First author Patricia Cavazos-Rehg of Washington University School of Medicine in St. Louis, found alcohol dependence had the most influence on the number of sex partners.

"Some participants in the study reported 50 or 100 partners, and research shows -- and common sense tells you -- that the more sex partners you have, the more likely you'll encounter someone with a sexually transmitted diseases," Cavazos-Rehg said in a statement. "Chances also increase for unintended pregnancies and other health complications."

The study, published in the journal Alcoholism: Clinical & Experimental Research, found that of those alcohol dependent, 45 percent reported having 10 or more sexual partners.

"To my knowledge, most research in young adults has used a standard of 'up to six' sex partners when examining risk," Cavazos-Rehg said. "But the average number of partners for the people in this study was 9.26, so instead of using 'six or more' partners as our standard for high risk, we increased that number to 10."