Weight change, variability, and trajectories and risk of hip fracture among older adults with Dysglycemia: the cardiovascular health study.

Background: Type 2 diabetes mellitus and lower weight are both associated with osteoporotic fractures, but the roles of variability and trajectory are less clear.1 The associations of these factors among older adults with dysglycemia, who are at highest risk of fracture, with fracture risk and bone mineral density (BMD) remains uncertain.

Methods: We followed 775 men and 1080 women from the Cardiovascular Health Study (mean age 77.4 years) with abnormal oral glucose tolerance testing in 1989-1990. We measured their weights yearly through 1994-1995 and derived intra-individual mean weight, weight slope, and weight variability. We also used growth mixture modelling to derive four latent body-mass index trajectories over time. We used Cox proportional hazards models to calculate hazard ratios (HR) and 95% confidence intervals (CI) for subsequent hip fracture through 2015 and linear regression models to estimate cross-sectional associations with bone mineral density (BMD) of the hip.

Results: Each 10 kg higher mean weight was associated with a lower risk of subsequent hip fracture overall (HR 0.81; CI 0.70-0.94) and among women (HR 0.76; CI 0.64-0.91) and with higher BMD (P-value <0.001). Higher weight variability was directly associated with incident hip fracture among women (HR 1.18; CI: 1.03-1.35). Compared with a stable trajectory, a "progressive overweight" trajectory was associated with lower risk of hip fracture (HR 0.66; CI: 0.44-0.99). An uncommon trajectory of "accelerating obesity" was associated with higher BMD.

Conclusions: Among older adults with dysglycemia at high risk for fracture, lower mean weight is associated with higher fracture risk, but variability and trajectory may also contribute. These results highlight the complex effects of weight in older age.