Now there's another reason to attempt to save more for retirement.

A brief from the Center for Retirement Research at Boston College that posed the question of whether a growing retiree population will exert an effect on investment returns came to the conclusion that the demographic transition would, indeed, create a drag on investment returns—even as those returns become increasingly important to the retiree population.

The question of the impact of a growing retiree population on the growth—or lack thereof—of returns on investments arises out of what the brief credits to economic theory: the suggestion that as retirees draw down their assets, a higher retiree-worker ratio reduces the supply of saving, thereby increasing investment returns.