The report, released Friday, revealed that this rise in deaths is attributable to injury-related deaths, such as traffic accident fatalities, drug overdoses, homicides and suicides, as opposed to illness, such as cancer or heart disease.
"When I first conceded to do this report 2½ years ago, I thought that we would be documenting a decline," said Sally Curtin, a statistician at the CDC in Washington and lead author of the report.
"We were surprised that there was such a broad increase across so many causes of death," she said. "There wasn't just one that was contributing."
In general, the leading causes of death among adolescents
ages 15 to 19 in the United States are unintentional injuries such as car crash-related injuries, followed by suicide and homicide, according to the CDC.
Among 10- to 19-year-olds around the world, road traffic injuries were the leading cause of death in 2015, followed by lower respiratory infections and suicide, according to the World Health Organization
Car crashes, drug overdoses and gun deaths
The new report was based on data from death certificates filed in all 50 states and the District of Columbia between 1999 and 2016. Death certificates are generally completed by funeral directors, attending physicians, medical examiners and coroners.
Those data, from the National Vital Statistics System
, were collected and processed through the Vital Statistics Cooperative Program. Researchers analyzed the data, taking a close look at the age of the person who died and the reported cause of death.
The data showed that unintentional injuries or accidents were the leading cause of injury-related deaths among 10- to 19-year-olds in 2016, followed by suicide and then homicide.
The rate of accidental deaths for 10- to 19-year-olds declined 49% between 1999 and 2013, dropping from 20.6 deaths per 100,000 people to 10.6 per 100,000. Then, the rate rose 13% between 2013 and 2016, increasing to 12 per 100,000.
Motor vehicle traffic fatalities accounted for 62% of these unintentional injury deaths, followed by poisoning at 16% and drowning at 7%. Those three methods of accidental deaths accounted for 85% of all unintentional injury-related deaths in 2016.
"The poisoning deaths do include drug overdoses: Ninety percent of poisoning deaths are drug overdoses, and most of them are in older adolescents," Curtin said.
The data showed that suicide rates among 10- to 19-year-olds declined by 15% between 1999 and 2007, dropping from 4.6 per 100,000 to 3.9 per 100,000. Then the rate increased by 56%, going up to 6.1 in 2016. The three leading methods of suicide that year were suffocation, firearms and poisoning.
As for homicides, the data showed a brief period of decline in rates between 1999 and 2001, followed by an increase between 2001 and 2007. Homicide rates dropped 35% between 2007 and 2014, from 5.7 per 100,000 to 3.7 per 100,000, and then rose 27% to 4.7 per 100,000 in 2016. Among the leading methods of homicide were firearms and cutting or piercing.
Firearms, in general, accounted for 87% of all homicides and 43% of all suicides.
These findings have some limitations, including that there is variation by state or geographic area in how medical examiners classify deaths and are required to rule a death a suicide. Suicide tends to be under-reported, especially when it involves drug overdoses.
"Accurate recording of the circumstances surrounding the death as well as classifying the death obviously would be a limitation, and especially within the context of a drug overdose," Curtin said. "Oftentimes, it's hard to tell, unless there's a suicide note, whether it was a suicide or unintentional."
'This is a wake-up call that we need to pay attention'
Dr. Thomas Weiser, a trauma surgeon at Stanford University Medical Center
who was not involved in the new report, called the findings "very concerning."
"This should not be happening and bucks the trend that we as a country have experienced in the past several decades. We should be worried about this," said Weiser, who's also an associate professor of surgery at Stanford University School of Medicine.
"Our children are our country's future, and we as a society need to recognize when they are in trouble. This disturbing trend should be a wake-up call that mental health services, injury prevention, gun safety and ongoing efforts to improve car and driver safety need support, attention, and financial resources," he said. "Our investments now as a society will be paid back handsomely when our children grow up to be healthy, productive adults."
His concerns were echoed by Dr. Tina Cheng, director of the Department of Pediatrics at Johns Hopkins Medicine
who was not involved in the new report.
"As a pediatrician and health care leader, the findings are consistent with what we are seeing: greater numbers of children coming to our clinics and emergency departments with mental health problems including depression, suicide and aggression, full beds on our mental health ward and lack of inpatient and outpatient services for children in dire need of treatment," said Cheng, who's also a professor at Johns Hopkins University School of Medicine and Johns Hopkins Bloomberg School of Public Health.
Yet "this is a wake-up call that we need to pay attention to the health and well-being of our children," she added. "It is hard to know the precise reason for the upturn in unintentional, intentional and self-inflicted injuries. Some have suggested that social media and cyberbullying may be contributing. Others have pointed to growing income inequality."
In 2016, 19% of children under 18 in the United States -- about one in five -- lived in families with incomes below the federal poverty threshold, which at the time was $24,339 for a family of four with two children, $19,318 for a family of three with one child and $16,543 for