Biomarkers and longitudinal changes in lumbar spine degeneration and low back pain: the Johnston County Osteoarthritis Project.

OBJECTIVE: To determine if baseline biomarkers are associated with longitudinal changes in the worsening of disc space narrowing (DSN), vertebral osteophytes (OST), and low back pain (LBP). DESIGN: Paired baseline (2003-2004) and follow-up (2006-2010) lumbar spine radiographs from the Johnston County Osteoarthritis Project were graded for severity of DSN and OST. LBP severity was self-reported. Concentrations of analytes (cytokines, proteoglycans, and neuropeptides) were quantified by immunoassay. Pressure-pain threshold (PPT), a marker of sensitivity to pressure pain, was measured with a standard dolorimeter. Binary logistic regression models were used to estimate odd ratios (OR) and 95% confidence intervals (CI) of biomarker levels with DSN, OST, or LBP. Interactions were tested between biomarker levels and the number of affected lumbar spine levels or LBP. RESULTS: We included participants (n = 723) with biospecimens, PPT, and paired lumbar spine radiographic data. Baseline Lumican, a proteoglycan reflective of extracellular matrix changes, was associated with longitudinal changes in DSN worsening (OR = 3.19 [95% CI 1.22, 8.01]). Baseline brain-derived neuropathic factor, a neuropeptide, (OR = 1.80 [95% CI 1.03, 3.16]) was associated with longitudinal changes in OST worsening, which may reflect osteoclast genesis. Baseline hyaluronic acid (OR = 1.31 [95% CI 1.01, 1.71]), indicative of systemic inflammation, and PPT (OR = 1.56 [95% CI 1.02, 2.31]) were associated with longitudinal increases in LBP severity. CONCLUSION: These findings suggest that baseline biomarkers are associated with longitudinal changes occurring in structures of the lumbar spine (DSN vs OST). Markers of inflammation and perceived pressure pain sensitivity were associated with longitudinal worsening of LBP.

Hip symptoms are associated with premature mortality: the Johnston County Osteoarthritis Project.

OBJECTIVE: To investigate the impact of hip osteoarthritis (OA) and/or hip symptoms on excess mortality. DESIGN: We analyzed data from 3,919 individuals in a community-based prospective cohort of African Americans and Caucasians age ≥45 years. Women ≥50 years of age and all men underwent supine anteroposterior pelvic radiography at baseline, with the participant's feet in 15 degrees of internal rotation. Hip radiographic (rOA) was defined as a Kellgren-Lawrence grade of ≥2 in at least one hip. Participants completed questionnaires at baseline to determine presence of hip symptoms and covariate status. Participants with symptomatic hip rOA (SxOA) are a subset of individuals with hip rOA and symptoms in the same hip. Multiple imputation was used to impute missing values of covariates. Mortality was determined through 2015 and follow-up time was calculated from baseline assessment until death or censoring which took place when a participant was lost to follow-up or reached the end of study period. Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI). We carried out additional analyses stratified by sex, race, age and obesity. RESULTS: Mean follow-up time was 14.2 years during which 1762 deaths occurred. There were 29.9% participants in our population with hip rOA at baseline. Compared to those with neither hip rOA nor hip symptoms, we observed an increased risk of all-cause mortality in participants with hip symptoms alone (HR = 1.28, 95% CI = 1.13-1.46), but no association for hip rOA either with or without symptoms. In stratified analyses we observed increased associations for hip symptoms alone and hip sxOA in those <65 years (43% and 39% increase, respectively) and in Caucasians (34% and 21% increase, respectively). CONCLUSIONS: Individuals who had hip symptoms without hip rOA had an increased risk of mortality. These effects were particularly strong for those who were <65 years of age and Caucasians. Effective interventions to identify those with hip pain in order to lessen it could reduce premature mortality.

A machine learning approach to knee osteoarthritis phenotyping: data from the FNIH Biomarkers Consortium.

