Osteoarthritis is the most common joint disease worldwide. Epidemiological
studies on the prevalence and incidence have documented the role of osteoar
thritis in industrial populations. More extensive clinical studies not only
focussed on the impact of osteoarthritis on the quality of life, but have
also helped to classify this heterogeneous disease and define clinical subs
ets. Although the methods of epidemiological osteoarthritis research are no
t without problems, epidemiology has nevertheless clearly defined risk fact
ors of osteoarthritis and evaluated environmental influences such as sports
or occupation. Apart from that, epidemiology has also brought new ideas to
basic science research and in particular to molecular research on the gene
tics of osteoarthritis.