Data compiled for the report, which was released Monday, showed that death rates due to coronary heart disease fell 37% over that decade. Death rates due to stroke fell 35%.
One ailment that bucked the trend was Alzheimer's disease, which saw death rates double, a sign of the aging population as well as increased awareness of the condition, the report noted.
"We're making great progress against several leading causes of death in the county," said public health director Dr. Jonathan Fielding, in a statement.
But "as the baby boomer generation ages," he added, "the burden of Alzheimer's disease is expected to increase significantly."
In 2010, 56,538 people died in Los Angeles County. Cancer caused 13,860 of those deaths, with lung cancer killing more people -- 2,941 -- than any other form of the disease. Coronary heart disease caused 12,635 deaths. Accidents were the biggest killer of people ages 1 to 44, with 739 deaths in 2010; among those 15 to 24, homicide was the leading cause of death. Firearms caused 796 deaths.