Relationships between markers of inflammation and bone density: findings from the Hertfordshire Cohort Study.

Among 365 Hertfordshire Cohort Study participants (aged 59-71 years at baseline), higher adiponectin and adiponectin to leptin ratios were associated with lower baseline lumbar spine and femoral neck bone mineral density (BMD). Lower IL-10 was associated with accelerated decline in lumbar spine BMD. This suggests that bone health can be influenced by changes in immune phenotype and alterations in adipokine homeostasis.

INTRODUCTION: The aim of this study was to examine the association between indices of inflammation and BMD in a population-based cohort of older adults in the UK.

METHODS: Analyses were based on a sample of 194 men and 171 women of the Hertfordshire Cohort Study (community-living, older adults). Dual energy X-ray absorptiometry (DXA) was performed at the lumbar spine and proximal femur at baseline and repeated at a median of 4.5 years (inter-quartile range 3.6 to 5.2). Inflammatory markers (CRP, TNF, IL-1β, IL-6, IL-8, IL-10, adiponectin and leptin) were ascertained at baseline using enzyme-linked immunosorbent assay (ELISA) techniques and Bio-Plex Pro Assays. Gender-adjusted linear regression was used to examine the associations between markers of inflammation and outcomes with and without adjustment for anthropometric and lifestyle factors.

RESULTS: The mean (SD) ages at baseline were 64.4 (2.5) and 66.5 (2.7) years for men and women respectively. Higher levels of adiponectin and adiponectin to leptin ratios were each associated with lower baseline lumbar spine and femoral neck BMD in gender-adjusted (p < 0.01) and fully adjusted (p < 0.05) analyses. Lower levels of IL-10 and TNF were each associated with accelerated decline in lumbar spine BMD in both gender-adjusted (p ≤ 0.05) and fully adjusted (p < 0.05) analyses.

CONCLUSIONS: In a cohort of older adults, high levels of adiponectin and adiponectin to leptin ratios were both associated with lower BMD at the lumbar spine and femoral neck at baseline, and lower IL-10 was associated with accelerated decline in BMD at the lumbar spine. This adds weight to the theory that bone health can be influenced by changes in immune phenotype and alterations in adipokine homeostasis.