Both the United States, a big country of 318 million, and the Netherlands, a smaller one of 17 million, spend a lot more on health care than the average rich country. But all that money has a highly unequal impact. The Dutch spend less than Americans per person, yet their children are some of the healthiest in the developed world, according to UNICEF. American children are some of the least.

This chart, which appears in a new study from the journal Health Affairs, may help explain why. Drawn from large national surveys in both countries, these statistics show that Dutch children get a lot more routine and preventive care. They visit or call the doctor about twice as often as American children. Ditto the dentist.

But what’s most interesting is how the countries deal with inequality differently. In the United States, access to primary care seems to be a matter of who can afford it. Poor children are much less likely than rich children to see a doctor or a dentist for outpatient treatment or checkups.

But in the Netherlands, it’s the opposite. The poorest children have more doctor’s visits and just as many visits to the dentist. (This excludes trips to the hospital or emergency room.)

Getting to the doctor early in life is important, says lead author Dougal Hargreaves, a pediatrician and associate professor at University College London. “We know health care in childhood and adolescence can have an especially big impact, both at the time, and on health outcomes later in life,” he says.

Consistent childhood checkups head off serious problems and set up good habits for adulthood. Yet, as the researchers note, the Centers for Disease Control and Prevention have warned that millions of U.S. children are not getting important preventive care, such as blood pressure checks and screenings for vision or developmental problems.

Hargreaves and his colleagues, Jeroen Struijs, a researcher with the Dutch Ministry of Health, and Mark Schuster, chief of general pediatrics at Boston Children’s Hospital, could not infer from the data why the children were contacting the doctor or the dentist. But from the broad patterns they could see that the United States and the Netherlands are mirror opposites.

“This study reminds us that we need to continue to look for ways to improve children’s access to health care and to assure that the care they receive is high quality,” Schuster said in an email.

Among children younger than 10 in the United States, the poorest 20 percent visit or call the doctor about twice a year. The richest 20 percent visit or call three times a year, a difference of 50 percent.

In the Netherlands, the poorer the child, the more likely they will get frequent outpatient care. Among children younger than 10, the poorest 20 percent contact the doctor about five times a year, compared to 3.7 times a year for the richest 20 percent.

In the United States, there’s also a relationship between income and visits to the dentist. The richest adolescents go to the dentist nearly twice a year, while the poorest barely go once a year. In the Netherlands, all kids go to the dentist at least twice a year on average.

The children with the most health problems, of course, are the poor, not the rich. As this chart illustrates, poor kids in both the United States and the Netherlands are more likely to say (or have their parents say) that they are not in good health. Poor kids in both countries also more regularly end up in the hospital.

“The aim of health care should be meeting the needs of every child, no matter their background,” Hargreaves says. “And these data really show that children from lower income households, on average, tend to have greater needs.”

Yet, only in the Netherlands are poorer kids getting more routine care, more non-emergency interactions with doctors. The question is how these differences in access contribute to the Dutch advantage in children's health.

In fairness, the gap might better be described as the American disadvantage. From birth to old age, Americans are sicker and die earlier than people from most other wealthy countries. “The health disadvantage is pervasive,” warned a 2013 report from the National Research Council. “It affects all age groups up to age 75 and is observed for multiple diseases, biological and behavioral risk factors, and injuries.”

The report names two major causes for the health disparities. First, Americans just seem to lead riskier lives overall. They are at higher risk for obesity, heart disease and STDs, and are more likely to die by gun violence or in car crashes.

Then, inequality exacerbates these problems. Despite the rollout of the Affordable Care Act, the United States still has higher levels of poverty and uninsurance than many of its peers. About 10 percent of Americans are uninsured, compared to less than one percent in the Netherlands. So even though the U.S. health-care system spends a lot more money on people, a lot of people are out of the system.

The comparison between the United States and the Netherlands is interesting, Hargreaves adds, because there are many similarities between their health-care systems. The Netherlands requires citizens to buy private health insurance on competitive but highly regulated exchanges, and provides subsidies to those with lower incomes. This setup resembles what the ACA looks like for people in the United States who don’t have health insurance through their employers.

The major difference is that the Dutch system, although it too is market-based, places a much bigger emphasis on health-care access and primary care.

Expanding access to routine care was also one way the ACA was supposed to bring down health-care costs. It’s easier to fix a problem if you catch it early, or so the logic goes. So far, it’s not clear whether this argument proves true for adults. But it may make more sense for children, who have much longer lives ahead of them. There are many conditions in youth that benefit from timely medical attention. The ACA lists 26 preventive measures, from autism screening to obesity counseling, that insurance companies must make free to encourage people to come in.

Another lesson from the Netherlands is that it’s not enough to force people to get insurance. They have to use it. The Dutch, overall, rich or poor, are much more likely than Americans to take their children to the doctor’s office.

This may be a cultural thing. But the Dutch also have a more robust and family-friendly primary care system, the researchers note. Doctors are more available outside work hours, in part because they get paid a bonus. Physicians also get paid more for taking on patients from low-income neighborhoods. This means it's easier for parents to bring their children in for routine care, without having to wait too long or take a day off.

The Dutch are an example of what happens when a nation makes equal access to health care a national goal. There's less inequality. Poor kids get to see a doctor more.

"Fundamentally, these are choices that we as a society make," Hargreaves says. "And we, as a society, can change these things."