Question

discuss the concepts of relative risk and absolute risk as applied to eating day to day foods. Use examples from the HERP values to dicuss. For example, red meat, particularly meat cured with nitrites, is a Class 1 carcinogen according to the World Health Organisation

Answer 1

Absolute risk is the chance, or probability, that a specific health event will happen to you (or to anyone in a similar group of people). Absolute risk is risk stated without any context. For example, you have a 50 percent chance of flipping a coin and getting heads. This risk is not compared to any other risk; it’s just the actual probability of something occurring.

Relative risk is a comparison between different risk levels. For example, your relative risk for lung cancer is (approximately) 10 if you have ever smoked, compared to a non-smoker. This means you are 10 times more likely to get lung cancer. But the relative risk (or risk ratio) is not the same as an increase in risk. In fact, it tells us nothing about the actual risk.

That’s what’s disturbing about the sensational attention around the Harvard red meat study’s report based on relative risk: it tells us nothing about the actual risk of eating red meat. The risk estimates for a chemical are based on the assumption that a compound produces a non-cancer effect or is a carcinogen. This judgment is based on the evidence that a chemical compound produced either cancer and/or a non-cancer effect. Since the evidence is never perfect, it is always possible that a compound labeled a carcinogen produces a non-cancer effect in humans, or produces no effect at all. Vice versa, a chemical compound deemed to produce non-cancer effects might in fact produce no such effect in humans or be a human carcinogen. This introduces uncertainty into the calculation of risk, since there it is possible either that the risk is zero or an erroneous critical effect was ascertained. This possibility decreases as the evidence on the effects of the chemical compoundincreases.