The surge in outlets for legal medical marijuana have not boosted pot use by teens, according to a new study by economists at University of Colorado Denver and other colleges.

The economists’ review of national and state surveys and drug tests showed no correlation between an uptick in recent teen drug use and the increased availability of pot.

The best numbers available don’t show any greater use in states that have legalized medical marijuana dispensing, said CU Denver economist Daniel Rees.

“There’s just not a whiff of an increase” in states with more liberal marijuana laws, Rees said. “If anything it goes down.” Those critics pointing to an increase in teen drug use will have to look harder for valid causes, he said.

Some of the vocal Denver critics of expanded marijuana dispensaries were not available Monday for comment on the study. The White House’s Office of National Drug Control Policy criticizes medical marijuana’s spread and draws connections with youth drug use.

Rees and economists from Montana State University and the University of Oregon combed wide surveys from 1993 to 2009. In those years, 13 states including Colorado legalized marijuana for medicinal uses, with varying access to dispensaries.

The data included nationally respected surveys of high school behavior, as well as drug test screens from patients entering federally funded drug treatment centers. The economists’ results found no relation between teen drug use and the availability of medical marijuana in their state.

A subsequent blog post includes alternate statistics from the U.S. Drug Enforcement Agency, meant to illustrate some experts’ assertions that teenage marijuana use is rising.

Michael Booth: 303-954-1686 or mbooth@denverpost.com; Twitter: @MBoothdp

This story has been updated in this online archive. The final paragraph, including a link to a blog post by the reporter offering additional information, has been added.