One in four people may develop symptomatic hip osteoarthritis in his or her lifetime.
OBJECTIVE
To estimate the lifetime risk of symptomatic hip osteoarthritis (OA).


METHODS
We analyzed data from the Johnston County Osteoarthritis Project [a longitudinal population-based study of OA in North Carolina, United States (n=3068)]. The weighted baseline sample comprised 18% blacks and 54% women, and the mean age was 63 years (range=45-93). Symptomatic hip OA was defined as a Kellgren-Lawrence (K-L) radiographic score of ≥ 2 (anterior-posterior pelvis X-rays) and pain, aching or stiffness on most days, or groin pain, in the same hip. Lifetime risk, defined as the proportion who developed symptomatic hip OA in at least one hip by age 85, among people who live to age 85, was modeled using logistic regression with repeated measures (through generalized estimating equations).


RESULTS
Lifetime risk of symptomatic hip OA was 25.3% [95% confidence interval (CI)=21.3-29.3]. Lifetime risk was similar by sex, race, highest educational attainment, and hip injury history. We studied lifetime risk by body mass index (BMI) in three forms: at age 18; at baseline and follow-up; and at age 18, baseline and follow-up and found no differences in estimates.


CONCLUSIONS
The burden of symptomatic hip OA is substantial with one in four people developing this condition by age 85. The similar race-specific estimates suggest that racial disparities in total hip replacements are not attributable to differences in disease occurrence. Despite increasing evidence that obesity predicts an increased risk of both hip OA and joint replacement, we found no association between BMI and lifetime risk.
Murphy
L B
LB
Arthritis Program, Division of Adult and Community Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA. lmurphy1@cdc.gov
Helmick
C G
CG
Schwartz
T A
TA
Renner
J B
JB
Tudor
G
G
Koch
G G
GG
Dragomir
A D
AD
Kalsbeek
W D
WD
Luta
G
G
Jordan
J M
JM
D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009657:North Carolina / Q000453:epidemiology; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000453:epidemiology*; D011859:Radiography; D012307:Risk Factors; D012737:Sex Factors