The growth in health insurance coverage√ is one of the clearest signs of improvements in children's health in the foundation's annual report, which analyzes trends in children's well-being.
It's also the most vulnerable to backsliding, advocates say, as Congress weighs plans to rewrite the Affordable Care Act and cut funding that has fueled an expansion of Medicaid and the Children's Health Insurance Program for poor families.
"We have seen firsthand that success is possible when local and federal policymakers prioritize child well-being," said Shana Bartley, acting executive director of DC Action for Children. "But much of these gains could be lost," she said.
Bartley and other advocates for children are calling on the Trump administration and Congress to preserve health-care funding, as well as funding for other programs that create a safety net for children. President Trump's budget plan includes significant cuts to food stamps, family welfare and earned income tax credits that help many families who live in poverty.
Advocates say the expansion of health insurance has a clear impact on children's well-being. Fewer uninsured children translates into fewer emergency room visits and earlier identification and better treatment of potentially life-threatening diseases such as asthma.
Higher insurance coverage among adults also can benefit children, starting with better prenatal care for pregnant women and fewer preterm births and low-birth-weight babies, according to the advocates.√
In Maryland, the rate of children who are insured grew from 95 percent to 96 percent between 2010 and 2015, and in Virginia, it grew from 93 percent to 95 percent. California saw the biggest gains in coverage for children, increasing from 91 percent to 97 percent in the same five years, according to the report.
Ted Lempert, president of Children Now, a California-based advocacy group, said the progress is due to the state's implementation of the Affordable Care Act and to a 2015 state law that enabled children to receive a wider range of medical services, regardless of immigration status.
The foundation's annual report card analyzes a trove of data each year, including poverty rates, education attainment and family structure, to measure the overall well-being of the nation's children over time. It also ranks states according to how they are doing.
Nationwide, the poverty rate declined from 22 percent to 21 percent between 2010 and 2015, based on the portion of children who live in families with incomes below the federal poverty line. And the unemployment rate dropped from 5.3 percent in 2015 to 4.5 percent this year.
"Eight years after the most devastating recession of our lifetime, we are pleased to see some positive trends in many areas of child well-being," said Patrick McCarthy, president and chief executive of the Annie E. Casey Foundation.
One concerning trend, he noted, is the increase of children living in high-poverty areas, defined as neighborhoods where poverty rates surpass 30 percent and where children have less access to quality schools and other resources.
From 2011 to 2015, 14 percent of children lived in high-poverty areas, compared with 13 percent the previous four-year period. In the District, that rate was 25 percent, down from 31 percent four years earlier.
In the District, the poverty rate for children also declined from 30 percent to 25 percent between 2010 and 2015. Other positive indicators showed that the teen birthrate decreased by 42 percent in the same time, and the portion of children living in families where the head of household had less than a high school diploma decreased from 19 percent to 14 percent.
Locally, analysts say they are still analyzing the report to see where there are signs of improvement in the lives of low-income District residents and where the numbers could be signs of gentrification and more poor people moving out of the city.
"It's important to celebrate progress that has happened," said Adrienne Lloyd, a policy analyst at DC Action for Children. "But there is a lot of unequal prosperity across the District."