People who live a harder life usually have a shorter life expectancy. For instants, where I live, Canada its 80+ years. most people dont work until they are 15 and retire at 65. Where in africa its 50+ they work as soon as they can walk, never retire and have a harder way of life. Money matters, and also the economy.
Life expectancy is a good indicator of the quality of life, because life is all about quality sanitation, nutrition, medicine, as well as medical technology. If all these are not up to standard, then life expectancy will be affected.