With a higher life expectancy, lower income and shorter careers than men, many retired women are struggling to make ends meet, according to a recent study by the Women's Institute for a Secure Retirement, a Washington, D.C.-based nonprofit group.

Despite income gains in recent years, women on average still earn 23 percent less than men in the workforce, while their median retirement income is 42 percent less, the study reports. While women work an average of 12 years less than men during their lifetimes, their life expectancy is six years higher.

As a result of shorter careers, women also face slimmer benefits packages from their employers and lower Social Security income in retirement, the study found. In 2005, the average Social Security income for retired women was $800 a month, compared to nearly $1,200 for men. In addition, more than 11 percent of women aged 65 and older live below poverty line. Sixty percent of elderly women are single, widowed or divorced, compared to only a quarter of elderly men.

"With more years out of the workforce to care for family, combined with lower wages and a greater life expectancy, it's clear that simply being a woman in our society may jeopardize your financial security," Cindy Hounsell, the study's lead researcher, said in a statement.

The study is based on data from the U.S Census Bureau, the Labor Department, and the Social Security Administration, among other sources.