The study, conducted by Professor Carol Jagger and colleagues of the University of Leicester, found that people grew old most comfortably in Denmark, where men could look forward to 23.6 'healthy life years' and women 24.1.
On the other hand, men in Estonia could expect no more than 9.1 trouble-free years after their 50th birthday and women in the eastern European country had just 10.4 years of healthy life ahead of them after turning 50.
The study found that generally, people in 'established' western EU countries were far more likely to enjoy good health in their later years than those in the newer, eastern states.
According to experts, 'healthy life years' provide a better way to make health comparisons between regions than life expectancy.
The study found that in 2005 an average 50-year-old man in the EU could expect to live a healthy active life until the age of 67.3. Women were likely to enjoy good health until 68.1.
However, 'healthy life years' varied by as much as 14.5 years for men and 13.7 for women.
The UK was ranked seventh in the 'healthy life years' league table, with a healthy life expectancy for 50-year-olds of 19.7 years for men and 20.8 for women.
"We noted a large variation in the remaining years spent free of activity limitations in men and women at 50 years of age between the 25 EU countries in 2005," Scotsman quoted the authors, as stating in the Lancet.
The research is published in an early online edition of The Lancet medical journal.