What is the name given to the phenomenon that, either on a national or individual level, as income increases so does life expectancy?

Life expectancy, also called life expectancy, is the average number of years that a country's population can expect to live, if the same living conditions experienced at birth are maintained. Life expectancy is closely related to the quality of life that a country has, since factors such as education, health, social assistance, basic sanitation, safety at work, violence rates, absence or presence of wars and internal conflicts influence on directly.