Associations between the chemokine biomarker CCL2 and knee osteoarthritis outcomes: the Johnston County Osteoarthritis Project.

OBJECTIVE: Our study analyzes the association between chemokine-ligand-2 (CCL2) serum concentrations at baseline and knee radiographic osteoarthritis (OA) (knee-rOA), knee-rOA progression, individual radiographic features and knee symptomatic OA at 5-year follow-up. DESIGN: OA outcomes were analyzed in a community-based cohort including a baseline enrollment and a 5-year follow-up. Baseline CCL2 serum concentrations were assessed by multiplex assay and associated with presence or progression of individual radiographic features at 5-year follow-up. Separate multiple logistic regression models were used to examine adjusted associations between baseline CCL2 and each of the knee OA variables at follow-up. CCL2 at baseline was modeled as an explanatory variable, whereas each of the knee OA variables at follow-up served as the response variables. Models were adjusted for age, BMI, race, and sex. Trend tests were conducted to assess any linear effect on outcomes across CCL2 tertiles. RESULTS: Participants (n = 168) had a median age of 57-years and median BMI of 29 kg/m2. About 63% of all participants were women, and 58% Caucasian (42% African American). In adjusted logistic models, continuous log-CCL2 was significantly associated with knee-rOA. For each unit increase in log CCL2, the odds of having knee-rOA at follow-up was increased by 72%. CCL2 tertiles showed significant linear associations with presence and progression of knee-rOA and medial joint space narrowing (JSN), but not with presence or progression of osteophytes, bone sclerosis, knee symptoms, or symptomatic knee-rOA. CONCLUSIONS: Serum CCL2 may help to elucidate some mechanisms of joint destruction and identify individuals with higher odds of structural knee changes.

Measures of hip morphology are related to development of worsening radiographic hip osteoarthritis over 6 to 13 year follow-up: the Johnston County Osteoarthritis Project.

OBJECTIVES: We sought to describe the effect of alterations in hip morphology with respect to worsening hip OA in a community-based sample including African American (AA) and white men and women. METHODS: This nested case-control study defined case hips as Kellgren Lawrence grade (KLG) <3 on baseline supine pelvis radiographs and KLG ≥3 or THR for OA at the 1st or 2nd follow-up visit (mean 6 and 13 years, respectively); control hips had KLG <3 at both visits, with gender/race distribution similar to cases. Hip morphology was assessed using HipMorf software (Oxford, UK). Descriptive means and standard errors were obtained from generalized estimating equation (GEE) models. Sex-stratified GEE regression models (accounting for within-person correlation), adjusted for age, race, BMI, and side were then employed. RESULTS: A total of 120 individuals (239 hips; 71 case/168 control) were included (25% male, 26% AA, mean age 62 years, BMI 30 kg/m(2)). Case hips tended to have greater baseline AP alpha angles, smaller minimum joint space width (mJSW) and more frequent triangular index signs. Adjusted results among men revealed that higher AP alpha angle, Gosvig ratio, and acetabular index were positively associated with case hips; coxa profunda was negatively associated. Among women, greater AP alpha angle, smaller mJSW, protrusio acetabuli, and triangular index sign were associated with case hips. CONCLUSIONS: We confirmed an increased risk of worsening hip OA due to baseline features of cam deformity among men and women, as well as protrusio acetabuli among women, and provide the first estimates of these measures in AAs.

Failure of serum transforming growth factor-beta (TGF-beta1) as a biomarker of radiographic osteoarthritis at the knee and hip: a cross-sectional analysis in the Johnston County Osteoarthritis Project.

PURPOSE: To assess associations between serum transforming growth factor-beta (TGF-beta1) and radiographic knee and hip osteoarthritis (rOA) in African American (AA) and White men and women. METHODS: Baseline data from 330 participants in the Johnston County Osteoarthritis Project were used in the analysis. Radiographs were scored with the Kellgren-Lawrence scale and rOA defined as grade> or =2. Individual radiographic features (IRFs) were rated 0-3. TGF-beta1 was measured using a sandwich enzyme-linked immunosorbent assay (ELISA). General linear models were used to estimate associations between lnTGF-beta1 and rOA presence, laterality or severity, and IRF presence and severity, adjusting for age, gender, race and body mass index. Interactions by race and gender were considered significant at P<0.1. RESULTS: Mean lnTGF-beta1 levels were higher among AAs compared to Whites, and among women compared to men (P<0.009). Mean lnTGF-beta1 levels were higher in those with knee osteophytes (OST), but this association was not significant after adjustment. There were no other significant differences in mean lnTGF-beta1 levels by presence, laterality, or severity of knee or hip rOA or IRFs. No race or gender interactions were identified, although a borderline significant association between lnTGF-beta1 and knee OST was seen among AAs (P<0.06). CONCLUSIONS: Although serum TGF-beta1 varied by race and gender and several rOA variables, there were no independent significant associations with presence, laterality, or severity of knee or hip rOA by K-L grade or IRFs, suggesting that serum TGF-beta1 is unlikely to be useful as a stand-alone biomarker in OA studies. A possible association between TGF-beta1 and OST in AAs cannot be excluded.