations (p ​= ​0.0480) were elevated, and cartilage oligomeric matrix protein (COMP) concentrations (p ​< ​0.0001) were reduced; further analysis revealed that reductions in serum COMP concentrations were greater in OA-negative individuals.

Conclusions: These results suggest that weight loss in older adults with and without OA may provide a protective effect to cartilage and OA. In particular, OA-negative individuals may be able to mitigate changes associated with OA through weight loss.

Keywords: (3–6): Obesity; Biomarkers; Cartilage; Lifestyle intervention; Older adults; Osteoarthritis.

Fig. 1

Schematic of study design. Baseline assessments were collected following consent and enrollment into the study. Participants were randomized into a dietary arm and received individually tailored dietary plans that aimed to cut 500 kcal/day. Participants received weekly nutrition counseling and participated in low intensity exercise. At the 6-month endpoint, outcome measures were collected. For data analysis, initial tests did not detect effects of the dietary arm on outcome measures. Thus, subjects were pooled by dietary arm and stratified according to OA status.

Fig. 2

Change in biomarker concentration from baseline to 6-month timepoint. Serum concentrations of adiponectin were increased from the baseline to 6-month timepoints, whereas COMP decreased. T-tests were utilized to evaluate changes in biomarker concentrations from the baseline to 6-month timepoints. ∗p < 0.05.

Fig. 3

Logged change in serum biomarker concentration versus OA status. OLS regression revealed that OA-negative individuals experienced a greater reduction in COMP concentrations than OA-positive individuals. ∗p < 0.05.