Does tallness cause heart disease? No, but sex does

var citeN=0Popular beliefs about medical problems are occasionally motivated by a statistical phenomenon acknowledged as “spurious relationship”, amid other names. Two variables X and Y are influenced by a third variable C, which prospects to X and Y getting correlated and as a result the effect that X and Y are causally linked.

Just take a search at the desk under, which I blogged about in a prior publish (citeN=citeN+1document.publish(Amount(citeN))). This desk displays that there is a sturdy unadjusted correlation amongst height and arterial stiffness, a marker of coronary heart condition. The likelihood that the correlation is due to possibility is decrease than 1 tenth of a proportion point (P<.001).

Apparently, the authors of the study even use height as a handle variable to slender down the “true” leads to of arterial stiffness (column with adjusted final results), assuming that top did indeed influence arterial stiffness and what they located to be a crucial predictor of arterial stiffness, 2-hour postprandial glucose.

But there is no convincing evidence that top causes coronary heart disease, with exception of pathological extremes – e.g., acromegaly. Extremes are likely to influence statistical benefits relatively, top to conflicting conclusions that stop up currently being disseminated by the well-known media (citeN=citeN+1document.publish(Quantity(citeN))). This is a single of the resources of popular beliefs about health-related problems.

Yet another, a lot more crucial, source are actual confounders. And this takes us back to the issue of top becoming linked with heart condition. In fact, top will usually be significantly related with heart disease in nearly any research that consists of guys and ladies and does not control for biological sexual intercourse.

One particular of the causes is that females all round have a tendency to have a considerably reduce incident of coronary heart ailment than gentlemen. The other is that top is substantially reduced amid ladies than men, on typical, even though there are numerous girls who are taller than the common male.

The table previously mentioned was from a study which includes both sexes. As a result, the robust association amongst peak and arterial stiffness is a “reflection” of the powerful affiliation between currently being male and enhanced arterial stiffness. If 1 were to include a variable coded as for male and 1 for female, and use it in a multivariate examination of predictor of arterial stiffness, jointly with peak, the impact of top would almost certainly “disappear”.

Biological intercourse is the control variable, the “confounder”, that the authors ought to have used to slim down the “true” brings about of arterial stiffness (next column in the desk). In the absence of biological sexual intercourse, managing for top completed something equivalent, but in a “wobbly” way, leaving several readers scratching their heads in confusion.

Title: Does tallness cause heart disease? No, but sex does
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Posted by: Admin Updated at: 12:45 PM