Married people in the United States are living longer these days, but the widowed are experiencing a higher mortality rate, according to new research by a Michigan State University sociologist.

The widening mortality gap between the two groups is a disturbing trend that should prompt scholars and politicians to seek out strategies to better protect and promote health for the widowed, said Hui Liu, study author and assistant professor of sociology.

Liu's study, called "Till Death Do Us Part: Marital Status and U.S. Mortality Trends, 1986-2000," appears in the December issue of the Journal of Marriage and Family.

"It's a bit surprising to me," Liu said of the growing mortality rate for the widowed. "With the improvements in medical technology, it seems all population groups should be healthier and living longer."

Research from as far back as 1858 has shown that married people generally live longer than the nonmarried, but little is known how this relationship has changed over time in the United States. Liu set out to explore recent trends in mortality by marital status.

She analyzed the data of more than a half-million people in the federal government's National Health Interview Survey and found that, as expected, the overall mortality rate for married people decreased from 1986 to 2000. The rate also decreased or at least remained stable among all cause-specific deaths examined except diabetes, which saw an increase.

The mortality rate for the never-married also decreased, although it remained higher than that of married people.

But when it came to widowed people, the overall mortality rate increased. This was especially true for white women.

The results echo another study by Liu and colleagues that found a significant decline in self-reported health among the widowed from 1972 to 2003 in the United States.

In general, widowhood is associated with reduced economic resources and loss of social support, which may contribute to a higher mortality risk, the new study says.

But the stress and emotional trauma of losing a spouse as a confidant might be greater now than in the past as the average duration of marriage becomes longer with increasing life expectancy, the study notes. Further, men and women generally are losing their spouse later in life -- another factor that may contribute to a more frail widowed population.

"The growing mortality gap between the married and the unmarried, especially the widowed, raises concerns," Liu said. "As a frail population in terms of health status and mortality, the widowed clearly warrant greater research and policy attention."