scholarly journals Naked mole-rat mortality rates defy Gompertzian laws by not increasing with age

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
J Graham Ruby ◽  
Megan Smith ◽  
Rochelle Buffenstein

The longest-lived rodent, the naked mole-rat (Heterocephalus glaber), has a reported maximum lifespan of >30 years and exhibits delayed and/or attenuated age-associated physiological declines. We questioned whether these mouse-sized, eusocial rodents conform to Gompertzian mortality laws by experiencing an exponentially increasing risk of death as they get older. We compiled and analyzed a large compendium of historical naked mole-rat lifespan data with >3000 data points. Kaplan-Meier analyses revealed a substantial portion of the population to have survived at 30 years of age. Moreover, unlike all other mammals studied to date, and regardless of sex or breeding-status, the age-specific hazard of mortality did not increase with age, even at ages 25-fold past their time to reproductive maturity. This absence of hazard increase with age, in defiance of Gompertz’s law, uniquely identifies the naked mole-rat as a non-aging mammal, confirming its status as an exceptional model for biogerontology.

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
J Graham Ruby ◽  
Megan Smith ◽  
Rochelle Buffenstein

For most adult mammals, the risk of death increases exponentially with age, an observation originally described for humans by Benjamin Gompertz. We recently performed a Kaplan–Meier survival analysis of naked mole-rats (Heterocephalus glaber) and concluded that their risk of death remains constant as they grow older (Ruby et al., 2018). Dammann et al. suggest incomplete historical records potentially confounded our demographic analysis (Dammann et al., 2019). In response, we applied the left-censorship technique of Kaplan and Meier to exclude all data from the historical era in which they speculate the records to be confounded. Our new analysis produced indistinguishable results from what we had previously published, and thus strongly reinforced our original conclusions.


1993 ◽  
Vol 175 (5) ◽  
pp. 447-452 ◽  
Author(s):  
Daniel W. Onyango ◽  
Dominic Oduor-Okelo ◽  
George E. Otiang'a-Owiti

Bone ◽  
2019 ◽  
Vol 128 ◽  
pp. 115035 ◽  
Author(s):  
Shira Carmeli-Ligati ◽  
Anna Shipov ◽  
Maïtena Dumont ◽  
Susanne Holtze ◽  
Thomas Hildebrandt ◽  
...  

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