DOI: 10.5061/dryad.dv41ns2c6
title: Code and data from: No evidence for squaring the survival curve; lifespan-extending treatments increase variation in age-at-death

description: Geroscience has the goal of extending lifespan through geroprotective
 interventions. These interventions are typically imparted on groups, with
 their efficacy judged by increases in the average age-at-death. A more
 equitable outcome, which looks beyond the average, is to attain a long
 life for all individuals, such that the average age-at-death is high while
 variability is low. This goal of increasing the mean while reducing
 variation is sometimes referred to as “squaring the survival curve”. A
 recent meta-analysis of vertebrate data found that dietary restriction
 (DR) and the DR-mimetic, rapamycin, generally increase the average
 age-at-death, while metformin (also considered a DR-mimetic) is less
 effective. We have re-analysed this recently published data to study the
 effects of lifespan-extending treatments on variation in the age-at-death.
 On average, all three treatments increase the variance in the
 age-at-death, but not the coefficient of variation (i.e.,
 standard-deviation relative to the mean). This suggests that
 lifespan-extending treatments do not reduce variance and “square the
 survival curve”. Rather, any gains in mean age-at-death are matched by
 corresponding increases in variation. Interestingly, this result is
 consistent with the treatments proportionally reducing both the
 age-dependent and age-independent parameters in a Gompertz-model of
 mortality.
description: # Code and data from: No evidence for squaring the survival curve;
 lifespan-extending treatments increase variation in age-at-death Dataset
 DOI: [10.5061/dryad.dv41ns2c6](https://doi.org/10.5061/dryad.dv41ns2c6) ##
 Description of the data and file structure \######README######
 Analysis.Rmd - code to download data and for all data processing and
 statistical analyses Data published in Ivimey‐Cook, E.R., Sultanova, Z.,
 and Maklakov, A.A., 2025. Rapamycin, Not Metformin, Mirrors Dietary
 Restriction‐Driven Lifespan Extension in Vertebrates: A Meta‐Analysis.
 Aging Cell, p.e70131 Data downloaded from
 [https://doi.org/10.5281/zenodo.15673918](https://doi.org/10.5281/zenodo.15673918) Once downloaded using the code in Analysis.Rmd, the analyses are performed on analysis_data ### analysis_data column names (from Ivimey-Cook and Sultanova et al (2025), downloaded using Analysis): id = 1:911 unique individual ID Author list: list of authors title: title of paper Year: year paper was published (extracted from Scopus/WoS) m_control: control lifespan measure n_control: sample size for control sd_control: standard deviation for control (left blank if not available) se_control: standard error for control (left blank if not available) m_treatment: treatment lifespan measure n\_ treatment: sample size for treatment sd\_ treatment: standard deviation for treatment (left blank if not available) se\_ treatment: standard error for treatment (left blank if not available) m_Measure: median or mean lifespan m_raw: Whether raw data was given to calculate measures. m_time: unit of lifespan measure m_Location: Location of lifespan measure in the paper. Species: species sampled Treatment_Type: Type of treatment used (e.g. fasting, percent reduction, rapamycin..) Treatment_Overall: Broad treatment groups (Rapamycin, Metformin, DR). Treatment_Name: Treatment name in paper Sex: Sex studied Strain: The name of any strain used if appropriate. Other Variables: Whether any other variables tested in the experiment. Notes: Additional notes mice900_keep: whether or not the mice paper passed the 900 day rule. Additional columns are generated in Analysis.rmd under the "Effect size calculation" #### File: Analysis.Rmd **Description:** code to download data and for all data processing and statistical analyses #### File: README.txt **Description:** README text file #### File: Analysis.html **Description:** html proof of Analysis code functioning at time of submission, shows all published results #### File: Fig1_TF.tif **Description:** figure 1 ## Code/software See materials and methods of manuscript. Code can be run in R and/or RStudio. ## Access information Other publicly accessible locations of the data: * [https://github.com/elmacartney/lifespan-extension-variability](https://github.com/elmacartney/lifespan-extension-variability) Data was derived from the following sources: * [https://zenodo.org/records/15673918](https://zenodo.org/records/15673918)