Russians are dying at a rate unprecedented outside times of famine or war in an alarming development that could be tied to rising levels of stress, according to Western experts studying mortality rates here."It's a very disturbing phenomenon," said Michael Ellman, a professor of economics at the University of Amsterdam. "The whole thing is mysterious. I don't know of any similar cases in non-famine, non-war conditions" anywhere in the world.Russia's death rate jumped by 18 percent in 1993, from 12.2 deaths for every 1,000 people in 1992 to 14.5 deaths for every 1,000 people in 1993, according to the State Statistics Committee. By comparison, the death rate in the United States is 9 deaths for every 1,000 people.In real terms, the number of deaths in Russia rose from roughly 1.8 million in 1992 to roughly 2.1 million in 1993, an addition of 300,000 mortalities over a 12-month period.The primary factors responsible for the soaring death rate are an increase in infant mortality, cardiovascular disease, and trauma which includes deaths from accidents, suicide, murder and alcohol abuse, according to Natalya Rimashevskaya, head of the Institute of Socio-Economic Problems of the Academy of Sciences in Moscow.Infant mortality, already high in Russia, rose by 8 percent in 1993, from 17.8 deaths per 1,000 babies in 1992 to 19.3 deaths per 1,000 babies, according to Russian government statistics. Western analysts believe the actual figures are much higher.Russia's mortality rate is inextricably tied to problems associated with the collapse of the Soviet Union such as the country's rising homicide rate, poverty and a dearth of medical supplies. But specialists underscore one fact that may set contemporary Russia apart: Stress can kill."One of the most popular explanations for the rising mortality rate is that people are working and living under stress," said Sergei Litvinov, a regional advisor with the World Health Organization in Copenhagen.The changes of the past several years have been bewildering to many Russians, forced to fend for themselves after a lifetime of having the state tend to their needs. Pensioners, who expected to be supported through retirement, have been driven into poverty by runaway inflation; academics who had devoted decades to their careers have found themselves unable to make a living in their fields; and millions face either unemployment or the constant threat of losing their jobs."People's ability to carry on living is affected by their perception of the environment in which they live," said Ellman. "If you have confidence in your environment as normal and stable, that's an important factor that keeps you alive. If you are completely disoriented from all sorts of shocks, your life is destabilized."The number of deaths resulting from heart disease is a good indicator that stress is playing a major role in increasing Russia's death rate, said Judith Shapiro, a Moscow-based economist. In a recently completed study of summaries of Russian death certificates, Shapiro noted that roughly half of the increased deaths in 1993 were caused by circulatory and heart disease. One quarter were caused by deaths from trauma.She said she did not think deterioration in medical care was responsible for the deaths from cardiovascular illnesses. "There is no evidence whatsoever that more patients are dying in hospitals. It's that more are coming in," said Shapiro, a professor at the University of London.At Moscow's Hospital No. 29, doctors have noticed an increase in heart attacks, particularly among younger patients. Many of the patients are as young as 25 and 30, said Dr. Alexander Lysov, head of the hospital's cardiology department. "Most of them are businessmen and they are having heart attacks for three reasons," Lysov said. "They work intensively with absolutely no rest, they have a bad diet and they smoke and drink alcohol as a way to relax after a hard day at work."Diet plays a key role in the increased number of heart attacks because Russians, who once subsisted largely on bread and potatoes, now have access to more high-cholesterol foods such as meat and Western snacks, said Lysov.Though data on deaths was considered top secret in the Soviet Union, Western economists said they do not question the accuracy of the current statistics."Everybody knows that all statistics, Russian ones in particular, have to be taken with a pinch of salt, but as far as I can make out there is a real phenomenon going on here," said Ellman. "It isn't an illusion created by bad statistics."He said that death rates have increased in several Eastern European countries in recent years, particularly in Romania and Bulgaria, but that Russia's death rate, which has been rising since 1989 after a few years of stability, far exceeds them.