A new study says humanity is hitting the upper limit of life expectancy.  一项新的研究表明，人类正在达到预期寿命的上限。  Developments in medical technology and genetic research are not leading to major increases in lifespan overall, the researchers said.  研究人员表示，医疗技术和基因研究的发展并没有导致整体寿命的大幅延长。  The study was published recently in Nature Aging.  该研究最近发表在《自然衰老》杂志上。  “We have to recognize there’s a limit” and possibly change ideas about when people should retire and how much money they will need to live out their lives, said S. Jay Olshansky of the University of Illinois-Chicago. Olshansky was the lead writer of the study.  伊利诺伊大学芝加哥分校的 S. Jay Olshansky 表示，“我们必须认识到这是有限制的”，并可能改变人们关于何时退休以及需要多少钱来度过余生的想法。奥尔尚斯基是这项研究的主要作者。  Mark Hayward of the University of Texas was not involved in the study. However, he called it “a valuable addition to the mortality literature.”  德克萨斯大学的马克·海沃德没有参与这项研究。然而，他称其为“对死亡率文献的宝贵补充”。  “We are reaching a plateau” in life expectancy, he said.  他说，预期寿命“我们正在达到一个平台期”。  It is always possible that some new development could push survival to greater lengths, “but we don’t have that now,” Hayward said.  海沃德说，一些新的发展总是有可能将生存推向更大的长度，“但我们现在还没有这样的能力”。 Life expectancy is an estimate of the average number of years a baby born in a particular year might expect to live. The measurement assumes death rates at the time of birth do not change.  预期寿命是对特定年份出生的婴儿预期寿命的平均年数的估计。该测量假设出生时的死亡率没有变化。  Life expectancy is one of the world’s most important health measures. Still the life expectancy measurement has problems. For example, life expectancy is an estimate that cannot include new developments or changes that might affect the length of people’s lives.  预期寿命是世界上最重要的健康指标之一。预期寿命的测量仍然存在问题。例如，预期寿命是一种估计值，不能包括可能影响人们寿命长度的新发展或变化。  These unknown developments could include pandemics or new treatments for diseases.  这些未知的发展可能包括流行病或疾病的新疗法。  In the recent study, Olshansky and other researchers followed life expectancy estimates for the years 1990 to 2019. They took information from a database administered by the Max Planck Institute for Demographic Research.  在最近的研究中，奥尔尚斯基和其他研究人员跟踪了 1990 年至 2019 年的预期寿命估计。他们从马克斯·普朗克人口研究所管理的数据库中获取信息。  The researchers paid special attention to eight of the places in the world where people live the longest: Australia, France, Hong Kong, Italy, Japan, South Korea, Spain and Switzerland. 研究人员特别关注了世界上人们寿命最长的八个地方：澳大利亚、法国、香港、意大利、日本、韩国、西班牙和瑞士。  The United States does not rank in the top 40, but it was included in the study because the researchers live in the U.S. Also, some experts have made estimates that life expectancy in the U.S. would increase greatly in the 2000s, Olshansky said.  奥尔尚斯基表示，美国并未进入前40名，但由于研究人员居住在美国，因此被纳入研究范围。此外，一些专家估计，美国的预期寿命将在2000年代大幅增加。 Women continue to live longer than men. Female life expectancy improvements are still happening — but at