The poor levels of life expectancy in the U.S. against other rich nations has been laid bare in a new report, which predicts that minimal gains over the coming years will see the country have similar rates to Mexico by the year 2030.

In general, global life expectancy is on track to increase by the year 2030, according to the study released on Monday, but the U.S. is predicted to continue to lag behind its peers .

"Notable among poor-performing countries is the USA, whose life expectancy at birth is already lower than most other high-income countries, and is projected to fall further behind such that its 2030 life expectancy at birth might be similar to the Czech Republic for men, and Croatia and Mexico for women," the study, published in the U.K. medical journal Lancet, said.

The research – undertaken by the World Health Organization and Imperial College London - assessed life expectancy rates of 35 developed countries across the globe. South Korean women are poised to become the first in the world to have a life expectancy of over 90 by the year 2030 with men from the same nation projected to live to an average of 84.1 years from birth.

However, the U.S. was found to be on course for the lowest average life expectancy levels of all the rich countries worldwide. The study predicted an average age of 83.3 for women and 79.5 for men by 2030, not dissimilar to levels forecast in Mexico and Croatia. Current levels are 76.5 for men in the U.S. and 81.2 women, according to the study.

"(The U.S.) are almost the opposite of South Korea," said Majid Ezzati, professor of global environmental health at Imperial College London and the leader of the latest medical research. "(Society in the U.S. is) very unequal to an extent the whole national performance is affected – it is the only country without universal health insurance," Ezzati added.

The research described how the U.S. has the highest child and maternal mortality, homicide rate, and body-mass index of any high-income country.

"The USA is also the only country in the OECD (Organization for Economic Co-operation and Development) without universal health coverage, and has the largest share of unmet health-care needs due to financial costs. Not only does the USA have high and rising health inequalities, but also life expectancy has stagnated or even declined in some population subgroups," the research document said.

"Therefore, the poor recent and projected U.S. performance is at least partly due to high and inequitable mortality from chronic diseases and violence, and insufficient and inequitable health care."

Gap closing between men and women

The research also found the gap in average life expectancy between women and men is set to narrow as lifestyles become more similar to one another. Traditionally, the research team said men had previously had unhealthier lifestyles which featured more road traffic collisions and homicides.

Much of the increase to global average life expectancy rates had been due to improvements in elderly care rather than significant reductions in childhood deaths, the study said. The researchers suggested the findings could pose a serious challenge for governments when it comes to social care and pensions.

"Places that perform well do so by investing in their health system and making sure it reaches everyone," Ezzati said. "This (study) shows that even if there is a limit to longevity, we are nowhere near it … We should be planning for more life," he concluded.