Osteoarthritis (OA) is a common, chronic disabling disease characterized by pain and disability, affecting mainly the elderly population. The American College of Rheumatology defined OA as “a heterogeneous group of conditions that lead to joint symptoms and signs which are associated with defective integrity of articular cartilage, in addition to related changes in the underlying bone at the joint margins”. Although a disease like OA will not directly lead to a higher mortality, the burden of disease and health care expenditure is enormous. In 2005, healthcare costs for OA in the Netherlands were approximately 540 million euro, which is in women higher than costs for hypertension, asthma or hip fracture. At the same time, the burden of OA is increasing because of aging and the obesity pandemic. In the Netherlands, already 650.000 persons (4% of the total population) had a diagnosis of OA in 2007. Although the incidence of disease stays stable over time, the prevalence is increasing due to the aging population and the population structure in the Netherlands. In addition, the World Health Organization showed in the Global Burden of Disease report that OA is the 4th leading cause of years lived with disability (YLD) at a global level. Only scarce symptomatic treatment options are available for OA, such as pain medication, exercise programs and eventually joint replacement. In summary, we can conclude that OA causes a large disease burden to patients and society and a better understanding of the pathophysiology is essential to discover new treatment options. Osteoarthritis is a degenerative joint disease affecting the whole joint. In Figure 1 the main structures of the joint affected by osteoarthritis are shown. The main characteristics of the disease process are articular cartilage loss, formation of new bone at the joint margins (osteophytes), increased thickness of the bone (subchondral sclerosis) and cyst formation. However, also soft-tissue structures surrounding the joint are affected, including the synovium, ligaments and muscles, making OA a whole-joint disease.

Genetics, Osteoarthritis, rheumatology
A.G. Uitterlinden (André)
Erasmus University Rotterdam
Financial support for the publication of this thesis was kindly provided by the TREATOA consortium, Pfizer B.V., Servier Nederland Farma B.V., Dutch Arthritis Foundation (Reumafonds), Anna Foundation| NOREF, Nederlandse Vereniging voor Calcium en Botstofwisseling (NVCB) and the Netherlands Consortium for Healthy Ageing (NCHA).
978-94-6169-226-9
hdl.handle.net/1765/38186
Erasmus MC: University Medical Center Rotterdam

Kerkhof, J.M. (2012, May 11). Genetics of Osteoarthritis: What a Pain!. Erasmus University Rotterdam. Retrieved from http://hdl.handle.net/1765/38186