A key goal in ageing research is not just to extend life, but to ensure more people live longer and healthier lives with less variation in age-at-death; a concept known as “squaring the survival curve.” Using a recent meta-analysis, Dr Tahlia Fulton and Associate Professor Alistair Senior from the University of Sydney School of Life and Environmental Sciences re-examined how dietary restriction and two related drugs, rapamycin and metformin, affect variation in age-at-death in vertebrates.
While two of the treatments increased average lifespan, all three increased variance. This means current lifespan-extending interventions do not "square the survival curve". Instead, the gains in average lifespan are matched by proportional increases in variability.
Dr Fulton said: "These approaches can make animals live longer, but the benefits aren’t shared equally. Without more information, the outcome looks like a biological lottery. We’re working to understand why, so future longevity science helps everyone."
Biology Letters
Meta-analysis
Animals
'No evidence for squaring the survival curve: lifespan-extending treatments increase variation in age-at-death'
24-Feb-2026
No conflicts.