Teenage sexuality spiked in the 1970s and 1980s and then began to decline.   Part of the reason is targeting alcohol, drugs and smoking.  It turns out that while sexual behavior can vary considerably among teens, nonsexual risk behaviors are similar among them, according to study findings from the Journal of Adolescent Health .

Adolescent health risk behaviors often occur together, suggesting that youth involvement with one risk behavior may inform understanding of other risk behaviors, but in a study to examine the association between involvement in non-sexual risk behaviors and trends among sexual behaviors, Mailman School of Public Health researchers found that sexual behaviors vary considerably between those youth engaged in no risk health behaviors and those engaged in multiple health risk behaviors. Despite these differences, trends in sexual risk behaviors among youth engaged in multiple nonsexual risk behaviors -- such as smoking and driving while drinking -- and those engaged in few or no risk sexual behaviors are remarkably similar.

"These analyses suggest caution about assuming that one can readily improve sexual risk behaviors by targeting other teen risk behaviors," says John Santelli, MD, MPH, professor and chair of the Heilbrunn Department of Population and Family Health at the Mailman School of Public Health, and lead author. "Trends in nonsexual health risk behaviors are quite different from patterns of change in sexual behavior and thus are unlikely to be driving trends in sexual behaviors, despite the strong associations between non sexual and sexual risk behaviors."

Dr. Santelli and his team analyzed data from the Youth Risk Behavior Survey, a nationally representative survey of U.S. high school students, collected from 1991 to 2007. Students were categorized into groups according to risky behaviors — such as smoking or alcohol use — and each group was examined for trends in four sexual behaviors: ever having sexual intercourse, having four or more lifetime partners, current sexual activity, and the use of contraception during the last sexual experience. 

The findings indicate that students who engaged in nonsexual high risk behaviors were three times more likely than lower risk students to say they had had four or more lifetime sexual partners. About 87 percent of students engaging in the highest risk behaviors ever had sex, compared with only 13 percent of those engaging in low or no risk nonsexual behaviors. 

However, the data confirm no matter where they fell on the risk spectrum, teens seemed positively influenced by social forces and intervention messages in the 1990s and early 2000s, when there was a decline in sexual experience and number of sexual partners across the board.

"The three biggest changes in adolescent behaviors in the last 16 years have been delaying sex, increasing the use of condoms, and reducing the number of partners," notes Dr. Santelli. "All three are areas that HIV education has clearly identified as goals."

However, while interventions aimed at reducing risky sexual behaviors in adolescents seemed successful for a while, the new data also show that this trend might be reversing, Dr. Santelli said. He also suggests that recent increases in sexual risk behaviors may have ominous implications for prevention of unplanned pregnancy and STIs among youth.