[VladVladikoff]

One problem with nutrition based science is it suffers from nutrigenomics bias. It’s possible to study small cohorts of similar genetics and come to conclusions which fail to extrapolate to larger populations. It’s possible that this same problem does not apply to air filtration.

[ted_dunning]

It's possible, but much less likely since they controlled for demographics and cited a number of related studies that show comparable effects.