In both countries, study participants over 50 years of age were divided into three groups by total household wealth and their health was tracked up until 2013.
The researchers set out to examine how long people in England and the USA could expect to live free from disabilities, such as being unable to get in and out of bed or to cook for themselves.
Dr Paola Zaninotto (UCL Epidemiology and Health Care), lead author of the study, said: "While life expectancy is a useful indicator of health, the quality of life as we get older is also crucial".
The study, which looked at 10 years of data, investigated socioeconomic inequalities in disability-free life expectancy in older people in England and the US.
The paper shows that at 50 the wealthiest men in England and the United States lived about an additional 31 healthy years, compared with about 22 to 23 years for those in the poorest wealth groups. The U.K., meanwhile, established its National Health Service (NHS) in 1948. Previous research also has shown that Americans are worse off in terms of health compared to the British.
Of course, lack of access to health care isn't the sole reason for declining health, researchers note. "We have shown that in England and the United States, despite living longer lives, not all the increased years of life are being spent in optimal health".
Women from the wealthiest groups in the United States and England lived around an extra 33 years in good health compared with 24-25 years for the poorest.
People with more money, the study found, were living "disability-free" lives for almost a decade longer than those with less money. "Furthermore, our results of similar levels of socioeconomic disadvantage in health expectancy in England and the United States suggest that in both countries greater efforts should be put into reducing health inequalities".
Researchers said they hope that this contribution to the growing literature about income inequality and quality of life motivates policymakers to make health care accessible to everyone. Since those with a lower socioeconomic status are more likely to get sicker and die early, they are less likely to be shaping American politics; which is why we have a stereotype of right-leaning seniors, as the wealthy - and thus more likely to lean right - merely live longer.