Background: We prospectively investigated the association between uric acid (UA), bone mineral density (BMD) at femoral neck (FN-BMD), hip bone geometry (HBG) parameters and incident fracture risk in elderly men and women and if these associations were modified by age and vitamin C intake.
Methods: Data of 5,074 participants of the Rotterdam Study (RS), a prospective population based cohort, were available (mean follow-up 9,9 years). Serum UA was assed at baseline. FN-BMD was measured at baseline and the 2nd, 3rd and 4th visit of the RS, whereas HBG parameters were measured at baseline and the 2nd and 3rd visit. We fitted linear regression models in generalized estimated equations to study UA in relation to FN-BMD and HBG. Cox proportional hazard regression models were used to look at the association of serum UA with fracture risk. All associations were corrected for age, gender, and confounders.
Results: Serum UA levels (per SD increase) were associated with higher FN-BMD (β=0.007, P=0.0002), thicker cortices (β=0.002, P=0.014) and lower bone width (β=-0.013, P=0.008). Also, UA was related to lower cortical buckling ratio (β=-0.19, P=0.005). Hazard Ratios (HRs) per SD increase of baseline UA levels for the development of any type of incident fractures, non-vertebral fractures and osteoporotic fractures were 0.93 (95%CI=0.86-0.995), 0.92 (95%CI=0.86-0.998) and 0.91 (95%CI=0.84-0.977), respectively. All associations were more prominent in older individuals and in participants with high intakes of vitamin C (>median) (interactions with age or vitamin C both P<0.05).
Conclusion: Higher levels of serum UA are associated with higher BMD (at expense of thicker cortices and narrower bone diameters) and could be a protective factor in bone metabolism among men and women. However, interactions with age and vitamin C may be present.
Disclosure: The authors declared no competing interests.