Image copyright Janet Dupree Image caption Janet Dupree has had her wages garnished

Around the world, student debt is a financial burden for millions - and in the US, a growing number of senior citizens are still repaying the cost of their education into retirement age.

Janet Lee Dupree is 72 years old and has a financial burden that will not leave her in peace: she owes $16,000 (£9,957) in student loans she acquired in 1971 and 1972.

Dupree, who lives in Citra, Florida, admits she forgot for many years that she had borrowed the money - originally $3,000 - in order to complete her undergraduate studies in Spanish.

"I am an alcoholic and I have HIV," she tells the BBC. "That's under control, but at that time I was sick and I didn't worry about paying back the debt."

Dupree defaulted on her loan, and since she turned 65 she has had money withheld from her Social Security benefits.

"Just recently I received a notification that they are going to garnish my wages because I am still working," says Dupree, who works 30 hours a week as a substance abuse counsellor.

Retirement is not part of my vocabulary Rosemary Anderson

In 2005, older adults owed $2.8bn (£1.61bn) in federal student debt. By 2013, that figure had ballooned to $18.2bn, according to a report released last month by the Government Accountability Office (GAO).

These seniors account for 706,000 households in the United States - small compared to the 22 million households with non-seniors who hold student load debt, but a growing problem. People over 65 also defaulted on their student loan debt at a much higher rate than other segments of the population, says Charles Jeszeck, author of the GAO report.

Students in the US often take out loans, both privately funded and financed by the US Department of Education, to pay their school fees. While other loans, such as a home mortgage, can be forgiven if a borrower files for bankruptcy, it maybe more difficult to do so with a student loan.

According to the GAO study, the number of individuals whose Social Security benefits were offset to pay student loan debt increased from about 31,000 to 155,000 between 2002-13. Jeszeck tells the BBC that this situation can cause considerable problems for older adults who, like Dupree, may have to extend their working life well beyond retirement age.

"They face the potential of reduced social security benefits and a lower standard of living, possibly a poverty-level standard of living in retirement," Jeszeck says.

Rosemary Anderson, 57, says she is fortunate not to have defaulted on her student loan, but she already knows she will grow old with a debt "hanging over her head".

Between 1991-2000 she borrowed $64,000 in order to complete both her undergraduate and her graduate studies in organisational behaviour and development.

Soon after, though, she began what she calls a "steep decline into financial hell".

She says she divorced her husband of 24 years, had health issues that prevented her from working full time, and had her salary reduced when the financial crisis hit.

Image copyright Thinkstock

Student debt in the United States

•Outstanding student loan debt in the US amounts to $1tr

•3% of households headed by individuals 65 or over carry student debt (706,000 households)

•24% of households headed by individuals 64 or under carry student debt (22 million households)

•The outstanding federal debt for older adults grew from $2.8bn in 2005 to $18.2bn in 2013

•27% of federal student loans held by individuals aged 65 to 74 are in default, compared to 12% of loans to people between the ages of 25 and 49

Anderson, who works as a member of the emergency management team at the University of California, Santa Cruz, couldn't afford her monthly loan payments, so she entered into a series of deferment options with the Department of Education.

Today, she owes $128,000 and is hoping to get additional help from the government in reducing that amount.

The vast majority of older borrowers took out their loans in order to pay for their own studies, although a small percentage used the loans for their spouses, children or grandchildren.

Many borrowed money to pay for mid- or late-career retraining, or may have acquired loans with a very long repayment term. Others defaulted at a younger age, were unable to dig themselves out of the problem and carried it through into retirement.

The Department of Education says it is "committed to working with older borrowers to help them understand and manage debt", as William Leith, chief business officer for federal student aid, explained in a recent Senate hearing where different measures were discussed.

A department spokesperson told the BBC that there are "many repayment options available, including those based on income, as well as forgiveness programmes".

Meanwhile, Rosemary Anderson is worried. She says she never imagined that she would have this problem at her age.

She feels fortunate to have a job but recognises that she will have to continue working as long as she is physically able to.

"Retirement is not part of my vocabulary," she says.

"I will never live long enough to pay off my loan."