Black Americans and Americans with a low level of education have long been known to die earlier than white Americans and better educated Americans. But a new study shows that black people and less educated Americans have different causes of death from other people and suggests a change in direction of public health messages. Race and education have "strong, independent effects," the authors say.
The study used data on almost 700 000 people that were collected in the annual national health interview surveys from 1986 to 1994 and that were then matched with data from death certificates (New England Journal of Medicine 2002;347:1585-92). Personal identifiers had been removed.
Black Americans died earlier than white Americans for most of the causes of death looked at in the study. "When adjusted for age, sex, and level of education, the number of potential life-years lost from all causes was 35% greater for blacks than for whites. Black persons and white persons lost 7.0 and 5.2 potential life-years before the age of 75 per person, respectively, a difference of 1.8 years (99% confidence interval, 1.4 to 2.8)," the authors wrote.
The causes of death that mostly contributed to the disparity between the races were hypertension, HIV, diabetes, and homicide. Cardiovascular disease was the leading cause of death among black people (31%) and second among white people (30%).
Whether black or white, people who had not completed high school "lost more potential life-years than more educated persons for every specific cause we examined, though not all differences were statistically significant."
When adjusted for age, sex, and race, the data showed that people who had not completed high school lost 12.8 years of potential life before the age of 75, compared with 3.6 years among people with more education, a difference of 9.2 years (99% confidence interval 8.5 to 10.7).
The diseases causing 40% of the disparity between the less educated and better educated groups were ischaemic heart disease, lung cancer, stroke, pneumonia, congestive heart failure, and lung disease—all smoking related diseases.
Lead author Dr Mitchell Wong, assistant professor of medicine at the University of California in Los Angeles, told the BMJ , "We haven't known this [the different causes of premature mortality] before. It's a real challenge for our public health system." But he said it was encouraging because it could lead to more effective health messages.
He suggested that public health messages to less educated people should focus on preventing ischaemic heart disease and lung cancer through antismoking campaigns. The message for black people should be screening for and treatment of hypertension, prevention of HIV, and control of diabetes—all strategies that public health professionals know how to do and that are cheap. Prevention of homicide by gun control, though important, is politically difficult to address, he said.
The study covered only black and white Americans, not Asians, Hispanic Americans, or other groups.