Paperwork, the demands of the chronically sick, and the need to bring work home are among the factors pushing young doctors away from careers in primary care, the survey found.
"I didn't want to fight the insurance companies," said Dr. Jason Shipman, 36, a radiology resident at Vanderbilt University Medical Center in Nashville, who is carrying $150,000 in debt.
Primary care doctors he met as a student had to "speed to see enough patients to make a reasonable living," Shipman said.
Dr. Karen Hauer of the University of California, San Francisco, the study's lead author, said it's hard work taking care of the chronically ill, the elderly, and people with complex diseases - "especially when you're doing it with time pressures and inadequate resources."
The salary gap may be another reason. More pay in a particular specialty tends to mean more US medical school graduates fill residencies in those fields at teaching hospitals, Dr. Mark Ebell of the University of Georgia found in a separate study.
Family medicine had the lowest average salary last year, $186,000, and the lowest share of residency slots filled by US students, 42 percent. Orthopedic surgery paid $436,000, and 94 percent of residency slots were filled by US students.
Meanwhile, medical school is getting more expensive. The average graduate last year had $140,000 in student debt, up nearly 8 percent from the previous year, according to the Association of American Medical Colleges.
Another likely factor: Medicare's fee schedule pays less for office visits than for simple procedures, according to the American College of Physicians.
A separate study in the Journal of the American Medical Association suggests that graduates from international medical schools are filling the primary care gap.
About 2,600 fewer US doctors were training in primary care specialties - including pediatrics, family medicine, and internal medicine - in 2007 compared with 2002. In the same span, the number of foreign graduates pursuing those careers rose by nearly 3,300.
"Primary care is holding steady but only because of international medical school graduates," said Edward Salsberg of the Association of American Medical Colleges, coauthor of the study.
