Tropical countries tend to have poorer health conditions than countries in temperate climate zones. Diseases such as malaria, hookworm, river blindness, and yellow fever are hard to control in tropical regions because the lack of seasons makes the reproduction of mosquitoes and other disease transmitters almost constant throughout the year. Many companies do not consider tropical countries profitable because of this threat of widespread disease. Also, when considering income levels and female education, life expectancy in tropical regions is seven years lower than in temperate zones. These factors make these countries unattractive to foreign investment. If a company cannot rely on a dependable, healthy workforce that is educated and has the basic amenities they need, they will not be sure that production will be timely or that their product will be of the quality they desire. As a result, tropical nations tend to have a much lower rate of economic growth. Nations in tropical areas often have income distributions that are extremely uneven. In Africa and Latin America, for example, the richest 5 percent of the population earn almost 25 percent of the national income, while in industrial countries they earn only 13 percent (World Politics, pg.42). Even some regions in the same country show an inequality in income that is geographically linked. For example, in Mexico, the southern states of Chiapas, Oaxaca, and Guerrero have twice the infant mortality rate and only half of the educational opportunities as the country's northern states (World Politics, pg.42). .
Nations that are located far from a coastline are also usually poorer and have lower rates of economic growth than coastal countries. It has been reported that a country whose population is farther than 100 kilometers from the sea grows 0.6 percent slower per year than nations where the majority of the population lives within 100 kilometers of the coast (World Politics, pg.