Looks like the statistical geneticists have jumped the shark with this one. This big problem here is that their endpoint (chills) is poorly defined, reported by subjects (and thus highly subjective), and not measured using any type of validated instrument. So I question whether they might be fitting a model to noise here.

In the land of drug development patient reported outcomes, even when captured with meticulously designed instruments in prospectively designed clinical trails, are notorious for being noisy and confounded by the placebo effect.