Attitude towards the aged?

I read recently that treatment of the aged varies between cultures to the extent ranging from 'the execution of the aged, through indifference, to extreme care' : Problems of Ageing, 2nd ed., ed. E Cowdry, 1942 : 87. An old text, I know, but it still might be true. Yet I don't know of a past or present culture that executed or executes the aged. Any ideas ?