What was the number one cause of death in 1918?

The number one cause of death in 1918 was the influenza pandemic, often referred to as the Spanish flu. This outbreak infected about one-third of the world's population and resulted in an estimated 50 million deaths globally. It disproportionately affected young adults, a demographic typically less vulnerable to influenza. The pandemic's rapid spread was exacerbated by the conditions of World War I, including troop movements and crowded living conditions.