Effusion-synovitis worsening mediates the association between body mass index and Kellgren-Lawrence progression in obese individuals: data from the Osteoarthritis Initiative.

OBJECTIVE: Both obesity and synovitis are independently associated with knee osteoarthritis (KOA) progression. We examined whether synovitis mediates the relationship between body mass index (BMI) and KOA radiographic progression in the Osteoarthritis Initiative (OAI) cohort. DESIGN: We conducted a case-control study within the OAI. Cases (n = 315) were right knees with an increase of ≥1 Kellgren-Lawrence from baseline to 48 months of follow-up. Controls (n = 315) were right knees with no KL change. Cases and controls were matched by age, sex, race, and baseline KL. MRI Osteoarthritis Knee Score (MOAKS) at baseline and at 2 years was used for a semi-quantitative scoring (0-3) of effusion-synovitis and Hoffa-synovitis. Conditional logistic regression estimated associations between BMI and synovitis with KOA progression. Mediation analysis was used to assess the mediating effects of synovitis. RESULTS: The mean age of participants was 61 years, 70.8% were women, and 87% were White. KOA progression was associated with higher BMI (adjusted OR 1.05; 95%CI 1.01-1.09) and effusion-synovitis relative to no effusion-synovitis (adjusted OR 2.2; 95%CI 1.6-3.1). Associations between effusion-synovitis worsening and KOA progression were more pronounced among obese individuals (OR 34.1; 95%CI 4.2-274.8; P = 0.001) compared to normal weight (OR 3.2; 95%CI 0.8-12.8, P=0.096) individuals. Effusion-synovitis at 2 years, but not at baseline, mediated the relationship between BMI and KOA progression over a 4-year period. CONCLUSIONS: We found that effusion-synovitis worsening mediated the association between BMI and KOA progression and was associated with increased risk of KOA progression, particularly among obese individuals.

The mediating role of socioeconomic status on the relationship between pregnancy history and later-life cognition.

OBJECTIVE: The association of pregnancy with later-life cognition is not well understood. We examined whether full-term and incomplete pregnancies were associated with cognition in a sample of postmenopausal women, and whether socioeconomic status (SES) factors mediated these relationships. METHODS: A total of 1016 cognitively normal women from the National Health and Nutrition Examination Survey (NHANES) were examined. Cognitive measures included the Digit Symbol Substitution Test (DSST), Animal Fluency (AF) and the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word Learning (CERAD-WL) and Delayed Recall (CERAD-DR) tasks. Analyses examined the relationship between the number of term and incomplete pregnancies with cognitive performance, as well as the mediating effects of education and the federal income-to-poverty ratio (PIR). RESULTS: A greater number of term pregnancies was associated with worse performance on the DSST (ß = -0.09, 95% confidence interval [CI]: -0.12, -0.06), AF (ß = -0.03, 95% CI: -0.07, 0.00) and CERAD-DR (ß = -0.04, 95% CI: -0.08, -0.01). More incomplete pregnancies were associated with better CERAD-DR performance (ß = 0.07, 95% CI: 0.01, 0.13), and 28% (95% CI: 0.17, 0.42) of the association of term pregnancies with the DSST was mediated by the PIR. CONCLUSIONS: A higher number of term pregnancies was associated with worse cognitive performance, whereas a higher number of incomplete pregnancies was associated with better cognitive performance. Results indicate the necessity to consider SES factors when studying the relationship between pregnancy and cognition.

Racial and ethnic disparities in utilization of total knee arthroplasty among older women.

