Genetic risk of knee osteoarthritis: a sibling study.
OBJECTIVE
To determine whether there is a genetic contribution to knee osteoarthritis (OA) as defined by structural change on plain radiographs.


METHODS
Sibling study. Comparison of knee OA prevalence in the community with knee OA prevalence among siblings of index cases with knee OA.


METHODS
490 knee OA index cases listed for total knee replacement and 737 of their siblings aged >40 years, 1729 community subjects aged >40 years.


METHODS
Odds ratio for radiographic knee OA in siblings v community participants.


RESULTS
The age, sex, and knee pain adjusted odds ratios in siblings were 2.9 (95% confidence interval 2.3 to 3.7) for tibiofemoral OA and 1.7 (1.4 to 2.2) for patellofemoral OA. This difference remained after adjustment for important environmental risk factors. The heritability estimate for knee OA was 0.62.


CONCLUSIONS
Siblings are at increased risk of knee OA in comparison with the general population. This is likely to be due to genetic factors.
Neame
R L
RL
Academic Rheumatology, Clinical Sciences Building, City Hospital, Nottingham, NG5 1PB, UK.
Muir
K
K
Doherty
S
S
Doherty
M
M
D000328:Adult; D017677:Age Distribution; D000368:Aged; D004739:England / Q000453:epidemiology; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000235:genetics*; D015995:Prevalence; D011859:Radiography; D015203:Reproducibility of Results; D012307:Risk Factors; D017678:Sex Distribution