Alkylresorcinol, a biomarker for whole grain intake, and its association with osteoarthritis: the MOST study.

INTRODUCTION: Higher intake of fiber has been associated with lower risk of incident symptomatic osteoarthritis (OA). We examined whether levels of alkylresorcinol (AR), a marker of whole grain intake, were associated with OA in subjects in The Multicenter Osteoarthritis (MOST) Study. METHOD: Knee x-rays and knee pain were assessed at baseline and through 60-months. Stored baseline fasting plasma samples were analyzed for AR homologues (C17:0, C19:0, C21:0, C23:0, C25:0) and total AR levels (AR sum). Two nested case-control studies, one for incident radiographic OA and one for incident symptomatic OA were performed with participants re-assessed at 15, 30 and 60 months. Multivariable conditional logistic regression with baseline covariates including age, sex, BMI, physical activity, quadriceps strength, race, smoking, depressive symptoms, diabetes and knee injury tested the association of log transformed AR levels with OA outcomes. RESULTS: Seven hundred seventy-seven subjects were, on average, in their 60's, and most were women. For 60-month cumulative incidence, there was no significant association between quartiles of AR concentration and incident radiographic (e.g., for incident radiographic OA, highest vs lowest quartile of AR sum showed RR = 0.93 (95% CI 0.59, 1.47), and for symptomatic OA RR was 1.22 (95% CI 0.76, 1.94). In secondary analyses examining 30-month incidence, high AR levels were associated with a reduced risk of X-ray OA (RR = 0.31 (95% CI 0.15, 0.64). CONCLUSION: In primary analyses, AR levels were not associated with risk of OA, but secondary analyses left open the possibility that high AR levels may protect against OA.

Heterogeneity of cartilage damage in Kellgren and Lawrence grade 2 and 3 knees: the MOST study.

OBJECTIVE: Eligibility for clinical trials in osteoarthritis (OA) is usually limited to Kellgren-Lawrence (KL) grades 2 and 3 knees. Our aim was to describe the prevalence and severity of cartilage damage in KL 2 and 3 knees by compartment and articular subregion. DESIGN: The Multicenter Osteoarthritis (MOST) study is a cohort study of individuals with or at risk for knee OA. All baseline MRIs with radiographic disease severity KL2 and 3 were included. Knee MRIs were read for cartilage damage in 14 subregions. We determined the frequencies of no, any and widespread full-thickness cartilage damage by knee compartment, and the prevalence of any cartilage damage in 14 articular subregions. RESULTS: 665 knees from 665 participants were included (mean age 63.8 ± 7.9 years, 66.5% women). 372 knees were KL2 and 293 knees were KL3. There was no cartilage damage in 78 (21.0%) medial tibio-femoral joint (TFJ), 157 (42.2%) lateral TFJ and 62 (16.7%) patello-femoral joint (PFJ) compartments of KL2 knees, and 17 (5.8%), 115 (39.3%) and 35 (12.0%) compartments, respectively, of KL3 knees. There was widespread full-thickness damage in 94 (25.3%) medial TFJ, 36 (9.7%) lateral TFJ and 176 (47.3%) PFJ compartments of KL2 knees, and 217 (74.1%), 70 (23.9%) and 104 (35.5%) compartments, respectively, of KL3 knees. The subregions most likely to have any damage were central medial femur (80.5%), medial patella (69.8%) and central medial tibia (69.9). CONCLUSIONS: KL2 and KL3 knees vary greatly in cartilage morphology. Heterogeneity in the prevalence, severity and location of cartilage damage in in KL2 and 3 knees should be considered when planning disease modifying trials for knee OA.

Factors associated with pain resolution in those with knee pain: the MOST study.

OBJECTIVES: To determine how many persons with knee pain have subsequent pain resolution and what factors are associated with resolution, focusing especially on types of physical activity. METHODS: Using data from MOST, an NIH funded longitudinal cohort study of persons with or at risk of knee osteoarthritis, we studied participants who at baseline reported knee pain on most days at both a telephone interview and clinic visit. We defined pain resolution if at 30 and 60 month exams, they reported no knee pain on most days and compared these participants to those who reported persistent pain later. In logistic regression analyses, we examined the association of baseline risk factors including demographic factors, BMI, depressive symptoms, isokinetic quadriceps strength and both overall physical activity (using the PASE survey) and specific activities including walking, gardening, and different intensities of recreational activities with pain resolution. RESULTS: Of 1,304 participants with knee pain on most days at baseline, 265 (20.3%) reported no knee pain at 30 and 60 months. Lower BMI and stronger quadriceps were associated with higher odds of pain resolution while overall physical activity was not. Of activities, walking decreased the odds of pain resolution (adjOR = 0.86 (95% CI 0.76, 0.98)), but gardening (adjOR = 1.59 (1.16, 2.18)) and moderate intensity recreational activities ((adjOR = 1.24 (1.05, 1.46)) increased it. CONCLUSION: Pain resolution is common in those with knee pain. Factors increasing the odds of pain resolution include lower BMI, greater quadriceps strength and gardening and moderately intensive recreational activities.