One of the great mysteries of modern medicine: Why do rich people live longer than poor people? Why is it that, all around the world, those with more income, education and high-status jobs score higher on various measures of health? As stated in a World Health Organization pamphlet: “People further down the social ladder usually run at least twice the risk of serious illness and premature death of those near the top.”
The traditional answer to these questions has been that greater wealth and social status mean greater access to medical care. But even ten years ago, when this magazine last delved into the topic (FORBES, Jan. 31, 1994), the available answers seemed inadequate. If access was the key, then one would have expected the health gap between upper and lower classes to shrink or disappear with the advent of programs like Britain’s National Health Service and America’s Medicare and Medicaid, not to mention employer-sponsored health insurance. In fact, the gap widened in both Britain and America as these programs took effect. The 1994 article cited a study of British civil servants–all with equal access to medical care and other social services, and all working in similar physical environments–showing that even within this homogeneous group the higher-status employees were healthier: “Each civil service rank outlived the one immediately below.” How could this be?
Today the standard answer–or, at least, the answer you are guaranteed to get from the WHO and other large health bureaucracies–is that inequality itself is the killer. The argument is that low status translates into insecurity, stress and anxiety, all of which increases susceptibility to disease. This psychosocial case is lengthily elaborated in Social Determinants of Health, a 1999 publication collectively created by 22 medical specialists and endorsed by the WHO. “Is it plausible,” the book asks at one point, “that the organization of work, degree of social isolation and sense of control over life could affect the likelihood of developing and dying from chronic diseases such as diabetes and cardiovascular disease?” The authors’ answer is a resounding yes. Pushing their case to the outer limits, the authors supply data indicating that in the world of African wild baboons, those who are socially dominant tend to be most healthy (as mainly evidenced in their higher levels of good cholesterol).
This revised standard answer has some plausibility, but also some serious weaknesses. One of its problems is that we lack serious comparative data on tension and anxiety levels in low- and high-status jobs. It is far from clear that barbers, elevator operators and lower-level civil servants suffer more tension than do surgeons, executive vice presidents and higher-level civil servants. Another problem is that psychosocial explanations don’t tell us why the health gap would widen when employers and governments provide more health care. Nor do they explain one well-known source of the health gap: the notoriously high rate of smoking in the low-status population.
An explanation not presenting these problems has recently been proposed in several papers by two scholars long associated with IQ studies: Linda Gottfredson, a sociologist based at the University of Delaware, and psychologist Ian Deary of the University of Edinburgh. Their solution to the age-old mystery of health and status is at once utterly original and supremely obvious. The rich live longer, they write, mainly because the rich are smarter. The argument rests on several different propositions, all well documented. The crucial points are that (a) social status correlates strongly and positively with IQ and other measures of intelligence;(b) intelligence correlates strongly with “health literacy,” the ability to understand and follow a prescription for disease prevention and treatment; and (c) intelligence is also correlated with forward planning–which means avoidance of health risks (including smoking) as they are identified.
The first leg of that argument has been established for many decades. In modern developed countries IQ correlates about 0.5 with measures of income and social status–a figure telling us that IQ is not everything but also making plain that it powerfully influences where people end up in life. The mean IQ of Americans in the Census Bureau’s “professional and technical” category is 111. The mean for unskilled laborers is 89. An American whose IQ is in the range between 76 and 90 (i.e., well below average) is eight times as likely to be living in poverty as someone whose IQ is over 125.
Second leg: Intelligent people tend to be the most knowledgeable about health-related issues. Health literacy matters more than it used to. In the past big gains in health and longevity were associated with improvements in public sanitation, immunization and other initiatives not requiring decisions by ordinary citizens. But today the major threats to health are chronic diseases–which, inescapably, require patients to participate in the treatment, which means in turn that they need to understand what’s going on. Memorable sentence in the Gottfredson-Deary paper in the February 2004 issue of Current Directions in Psychological Science: “For better or worse, people are substantially their own primary health care providers.” The authors invite you to conceptualize the role of “patient” as having a job, and argue that, as with real jobs in the workplace, intelligent people will learn what’s needed more rapidly, will understand what’s important and what isn’t and will do best at coping with unforeseen emergencies.
It is clear that a lot of patients out there are doing their jobs very badly. Deary was coauthor of a 2003 study in which childhood IQs in Scotland were related to adult health outcomes. A central finding: Mortality rates were 17% higher for each 15-point falloff in IQ. One reason for the failure of broad-based access to reduce the health gap is that low-IQ patients use their access inefficiently. A Gottfredson paper in the January 2004 issue of the Journal of Personality & Social Psychology cites a 1993 study indicating that more than half of the 1.8 billion prescriptions issued annually in the U.S. are taken incorrectly. The same study reported that 10% of all hospitalizations resulted from patients’ inability to manage their drug therapy. A 1998 study reported that almost 30% of patients were taking medications in ways that seriously threatened their health. Noncompliance with doctors’ orders is demonstrably rampant in low-income clinics, reaching 60% in one cited study. Noncompliance is often taken to signify a lack of patient motivation, but it often clearly reflects a simple failure to understand directions.
A new Test of Functional Health Literacy of Adults can evaluate the problem in a mere 22 minutes. It measures comprehension of the labels on prescription vials, of appointment slips, of what the patient is expected to do before diagnostic tests, etc. The results turn out to be somewhat horrifying. In a sample of 2,659 clinic patients in two urban hospitals, 42% did not understand the instructions for taking medicine on an empty stomach, and 26% did not understand when the next appointment was scheduled. The problem is maximized for patients with chronic illnesses. Asthma, diabetes and hypertension all require patients to make a lot of decisions daily as well as in emergencies, but many patients are simply not up to it. A study cited in the Gottfredson-Deary paper mentions that a high proportion of insulin-dependent diabetics did not know how to tell when their blood sugar was too high or too low or how to get it back to normal.
And then there is the third leg of the IQargument: the lifestyle question. Smoking, obesity and sedentary living are more prevalent among low-status citizens. A 2001 study by the Centers for Disease Control & Prevention found that college graduates are three times as likely to live healthily as those who never got beyond high school. Not clear is what the government can do about this.
The data on IQ, social status and health present some huge conundrums for policymakers. For years Americans debated what to do for, and about, poor people unable to pay for health care. Ultimately they decided it simply had to be paid for. But now, with money ordinarily not a barrier to medical care, we are discovering another obstacle: “regimen complexity.” As this fact of life sinks in, the system will be under pressure to find ways to deliver high-quality care to the low-status population much more simply, understandably–and economically. Not an easy task.