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Age, period, and cohort effects on ADL, physical performance, and cognitive function impairment prevalence in the Chinese oldest-old male (a) and female (b) populations. The intrinsic estimator (IE) estimate is the mean change in impairment associated with an age–period–cohort (APC) group relative to the mean of all APC groups combined. Solid lines, IE estimates; gray bands, 95% confidence intervals.
