U.S. residents who earn high incomes over many years may face much more longevity risk than lower-income people face.

Julian Cristia, an analyst at the Congressional Budget Office, looks at lifetime earnings, rather than earnings for a specific year, in an analysis of the relationship between income and mortality.

Short-lived people may earn less over a lifetime than longer-lived people because they work for fewer years, but using lifetime earnings helps filter out statistical noise caused by ordinary variations in income and the effects of illness on income in specific years, Cristia writes.

During the 1998-2003 period, men ages 35 to 49 in the bottom fifth of individual lifetime earnings were about 8.4 times more likely to die in a given year than men in that age range in the top income group, Cristia writes.

The mortality differential for bottom earners and top earners increased from 5.9 for the 1983-1997 period, Cristia writes.

The differential for top earning and bottom earning women increased to 4.8 for the 1998-2003 period, from 1.8 for the 1983-1997 period, Cristia writes.

“If the ‘life-expectancy premium’ for high-earners is increasing over time, this may worsen the budgetary pressures facing the U.S. Social Security system, given that high earners receiving larger benefits will collect them (on average) for a longer period of time,” Cristia warns.

Cristia’s tables also show big mortality gaps between men in the top lifetime income quintile and the second quintile.

Men in the 35-49 age group and the top lifetime individual income quintile are about 65% less likely to die in a given year than typical men in the age group, while the reduction in mortality is just 44% for men ages 35-49 who rank in the second lifetime income quintile.

Women in the age 35-49 age group and the top lifetime household income quintile are 51% less likely to die in a given year than typical women in their age group, while women who rank in the second household income quintile enjoy only a 25% reduction in mortality, according to Cristia.

The Cristia mortality study is on the Web