Complex sentence: In fact, the United Nations predicted an increase of those aged 60 and above from 629 million in 2002 to approximately two billion in 2050 but increased life expectancy does not necessarily translate to a better quality of life.
Split into simpler sentences: In fact, the United Nations predicted an increase of those aged 60 and above from 629 million in 2002 to approximately two billion in 2050. With that being said, increased life expectancy does not necessarily translate to a better quality of life.