S19	S16 AND S17 AND S18
S18	S1 OR S2 OR S3 OR S4
S17	S5 OR S6 OR S7 OR S8 OR S9 OR S10 OR S11 OR S12
S16	S13 OR S14 OR S15
S15	arthr*
S14	degenerative joint disease*
S13	osteoarthr*
S12	ex-athlete*
S11	elite athlete*
S10	retired athlete*
S9	former athlete*
S8	Sportswoman
S7	Sportsman
S6	Sportsperson
S5	athlete*
S4	probability
S3	epidemiolog*
S2	Incidence
S1	prevalence