The nation may have more elderly persons living in poverty than previously estimated, according to a census study released this month.

The Supplemental Poverty Measure, which incorporates a new federal definition of poverty, revealed that one in six Americans lived in poverty in 2009 when out-of-pocket health and medical costs, after tax income, regional variations and other measures were factored. Many of these previously overlooked residents–16 percent–are 65 and older.

“Too often, the struggles of elder poverty are invisible to policymakers and the public, yet millions are suffering and millions more are living on the edge of a financial crisis,” Sandra Y. Nathan, senior vice president of the non-profit National Council on Aging’s economic security initiative, said in a statement.

“Many seniors desperately need help assessing and navigating the options available to assist them in getting on a pathway to economic security, to meet their basic needs, survive an emergency, and afford medical care,” she added.

The U.S. Census Bureau released the measure’s preliminary results Jan. 5 in response to years of recommendations to revise the benchmarks for poverty and congressional legislation in 2009 to examine poverty threshold measures.

Under the measure’s calculations, 47.8 million people were in poverty in 2009, compared to the official 43.6 million originally reported by the census—an increase of 4.2 million people. The current poverty estimation method was developed in the 1960s.

The number of Whites in poverty swelled to more than 13 percent, while the overall count for Blacks and Hispanics saw insignificant increases, increasing by just one to three points.

The “new group of poor would consist of a larger population of elderly people, working families and married-couple families than are identified in the official poverty measure,” Kathleen S. Short, Census Bureau researcher and the report’s author, told The Los Angeles Times.

In the future, the new poverty threshold will appear alongside the traditional census figure as an additional assessment.