Understanding Absolute Versus Relative Risk and Study Bias

We all have a 100% absolute risk of dying from something. We also have a much smaller absolute risk of developing cancer, having a heart attack, etc.  Although small, these absolute risks accumulate as we age and often accelerate in old age.  This would explain why few children and many more older adults have heart attacks for example.  Knowing your absolute risk is important.  The trick is finding absolute risk information from the literature.

Most studies don’t bother mentioning the absolute risk or they (rightly) point out that absolute risk changes over time and circumstances.  That said, there really should be a database that gives absolute risk for any member of a population dropping dead from whatever your morbid curiosity has led you to try to look up.  Maybe it’s out there and I just haven’t found it.

In the mean time you will encounter many studies that talk about RELATIVE RISK, so let’s look at an example of how the same risk data can be stated as both absolute and relative.  NB – relative risk is also called hazard ratio (HR), relative risk reduction (RRR), or sometimes just risk reduction (RR) and while some […]