Association of white matter hyperintensities with BMD, incident fractures, and falls in the UK Biobank cohort

Abstract

Osteoporosis is the most common metabolic bone disease in the world, which increases the healthcare service burden. Recent studies have linked higher white matter hyperintensities (WMH) to reduced bone mineral density (BMD), increasing the risk of fractures and falls in older adults. However, limited evidence exists regarding the dose–response relationship between WMH and bone health in a larger and younger population. Our study aimed to examine the association of WMH volume with BMD, incident fractures and falls, with a particular focus on dose–response relationship with varying levels of WMH volume. We included 26 410 participants from the UK Biobank. The association between WMH volume and BMD was analyzed using multiple linear regression. Cox regression models were used to estimate the hazard ratios of incident fractures and falls. Restricted cubic spline (RCS) fitted for linear and Cox regression models were employed to explore potential non-linearity. Over a mean follow-up time of 3.8 years, we documented 59 hip fractures, 392 all fractures, and 375 fall incidents. When applying RCS, L-shaped relationships were identified between WMH volume and BMD across all 4 sites. Compared with those in the lowest fifth of WMH volume, the second to the highest fifths were associated with a reduction of 0.0102-0.0305 g/cm2 in femur neck BMD, 0.0075-0.0273 g/cm2 in femur troch BMD, 0.0173-0.0345 g/cm2 in lumbar spine BMD, and 0.0141-0.0339 g/cm2 in total body BMD. The association was more pronounced among women and younger participants under age 65 (Pinteraction < 0.05). Per 1 standard deviation increment of WMH volume was associated with 36.9%, 20.1%, and 14.3% higher risks of incident hip fractures, all fractures, and falls. Genetically determined WMH or APOE genotypes did not modify these associations. We demonstrated that a greater WMH was associated with BMD in a L-shaped dose–response manner, especially in women and those under 65 years.