(Reuters Health) - New research contradicts politicians’ claims that undocumented immigrants are prone to criminal trespasses.

As the percentage of immigrants without papers rose in the U.S. population between 1990 and 2014, arrests for drugs and drunken-driving dropped, according to a study in the American Journal of Public Health.

“The results of this study challenge the notion that undocumented immigrants cause higher crime rates and general chaos in our communities,” said Josefina Alvarez, a psychology professor at Adler University in Chicago, who was not involved with the research.

In the first study of its kind, researchers used immigration estimates from the Center for Migration Studies and the Pew Research Center to test the premise that those who entered the U.S. unlawfully placed the public at greater risk by driving under the influence and using illegal drugs.

Contrary to the rhetoric, with every 1 percent increase in the proportion of undocumented immigrants in a population of 100,000, there were 42 fewer drunken-driving arrests, 22 fewer drug arrests and roughly one less drug overdose, the study found.

Researchers found no difference in the frequency of drunken-driving deaths.

“The debate, both public and political, has far outpaced the research,” said Michael Light, a sociology professor at the University of Wisconsin - Madison who led the study while at Purdue University in West Lafayette, Indiana.

“Our study takes a step toward informing these debates with the available data, which says that as the prevalence of undocumented immigrants increases in society, the prevalence of drug and alcohol problems do not increase in tandem,” he said in a phone interview. “In fact, the data seem to suggest the opposite.”

The study cites politicians’ claims about undocumented immigrants jeopardizing the health and safety of citizens starting in 2006, when an Iowa congressman claimed that 13 Americans died daily as a result of undocumented drunken drivers.

During the 2016 presidential campaign, Senator Ted Cruz promised to build a border wall, which he said would end the nation’s drug epidemic, and President Donald Trump vowed to erect a wall to protect against “bad hombres.”

“We think these conversations are too important to have in the absence of evidence,” Light said. “If you want to fight the opioid epidemic or reduce drunk driving, deporting undocumented immigrants residing in the U.S. is likely not going to be the most effective policy.”

The number of undocumented immigrants living in the U.S. tripled from an estimated 3.5 million in 1990 to an estimated 10.9 million in 2014. At the same time, violent crime rates fell by half, giving pause to arguments that unlawful immigrants increase violent crime, Light said.

Although his study links an increase in undocumented immigration with a decrease in drug and alcohol arrests, it does not establish a causal relationship between the two.

But Alvarez said the new study supports previous evidence that immigrants tend to be law-abiding.

“Although we don’t have as much research on undocumented immigrants as we would like to have, there is plenty of research showing that immigrants in general are less likely to abuse drugs and alcohol than native-born citizens,” she said in an email.

Fear of police surveillance and deportation may deter undocumented immigrants from drinking and driving, or driving at all, Light and his co-authors write.

Alvarez has studied drug and alcohol use among Latinos in the U.S. and has seen a phenomenon dubbed the “immigrant paradox” - immigrants living under stressful conditions in poor, crime-ridden communities are less likely to drink alcohol and do illegal drugs, she said.

The “healthy immigrant thesis” or “Latino paradox” may explain the new study’s findings, Light said.

“When you look at things we think of as predictive of criminal behavior and poor health outcomes - low levels of education, few economic assets, immigrants tend to be engaging in less crime and staying healthier than we would expect,” he said.

SOURCE: bit.ly/2wF9xRQ American Journal of Public Health, online July 20, 2017.