Students over the age of 40 now comprise the fastest-growing group on United States campuses, according to a study by two national higher education organisations.
Enrolment of fortysomethings has tripled since 1970, the largest jump of any group, thanks to the ageing of the baby boom generation and the endless cycle of retraining needed by a high-tech workforce. More than one in ten of all college students today are 40 or older.
Two-thirds of these older students are women, many of them returning to school after their children have grown older, the Education Resources Institute and the Institute for Higher Education Policy reported. There also has been a 21 per cent increase in ten years in the number of older workers requiring mid-career job training.
Today there are more than 1.6 million people over 40 studying at colleges and universities, up from 477,000 in 1970, according to the two groups.
The numbers threaten to overwhelm some universities and colleges, which were not expecting them and find themselves having to provide such services as evening faculty hours for older students who attend at night.
Meanwhile, record numbers of traditional-age students now are making their way through primary and secondary schools and will soon flood US campuses.
Jamie Merisotis, director of the Institute for Higher Education Policy, said: "American higher education has been busy gearing up for the baby boom echo, the children born to the baby boomers, who are traditional college-age, dependent, undergraduate students.
"Now they're going to have to simultaneously prepare to have their parents attending at the same time," he added.
The schools are not likely to complain, however, since these older students almost always pay full tuition, need no financial aid or housing and seldom disrupt the campuses with drunken behaviour or reckless pranks.
Students 40 and over make up 10 per cent of undergraduates, 22 per cent of graduate students and 6 per cent of medical, law or other professional students. Nearly 80 per cent study part-time. And nearly 60 per cent work at least 30 hours per week, compared to 25 per cent of students aged 18 to 24.
The trend has also spawned new kinds of colleges called corporate universities, sponsored by employers to retrain their workers. There were 400 such schools in 1970. Their ranks have swelled to more than 1,000 today. Other colleges and universities are gradually adapting to the influx.
"The needs are considerably different between the traditional students and the students over 40," Mr Merisotis said. "Campuses that have big proportions of both age cohorts are going to have to invest heavily in student services. Given that this population is still growing, it's certainly something that we think we're going to see a lot more of."