ATLANTA—May 13, 2008—A new study finds a gap in overall death rates between Americans with less than high school education and college graduates increased rapidly from 1993 to 2001. The study, which appears in the May 14 issue of PLoS ONE, says the widening gap was due to significant decreases in mortality from all causes, heart disease, cancer, stroke, and other conditions, in the most educated while death rates among the least educated remained relatively unchanged. The study is the first to examine recent trends in socioeconomic inequalities in mortality from all causes as well as several leading causes of death in the United States using national individual-level socioeconomic measures.
American Cancer Society epidemiologists led by Ahmedin Jemal, Ph.D., working with scientists from the Centers for Disease Control and Prevention’s National Center for Health Statistics (NCHS) used data from the National Vital Statistics System (NVSS) and death certificate information to analyze more than 3.5 million deaths recorded from 1993 to 2001. They found the overall death rate from all causes decreased significantly during the time period among the most educated (≥16 years) men and women, with the largest decrease in black men. In contrast, the all cause death rate actually increased in those with less than a high school education. The annual percent increase was largest among white women with less than 12 years of education (3.2 percent per year), but was also statistically significant (0.7 percent per year) in white women who had completed high school. The authors say the growing gap was caused largely by an unprecedented decrease in the all-cause death rate among the most educated men (totaling 36 percent in black men and 25 percent in white men over the nine-year interval) largely due to decreases in death rates from HIV infection, cancer, and heart disease.
We calculated annual age-standardized death rates from 1993–2001 for 25–64 year old non-Hispanic whites and blacks by level of education for all causes and for the seven most common causes of death using death certificate information from 43 states and Washington, D.C. Regression analysis was used to estimate annual percent change. The inequalities in all cause death rates between Americans with less than high school education and college graduates increased rapidly from 1993 to 2001 due to both significant decreases in mortality from all causes, heart disease, cancer, stroke, and other conditions in the most educated and lack of change or increases among the least educated. For white women, the all cause death rate increased significantly by 3.2 percent per year in the least educated and by 0.7 percent per year in high school graduates. The rate ratio (RR) comparing the least versus most educated increased from 2.9 (95% CI, 2.8–3.1) in 1993 to 4.4 (4.1–4.6) in 2001 among white men, from 2.1 (1.8–2.5) to 3.4 (2.9–3–9) in black men, and from 2.6 (2.4–2.7) to 3.8 (3.6–4.0) in white women.
Why do I make the claim that this result is due more to intelligence than to education? Linda Gottfredson and Ian Deary have demonstrated intelligence is a powerful variable for influencing longevity (PDF format).
ABSTRACT—Large epidemiological studies of almost an entire population in Scotland have found that intelligence (as measured by an IQ-type test) in childhood predicts substantial differences in adult morbidity and mortality, including deaths from cancers and cardiovascular diseases. These relations remain significant after controlling for socioeconomic variables. One possible, partial explanation of these results is that intelligence enhances individuals’ care of their own health because it represents learning, reasoning, and problem-solving skills useful in preventing chronic disease and accidental injury and in adhering to complex treatment regimens.
Also see Gottfredson's paper Intelligence: Is it the epidemiologists' elusive "fundamental cause" of social class inequalities in health? (PDF format).
My guess is that as the amount of useful knowledge available to influence longevity has increased (e.g. results from dietary and lifestyle research and new types of treatments that require patients to do much self-administration of drugs and therapies) the advantage of being smart has been amplified. If you get sick and you are smart you have more clinical trials to investigate, diets to try, and treatments to follow carefully. You are better able to understand why a treatment should benefit you and therefore more motivated to stick with it. Rather than follow the advice of one doctor you can seek out multiple experts, ask tough questions, and compare notes with other smart people chasing better treatments. You are better able to see through self-serving advice of specialists who are trying to boost their income. You are more likely to recognize serious side effects of treatments and challenge the wisdom of continued use of a treatment.
In the much longer run rejuvenation treatment delivery will become so automated and the treatments so incredibly effective that even the dumbest among us will benefit. But in the shorter run having brains and utilizing those brains to make diet, lifestyle, and other choices to maximize health can provide a big edge.
|Share |||Randall Parker, 2008 May 15 09:58 PM Aging Studies|