OBJECTIVE: Knee osteoarthritis (KOA) is a heterogeneous condition representing a variety of potentially distinct phenotypes. The purpose of this study was to apply innovative machine learning approaches to KOA phenotyping in order to define progression phenotypes that are potentially more responsive to interventions. DESIGN: We used publicly available data from the Foundation for the National Institutes of Health (FNIH) osteoarthritis (OA) Biomarkers Consortium, where radiographic (medial joint space narrowing of ≥0.7 mm), and pain progression (increase of ≥9 Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] points) were defined at 48 months, as four mutually exclusive outcome groups (none, both, pain only, radiographic only), along with an extensive set of covariates. We applied distance weighted discrimination (DWD), direction-projection-permutation (DiProPerm) testing, and clustering methods to focus on the contrast (z-scores) between those progressing by both criteria ("progressors") and those progressing by neither ("non-progressors"). RESULTS: Using all observations (597 individuals, 59% women, mean age 62 years and BMI 31 kg/m2) and all 73 baseline variables available in the dataset, there was a clear separation among progressors and non-progressors (z = 10.1). Higher z-scores were seen for the magnetic resonance imaging (MRI)-based variables than for demographic/clinical variables or biochemical markers. Baseline variables with the greatest contribution to non-progression at 48 months included WOMAC pain, lateral meniscal extrusion, and serum N-terminal pro-peptide of collagen IIA (PIIANP), while those contributing to progression included bone marrow lesions, osteophytes, medial meniscal extrusion, and urine C-terminal crosslinked telopeptide type II collagen (CTX-II). CONCLUSIONS: Using methods that provide a way to assess numerous variables of different types and scalings simultaneously in relation to an outcome of interest enabled a data-driven approach that identified key variables associated with a progression phenotype.

The impact of painful knee osteoarthritis on mortality: a community-based cohort study with over 24 years of follow-up.

OBJECTIVE: To investigate the impact of knee osteoarthritis (OA) and/or knee pain on excess mortality. METHOD: We analyzed data from 4,182 participants in a community-based prospective cohort study of African American and Caucasian men and women aged ≥45 years. Participants completed knee radiographs and questionnaires at baseline and at up to three follow-ups to determine knee OA (rOA), knee pain and covariate status. Mortality was determined through 2015. We used Cox proportional hazards regression with time-varying covariates (TVC) to estimate hazard ratios (HR) and 95% confidence intervals (CI). Additional analyses stratified by sex, race and age were carried out. RESULTS: Median follow-up time was 14.6 years during which 1822 deaths occurred. Baseline knee radiographic osteoarthritis (rOA) was 27.7%, 38.8% at first follow-up, 52.6% at second follow-up and 61.9% at the third follow-up. Knee rOA with pain and knee pain alone were both associated with a >15% increase in premature all-cause mortality. In analyses stratified by sex, race and age, associations between knee pain, with or without knee rOA, and all-cause death were found among women, Caucasians, those ≤65 years of age, and those with a body mass index (BMI)≥30, with observed increased risks of death between 21% and 65%. We observed similar, somewhat attenuated, results for cardiovascular disease (CVD) deaths. CONCLUSION: In models taking into account variables that change over time, individuals who had knee pain, alone or with knee rOA, had increased mortality. These effects were particularly strong among those obese. Effective interventions to reduce knee pain, particularly those including weight management and prevention of comorbidities, could reduce mortality.

Osteoarthritis induced by destabilization of the medial meniscus is reduced in germ-free mice.

OBJECTIVE: To determine the contribution of the gut microbiota to the development of injury-induced osteoarthritis (OA). DESIGN: OA was induced using the destabilized medial meniscus (DMM) model in 20 germ-free (GF) C57BL/6J male mice housed in a gnotobiotic facility and 23 strain-matched specific pathogen free (SPF) mice in 2 age groups -13.5 weeks avg age at DMM (17 SPF and 15 GF) and 43 weeks avg age at DMM (6 SPF and 5 GF). OA severity was measured using scores for articular cartilage structure (ACS), loss of safranin O (SafO) staining, osteophyte size, and synovial hyperplasia. Microbiome analysis by 16S rRNA amplicon sequencing was performed on stool samples and LPS and LPS binding protein (LBP) were measured in plasma. RESULTS: Compared to the SPF DMM mice, the maximum (MAX) ACS score per joint was 28% lower (p = 0.036) in GF DMM mice while the SafO sum score of all sections evaluated per joint was decreased by 31% (p = 0.009). The differences between SPF and GF mice in these scores were greater when only the younger mice were included in the analysis. The younger GF DMM mice also had significant reductions in osteophyte size (36%, P = 0.0119) and LBP (27%, P = 0.007) but not synovial scores or LPS. Differences in relative abundance of a number of Operational Taxonomic Units (OTUs) were noted between SPF mice with high vs low maximum ACS scores. CONCLUSIONS: These results suggest factors related to the gut microbiota promote the development of OA after joint injury.

