Low IQ second-highest predictor of heart disease (after smoking)

The British Medical Research Council funded a large study on causes of cardiovascular disease that concluded that, after smoking, low IQ is the largest predictor of cardiovascular disease:
The findings, published in the February issue of the European Journal of Cardiovascular Prevention and Rehabilitation, are derived from the West of Scotland Twenty-07 Study, a population study designed to investigate the influence of social factors on health. The present analysis was based on data collected in 1987 in a cohort of 1145 men and women aged around 55 and followed up for 20 years. Data were collected for height, weight, blood pressure, smoking habits, physical activity, education and occupation; cognitive ability (IQ) was assessed using a standard test of general intelligence...

The investigators note "a number of plausible mechanisms" whereby lower IQ scores could elevate cardiovascular disease risk, notably the application of intelligence to healthy behaviour (such as smoking or exercise) and its correlates (obesity, blood pressure). A further possibility, they add, "is that IQ denotes 'a record' of environmental insults" (eg, illness, sub-optimal nutrition) accumulated throughout life.

Low IQ Among Strongest Predictors of Cardiovascular Disease -- Second Only to Cigarette Smoking in Large Population Study

(Image: Left ventricular aneurysm, apical four-chamber echocardiography view, Patrick J. Lynch/Wikimedia Commons, Creative Commons Attribution License)


    1. It depends what you mean by ‘valid’. IQ can be considered a useful construct, and is measured frequently. When someone is high or low in IQ that can give us useful information about whether they need extra attention to learn new tasks, or whether they are likely to be able to understand and implement new tasks (such as in therapy or at school). Predictive validity is one of the best ways to decide whether a measure is useful. IQ is not that useful at predicting success in life, but may be useful for other things, such as predicting heart disease as in this study.

      It is far too simple to say that IQ is a useful or a useless measure. It depends how you are measuring, why you are measuring it, and how that information will be used. I am trained in administering and interpreting IQ and other neuropsychological test measures. That training happened after several years worth of stats training, and training in test theory, and of reading the literature regarding the history and controversies of IQ testing. Unfortunately not everyone who uses IQ measures has such training.

      1. And after all this training do you believe black people are dumber than white people? IF not, what does IQ measure exactly?

        1. It’s well accepted that children who were read to tend to do better on test scores.

          Given that integration occurred only 50 years ago in the south (where lots and lots of black people live), there are few black people alive today who had well educated parents. Give a few more generations and see if the IQ gap closes (assuming there is one).

          I just happened to be thinking of his earlier today, though. I’m really not sure what you’re being touchy about. There are many kinds of intelligence, sure.

          1. There’s a lot of different ways to step on people and reasons to justify it. Use of a flawed and evidently biased metric that purports to measure native intelligence is a pretty familiar one… to Jews, Gypsies, and any number of people classified as undesirable.

        2. After all this training I know not to ask such simple questions as the one you just posed.

          A lot of the tests we used now were constructed from the beginning of the 20th century for the first world war, and later on for the second world war. They were developed primarily by Caucasian people to measure what they thought was important for intelligence, i.e. what their culture valued as knowledge. People who are not Caucasian generally have lower scores because they are being tested using tests designed for Caucasian people. A lot of hard work and effort is put into obtaining representative data for these tests.

          I live in New Zealand. When I interpret an IQ test I don’t really have to think about black people. I have to decide whether American norms are relevant to New Zealanders: Caucasion, Maori, Pacific Island, Asian etc. In order to do this I look at the culture of the person, their education and schooling, how much they liked school, how often they attended, the likelihood of a learning disability interfering with test scores, their strengths and weaknesses among many other factors.

          To reduce the argument about IQ down to “do you believe black people are dumber than white people?” is absurd and demonstrates you don’t know much about it. IQ is far more complicated than that.



    Dumb people make poor food choices, and don’t maintain their bodies with exercise.

    Poor food choices + sedentary life = Heart Disease.


    Not everyone with poor food choices has a low IQ.


      Who implied otherwise? The linked article specifically mentions your “dumb people make poor choices” theory as one plausible mechanism.

  2. Correlation does not, indeed, indicate causation.

    Perhaps we should look and see if both heart disease and low IQ (whatever it measures) are the symptoms of poor genetic heritage? In other words, it may be that certain inheritable traits may lead to both lower IQ and to increases in heart disease.

  3. My guess is that “a record of environmental insults” is the right answer. Exposure to environmental toxins as a child (like lead and mercury) can cause brain damage, which would show up as lower IQ; I assume that this stuff also affects the developing heart.

    There’s an interesting hypothesis that part of the reason for the drop in the crime rate since the 1970s is that we took lead out of gasoline; inner city youth grew up lead-poisoned, which can make people stupid as well as violent.

  4. Ahem –

    Indeed, to a scientist, causation <> correlation. Agreed. But you’re missing the point.

    To an actuarial or a statistician (and an insurance company), causation is irrelevant.

  5. IQ is still under debate, as it’s a locally nfluence, culturally nfluenced construct. What that translates to, is, very little in terms of real brain science is used to determine IQ. Just tests. There’s much literature on Q tests demonstratng some child’s IQ as seemingly low, when under different testing, it’s shown to be high.
    If IQ tests are demonstrated, as they often are, to be of little value in the nature of actual research, actual facts, and as somethng that cannot be defined (too many cultural variables, too many other variables) then it renders the statement ‘dumb people get more heart disease’ invalid as a predictor.
    Besides, duh, there are many actual physical predictors that any doctor can look at, to predict heart disease. Diet, chloosterol, thinning or blocked arteries, without needing to resort to an IQ test.

    Yeah, I can see some overworked physician now faced with having to e-mal some school, just to request IQ test results. It’s simply unnecessary

  6. I wonder if they would find the same with high IQ. Most of us at the top end of the spectrum tend to be rather loopy and maladjusted.

    Don’t knock IQ. IQ is excellent in predicting how well someone does on IQ tests.

  7. Wonder if it could be that lower IQ people get frustrated more easily and that adds to stress. Or perhaps people who are not very ‘wise’ or ‘deep’ (qualities that I associate with being intelligent) make poor life choices and lack perspective. I know someone who just had a heart attack. A very successful person money wise, but also a sociopath…completely incapable of looking at himself objectively (or even trying), always blames others, not very good at supporting anything that doesn’t lead to either more money or notoriety for himself. People like that seem ‘dumb’ to me…like not being able to get outside your own ego is stupid…and stressful.

      1. “If you live to the age of a hundred you have it made because very few people die past the age of a hundred.” – George Burns

  8. They were probably right that the results of this study are so, because IQ probably “denotes ‘a record’ of environmental insults”. Growing up in poverty would mean poor childhood nutrition and an unstimulating environment. That leads to lower cognitive ability, and while the impoverished person leads his/her life, there are few luxuries they can afford but cigarettes, and scant access to fresh fruits and vegetables, especially since all the Trader Joes’s and Costcos are deeply nestled in suburbs.

  9. The anatomy professor in me just wanted to say that the heart illustration is upside down. The atria should be on the top and the ventricles on the bottom.

  10. Does an inactive life lead to low IQ? For example, if I’ve been raised in front of the TV, without challenging my brain to learn or experience much, will I test lower on an IQ test?

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