Introduction: Due to the greying of (industrialized) societies the incidence of osteoporosis and fragility fractures is expected to be increasing. Our aim was to investigate in an elderly population if the incidence of non-vertebral fractures (overall and site specific) has changed after a longer follow-up, and its relation with osteoporosis or osteopenia assessed by bone mineral density (BMD) at baseline.
Methods: Incident non-vertebral fractures were assessed in 14 619 men and women, age ≥45, participants of a prospective cohort study, during a median follow-up of 11.7 (S.D.±6.2) years (median follow-up: round-1=14.5, round-2=12.0, round-3=5.6 years). Baseline femoral neck BMD was measured and gender specific T-scores (NHANES) were calculated. Age adjusted hazard ratios (HR) per SD decrease in BMD were estimated from Cox regression models.
Results: In total, 3981 fractures were observed of which hip (21.3%), wrist (19.3%) and proximal humerus (9.1%) fractures were the most frequent in men and women. Incidence rates per 1000 person-years for all fractures were 21.4 and 5.4, 5.0 and 2.3 for hip, wrist and humerus, respectively. While all- and site-specific fracture incidence was higher in women (and all increased exponentially with age) the HR per SD decrease in BMD was 1.5 (95% CI 1.41.6) in women and 1.4 (95% CI 1.31.5) in men for all-type of fractures and 2.5 (95% CI 2.03.0) in men and 2.1 (95% CI 1.92.4) in women for hip fractures. The majority (85%) of non-vertebral fractures occurred above the osteoporosis threshold (T-score<−2.5). As compared to individuals with normal BMD levels, individuals with osteoporosis had two-fold higher incidence rate and two- to three-fold higher fracture risk.
Conclusion: After longer follow-up the incidence of fracture seems to remain unchanged with a large fraction of the population fracturing above the BMD threshold of osteoporosis. Combining additional fracture risk assessment tools with BMD remains a need in order to facilitate the implementation of preventative strategies that can decrease fracture incidence.
14 May 2016 - 17 May 2016