The researchers discovered that the death rates for all cancers combined, as well as for lung, colorectal, breast, and prostate cancers, were strongly associated with years of education.
Significantly, those with 12 or fewer years of education had higher rates of cancer deaths than those with more than 12 years.
Lead researcher Jessica Albano of the American Cancer Society in Atlanta and his team used data collected from death certificates and the U.S. Bureau of the Census, to study the associations between education and cancer death rates. The data comprised 137,708 cancer deaths that occurred in 2001 among black and white men and women between the ages of 25 and 64.
The study found that at every level of education, cancer death rates were generally higher among U.S. blacks than among whites. Only among black and white men with zero to eight years of education were the death rates nearly identical.
The authors put down the differences between black and white death rates as likely related to other factors that are more directly associated with cancer risks, which are tobacco use and access to health care and cancer screening.
Says Albano: "Higher cancer mortality among blacks compared with whites at similar levels of education likely reflects socioeconomic disparities in work, wealth, income, housing, overall standard of living, and access to medical care that are not fully captured by the single measure of socioeconomic status available for our analysis (i.e. years of education)".
It was also found that relationships between the level of education and cancer death rates were weaker for women than for men. They were also weaker for black women compared to white women.
Yet, a very strong relationship between years of education and prostate cancer was found for black men. At every level of education, death rates for black men were substantially higher than those for white men.
Coming to breast cancer, white women with higher levels of education were found to have lower breast cancer death rates than those with less education. Significantly, this reverses the typical pattern that has found that more-educated women are more likely to develop and die of breast cancer, perhaps because of their tendency for delayed childbirth.