Much industry was privatised following the break up of the Soviet Union
The rapid mass privatisation which followed the break up of the Soviet Union fuelled an increase in death rates among men, research suggests.
The UK study blames rapidly rising unemployment resulting from the break-neck speed of reform.
The researchers said their findings should act as a warning to other nations that are beginning to embrace widespread market reform.
The study features online in The Lancet medical journal.
The researchers examined death rates among men of working age in the post-communist countries of eastern Europe and the former Soviet Union between 1989 and 2002.
They conclude that as many as one million working-age men died due to the economic shock of mass privatisation policies.
Following the break up of the old Soviet regime in the early 1990s at least a quarter of large state-owned enterprises were transferred to the private sector in just two years.
This programme of mass privatisation was associated with a 12.8% increase in deaths.
The latest analysis links this surge in deaths to a 56% increase in unemployment over the same period.
Mass privatisers: Latvia, Russia, Armenia, Czech Republic, Georgia, Kazakhstan, Kyrgyzstan, Lithuania, Moldova, Romania and Ukraine.
Non-mass privatisers: Albania, Azerbaijan, Turkmenistan, Poland, Belarus, Croatia, Estonia, Hungary, Macedonia, Slovakia, Slovenia, Tajikistan, Bulgaria and Uzbekistan.
However, it found some countries with good social support networks withstood the turmoil better than others.
Where 45% or more of the population were members of at least one social organisation, such as a church group or labour union, mass privatisation did not increase mortality.
But Russia, Kazakhstan, Latvia, Lithuania and Estonia were worst affected, with a tripling of unemployment and a 42% increase in male death rates between 1991 and 1994.
Countries that adopted a slower pace of change, gradually phasing in free-market conditions and developing appropriate institutions, fared much better.
The best were Albania, Croatia, Czech Republic, Poland and Slovenia, which experienced only a 2% increase in unemployment - and a 10% fall in male mortality.
The authors, led by sociologist David Stuckler, from Oxford University, wrote: "The policy implications are clear.
"Great caution should be taken when macroeconomic policies seek radically to overhaul the economy without considering potential effects on the population's health."
Researcher Professor Martin McKee, of the London School of Hygiene and Tropical Medicine, said the death rate was already high in the old Soviet Union, as the healthcare system was inadequate, while rates of smoking and alcohol use were high, and diets poor.
This was compounded as the unemployment rate began to rise as workers suffered from uncertainty and stress.
Not only does stress have a direct effect on health, it is also closely associated with unhealthy lifestyles, such as alcoholism.
Together this raises the risk of heart disease and strokes, as well as mental illness.
"The workplace also tended to provide what healthcare was available, along with social support," he said.
"People got everything from work - and when they lost their jobs all that just went."
In an accompanying article, Professor Martin Bobak and Professor Sir Michael Marmot, from University College London, said the findings were relevant today.
"Countries in other regions are, and have been, undergoing economic and social transitions.
"That the extent and speed of such changes are important is increasingly apparent."
However, they stressed that the impact on health also depended on historical and political contexts.