The Impact of Obesity and Metabolic Disorders on Early Cartilage Degeneration
This article was contributed to by Pia M. Jungmann, M.D. and Wilson Lin.
Osteoarthritis (OA) is a progressive joint disease that causes irreversible cartilage loss. The cost and burden of OA is staggering. In 2004, OA affected over 27 million Americans, which resulted in 11.1 million outpatient visits. Currently, treatment for OA is limited and typically begins once the disease has progressed well beyond its early stages, thus emphasizing a strong need to detect the disease earlier.
OA is characterized by disabling symptoms like pain, swelling, and reduced mobility. The risk for OA at the knee is increased by weight-bearing due to obesity. Recently, also metabolic disorders including high blood sugar (Diabetes Mellitus), high blood pressure and high daily fat intake were found responsible for OA. One of the main OA abnormalities found in magnetic-resonance imaging (MRI) is cartilage degeneration. Normal cartilage assists in smooth joint function. Recently, new MRI techniques, called T2 relaxation time measurements, were applied in our lab to detect cartilage degeneration very early, before any knee pain or dysfunction occurs. In this technique cartilage is segmented on special MR sequences and T2 maps are generated to determine mainly increases in water content and collagen disruption.
A group of more than 400 individuals from the National Institute of Health funded osteoarthritis initiative (OAI) was evaluated in a UCSF Radiology study. Knee MRIs were evaluated at two time points: at baseline and in a two-year follow-up. Individuals with obesity, high blood sugar, high blood pressure, or high fat intake showed higher cartilage degeneration at the baseline time-point and also a faster progression during the two-year observation period. The more of these parameters were present the more cartilage degeneration was found.
Higher cartilage degeneration measured by T2 relaxation time, predicts an early onset of OA. Our study identifies an association of metabolic risk factors, including obesity and diabetes mellitus, with high T2 relaxation times. This underlines the importance of public health initiatives for early prevention of OA.
The new Center of Research Translation is another way in which UCSF is working to prevent and treat OA. For more information, please click here.