Alcohol taxes can decrease STD rates, according to a series of U.S. studies. The latest such paper looked at the effects of a large increase in liquor taxes in Maryland.

But the expected decrease in infections only appeared in one of the two diseases they were looking at – and some critics doubt the cause-and-effect connection between taxes and health.

The new American Journal of Preventive Medicine study drew a connection between the large 2011 Maryland state alcohol tax increase with gonorrhea and chlamydia rates. 

The state’s tax rate for alcoholic beverages was raised from six to nine percent in July 2011. Monthly gonorrhea cases reported fell from 11 cases per 100,000 people to roughly nine cases per 100,000 people, they found. Throughout the state of Maryland, that would amount to a difference of roughly 1,600 over the course of a year.

[pullquote]The National Bureau of Economic Research independently found that sexual behavior does not directly correlate to drinking rates.[/pullquote]

But the study’s theories did not hold in the chlamydia rates, which actually increased from 35 to 39 cases per 100,000 people after the tax increase was levied.

Still, the authors conclude increased alcohol taxes are a good way to drive down STD rates.

“Right now, the only population-level intervention for STIs recommended by the Centers for Disease Control and Prevention is condom distribution,” said Stephanie Staras, the lead author, from the University of Florida College of Medicine. “However, the effects we observed in this study are comparable to the effectiveness of condom distribution, and taxes generate revenue rather than spend it — making it a powerful option for policymakers to consider.”

The tax-STD connection was previously suggested by a series of studies which have linked increased alcohol taxes with decreased STI rates. Those studies looked at a 2009 Illinois tax increase, and a federal beer tax increase in 1991 which coincided with a marked decrease in gonorrhea and syphilis case nationwide, among other increases. The CDC weighed in, with a 2000 study outlining the theory.

“The postulated causal relation is based on the assumptions that higher alcohol taxes and a higher minimum legal drinking age can reduce alcohol consumption, and that reduced alcohol consumption can reduce participation in risky sexual behavior,” wrote the CDC authors. “With few exceptions most studies have demonstrated that alcohol consumption declines after alcohol tax increases and have detected an association between risky sexual behavior and alcohol or drug use.”

But not all analysis connects the alcohol taxes, drinking, sex, and STDs so cleanly. A 1993 study in the journal American Psychology found that substance use did not correlate directly with “high risk” sexual behavior, and HIV transmission rates.

“We speculate that reliance on conventional wisdom about substance-induced disinhibition hinders progress in this field. An association of substance use and high-risk sex ‘feels’ right, given our folk models of the effects of alcohol and drugs on behavior,” write the authors. “If alcohol and drugs are assumed to cause various disapproved sexual behaviors, then research designed to examine the parameters and moderators of a substance use/sex link will not attract the careful scientific attention that we believe it deserves.”

The National Bureau of Economic Research independently found that sexual behavior does not directly correlate to drinking rates. They found in a 2005 working paper that though a beer tax decreased gonorrhea rates by about 1 percent, but attributed that not to the increase in sex – but a decline in use of condoms. Other laws controlling alcohol consumption didn’t alter the spread of STDs, they concluded.

“Neither the percentage of the population living in dry counties nor laws controlling blood alcohol rates affected either rate of infection,” said Linda Gorman, of the NBER.