Serum hyaluronan levels and radiographic knee and hip osteoarthritis in African Americans and Caucasians in the Johnston County Osteoarthritis Project.
OBJECTIVE
Serum hyaluronan (HA) has been proposed as a potential biomarker of osteoarthritis (OA). We examined associations between serum HA and radiographic OA in an ethnically diverse, population-based sample.


METHODS
Participants were selected from the Johnston County Osteoarthritis Project, using stratified simple random sampling to achieve balance according to radiographic knee OA status, ethnic group, sex, and age group. Serum HA was measured by enzyme-linked immunosorbent assay. Radiographic OA variables included knee OA, knee OA laterality, knee OA severity, concomitant knee and hip OA, and total number of OA-affected knee and hip joints. Analysis of covariance was used to assess differences in mean serum levels of natural log-transformed HA (ln serum HA) between groups, adjusting for ethnicity, sex, age, body mass index (BMI), and self-reported comorbidities.


RESULTS
Levels of ln serum HA were positively associated with all definitions of radiographic OA (P < 0.0001). Levels of ln serum HA were higher in Caucasians (P = 0.0094) and in men (P = 0.0038) and were moderately correlated with age (r = 0.35, P < 0.0001). The associations with radiographic OA, ethnicity, sex, and age remained statistically significant after adjustment (P < 0.0045). There were no interactions between ethnicity and the other covariates.


CONCLUSIONS
These cross-sectional data support a role for serum HA as a biomarker of radiographic OA. The variations in levels of serum HA attributable to ethnicity, sex, and age were not explained by radiographic OA, BMI, or comorbidities. The lack of strong confounding between serum HA and comorbidities further supports a role for serum HA as a potential biomarker.
Elliott
Alan L
AL
Division of Rheumatology, School of Medicine, University of North Carolina at Chapel Hill, Thurston Arthritis Research Center, 3330 Thurston Building, CB #7280, Chapel Hill, NC 27599, USA.
Kraus
Virginia B
VB
Luta
Gheorghe
G
Stabler
Thomas
T
Renner
Jordan B
JB
Woodard
Janice
J
Dragomir
Anca D
AD
Helmick
Charles G
CG
Hochberg
Marc C
MC
Jordan
Joanne M
JM
D001741:Black or African American; D000375:Aging / Q000097:blood; D001175:Arthrography; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging; D006801:Humans; D006820:Hyaluronic Acid / Q000097:blood*; D007719:Knee Joint / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000097:blood* / Q000000981:diagnostic imaging* / Q000208:ethnology; D011446:Prospective Studies; D012727:Sex Characteristics; D044465:White People
D015415:Biomarkers; D006820:Hyaluronic Acid