California will not have enough pharmacists, dental hygienists, respiratory therapists and other health-care workers by 2020, putting the health of a growing senior population at risk, a study released Monday found.

The study, funded by Kaiser Permanente and the California Wellness Foundation, traced the shortfall to a lack of college courses, high dropout rates in health-care college programs and low retention rates at medical offices and hospitals.

The state's senior citizen population is projected to increase by 3.2million by 2020.

At the same, some allied health professions are seeing up to an 85percent shortage of students, according to the report.

"This is the first time we've taken a look at the major allied health professions in a decade," said Ed O'Neil, director of the Center for Health Professions in San Francisco.

"In over three-quarters of these professions, we have significant shortfalls," he said. "Some of these shortfalls are so significant that they are likely to endanger the health of California's residents because those skills that are needed won't be there."

The report said not enough students are passing basic math and science classes, schools and colleges offer little or no information about the wide ranges of professions with the allied health fields and a high number of graduates quit the field because they are unprepared for the high demands of the job.

Among California's nursing students for example, 25percent graduated behind schedule, while 25percent did not graduate at all.

And while many local colleges have expanded the offerings, there also is a shortage of instructors willing to teach.

As a result, health-care facilities are spending thousands to recruit from other states and other countries to fill the gaps, instead of investing in classes, O'Neil said.

"A whole generation of baby boomers are getting older, needing more health care, while the work force is ready to retire," said Marilyn Chow, vice president of patient-care services at Kaiser Permanente.

Kaiser is the largest private employer of those in the allied health field, Chow said.

One of the ways Kaiser is fixing the problem is by creating channels between its centers and local colleges, said Nancy Tankel, clinical director for medical, surgical and nursing care at Kaiser in Woodland Hills.

"We've opened our doors to about six or seven schools, but there's always more that needs to be done," Tankel said.

"It's all very true what the report says. We don't have enough nursing professors, we don't have enough slots, we don't have enough schools."

In addition, California's nurses are aging.

The average age is 47 years old, an issue that concerns professionals already working in the field.

"We always joke we're going to be taking care of each other," Tankel said.

Some groups are calling on state and college officials to increase the number of spaces for students in health-care programs and program prerequisites, and to assist student success once in college.

"As Californians, all of our health care depends on getting more students into and through community college and university training programs," said Abdi Soltani, executive director of the Campaign for College Opportunity, which sponsored the study.

Other findings in the report: