Correlation or Cause?

Friday 5 August 2011

Heart disease factor?

A recent study by Kimber Stanhope at the University of California, Davis has been released that claims to establish a link between sugary diets and heart disease.  The study is based on a trial group of 48 men who limited their sugar intake for just over one month.  After this time, three groups of adult men were given one of three diets with a quarter of their calories coming from sugars either glucose, fructose or high fructose corn syrup (HFCS).  HFCS is a major constituent of most soft drinks and processed foods. Glucose and fructose are naturally occuring sugars while HFCS is a processed sweetner made from maize ( corn ). 

"within two weeks, study participants consuming fructose or high fructose corn syrup exhibited increased bloodstream concentrations of three known risk factors for heart disease: LDL cholesterol, triglycerides and a protein known as apolipoprotein-B, which can lead to plaque buildup in arteries."[1]

The controlled group consuming the glucose diet did not exhibit elevated levels of these indicators, according to the study.

Factors that increase the risk of heart disease is addressed in Option H - Human Physiology.  The concept of correlation or cause and effect  appears in Statistical analysis.  A correlation refers to the relationship between two variables.  A positive correlation is one where as one variable increases so does the other.  When the slope or gradient of the line of best fit is +1, there is a strong correlation.  But a correlation does not necessarily mean that one variable causes the other variable to increase. A causative situation means that an increase of y values is due only to the increase of x values.  This can only be shown by controlled experiments in carefully planned studies.

This study shows that indicators of heart disease are increased with the non-glucose diets.  These indicators are nearly always high in those people who suffer from heart diseases so the justification for the causative agent.


Footnotes

  • 1. Stanhope, Kimber. "UC Davis News & Information :: Eating too much sugar can increase heart disease risk factors, study finds." UC Davis News & Information. N.p., n.d. Web. 5 Aug. 2011. .

Tags: heart cardiovascular diet sugar cholesterol optA topic6