From their conclusions, I wonder if there is some kind of "use-it-or-lose-it" effect going on in the sample of older physicians, which does not affect the sampl

From their conclusions, I wonder if there is some kind of "use-it-or-lose-it" effect going on in the sample of older physicians, which does not affect the sample of younger physicians as severely due to their age. That is, the high volume physicians are kept sharp by the high patient workload regardless of age. Authors' conclusions reproduced below: "Within the same hospital, patients treated by older physicians had higher mortality than patients cared for by younger physicians, except those physicians treating high volumes of patients."