Metabolic factors and hip fracture risk in a large Austrian cohort study
Erlangga Dominic, Wolfgang Brozek, Raphael S. Peter, Ella Fromm, Hanno Ulmer, Kilian Rapp, Hans Concin, Gabriele Nagel
Abstract
To explore the association of incident hip fractures with metabolic syndrome (MetS) and its single components, we designed a prospective cohort study of hip fracture incidence among 117,053 participants of a population-based health surveillance program in Vorarlberg, the westernmost Austrian province. Incident hip fractures were recorded between 5 and 10 years after inclusion at baseline from 2003 to 2009. Applying Cox proportional hazard models for each MetS component and for a composite z-score for MetS, hazards for fracture were estimated in quintiles, as continuous z-score variables, and as pathological cut off values. Mean age was 50.1 ± 15.6 years at baseline, 5–10 years after which 947 incident hip fractures occurred. An association of a higher composite MetS score with decreased hip fracture risk was observed in women (HR 0.80, 95%-CI 0.88–0.96, p < 0.01) which disappeared upon adjustment for BMI. BMI was inversely associated with hip fracture risk in women and men (HR for the highest compared with the lowest quintile: 0.83 (95%-CI: 0.63–1.10, ptrend < 0.05) and 0.55 (95%-CI: 0.38–0.79, ptrend < 0.001), respectively). Only in women, hip fracture risk was reduced at high cholesterol levels (HR for the highest relative to the lowest quintile: 0.64, 95%-CI: 0.48–0.84, ptrend < 0.05) and in hypercholesterolemic patients (HR 0.82, 95%-CI: 0.67–0.99, p < 0.05), but elevated in hyperglycemic patients (HR 1.33, 95%-CI: 1.05–1.70, p < 0.05). Hypertriglyceridemia was associated with increased male hip fracture risk (HR 1.33, 95%-CI: 1.03–1.72, p < 0.05). The inverse association between the MetS and hip fracture risk is mainly driven by one single component, namely BMI.