By 2020, the population of children is expected to increase only by about 9 percent nationally while the number of pediatricians will jump 58 percent, the study says.
The numbers are subject to change depending on many factors, including unexpected population shifts, new childhood diseases or improved technology, said Dr. Scott Shipman, an Oregon Health & Science University pediatrician who led the study.
But overall, the trends seem clear no matter what adjustments are made to the statistical model, he said.
"It's impossible to predict all the factors that could influence those exact numbers, but that's the general direction that things are going," Shipman said. "Even with extreme changes in the model, that trend didn't go away."
The study, published Monday in the March issue of the journal Pediatrics, is one of the first to use a statistical model to assess outside forces that could affect the size of the physician work force devoted to child health.
The results contradict the predictions of other studies that suggest a shrinking supply of general pediatricians, said Dr. F. Bruder Stapleton, chairman of the pediatrics department at the University of Washington School of Medicine.
"If you look at the number of physicians predicted, based on trends in the economy, we're pretty much where we should be now, and will actually fall behind," said Stapleton, who was not part of the latest study.
There have been three main models for estimating the size of the pediatric work force since the 1980s, and two have predicted a surplus while the third warned of a shortfall, Stapleton said.
The surplus has not appeared and there are shortages of doctors in many areas of the country, he said.
Stapleton noted that the five Western states served by the University of Washington School of Medicine — Washington, Alaska, Idaho, Montana and Wyoming — have 767 pediatricians for 2.4 million children.
New York, by comparison, has 3,027 pediatricians for 4.6 million children — roughly twice as many doctors per child, he said.
Shipman said his study does not take into account the significant regional variation in the pediatrician work force nationally — variation that has produced up to three times as many pediatricians in some areas compared to others.
"The geographic maldistribution is the most alarming issue when it comes to the pediatrician work force," Shipman said.
But overall, the model suggested a surplus, he said.
"It seems the trend of the pediatrician work force is pretty resistant to any changes in demographics," Shipman said.
Shipman joined researchers at Dartmouth Medical School to create a statistical model that looked at several factors that may contribute to the change in the pediatrician work force, including the age and gender of new pediatricians, pediatricians from other countries, changing work styles that range from full-time to part-time, and the death and retirement ages for pediatricians.
The study used U.S. Census Bureau numbers from 2000 as a baseline, along with figures from medical groups and the Bureau of Health Professions. There were 38,457 general pediatricians in practice nationally that year, or about 49 per 100,000 children.
By 2020, the model predicts 61,800 general pediatricians, or about 72 per 100,000 children.
Even adjusted downward for factors such as more doctors working part-time — a trend among busy pediatricians seeking more time with their own families — the projections show a surplus, the study said.