A new study by researchers at McGill University finds that more needs to be done to reduce the wide variability among U.S. states in life expectancy between blacks and whites.

While racial differences in longevity have dropped across the country, the study authors say there are still sharp differences in how long blacks and whites live in many of the states and the District of Columbia.

The researchers used data from the National Vital Statistics System, which is administered by the National Center for Health Statistics and collects information on all deaths occurring in the United States each year. During the twenty-year study period, the national life expectancy gap between blacks and whites dropped by 2.7 years for men and by 1.7 years for females. The estimated state-specific racial gap in life expectancy among males in 1990 ranged from 14.4 years the District of Columbia to 0.0 years in New Hampshire. (no similar comparison data in the study for females.)

The researchers found that New York has had the most success in reducing the gap, but other states, including California, have been less successful. The issue is critical, say the study authors, because it reflects disadvantages for blacks in terms of disease risk factors and health interventions and because the disparities are preventable.

In 1990, the first year reviewed by the McGill researchers, California had the same life expectancy gap as New York, but has had less success in erasing the gap.

The researchers say policy decisions may be the reason for the differences. New York City has made significant improvements in reducing homicides and HIV/AIDS related deaths during the two decades studied which disproportionately benefited blacks and also saw reductions in drug and alcohol related deaths.

During the same period, California had strong declines in tobacco use and outpaced the rest of the country in declines in heart disease and smoking rates. However, according to the McGill researchers, the gains in California may have benefitted whites relative to blacks when assessing progress in erasing the black/white life expectancy gap.

“We want to know how to reduce these differences,” says Sam Harper, assistant professor in the Department of Epidemiology, Biostatistics & Occupational Health at McGill University. “Given that many social and health policies are implemented at the state level, looking at how specific states have fared can provide important clues for addressing these health inequalities, says Harper.

The study was published in the journal Health Affairs.