Systemic bone mineral density and its change in relation to progression of knee osteoarthritis: a longitudinal study.
Lee, Ji Yeon.
Background: Bone and cartilage are closely associated in Osteoarthritis (OA)
pathophysiology. Increased bone mineral density (BMD) has been observed to be associated
with OA in cross-sectional studies but data on the longitudinal relationship between BMD
and knee OA progression are few and inconsistent. Methods:We used observational cohort
data from the Vitamin D for Knee Osteoarthr... read moreitis trial to examine the relationship of
BMD, and change in BMD, to progression of knee OA, as measured by cartilage outcomes. We
obtained bilateral femoral neck BMDs as well as knee MRIs in each subject at baseline
and subsequently at 12 and 24 months. We measured change in total cartilage volume,
tibial and femoral cartilage thickness by manual cartilage segmentation of two
sequential knee MRIs in each subject. We computed the associations of baseline BMD and
BMD change with the cartilage outcomes, adjusting for baseline age, gender, BMI,
malalignment and vitamin D treatment using multivariable linear regression models. We
validated model fit and assumptions using diagnostic plots. Results:127 subjects were
included in the analyses. There were no significant associations between baseline BMD
and any of the cartilage outcomes. However, longitudinal BMD loss of 0.1 g/cm² was
associated with cartilage volume loss (β=1.25, p=0.02) and tibial cartilage
thickness loss per year (β=0.028, p=0.03). BMD loss of a magnitude greater than
least significant change was associated with average of 1.02% cartilage volume loss
(p=0.005), 0.014mm of femoral cartilage thickness loss (p=0.04) as well as 0.021mm of
tibial cartilage thickness loss per year (p=0.009), compared with those without BMD
change. Conclusions: Longitudinal BMD loss could be associated with progression of
cartilage loss in knee OA. This could be explained by direct biological interaction
between the structures on a biomechanical or autocrine basis, or these could be
concurrent manifestations of a more systemic process relating to aging. Further work to
clarify the basis of this relationship would be informative and potentially lead to
novel therapeutic interventions for knee OA
Thesis (M.S.)--Tufts University, 2012.
Submitted to the Dept. of Clinical & Translational Science.
Advisor: Timothy McAlindon.
Committee: William Harvey, Lori Lyn Price, and Jessica Paulus.
Keywords: Health sciences, and Epidemiology.read less