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NEW YORK (Reuters Health) - A new study finds that the purity of cocaine, heroin and methamphetamines sold illegally in the U.S. tends to decline with distance from the Mexican border -- though, for heroin and methamphetamines, it rises once again in the Northeast.
In general, the greater the purity of an illicit drug, the higher the risk of a user becoming addicted or suffering an overdose. So the findings raise the possibility that drug users in certain U.S. regions face relatively greater health hazards.
Whether that is the case is not yet clear. But now that researchers know how drug purity varies by U.S. region, they say they can look at whether those patterns help predict higher rates of drug dependence and overdose.
In general, it's expected that drug purity would decline the farther it gets from its point of import, which, in the U.S., is most commonly the border with Mexico. Transporting drugs greater distances carries costs -- from financial ones to the increased risk of being caught and arrested -- so traffickers often seek to increase their profits by "cutting" drugs with diluting agents or other substances.
For the new study, published in the journal Addiction, researchers used a database on drug seizures maintained by the U.S. Drug Enforcement Administration to see how the purity of cocaine, heroin and methamphetamine varied by region between 1990 and 2004.
They found that with heroin, purity was highest near the Mexican border, then gradually declined with distance, for about the first 900 miles from the border (which included much of the Midwest). It then started to curve upward again, peaking in the Northeast.
Methamphetamine purity showed a similar pattern, but not until after the year 2000.
Cocaine purity was more across geographic areas, and across time, the study found. Still, purity did tend to be highest within 300 miles of the Mexican border, then dip somewhat with distance.
The findings on methamphetamine were somewhat surprising, lead researcher Dr. James K. Cunningham, of the University of Arizona in Tucson, told Reuters Health.
In more recent years, he noted, Canada has become a larger supplier of meth, and increased imports from southeastern Canada may explain the higher purity of the drug in the northeastern U.S. since 2000.
However, the current findings imply that meth imports from Canada may be a bigger problem than commonly thought, according to Cunningham.
If further research confirms that a region's drug purity translates into greater health risks for users, then that information could be used to better allocate resources, Cunningham said. Local areas known to have greater drug purity might win more funding to improve enforcement or drug-abuse prevention and treatment, for example.
It could also be useful for local treatment programs to know that clients may face more-serious dependence or risks of overdose, according to Cunningham. In addition, he said, local prevention efforts might use that information to warn the public of the relatively increased risks of the drugs sold in the region.
SOURCE: link.reuters.com/veg74n Addiction, August 2, 2010.