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.

Physical therapy vs internet-based exercise training for patients with knee osteoarthritis: results of a randomized controlled trial.

OBJECTIVE: To compare the effectiveness of physical therapy (PT, evidence-based approach) and internet-based exercise training (IBET), each vs a wait list (WL) control, among individuals with knee osteoarthritis (OA). DESIGN: Randomized controlled trial of 350 participants with symptomatic knee OA, allocated to standard PT, IBET and WL control in a 2:2:1 ratio, respectively. The PT group received up to eight individual visits within 4 months. The IBET program provided tailored exercises, video demonstrations, and guidance on progression. The primary outcome was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC, range 0 [no problems]-96 [extreme problems]), assessed at baseline, 4 months (primary time point) and 12 months. General linear mixed effects modeling compared changes in WOMAC among study groups, with superiority hypotheses testing differences between each intervention group and WL and non-inferiority hypotheses comparing IBET with PT. RESULTS: At 4-months, improvements in WOMAC score did not differ significantly for either the IBET or PT group compared with WL (IBET: -2.70, 95% Confidence Interval (CI) = -6.24, 0.85, P = 0.14; PT: -3.36, 95% (CI) = -6.84, 0.12, P = 0.06). Similarly, at 12-months mean differences compared to WL were not statistically significant for either group (IBET: -2.63, 95% CI = -6.37, 1.11, P = 0.17; PT: -1.59, 95% CI = -5.26, 2.08, P = 0.39). IBET was non-inferior to PT at both time points. CONCLUSIONS: Improvements in WOMAC score following IBET and PT did not differ significantly from the WL group. Additional research is needed to examine strategies for maximizing benefits of exercise-based interventions for patients with knee OA. TRIAL REGISTRATION: NCT02312713.

Population-based prevalence of multiple radiographically-defined hip morphologies: the Johnston County Osteoarthritis Project.

OBJECTIVE: To provide the first prevalence estimates of different radiographic hip morphologies relevant to dysplasia and femoroacetabular impingement in a well-characterized USA population-based cohort. METHODS: Cross-sectional data were from the baseline examination (1991-1997) of a large population-based prospective longitudinal cohort study (The Johnston County Osteoarthritis Project). HipMorf software (Oxford, UK) was used to assess hip morphology on anteroposterior (AP) pelvis radiographs. Weighted, sex-stratified prevalence estimates and 95% confidence intervals for four key hip morphologies (AP alpha angle, triangular index sign, lateral center edge angle (LCEA), and protrusio acetabula) were derived and further stratified by age, race and body mass index (BMI). RESULTS: A total of 5192 hips from 2596 individuals were included (31% African American, 43% male, mean age 63 years, mean BMI 29 kg/m2). Cam morphology was seen in more than 25% of men and 10% of women. Mild dysplasia was present in about 1/3 of men and women, while pincer morphology was identified in 7% of men and 10% of women. Femoral side (cam) morphologies were more common and more frequently bilateral among men, while pincer morphologies were more common in women; mixed morphologies were infrequent. African-Americans were more likely to have protrusio acetabula than whites. CONCLUSION: We report the first population-based prevalence estimates of radiographic hip morphologies relevant to femoroacetabular impingement (FAI) and dysplasia in the USA. These morphologies are very common, with » men and 1/10 women having cam morphology, 1/3 of all adults having mild dysplasia, and 1/15 men and 1/10 women having pincer morphology in at least one hip.

Annual incidence rates of hip symptoms and three hip OA outcomes from a U.S. population-based cohort study: the Johnston County Osteoarthritis Project.