OBJECTIVE: To evaluate racial and ethnic disparities in utilization of total knee arthroplasty (TKA) in relation to demographic, health, and socioeconomic status variables. DESIGN: Prospective study of 102,767 Women's Health Initiative postmenopausal women initially aged 50-79, examining utilization rates of primary TKA between non-Hispanic Black/African American, non-Hispanic White, and Hispanic/Latina women (hereafter referred to as Black, White, and Hispanic). A total of 8,942 Black, 3,405 Hispanic, and 90,420 White women with linked Medicare claims data were followed until time of TKA, death, or transition from fee-for-service coverage. Absolute disparities were determined using utilization rates by racial/ethnic group and relative disparities quantified using multivariable hazards models in adjusting for age, arthritis, joint pain, mobility disability, body mass index, number of comorbidities, income, education, neighborhood socioeconomic status (SES), and geographic region. RESULTS: TKA utilization was higher among White women (10.7/1,000 person-years) compared to Black (8.5/1,000 person-years) and Hispanic women (7.6/1,000 person-years). Among women with health indicators for TKA including diagnosis of arthritis, moderate to severe joint pain, and mobility disability, Black and Hispanic women were significantly less likely to undergo TKA after adjusting for age [Black: HR (95% confidence interval) = 0.70 (0.63-0.79); Hispanic: HR = 0.58 (0.44-0.77)]. Adjustment for SES modestly attenuated the measured disparity, but significant differences remained [Black: HR = 0.75 (0.67-0.89); Hispanic: HR = 0.65 (0.47-0.89)]. CONCLUSIONS: Compared to White women, Black and Hispanic women were significantly less likely to undergo TKA after considering need and appropriateness for TKA and SES. Further investigation into personal-level and provider-level factors that may explain these disparities is warranted.

Prospective associations of C-reactive protein (CRP) levels and CRP genetic risk scores with risk of total knee and hip replacement for osteoarthritis in a diverse cohort.

OBJECTIVE: To examine associations of high-sensitivity C-reactive protein (CRP) levels and polygenic CRP genetic risk scores (GRS) with risk of end-stage hip or knee osteoarthritis (OA), defined as incident total hip (THR) or knee replacement (TKR) for OA. DESIGN: This study included a cohort of postmenopausal white, African American, and Hispanic women from the Women's Health Initiative. Women were followed from baseline to date of THR or TKR, death, or December 31, 2014. Medicare claims data identified THR and TKR. Hs-CRP and genotyping data were collected at baseline. Three CRP GRS were constructed: 1) a 4-SNP GRS comprised of genetic variants representing variation in the CRP gene among European populations; 2) a multilocus 18-SNP GRS of genetic variants significantly associated with CRP levels in a meta-analysis of genome-wide association studies; and 3) a 5-SNP GRS of genetic variants significantly associated with CRP levels among African American women. RESULTS: In analyses conducted separately among each race and ethnic group, there were no significant associations of ln hs-CRP with risk of THR or TKR, after adjusting for age, body mass index, lifestyle characteristics, chronic diseases, hormone therapy use, and non-steroidal anti-inflammatory drug use. CRP GRS were not associated with risk of THR or TKR in any ethnic group. CONCLUSIONS: Serum levels of ln hs-CRP and genetically-predicted CRP levels were not associated with risk of THR or TKR for OA among a diverse cohort of women.

Methicillin-resistant Staphylococcus aureus (MRSA) infections among HIV-infected persons in the era of highly active antiretroviral therapy: a review of the literature.

OBJECTIVES: Despite the rise of methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections (SSTIs) among HIV-infected persons during the era of highly active antiretroviral therapy (HAART), the precise relationship between these two infections has not been fully elucidated. Therefore, we provide a comprehensive, literature-based review of MRSA infections among HIV-infected persons. METHODS: A systematic search of MEDLINE using the search terms "HIV" and "MRSA" identified references published during the HAART era (January 1996 to January 2011). Relevant articles on MRSA in the general population were also reviewed for comparison. RESULTS: The most common type of MRSA infection among HIV-infected persons is SSTI caused by USA300, Panton-Valentine leukocidin (PVL)-positive strains. HIV-infected persons have an increased risk for both initial MRSA infections and recurrent infections compared with the general population. Risk factors for MRSA infections in this population include immunosuppression, comorbid conditions and certain lifestyle behaviours such as high-risk sexual behaviours and illicit drug use. Further research is needed on the optimal treatment and prevention strategies for MRSA infections among HIV-infected persons. CONCLUSIONS: HIV-infected persons have a propensity for MRSA SSTI and a high rate of recurrent disease. The reasons for the elevated rates of MRSA infections among HIV-infected persons appear to be multifactorial, but may be mitigated with optimized HIV control and reductions in associated risk factors.