Physician earnings have failed to keep pace with the earnings of other health professionals, according to a study tracking income growth over a 25-year period.

The study from Seth Seabury, an economist at the Rand Corp., included 30,556 survey respondents working in a number of healthcare fields. About one in five—or 6,258 respondents—were physicians. Results of the study are published in the Journal of the American Medical Association.

National studies already have found a decrease in physician salaries between 1995 and 2003 but have not compared doctors' earnings with those of other health professionals.

The JAMA results did not paint a brighter picture. The study found that between the periods of 1987-1990 and 2006-2010, adjusted physician earnings increased just 9.6% compared with 44% for pharmacists.

From 1996-2000 and 2006-2010, physician earnings decreased 1.6%, while pharmacists saw a 34.4% increase in pay.

Physicians earned a median of $143,963 in the period of 1987-1990 and $157,751 during 2006-2010.

The study pointed to the growth of managed care, Medicaid payment cuts, "sluggish" Medicare reimbursement increases and bargaining by insurance companies as possible explanations for the disparity in growth rates. Yet it noted that physician earnings still remain higher than those of other occupations.