The effect on subsequent fracture risk of age, sex, and prior fracture site by recency of prior fracture.

The risk of a recurrent fragility fracture varies by age and sex, as by site and recency of sentinel fracture. The recency of prior fractures affects subsequent fracture risk. Variable recency may obscure other factors that affect subsequent fracture risk. The aim of this study was to quantify the effect of a sentinel fracture by site, age, and sex where the recency was held constant. The study used data from the Reykjavik Study fracture register that documented prospectively all fractures at all skeletal sites in a large sample of the population of Iceland. Fracture incidence was compared to that of the general population determined at fixed times after a sentinel fracture (humeral, clinical vertebral, forearm, hip, and minor fractures). Outcome fractures comprised a major osteoporotic fracture and hip fracture. Sentinel osteoporotic fractures were identified in 9504 men and women. Of these, 3616 individuals sustained a major osteoporotic fracture as the first subsequent fracture, of whom 1799 sustained a hip fracture. Hazard ratios for prior fracture were consistently higher in men than in women and decreased progressively with age. Hazard ratios varied according to the site of sentinel fracture with higher ratios for hip and vertebral fracture than for humerus, forearm, or minor osteoporotic fracture. The risk of a recurrent fragility fracture varies by age, sex, and site of sentinel fracture when recency is held constant.