Trends in the Black-White Life Expectancy Gap, 2003-2008 FREE

To the Editor: Understanding the causes of black-white differences in mortality has important consequences for interventions to reduce health inequalities in the United States. A previous report found a nearly 2-year decline in the black-white life expectancy gap among men and a 1-year decline among women between 1993 and 2003.¹ We investigated whether these changes have continued in recent years.

Similar to a previous study,¹ we abstracted data on deaths and population from the US National Vital Statistics System by age and cause of death for non-Hispanic blacks and whites in 2003 and 2008. We used the Centers for Disease Control and Prevention's WONDER software² and abridged life table methods to estimate life expectancy at birth, and used the method by Arriaga³ for decomposing differences in life expectancy between populations by age and cause of death. We selected International Classification of Diseases, Tenth Revision codes to capture leading causes of death among sex and race groups, and calculated age-adjusted death rates using the US 2000 standard million population. The US mortality data are not subject to sampling error.⁴ Analyses were conducted using Stata software version 12 (StataCorp). This study used deidentified data and did not require ethics review.

Between 2003 and 2008, life expectancy at birth increased from 75.3 to 76.2 years among non-Hispanic white men and from 68.8 to 70.8 years among non-Hispanic black men, whereas for women the changes were from 80.3 to 81.2 years (non-Hispanic whites) and 75.7 to 77.5 years (non-Hispanic blacks). These changes reduced the racial gap from 6.5 to 5.4 years among men and from 4.6 to 3.7 years among women (Table 1). For men, heart disease (22%) and homicide (19%) were the leading contributors to the gap in 2008. For women, the leading causes were heart disease (29%) and diabetes (11%). However, the leading contributor to the 1.1-year decrease in the gap for men since 2003 was unintentional injuries (18% of the decrease), followed by human immunodeficiency virus (HIV, 15%) and heart disease (15%). Among women, heart disease was the dominant contributor to the decline (29%), followed by unintentional injuries (10%), HIV, diabetes, and stroke (approximately 8% each). Larger increases in poisoning mortality among whites were the primary reason why unintentional injuries reduced the racial gap. Age-adjusted rates of unintentional poisoning mortality among those aged 20 to 54 years increased by 58% and 74% for non-Hispanic white men and women, respectively, but only 0.1% and 9% among non-Hispanic blacks (Table 2).

Between 2003 and 2008, the gap in life expectancy between non-Hispanic blacks and whites declined by approximately 1 year for both sexes, a rate of decline that is equal to or greater than that observed over the entire decade from 1993-2003. These racial inequalities among men and women in 2008 are the lowest ever recorded in the United States.⁵ Heart disease, diabetes, homicide, HIV, and infant mortality remain the chief causes of the black-white gap. However, in contrast to 1993-2003,¹ homicide has not played an important role in reducing black-white differences among men since 2003. Rather, changes in unintentional injury deaths were a major reason, along with heart disease and HIV, for the narrowing gap among both men and women.

Historically, motor vehicle crashes have been the leading cause of unintentional injury death in the United States, but racial differences are small and have been stable over recent years.⁴ A potential explanation for the contribution of unintentional injury to the narrowing racial gap may be recent increases in poisoning mortality, which has now eclipsed motor vehicle crashes as the leading cause of injury death and has affected middle-aged white men more than any other group.⁶

Our analysis is limited by reliance on the underlying cause of death, which may underestimate the contribution of factors involved in multiple causes. The black-white life expectancy gap is still large, and declines since 2003 due to HIV and heart disease are a positive development, but rapid increases in accidental death among whites also have contributed to this change.