European journal of epidemiology
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The frailty index (FI), defined by a deficit accumulation approach, has emerged as a promising concept in gerontological research, but applications have been mostly restricted to populations from Canada and the United States aged 65 years or older. Baseline data from the German ESTHER cohort study (N 9,886; age 50-75; mean follow-up 8.7 years) were used to create a FI through a deficit accumulation approach. For estimation of frailty prevalence, we used cut-points for the FI to define three categories (non-frail 0 to ≤0.20; pre-frail >0.20 to <0.45; frail ≥0.45). ⋯ Adjusted hazard ratios (95% confidence intervals) for all-cause mortality were 1.08 (0.84-1.39), 1.32 (1.05-1.66), 1.77 (1.41-2.22), and 2.60 (2.11-3.20) for the 2nd, 3rd, 4th, and 5th quintile of the FI compared to 1st quintile, respectively. There was a strong dose-response relationship between the FI and total mortality among both men and women and both younger (<65 years) and older subjects. We found sex differences in the FI and its increase with age, along with a consistent strong association of the FI with mortality in both sexes, even for age group 50-64.