Tuesday, August 18, 2009

IQ a bigger contributor to socioeconomic influence on risk of CV death than conventional risk factors

To translate that heading into plain English: Poor people get more heart attacks not because they are fatter and smoke more (etc.) but because they are dumber. That reinforces the idea that IQ is a marker of general biological fitness as well as being a marker of mental ability. Another indication of that is that high IQ people live longer. I imagine that some readers think I overdo it in attributing so many epidemiological correlations to IQ and social class (which are themselves correlated) but the paper below shows just how important those factors are

A couple of footnote-type comments: 1). It is odd that alcohol consumption was not mentioned in the study. Perhaps they were afraid that they might find that boozers live longer. 2). There is a constant tendency for people to counter generalizations that they don't like with contrary examples, quite ignoring that you can prove anything by examples. So when confronted by the idea that IQ is a marker of general biological fitness, some people say: "What about Stephen Hawking? He's very bright but he's none too healthy". One might reply however that to have lived into his 60s with his severe disability his basic health must be exceptionally robust!

Intelligence appears to play a greater role than traditional cardiovascular risk factors in the relationship of socioeconomic disadvantage with cardiovascular disease (CVD) mortality, according to a new and unusual study.

This is the first research to properly examine this issue, say Dr G David Batty (University of Glasgow, Scotland) and colleagues in their paper published online July 14, 2009 in the European Heart Journal. "Our findings suggest that measured IQ does not completely account for observed inequalities in health, but probably— through a variety of mechanisms— may quite strongly contribute to them." The findings indicate the need to further explore how the links between low socioeconomic status, low IQ, and poor health might be broken, they observe.

In an accompanying editorial, Drs Michael Marmot and Mika Kivimäki (University College London, UK) say research such as this "is challenging . . . [but it] makes clear that what happens in the mind, whether the influence came from the material world or the social, has to be taken into account if we are to understand how the socioeconomic circumstances in which people live influence health and well-being." [It must have been hard for The Marmot to admit that. He is associated with the dubious WCRF and some equally dubious dietary claims]

Adding IQ to statistical models strengthens their power [But it is SO "incorrect"]

Batty and colleagues explain that controlling for preventable behavioral and physiological risk factors attenuates but fails to eliminate socioeconomic gradients in health, particularly CVD, which raises the possibility that as-yet-unmeasured psychological factors need to be considered, and one such factor is cognitive function (also referred to as intelligence or IQ).

They studied a cohort of 4289 US male former military personnel, from the Vietnam Experience Study, which they say had a number of strengths that enabled them to explore the role of IQ. It provides extensive data on IQ (early adulthood and middle age) and four widely used markers of socioeconomic position: early-adulthood and current income; occupational prestige and education; a range of nine established CVD risk factors; and cause-specific mortality.

They used the relative index of inequality (RII) to quantify the relation between each index of socioeconomic position and mortality. Over 15 years, there were 237 deaths (62 from CVD and 175 from other causes). In age-adjusted analyses, each of the four indices of socioeconomic position was inversely associated with total, CVD, and "other" causes of mortality, such that, as would be expected from previous findings, elevated rates were evident in the most socioeconomically disadvantaged men.

When IQ in middle age was introduced to the age-adjusted model, there was marked attenuation in the RII across the socioeconomic predictors for total mortality (average 50% attenuation in RII), CVD mortality (55%), and "other" causes of death (49%). When the nine traditional risk factors were added to the age-adjusted model, the comparable reduction in RII was less marked: all causes (40%), CVD (40%) and "other" mortality (43%).

And adding IQ to the model adjusted for age and CVD risk resulted in further explanatory power for all outcomes, they say.

Consider IQ when planning health promotion and in consultations

In their editorial, Marmot and Kivimäki say there is probably not a direct IQ effect but rather cognitive function more likely "explains" the link between socioeconomic position and mortality, insofar as intelligence is a determinant of social and economic success in life. Further research will help clarify this issue, they note. [The Marmot is trying to waffle his way out of it. I am not even sure what he means there]

Batty et al say their results suggest that individual cognition levels should be considered more carefully when health promotion campaigns are being prepared and in health-professional-client interactions.


Journal abstract follows:

Does IQ explain socio-economic differentials in total and cardiovascular disease mortality? Comparison with the explanatory power of traditional cardiovascular disease risk factors in the Vietnam Experience Study

By G. David Batty et al.

Aims: The aim of this study was to examine the explanatory power of intelligence (IQ) compared with traditional cardiovascular disease (CVD) risk factors in the relationship of socio-economic disadvantage with total and CVD mortality, that is the extent to which IQ may account for the variance in this well-documented association.

Methods and results: Cohort study of 4289 US male former military personnel with data on four widely used markers of socio-economic position (early adulthood and current income, occupational prestige, and education), IQ test scores (early adulthood and middle-age), a range of nine established CVD risk factors (systolic and diastolic blood pressure, total blood cholesterol, HDL cholesterol, body mass index, smoking, blood glucose, resting heart rate, and forced expiratory volume in 1 s), and later mortality.

