[by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:00.20]A new study suggests there may be a limit to how long people can live. [00:09.48]American researchers found that the longest a human being [00:15.76]can live is about 115 years. [00:22.40]The researchers are with the Albert Einstein College of Medicine in New York City. [00:31.68]Their findings were published in the journal Nature. [00:37.36]The study was based on mortality and population records [00:44.01]from the Human Mortality Database. [00:48.64]The database has a collection of records [00:54.20]from more than 40 countries dating back to 1900. [01:01.60]The researchers found that the average life expectancy [01:07.52]has risen greatly since the 19th century. [01:13.44]This has resulted partly from developments in modern medicine, [01:20.52]including the use of vaccines, antibiotic drugs [01:25.88]and improved treatments for cancer and heart disease. [01:32.08]In addition, there have been many improvements in public health and nutrition. [01:40.52]In 1900, someone born in the United States could expect to live 47 years. [01:50.80]Today, Americans can expect to live to an average age of 80. [01:57.68]According to the U.S. Central Intelligence Agency, [02:03.28]the Mediterranean nation of Monaco [02:07.32]has the highest average life expectancy in the world -- 89.5 years. [02:16.12]Next are Singapore and Japan -- each at 85 years. [02:23.88]The oldest documented person to ever live was Jeanne Calment of France. [02:32.40]Calment was 122 years old when she died in 1997. [02:42.88]An Italian woman, Emma Morano, [02:46.52]is currently recognized as the world's oldest living person. [02:52.20]She is 116 years old. [02:58.52]Researchers in the new study said their findings suggest [03:05.12]that the greatest average human lifespan was reached during the 1990s. [03:13.68]They noted that some individuals born in the U.S., France, [03:19.36]Japan and Britain lived to be at least 110 years old between 1968 and 2006. [03:31.36]But the number of people living past 110 years is very small, [03:39.24]and considered not reachable by most of the population. [03:47.08]The study found that survival rates have improved since 1900, [03:54.00]with some older adults living to age 100 and above. [04:00.04]But then many of those individuals died a short time later, [04:06.80]regardless of when they were born. [04:10.88]The head of the study, Jan Vijg, [04:15.32]is head of the genetics department at Albert Einstein College of Medicine. [04:22.88]He said the findings show a decrease [04:27.28]in the ability to reduce death rates among older adults. [04:32.64]He said this suggests a possible limit to human lifespan. [04:39.44]Brandon Milholland was a lead scientist on the study. [04:45.64]As he noted, "It is possible that someone might live slightly longer, [04:52.56]but the odds of anybody in the world surviving to 125 [04:59.04]in any given year is less than one in 10,000." [05:05.76]Jan Vijg noted that continued medical developments to improve the quality of life [05:14.20]- especially in the developed world - could push average life expectancy beyond 80. [05:23.24]But he said researchers still do not expect [05:28.12]the average human lifespan to ever break 100. [05:34.72]I'm Bryan Lynn. [05:36.12]更多听力请访问51VOA.COM