Association between inflammatory biomarkers and bone mineral density in a community-based cohort of men and women.

OBJECTIVE: Based upon evidence in animal and in vitro studies, we tested the hypothesis that higher serum concentrations of the cytokines interleukin-6 (IL-6) and tumor necrosis factor α (TNFα) and the inflammatory marker C-reactive protein (CRP) would be inversely associated with bone mineral density (BMD) in a community-based cohort of men and women, with the strongest associations among postmenopausal women not receiving menopause hormonal therapy (MHT). METHODS: We ascertained fasting serum concentrations of IL-6, TNFα, and CRP and measured BMD at the femoral neck, trochanter, total femur, and spine (L2-L4) using dual x-ray absorptiometry in 2,915 members of the Framingham Offspring Study (1996-2001). We used multivariable linear regression to estimate the difference (ß) in BMD at each bone site associated with a 1-unit increase in log-transformed serum concentrations of IL-6, TNFα, and CRP separately for men (n = 1,293), premenopausal women (n = 231), postmenopausal women receiving MHT (n = 498), and postmenopausal women not receiving MHT (n = 893). RESULTS: Inflammatory biomarkers were not associated with BMD in men. Among premenopausal women, there were statistically significant, modest inverse associations between IL-6 and trochanter BMD (ß = -0.030, P < 0.01) and between CRP and femoral neck (ß = -0.015, P = 0.05) and trochanter BMD (ß = -0.014, P = 0.04). TNFα was positively associated with spine BMD (ß = 0.043, P = 0.01). In postmenopausal women receiving MHT, CRP was positively associated with femoral neck BMD (ß = 0.011, P = 0.04). There were no associations among postmenopausal women not receiving MHT. CONCLUSION: The lack of consistency in our results suggests that elevated circulating concentrations of inflammatory biomarkers may not be a risk factor for low BMD.

No association between markers of inflammation and osteoarthritis of the hands and knees.

OBJECTIVE: Local inflammation plays a prominent role in osteoarthritis (OA). This could be reflected in the presence of elevated soluble inflammatory markers. We conducted analyses to assess the association of inflammatory markers with radiographic OA of the hands and knees in a large community-based cohort. METHODS: The Framingham Offspring cohort consists of the adult children of the original cohort and their spouses. In 1998-2001 these subjects provided blood specimens that were tested for 17 markers of systemic inflammation. In 2002-2005 these subjects had radiographs of both knees and hands. Each hand and knee joint was assigned a Kellgren and Lawrence (KL) score (0-4). We used logistic regression with generalized estimating equations and adjustment for age, sex, and body mass index to examine the association between each inflammatory marker and the presence of radiographic OA (ROA = KL grade ≥ 2) in any joint. We also constructed models for hand joints and knee joints alone. RESULTS: Radiographs and measures of inflammation were done for 1235 subjects (56% women, mean age 65 yrs). Of that group, 729 subjects (59%) had ROA in ≥ 1 hand or knee joint: 179 (14.3%) had knee OA, and 694 (56.2%) had hand OA. There were no significant associations between any marker of inflammation and ROA. CONCLUSION: In this large sample, in which OA was carefully assessed and multiple markers measured, we found no evidence of an association between any inflammatory marker and the presence of radiographic OA.