within a country, is the largest factor in mortality rates being higher in low-income countries. preventable mortality these rates are especially pronounced for children under 5 years old, particularly in lower-income, developing countries. these children have a much greater chance of dying of diseases that have become mostly preventable in higher-income parts of the world. more children die of malaria, respiratory infections, diarrhea, perinatal conditions, and measles in developing nations. data shows that after the age of 5 these preventable causes level out between high and low-income countries.