Metabolic syndrome and mortality in the elderly: A time-dependent association

Abstract Aims To evaluate the association between metabolic syndrome (MetS) components and mortality over time. Methods 3086 residents aged ≥49 years were followed in the Blue Mountains Eye Study, Australia. MetS components as defined by the International Diabetes Federation criteria were measured at baseline (1992–1994), 5-year (1997–1999) and 10-year (2002–2004). Using Cox proportional hazards and competing risks models with MetS as a time-dependent covariate, we estimated the effects of MetS on all-cause and cause-specific mortality. Time-dependent receiver-operating-characteristic curve, integrated-discrimination-improvement and net-reclassification-improvement tests assessed predicting abilities of individual and combined MetS components. Results Effect of MetS on mortality increased with time: all cause: 2-year: adjusted hazard ratio 0.96 [95% confidence interval 0.69–1.34]; 5-year: 1.06 [0.84–1.32]; 10-year: 1.23 [1.01–1.51]; and CHD: 2-year: 0.46 [0.20–1.03]; 5-year: 0.70 [0.41–1.21]; 10-year: 1.62 [1.02–2.59]. Conversely, MetS was associated with an increased risk of cancer death at 2-year only: 1.62 [1.01–2.62]; but not 5-year: 1.30 [0.94–1.81] or 10-year: 0.90 [0.57–1.44]. The discrimination analyses showed that different MetS components were associated with different causes of death. Conclusions The long-term effect of MetS on all-cause and CHD mortality in an older population was detected using time-dependent models while simulating the real scenarios of MetS changes over time.