Food Supply - Poor food supply causes malnutrition and fertility drops. Where agriculture is not well established the food supply can be uncertain.
Sewage Disposal & Drinking Water are linked therefore waterborne disease affects death rate (cholera is a bacterial disease and a common waterborne disease).
- Urbanisation without sanitation lowers life expectancy.
- Vaccination increases life expectancy.
- Prosperity increases life expectancy (better nutrition and healthcare).
- Increased levels of sanitation increases life expectancy.