Context: IL-1, IL-6, and TNF-α play an important role in the pathogenesis of osteoporosis in animals; however, evidence that these play a similar role in bone loss in human studies is limited. Objective: Our objective was to determine the associations between serum markers of inflammation and changes in bone mineral density (BMD) and urinary pyridinoline (PYR) to creatinine (Cr) ratio over 2.9 yr in older adults. Methods: A total of 168 randomly selected subjects (mean 63 yr, range 52–78, 48% female) was studied. BMD was measured by dual-energy x-ray absorptiometry at baseline (mean T score: −0.18 to −0.61) and 2.9 yr later. Serum high-sensitivity (hs) C-reactive protein (CRP), IL-6, TNF-α, and the urinary PYR/Cr ratio were measured on both occasions. Results: The mean annual loss of BMD was 0.15, 0.15, and 0.34% at total body, spine, and hip, respectively. Change in total body BMD was associated with baseline hs-CRP, IL-6, and TNF-α, as well as change in hs-CRP (β: −0.41%/U, 95% confidence interval −0.68%, −0.15%) and IL-6 (β: −0.62%/U, 95% confidence interval −1.01%, −0.23%). If these markers were put in the same predictive model, only IL-6 remained largely unchanged. Changes in other BMD sites were significantly predicted by IL-6 (hip and spine) and TNF-α (spine only). Finally, change in the PYR/Cr ratio was positively associated baseline IL-6, hs-CRP, and their changes (all P < 0.05) in women, but not men. Conclusions: Variation within the low levels of inflammatory markers observed in this study, especially IL-6, predicts bone loss and resorption, suggesting that targeted antiinflammatory therapy has potential for the prevention of osteoporosis.

Background There is emerging evidence that the development and progression of osteoarthritis (OA) is associated with inflammation. C reactive protein (CRP), a systemic marker for inflammation, may be elevated in OA patients but the evidence is conflicting. Objective To systematically review the literature for the relationship between serum CRP levels measured by a high sensitivity method (high sensitive CRP (hs-CRP)) and OA, as well as the correlation between circulating CRP levels and OA phenotypes. Methods MEDLINE, EMBASE and CINAHL databases were systematically searched from January 1992 to December 2012. Studies were included when they met the inclusion criteria and data from studies were extracted. Two independent reviewers assessed study quality using a modified Newcastle-Ottawa Quality Assessment Scale. Meta-analyses were performed to pool available data from included studies. Results 32 studies met the inclusion criteria. Serum hs-CRP levels in OA were modestly but statistically significantly higher than controls (mean difference=1.19 mg/L, 95% CI 0.64 to 1.73, p<0.001) with significant heterogeneity between studies. Levels were significantly associated with pain (r=0.14, 95% CI 0.09 to 0.20, p<0.001) and decreased physical function (r=0.25, 95% CI 0.13 to 0.39, p<0.001). No significant associations were found between hs-CRP levels and radiographic OA. Conclusions Low-grade systemic inflammation may play a greater role in symptoms rather than radiographic changes in OA.