We used the relative index of inequality (RII) to quantify the relation between each index of socio-economic position and mortality. Fifteen years of mortality surveillance gave rise to 237 deaths (62 from CVD and 175 from ‘other’ causes).

In age-adjusted analyses, as expected, each of the four indices of socio-economic position was inversely associated with total, CVD, and ‘other’ causes of mortality, such that elevated rates were evident in the most socio-economically disadvantaged men.

When IQ in middle-age was introduced to the age-adjusted model, there was marked attenuation in the RII across the socio-economic predictors for total mortality (average 50% attenuation in RII), CVD (55%), and ‘other’ causes of death (49%). When the nine traditional risk factors were added to the age-adjusted model, the comparable reduction in RII was less marked than that seen after IQ adjustment: all-causes (40%), CVD (40%), and ‘other’ mortality (43%).

Adding IQ to the latter model resulted in marked, additional explanatory power for all outcomes in comparison to the age-adjusted analyses: all-causes (63%), CVD (63%), and ‘other’ mortality (65%). When we utilized IQ in early adulthood rather than middle-age as an explanatory variable, the attenuating effect on the socio-economic gradient was less pronounced although the same pattern was still present.

Conclusion: In the present analyses of socio-economic gradients in total and CVD mortality, IQ appeared to offer greater explanatory power than that apparent for traditional CVD risk factors.

European Heart Journal 2009 30(15):1903-1909

WCRF crooks now attacking ham sandwiches

The newspaper accepts them as cancer experts. Frantically fundraising frauds would be a better name. They seem to come out with these scares every few months. Some background on the WCRF and their unsubstantiated scares here and here

Parents are being warned not to put ham, bacon and other processed meats in their children's packed lunches. Ham sandwiches are given to thousands of children every day in packed lunches. Many parents regard them as a healthy option. Now, however, parents are being urged not to put the sandwiches in their children's lunch boxes - because of the cancer risk. Ham, bacon and other types of processed meat raise the risk of bowel cancer over a lifetime, according to a cancer charity.

Giving sandwich fillers such as ham and salami to children means they get into habits that increase their risk of developing cancer later in life, it claims. Healthier alternatives are fish, low-fat cheese, houmous, or small amounts of unprocessed, lean meat such as chicken.

Scientists estimate that in the UK about 3,700 bowel cancer cases could be prevented if everyone ate less than 70grams of processed meat a week, which is roughly the equivalent of three rashers of bacon.

The World Cancer Research Fund charity said that although the research has not specifically looked at the effect of eating processed meat in childhood [That's a great basis for decision-making, isn't it?], the 'convincing' evidence in adults makes it important to teach children to avoid it where possible. Marni Craze, children's education manager for the charity said: 'If children have processed meat in their lunch every day then over the course of a school year they will be eating quite a lot of it. 'It is better if children learn to view processed meat as an occasional treat if it is eaten at all.

'We also need to do more to raise awareness of the issue, as a recent survey has shown that two thirds of people in Britain do not know that eating processed meat increases the risk of cancer. [Because it doesn't] 'This is despite the scientific evidence about a link being convincing.'

The warning applies to meats that have been processed by smoking or having salt or additives put in them. It does not relate to cooked meat, although the charity recommends limiting the intake of red meat to 500grams (cooked weight) per week to cut down the risk of developing bowel cancer.

The charity also says packed lunches that contain sugary drinks and items high in fat and calories could indirectly raise the risk of cancer by making children overweight - with the extra pounds carried into adulthood. [Funny that middling-weight people live longer, isn't it?]

Miss Craze said: 'If children are regularly eating high-calorie foods or sugary drinks then they are more likely to become overweight. Putting ham in your child's sandwich might seem like a convenient option, particularly for parents who do not have a lot of time to prepare their child's lunch box. 'But packed lunches are a part of a child's diet that is relatively easy to control. 'Putting some salad into a sandwich will count towards the five portions of fruits and vegetables children should be eating every day. [And that rule is totally made-up, with NO experimental support] 'A small fruit juice instead of a fizzy drink will also give a portion. Chicken that has not been processed, fish, houmous or low fat cheese are easy alternatives.'

Last year, the WCRF claimed that, after not smoking, staying a healthy weight is the most important way to prevent cancer. In 2007, the charity also blamed drinking and everyday foods, including processed meats, for cancer. Among the findings of the analysis of thousands of studies on lifestyle and cancer was that small amounts of processed meat raise the risk of bowel cancer by 20 per cent. Processed meats may also trigger cancer in the prostate, lung, stomach and oesophagus. Last year, the charity linked the research to a warning about traditional cooked breakfasts.



John A said...

The WCRF,like many others, misses the major cancer-associated risk behavior. I have no doubt that one hundred percent of people who get cancer have, at some time, ingested Di-hydrogen Monoxide. Why are they silent on this major point? Has Big Water been funding them?

Anthony said...

I make similar observations