4 ms·
Aren't the unexposed at a risk of zero? Or was that your point?
by chmod600 5y ago
Aren't the unexposed at a risk of zero? Or was that your point?
- coldtea 5y agoThere's no premise that you need to be exposed to develop some issue X. The comparison is between developing disease X while being exposed to something S, with developing it without being exposed. (The example the parent gives is "HPV and cervical cancer" - it's not necessary to have HPV to get the latter, so those not exposed to HPV don't get a 0% chance of that disease). E.g. say a study finds that if you're exposed to VirusX (or ShouldNotHaveBeenApprovedByFDADrugX, as this applies beyond viruses) you have 10% more chances to develop a heart arythmia than without being exposed to it (which, if I'm not mistaken, the latter should be the same as saying: "as compared to the control group").
- Fomite 5y agoThe unexposed aren't at zero risk, but are often quite close. For example, cervical cancer without HPV infection is extremely rare, but non-zero. Or someone at the party who didn't eat the potato salad could still come down sick by another pathway. On the other hand, for things like environmental exposures, you're often looking at very small increases in risk over baseline. For example, your increased risk of asthma with a higher increase in particulate matter in the air.
- lostlogin 5y agoA good example of this is one’s cancer risk, versus one’s cancer risk after a radiation dose. One is non zero, and the other is non zero + X.