俱舍論記 9.216

9.216

「以生為緣至廣說如經」者，出老死體。於初生後即立老死。又解：於生支位中建立老死。其老死相，髮白面皺等種種差別，廣說如經。又解：至髮白等已去方名老，後名死。

"Conditioned by birth... as taught at length in the sūtra": this identifies the substance of old age and death. Immediately following the initial birth, old age and death are established. Another explanation: old age and death are established within the stage of the limb of birth. The characteristics of old age and death, such as white hair, wrinkled face, and various other distinctions, are taught at length as in the sūtra. Another explanation: from reaching white hair and so on onward it is called old age, and afterward it is called death.