A new study suggests that individuals who contract sexually transmitted infections during their teen years have a greater HIV risk into young adulthood.

Furthermore, the greater the number of STIs contracted during their teen years, the greater the risk of subsequent HIV.

Researchers analyzed a large sample of Philadelphia high school students born between 1985 and 1993 who participated in the Philadelphia High School STD Screening Program.

The program, which includes education about STIs and HIV and STI screening, was studied between 2003 and 2010.

The studied cohort was matched to existing STI and HIV surveillance data sets and death certificates to estimate the connection between existing STIs and potential HIV risk.

Results indicated that 23 percent of participants did test positive for an STI between the ages of 11 and 19. The most common were chlamydia and gonorrhea.

All bacterial STIs reported during adolescence elevated the risk of HIV.

Furthermore, reporting more than one STI during adolescence increased the risk for HIV even more.

The study is published in the American Journal of Public Health.