OBJECTIVE: Estimate annual incidence rates (IRs) of hip symptoms and three osteoarthritis (OA) outcomes (radiographic, symptomatic, and severe radiographic) overall and by race, sociodemographic characteristics, and hip OA risk factors. DESIGN: Analyze baseline (1991-1997) and first follow-up (1999-2003) data (n = 1446) from the Johnston County Osteoarthritis Project, a population-based, prospective study of adults ≥45 years in North Carolina. Hip symptoms were pain, aching, and/or stiffness on most days, or groin pain. Radiographic and severe radiographic OA were Kellgren-Lawrence (KL) grades ≥2 and ≥3, respectively. Symptomatic OA was radiographic OA with symptoms in the same hip. Sociodemographics were age, gender, race, highest attained education, and annual household income. Hip OA risk factors were self-reported body mass index (BMI) at age 18 years, clinically measured BMI at baseline, and history of hip injury. RESULTS: Annual IRs (median = 5.5 years follow-up) were 37, 23, 13, and 2.9 per 1000 person-years for hip symptoms, and radiographic, symptomatic, and severe radiographic hip OA, respectively. We found low IRs of radiographic and symptomatic hip OA among African Americans and high IRs of hip symptoms among the obese and the very poor. Across outcomes, IRs were highest for those with hip injury. CONCLUSION: No prior studies have reported IRs of hip symptoms; IRs of radiographic and severe radiographic hip OA were similar to, and the IR of symptomatic hip OA was higher than, previous estimates. Prevention efforts should target low socioeconomic status (SES) populations and obese adults; interventions for hip OA and hip symptoms are imperative for those with hip injuries.

Novel statistical methodology reveals that hip shape is associated with incident radiographic hip osteoarthritis among African American women.

INTRODUCTION: Hip shape is a risk factor for the development of hip osteoarthritis (OA), and current methods to assess hip shape from radiographs are limited; therefore this study explored current and novel methods to assess hip shape. METHODS: Data from a prior case-control study nested in the Johnston County OA Project were used, including 382 hips (from 342 individuals). Hips were classified by radiographic hip OA (RHOA) status as RHOA cases (baseline Kellgren Lawrence grade [KLG] 0 or 1, follow-up [mean 6 years] KLG ≥ 2) or controls (KLG = 0 or 1 at both baseline and follow-up). Proximal femur shape was assessed using a 60-point model as previously described. The current analysis explored commonly used principal component analysis (PCA), as well as novel statistical methodologies suited to high dimension low sample size settings (Distance Weighted Discrimination [DWD] and Distance Projection Permutation [DiProPerm] hypothesis testing) to assess differences between cases and controls. RESULTS: Using these novel methodologies, we were able to better characterize morphologic differences by sex and race. In particular, the proximal femurs of African American women demonstrated significantly different shapes between cases and controls, implying an important role for sex and race in the development of RHOA. Notably, discrimination was improved with the use of DWD and DiProPerm compared to PCA. CONCLUSIONS: DWD with DiProPerm significance testing provides improved discrimination of variation in hip morphology between groups, and enables subgroup analyses even under small sample sizes.

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.

The family partners for health study: a cluster randomized controlled trial for child and parent weight management.

OBJECTIVE: The purpose of this study was to test a two-phased nutrition and exercise education, coping skills training, and exercise intervention program for overweight or obese low-income ethnic minority 2nd to 4th grade children and their parents in rural North Carolina, USA. METHODS: A cluster randomized controlled trial was carried out with 358 children (7-10 years) and a parent for each child (n=358). General linear mixed models were used to determine the effects of the intervention on weight, adiposity, health behaviors, and eating and exercise self-efficacy by examining changes in children and parents from baseline to completion of the study (18 months). RESULTS: At 18 months, children in the experimental group did not have a significantly decreased body mass index (BMI) percentile (P=0.470); however, they showed a reduction in the growth rate of their triceps (P=0.001) and subscapular skinfolds (P<0.001) and an improvement in dietary knowledge (P=0.018) and drank less than one glass of soda per day (P=0.052) compared with the control group. Parents in the experimental group had decreased BMI (P=0.001), triceps (P<0.001) and subscapular skinfolds (P<0.001) and increased nutrition (P=0.003) and exercise (P<0.001) knowledge and more often drank water or unsweetened drinks (P=0.029). At 18 months, children in the experimental group did not show significant improvement in eating (P=0.956) or exercise self-efficacy (P=0.976). Experimental parents demonstrated improved socially acceptable eating self-efficacy (P=0.013); however, they did not show significant improvement in self-efficacy pertaining to emotional eating (P=0.155) and exercise (P=0.680). CONCLUSION: The results suggest that inclusion of children and parents in the same intervention program is an effective way to decrease adiposity and improve nutrition behaviors in both children and parents and improve weight and eating self-efficacy in parents.

Meeting physical activity guidelines and the risk of incident knee osteoarthritis: a population-based prospective cohort study.

