ESPE Yearbook of Paediatric Endocrinology

To read the full abstract: Cell Reports vol. 29,13 (2019): 4276–4284.e3. doi: https://www.sciencedirect.com/science/article/pii/S221112471931589X?via%3Dihub

This study identifies that aging starts very early in life and is best defined by molecular damage rather than mortality.

Clinically, aging is classically defined by the age-related increases in frailty and mortality (1, 2). However, human mortality rates start high at birth then decline until puberty when it reaches its minimum (3). In this article, all-cause mortality rates were obtained from the Human Mortality Database for the years 1999–2015 and combined across 19 countries with very low child mortality and low adult mortality rates (4). Cause-specific mortality data from 1999 to 2013 were obtained from the US Center for Disease Control and Prevention (CDC) National Center for Health Statistics. The authors showed that the relationship between age and mortality is a U-shaped curve, with its lowest point before puberty at age 9 years. To the contrary, age-associated mutation accumulation in cancer tissues and DNA methylation changes showed a linear increase throughout the whole lifetime, suggesting that decreasing mortality in early life is a separate effect caused by non-aging related mechanisms.

In summary, the authors show that mortality rate reaches a nadir and then starts to increase before puberty. Separately, deleterious molecular changes begin very early in life and are the defining characteristics of aging.

References:

1. Gavrilov L, Gavrilova N. (2004). Why we fall apart: engineering’s reliability theory explains human aging. IEEE Spectr. 41:31–35.

2. Jones O, Scheuerlein A, Salguero-Gómez R. et al. (2014). Diversity of ageing across the tree of life. Nature. 505: 169–173.

3. Levitis DA. (2011). Before senescence: the evolutionary demography of ontogenesis Proc. Biol. Sci. 278:801–809.

4. Milne EM (2006). When does human ageing begin? Mech. Ageing Dev. 127:290–297.