In a recent Annals of Rheumatic Diseases study, Australian researchers reported that levels of circulating leptin—a hormone that influences body weight and regulates some inflammatory processes—are negatively associated with changes in knee-cartilage thickness.
This prospective cohort study of 163 randomly selected patients (mean age of 63) used MRI to assess knee-cartilage thickness and radioimmunoassay to measure serum leptin levels at baseline and again after an average of 2.7 years. Cross-sectionally, leptin levels were negatively associated with cartilage thickness at femoral, medial tibial, lateral tibial, and patellar sites, after researchers adjusted for age, sex, BMI, and disease status. Longitudinally, baseline levels and changes in leptin over time were associated with greater differences in tibial-cartilage thickness.
The authors speculate that leptin may have a catabolic effect on cartilage that contributes to the development of osteoarthritis (OA), and that decreases in leptin levels associated with weight loss may help explain the clinical improvement in patients with knee OA who lose weight.