Numerous factors were responsible for the growth of cities in the late 1800s in the United States, including the growth of factories, the need for jobs and the immigrants. Arriving from around the world. These immigrants helped the population growth of cities. Cities became very filthy. a large amount of food waste could be found on the roads between homes. A very few people used the indoor toilets. Hence, these conditions easily allowed diseases to occur. This even happened several times when cholera broke out and killed thousands of people. Therefore health became one of the major concerned in the large cities.