A landmark new study has revealed that living under communism has caused countries to become poorer and less healthy, with its effects lasting for decades.

By evaluating historical connections between cultures, researchers sought to determine whether living under communism was the factor that had the most profound effect on those with lower income and education levels, and poorer health.

In the first study of its kind, published in the journal Royal Society Open Science, researchers analyzed the fortunes of 44 European and Asian countries, taking into consideration their geography, religion, systems of government and an intangible characteristic called “deep cultural ancestry.”

Researchers matched the established factors against where the countries ranked on the United Nations Human Development Index, which measures per-capita income, life expectancy at birth and the number of years their citizens were educated.

Most of the factors analyzed by the researchers appeared to have minimal or no effect on the disparities between the countries, except for Islamic countries that garnered lower scores on education levels.

The New York Post reported, “Instead, the single strongest predictor for a country’s health, and the second-strongest for its wealth, turned out to be whether its rulers had embraced communism.”

According to the study, after World War II, economic growth in Communist Eastern Europe became slower than that in the West. Despite the collapse of the Soviet Union nearly three decades ago, the effects of communism are still being felt by its citizens.

The study also revealed that communism was responsible for the stagnation of life expectancy in the Soviet Union during the 1970s and 1980s, and those effects continue today.

The researchers wrote, “The proximate causes for this low life expectancy are complex, but high alcohol consumption, smoking and poor workplace safety, as well as low-quality diet and living conditions associated with lower income levels are implicated.”