Purpose To examine the longitudinal associations between body composition and incident vertebral deformities (VDs) over 10.7 years in community dwelling adults aged 50-80 years.
Methods Participants (n=780, 50% female) underwent whole-body dual-energy X-ray absorptiometry (DXA) scans at baseline, 2.5, 5.1 and 10.7 years later which were used to obtain body composition measures and lateral vertebral scans. VD was defined using 2 criteria: ≥20% (mild), and ≥25% (moderate) reductions in vertebral height (anterior vs posterior height) from T4-L4. Incident VD was defined as new VD at any follow-up visit. Change in body composition measures was defined as the difference between the latest available data point and baseline.
Results New vertebral deformities were common over 10.7 years (53% mild VD, 37% moderate VD). Neither total fat mass or lean mass at baseline predicted incident deformities but increase in total fat mass reduced risk and increased lean mass percentage increased risk of mild and moderate VDs in both sexes. >10% increase in lean mas percentage increased risk of both mild and moderate VD in both sexes [(Males: IRR 1.96, 95%CI 1.26-3.04 for mild vs IRR 3.05, 95%CI 1.63-5.70 for moderate VD) ;(Females: IRR 1.59,95%CI 1.12-2.25 for mild vs IRR 2.91,95%CI 1.87-4.51 for moderate VD). Among women, change in fat percentage showed U shaped associations with incidence of both mild and moderate VD (p=0.017 and p<0.001, respectively). Change in lean percentage also showed non-linear association with moderate incident VDs (p=0.015).
Conclusions Baseline body mass did not predict incident vertebral deformities but change in mass did. While increasing lean mass percentage is associated with higher risk of incident VD, increasing total fat mass may be protective. Among women, associations between increased fat percentage and lean percentage, and incident VDs are non-linear in nature and may have a U-shape relationship.