人的寿命有上限吗？新研究指出，没有上限

一份新的研究激起了一个老生常谈的基本生物学话题，也是生命科学领域的一个重要争议，那就是：人的寿命到底有没有上限？

这份研究报告发表在《科学》杂志上，意指人的寿命并没有上限。（《自然》杂志指出，这一发现与其他生物和人口统计学家作类似研究后的发现相矛盾。）

研究团队考查了大约4000名105岁及以上的高龄意大利人，他们发现在这些“超级年长”的人群中，过了某一节点后死亡风险反而趋于平缓。一般人随着年纪变大，死亡风险增加，尤其是到了八九十岁。但罗马大学的伊丽莎贝塔·巴尔比和罗马第三大学的弗朗西斯科·拉贡纳认为，人到了105岁期颐之年后，来年就去世的可能性反而降低至50%。

研究者们强调了其数据的可靠性，并认为他们的“预测摆脱了那些限制早期研究者的人为因素，提供了迄今为止关于超高年龄人群中存在‘ 死亡高原’的最佳证据”。如果高龄后确实存在“死亡高原”，理论上死亡并不必然。

但并不是所有科学家都会达致这样的结论，比如说纽约阿尔伯特·爱因斯坦医学院的研究团队，在分析了世界最高龄人群的年纪后，认定人的寿命的上限是115至125岁。（好奇者可知：有记录的最长寿的人是法国老妇雅娜·卡尔芒，1997年她去世时，享年122岁。）

阿尔伯特·爱因斯坦医学院的研究员们在2016年的一份报告中写道：“通过分析全球人口数据，我们发现在达到100岁高龄后，人的生存能力趋于下降，全球最长寿人士的死亡年龄在90年代以后并没有提高。我们的研究结果明确显示，人类的最长寿命是固定的，而且受自然的约束。”（财富中文网）

译者：宣峰

New research has revived one of the longest standing, and biologically fundamental, debates in the life sciences: Is there a set limit to how long humans can live?

The study, published in the journal Science, suggests that maybe there isn’t. (It should be noted that this finding contradicts other, similar research by biologists and demographers, as Nature notes.)

Researchers examined a population of nearly 4,000 Italians who were 105 years or older. What they found was that mortality risk essentially plateaus after a certain point for these “super-elderly” individuals. The risk of death increases gradually the older that someone gets, especially as they reach their 80s and 90s. But, say Sapienza University’s Elisabetta Barbi and University of Roma Tre’s Francesco Lagona, after reaching the ripe old age of 105, the odds of dying within the following year essentially drop down to 50%.

The researchers emphasized the quality of their dataset, asserting that their “estimates are free from artifacts of aggregation that limited earlier studies and provide the best evidence to date for the existence of extreme-age mortality plateaus in humans.” If a mortality plateau really does occur at higher ages, that theoretically means death doesn’t have to be an inevitability.

Not all scientists have reached that conclusion. For instance, a team from New York’s Albert Einstein College of Medicine analyzed the ages of the world’s oldest people and pegged the maximum length of human longevity at somewhere between 115 and 125 years. (For the curious: The oldest person ever in recorded history was a French lady named Jeanne Calment, who died at 122 years of age in 1997.)

“[B]y analyzing global demographic data, we show that improvements in survival with age tend to decline after age 100, and that the age at death of the world’s oldest person has not increased since the 1990s. Our results strongly suggest that the maximum lifespan of humans is fixed and subject to natural constraints,” wrote the Albert Einstein researchers in their 2016 report.