The Mediating Effect of Leptin on the Relationship Between Increasing Body Mass Index and Knee Osteoarthritis

• Activity Number: 517
• Type: Topic Contributed
• Date/Time: Wednesday, August 7, 2013 : 10:30 AM to 12:20 PM
• Sponsor: Committee on Statistics and Disability
• Author(s): Angela Fowler-Brown*+ and Dae Hyun Kim and Ling Shi and Edward Marcantonio and Christina Wee and Robert Shmerling and Lewis Lipsitz and Suzanne Leveille
• Companies: Beth Israel Deaconess Medical Center and Institute for Aging Research and University of Massachusetts, Boston and Beth Israel Deaconess Medical Center and Beth Israel Deaconess Medical Center and Beth Israel Deaconess Medical Center and Beth Israel Deaconess Medical Center and University of Massachusetts, Boston
• Keywords: Mediation analysis ; Obesity ; Osteoathritis

Abstract

Obesity is associated with increased osteoarthritis (OA) of the knee. Adipokines, substances produced by fat tissue, may contribute to knee OA associated with obesity. Our aim was to determine whether the adipokine, leptin, mediates the relationship between body mass index (BMI) and knee OA. Data was from 659 older participants in a population-based study. Average BMI and serum leptin was 27.5kg/m2 and 589pM, respectively; prevalence of knee OA was 25%. Using Sobel-Goodman mediation analysis, we found that BMI was positively associated with prevalence of knee OA(OR = 1.06, p=0.004), and with serum leptin (ß = 65.2, p< 0.001); increasing serum leptin was associated with a higher prevalence of knee OA (OR=1.0004, p=0.012).The ratio of indirect/total effect was 0.49, suggesting that approximately half of the total effect of BMI on knee OA could be mediated by serum leptin. Based on the bootstrap results, the indirect effect and total effect were both significant, whereas the direct effect was not statistically significant. Further research is warranted on the role of leptin in OA pathology.