Correlation of the year: Drinking encourages unsafe sex

If you thought the biggest science stories of 2011 concerned faster-than-light neutrinos, the Higgs Boson or the discovery of ever more exoplanets, you would be wrong.

Researchers at the Centre for Addiction and Mental Health in Toronto, Canada have performed a meta-analysis of 12 previously conducted experiments and found that drinking alcohol makes people want to have unsafe sex. Their paper, Alcohol consumption and the intention to engage in unprotected sex: systematic review and meta-analysis of experimental studies, published in the journal Addiction, showed that alcohol consumption directly impacts a person’s intention to have unsafe sex. That is, the more you drink, the stronger becomes your intention to engage in unsafe sex.

Well I never. Generations of children owe their lives to this phenomenon!

The researchers were actually testing something a little more subtle than this appears. They wanted to test whether alcohol consumption influenced the contraction of HIV via unsafe sex, or whether certain personality traits, such as a disposition to risky behaviour, would lead to both alcohol use and unsafe sex - that is, if the unsafe sex would have happened anyway, regardless of alcohol.

They found that the more people drank, the worse the decisions they made. An increase in blood alcohol level of 0.1 mg/mL led to a 5% increase in the likelihood of unprotected sex.

"Drinking has a causal effect on the likelihood to engage in unsafe sex, and thus should be included as a major factor in preventive efforts for HIV," said principal investigator Juergen Rehm in a statement. "This result also helps explain why people at risk often show this behaviour despite better knowledge: alcohol is influencing their decision processes."

So remember this over the holidays at your work Christmas parties when your boss starts to look good after 8 beers. And at your family gatherings, your second cousin is still related....

References:
Rehm, J., Shield, K., Joharchi, N., & Shuper, P. (2012). Alcohol consumption and the intention to engage in unprotected sex: systematic review and meta-analysis of experimental studies Addiction, 107 (1), 51-59 DOI: 10.1111/j.1360-0443.2011.03621.x