Although the global population continues to increase, the total fertility rate in many high-
income countries (HICs) is below replacement, a trend apparent over several decades. The
timing and pace of this change will shape the age distribution in these countries, leading to
an increasing proportion of older people. The well-established links of the “demographic
transition” between improving female education and improved access to contraception
continue to drive down the fertility rates in low-/middle-income countries. However, changes …