OBJECTIVE: Knee osteoarthritis (OA) is a leading cause of disability and joint pain. Although other risk factors of knee OA have been identified, how physical activity affects incident knee OA remains unclear. METHODS: Using data from the first (1999-2004) and second (2005-2010) followup periods of the Johnston County Osteoarthritis Project study, we tested the association between meeting physical activity guidelines and incident knee outcomes among 1,522 adults ages ≥45 years. The median followup time was 6.5 years (range 4.0-10.2 years). Physical activity at baseline (moderate-equivalent physical activity minutes/week) was calculated using the Minnesota Leisure Time Physical Activity questionnaire. Incident knee radiographic OA (ROA) was defined as the development of Kellgren/Lawrence grade ≥2 in a knee at followup. Incident knee symptomatic ROA (sROA) was defined as the development of ROA and symptoms in at least 1 knee at followup. Weibull regression modeling was used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for interval-censored data. RESULTS: In multivariable models, meeting the 2008 Department of Health and Human Services (HHS) physical activity guidelines (≥150 minutes/week) was not significantly associated with ROA (HR 1.20 [95% CI 0.92-1.56]) or sROA (HR 1.24 [95% CI 0.87-1.76]). Adults in the highest level (≥300 minutes/week) of physical activity had a higher risk of knee ROA and sROA compared with inactive (0 to <10 minutes/week) participants; however, these associations were not statistically significant (HR 1.62 [95% CI 0.97-2.68] and HR 1.42 [95% CI 0.76-2.65], respectively). CONCLUSION: Meeting the HHS physical activity guidelines was not associated with incident knee ROA or sROA in a cohort of middle-aged and older adults.

Regression models for patient-reported measures having ordered categories recorded on multiple occasions.

OBJECTIVES: The article reviews proportional and partial proportional odds regression for ordered categorical outcomes, such as patient-reported measures, that are frequently used in clinical research in dentistry. METHODS: The proportional odds regression model for ordinal data is a generalization of ordinary logistic regression for dichotomous responses. When the proportional odds assumption holds for some but not all of the covariates, the lesser known partial proportional odds model is shown to provide a useful extension. RESULTS: The ordinal data models are illustrated for the analysis of repeated ordinal outcomes to determine whether the burden associated with sensory alteration following a bilateral sagittal split osteotomy procedure differed for those patients who were given opening exercises only following surgery and those who received sensory retraining exercises in conjunction with standard opening exercises. CONCLUSIONS: Proportional and partial proportional odds models are broadly applicable to the analysis of cross-sectional and longitudinal ordinal data in dental research.

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). DESIGN: 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. CONCLUSION: 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.

Differences in radiographic features of knee osteoarthritis in African-Americans and Caucasians: the Johnston county osteoarthritis project.

OBJECTIVE: To examine racial differences in tibiofemoral joint (TFJ) and patellofemoral joint (PFJ) radiographic osteoarthritis in African-American (AA) and Caucasian men and women. METHOD: Multiple logistic regression was used to evaluate cross-sectional associations between race and tibiofemoral osteoarthritis (TF-OA) and the presence, severity and location of individual radiographic features of tibiofemoral joint osteoarthritis [TFJ-OA] (osteophytes, joint space narrowing [JSN], sclerosis and cysts) and patellofemoral joint osteoarthritis (PFJ-OA) (osteophytes, JSN and sclerosis), using data from the Johnston County Osteoarthritis Project. Proportional odds ratios (POR) assessed severity of TF-OA, TFJ and PFJ osteophytes, and JSN, adjusting for confounders. Generalized estimating equations accounted for auto-correlation of knees. RESULTS: Among 3187 participants (32.5% AAs; 62% women; mean age 62 years), 6300 TFJ and 1957 PFJ were included. Compared to Caucasians, AA men were more likely to have TF-OA (adjusted odds ratio [aOR]=1.36; 95% CI, 1.00-1.86); tri-compartmental TFJ and PFJ osteophytes (aOR=3.06; 95%CI=1.96-4.78), and TFJ and PFJ sclerosis. AA women were more likely than Caucasian to have medial TFJ and tri-compartmental osteophytes (aOR=2.13; 1.55-2.94), and lateral TFJ sclerosis. AAs had more severe TF-OA than Caucasians (adjusted cumulative odds ratio [aPOR]=2.08; 95% CI, 1.19-3.64 for men; aPOR=1.56; 95% CI, 1.06-2.29 for women) and were more likely to have lateral TFJ JSN. CONCLUSIONS: Compared to Caucasians, AAs were more likely to have more severe TF-OA; tri-compartmental disease; and lateral JSN. Further research to clarify the discrepancy between radiographic features in OA among races appears warranted.

