In 2006, there were nearly 3.5 million hospital discharges among people aged 1‒21 years, equaling 4.0 hospital discharges per 100 children. While injuries are the leading cause of death among this age group, they were not the most common cause of hospitalization. In 2005‒2006, diseases of the respiratory system were the most common cause of hospitalization among children aged 1‒4 and 5‒9 years, accounting for 39 and 24 percent of discharges, respectively. Mental disorders were the most common cause of hospitalization among children aged 10‒14 years (24 percent of discharges), and pregnancy and childbirth was the most common cause of hospitalization for adolescents aged 15‒19 years and young adults aged 20‒21 years (42 and 64 percent of discharges, respectively).
Between 1990 and 2006, hospital discharge rates for children aged 1‒14 years declined by almost 14 percent, which reflects decreases in several of the most common causes of hospitalization. Discharge rates for diseases of the respiratory system declined 26.4 percent, discharges due to injury declined 34.2 percent, and discharges for diseases of the digestive system declined 19.0 percent. The rate of discharges due to endocrine, metabolic, and immunity diseases and disorders, however, increased 36.8 percent. This category of diseases and conditions includes thyroid gland disorders, diabetes, nutritional deficiencies, and overweight and obesity (data not shown).