Women in their 50s are more financially fragile than they were a generation ago, according to new research.

Women in this age group are working longer and delaying retirement more than in the past because of more debt, more education, higher rates of combined divorce and widowhood, retirement researchers Olivia Mitchell and Annamarie Lusardi said in a paper released this week for the George Washington University Global Financial Literacy Excellence Center.

Mitchell is the International Foundation of Employee Benefit Plans Professor at the Wharton Business School of the University of Pennsylvania. Lusardi is the academic director of the GWU Financial Literacy Center.

The researchers noted debt has doubled in real dollars for women in their 50s since the early 1990s.

At the same time, they said the percentage of women having less than $25,000 in savings has doubled.

A large contributor to the added debt burden is the fact that women in their 50s are increasingly likely to have mortgage debt totaling more than half the value of their homes. Their mortgages are also larger because of the run-up in housing prices over the last 25 years.