Deaths due to the four most common cancersólung, colorectal, prostate, and breastóhave dropped substantially in the United States from 1993 to 2001 in working-aged individuals. However, not all Americans are equally likely to benefit from those gains.
A study published in the Journal of the National Cancer Institute shows that more highly educated individuals had mortality reductions in nearly all of these cancers, while less educated individuals had a mortality reduction in only one of the cancer types - breast.
In previous studies, researchers examined the impact of area-level socioeconomic status (SES) on cancer mortality trends and found an association between higher SES and bigger gains in mortality reduction. Investigators have not previously examined the association of individual SES components, such as education level, with cancer mortality.
In the current study, Ahmedin Jemal, D.V.M., Ph.D., of the American Cancer Society and colleagues obtained individual education and mortality data from death certificates for non-Hispanic whites and non-Hispanic blacks between the ages of 25 and 64 who died from one of the four major cancers between 1993 and 2001. The data are from the National Center for Health Statistics and cover approximately 86 percent of the U.S. population.
Jemal and colleagues found that there was a statistically significant decline in mortality from prostate, lung, and colorectal cancer for men, both white and black, who had 16 or more years of education (i.e., a college degree). Death rates also decreased for colorectal, breast, and lung cancers among white and black women with 16 or more years of education, although the decline in lung cancer mortality did not reach statistical significance in black women.
By contrast, the only statistically significant decrease in mortality in individuals with less than 12 years of education was a reduction in breast cancer mortality among white women. Over the same period, there was an increase in lung cancer mortality in less educated white women and an increase in the colon cancer death rate in less educated black men.
"This analysis of recent trends in mortality rates from the four most common cancer sites among 25- to 64-year old white and black men and women in the United States by educational attainment illustrates that the remarkable reduction in mortality from these common cancers during this 9-year interval was confined largely to more highly educated men and women," the authors conclude.
The authors discuss possible reasons for the differences in mortality that they uncovered and consider how previously reported information on behavioral risks, such as smoking, screening use, and treatment patterns, may be consistent with these new data.
Journal of the National Cancer Institute, online edition, July 8, 2008