Extremely low birth weight preterm infants lack vasomotor response in relationship to cold body temperatures at birth.

OBJECTIVE: This study evaluated peripheral vasoconstriction in extremely low birth weight (ELBW) infants when body temperature decreased during the first 12 h of life. STUDY DESIGN: An exploratory, within-subjects design with 10 ELBW infants. Abdominal and foot temperatures were measured every minute. Peripheral vasoconstriction (abdominal>peripheral temperature by 2 degrees C) and abdominal-peripheral temperature difference were also evaluated. RESULTS: Abdominal and peripheral temperatures were significantly correlated within each infant. One 880 g infant exhibited isolated peripheral vasoconstriction; a 960-g infant had abdominal temperatures >1 degrees C higher than peripheral temperatures. Eight smaller infants exhibited no peripheral vasoconstriction and spent most of their observations with peripheral greater than abdominal temperatures. In eight infants, mean temperature difference was significantly higher when abdominal temperature was <36.5 degrees C. CONCLUSION: Most ELBW infants did not exhibit peripheral vasoconstriction during their first 12 h of life, despite low temperatures. ELBW infants' vasomotor control may be immature during this period.

Racial differences in self-reported pain and function among individuals with radiographic hip and knee osteoarthritis: the Johnston County Osteoarthritis Project.

OBJECTIVE: This study compared pain and function among African Americans and Caucasian with radiographic hip and/or knee osteoarthritis (OA), controlling for radiographic severity and other patient characteristics. METHODS: Participants were 1368 individuals (32% African American) from the Johnston County Osteoarthritis Project with only knee OA, only hip OA, and both knee and hip OA. Linear regression models examined racial differences in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total scores and pain and function subscales, adjusting for radiographic severity, age, gender, education, body mass index (BMI), depressive symptoms, and WOMAC pain (last variable in models of function). RESULTS: Among those with only knee OA, African Americans had significantly worse mean WOMAC total scores than Caucasian (32.8 vs 24.3, P<0.001), and worse pain and function scores (P<0.001). Racial differences in WOMAC total, pain, and function scores persisted when controlling for radiographic severity and demographic factors but were not significant when also controlling for BMI and depressive symptoms. In models of WOMAC function, pain was the most strongly associated variable and substantially reduced the association of race with function. There were no racial differences in WOMAC scores among those with only hip OA or with both knee and hip OA. CONCLUSION: Among participants with knee OA, racial differences in pain and function may be explained by BMI and depressive symptoms, and racial differences in function may also be largely influenced by pain. Improving management of weight and depressive symptoms may be key steps toward reducing racial disparities in knee OA symptoms.

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.

Joint-specific hand symptoms and self-reported and performance-based functional status in African Americans and Caucasians: The Johnston County Osteoarthritis Project.

OBJECTIVE: To assess associations between joint-specific hand symptoms and self-reported and performance-based functional status. METHODS: Participants were from the population-based Johnston County Osteoarthritis Project. Symptoms in the distal interphalangeal (DIP), proximal interphalangeal (PIP), first carpometacarpal (CMC), and metacarpophalangeal (MCP) joints were assessed on a 30-joint diagram of both hands. Self-reported function was assessed by Health Assessment Questionnaire (HAQ) and performance-based function by timed repeated chair stands and 8-foot walk time. Separate multiple logistic regression models examined associations between symptoms in specific hand joint groups, symptoms in >/=2 hand joint groups and number of symptomatic hand joints, and functional status measures, controlling for age, race/ethnicity, sex, body mass index, radiographic knee and hip OA, knee and hip symptoms and depressive symptoms. RESULTS: Those with symptomatic hand joint groups were more likely than those without these complaints to report more difficulty and require longer times for performance measures. Those with 2 or more symptomatic hand joint groups were more likely to have higher HAQ scores (OR = 1.97 (1.53 to 2.53)) and require more time to complete 5 chair stands (OR = 1.98 (1.23 to 3.18)) and the 8 foot walk test (OR = 1.49 (1.12 to 1.99)). CONCLUSIONS: Joint-specific hand symptoms are associated with difficulty performing upper- or lower-extremity tasks, independent of knee and hip OA and symptoms, suggesting that studies examining functional status in OA should not ignore symptomatic joints beyond the joint site of interest, even when functional measures appear to be specific for the joint site under study.