Ho Minh Duy

1. Introduction According to the World Health Organization’s forecast, the 21st century is an era of population aging; by 2050, approximately two billion of the world’s population will be over 60 years of age, up from 900 million in 2015. Of these people, 80% will be living in developing countries [1]. In Vietnam, over 11 million people are aged 60 and above, accounting for 11.8% of the country’s population. It is projected that by 2050, this number will increase to 29 million [2].