When predicting biological age in research, regression to the mean can be an issue. Marije Sluiskes and others from LEGend posted a PubPeer comment (a postpublication peer review platform) to a recent publication of Daunay et al. 2022 (Aging) which did not consider this phenomenon.

Daunay et al. compare four types of epigenetic clocks in three groups: semi-supercentenarians (mean age ± standard deviation: 101.3 ± 1.4), offspring of nonagenarians and centenarians (61.2 ± 6.1), and individuals from the general population (56.0 ± 4.7). The authors suggest that the first two groups have slower epigenetic and biological aging compared to the last. Marije’s comment raises a methodological issue and skepticism about their conclusion.

Originally, the comment was sent as a letter to the editors of Aging, but it did not get considered due to publication priorities. Fortunately there’s PubPeer! See also the GitHub for a brief explainer on the regression to the mean phenomenon in a biological age prediction context.