health risks: how the numbers can be manipulated to scare you
TRANSCRIPT
Dr Arjun Rajagopalan
What’s up?Health risks How the numbers can be manipulated
to scare youDon’t do this;
don’t do that …
Dr Arjun Rajagopalan
It’s clear as mud Coffee is goodCoffee is harmful
Cigarettes - no, no! E-cigarettes - OK Obesity is bad
Says who?
Mediterranean dietAtkin’s diet
Forget dieting
Afraid of dying, afraid of living
Dr Arjun Rajagopalan
Risk is not cause For example:
A high level of cholesterol puts you at higher risk for cardiovascular
disorders but is not the cause of the problem.
Not everyone with high levels gets heart attacks and strokes. Some
people with high cholesterol escape heart attacks AND some people with
normal levels get heart attacks.“Lies, damned lies and statistics” Mark Twain
Dr Arjun Rajagopalan
It’s how you see it
Risk is often depicted in relative terms. The numbers look large and eye-catching
. Headlines sound more dramatic when they say
“4 times higher risk” than “6% increase in risk”
Half empty, or half full?
Risk present(100 people)
Risk not present(100 people)
Disease occurs 8 2
Absolute risk = 8% - 2% = 6% (not so scary)
Relative risk = (8/100)/ (2/100) = 4 (scary)4 times (400%) higher likelihood than those without risk
Dr Arjun Rajagopalan
Risk factor reduction cannot be confidently advocated to individuals
for 2 reasons:
Risk is not the same as cause,
Individuals often differ from the population data (“happy mean”) from which risk is calculated.
Risk represent good sense, not guarantee.
Risk works for populations and groups. It may not work for a
given individual.
What are my chances?