Human aging is marked by a steady rise in the risk of dying with age-a process demographers call senescence. Over the past century, life expectancy has risen dramatically, but is this because we are aging slower, or simply starting it later? Vaupel hypothesizes that the pace at which individuals age may be constant, with gains in longevity coming from the delayed onset of senescence rather than its slowing down. We test this idea using a new framework that decomposes the pace of senescence into three components: a biological baseline, a long-term trend, and the cumulative impact of period shocks. Applying this to cohort mortality data above age 80 from 12 countries, we find that once period shocks are accounted for, there is no statistical evidence of a long-term trend, consistent with Vaupel's hypothesis. Analyses using lower starting ages yield the same qualitative conclusion. Rather than indicating a change in the process that drives senescence, these variations are consistent with echoes of shared historical events. These results suggest that while longevity has shifted, the rhythm of human aging may be conserved.

翻译：人类衰老的特征是死亡风险随年龄稳步上升——人口学家称之为衰老过程。过去一个世纪里，预期寿命显著增长，但这究竟是因为我们衰老得更慢，还是仅仅因为衰老开始得更晚？沃佩尔假设个体衰老的速度可能恒定，长寿获益源于衰老起始的延迟而非其减速。我们采用新框架将衰老速度分解为三个组成部分：生物基线、长期趋势和周期冲击的累积效应。将此框架应用于12个国家80岁以上人群的队列死亡率数据后发现，在控制周期冲击后，不存在支持长期趋势的统计证据，这与沃佩尔假设一致。采用更低起始年龄的分析也得出了相同定性结论。这些变异并非指向驱动衰老过程的改变，而是与共同历史事件的回声相吻合。结果表明，尽管长寿水平已发生转变，人类衰老的节奏可能保持守恒。