IDUs and non-IDUs sexual partners of IDUs (participants of SATH-CAP study)
Age at first drink affects multiple sex partners through age at sexual debut and injection drug use, but no effect on unprotected sex; age at first drug use not related to sexual risk behaviors.
Men who had sex with a commercial sex worker and those who reported >8 lifetime partners or ≥2 recent sex partners were more likely to have other risk taking behaviors. Men who started sexual activity at a young age, defined as ≤14 years, were also more likely to report >8 sexual partners.
Adolescent girls (participants in the 1999–2003 YRBS survey)
Pregnancy linked with substance use onset; of girls pregnant by age 15 years 16% had smoked marijuana by age 10 years and >20% had smoked cigarettes and initiated alcohol use by age 10 years and marijuana use by age 14 years.
Men reported greater number of sexual partners than women, infrequent condom use at last sex; women ≥20 years of age, with ≥2 heterosexual partners in the past year and a younger age at sexual debut, were significantly more likely to have a prevalent STI.
Adolescents (from high risk families based on fathers’ SUD)
Earlier age at first intercourse and deviant activities of peers each predicted a significantly higher risk of subsequently developing substance use disorders (SUD).
Correlates of unsafe sex included younger age of sexual debut and having a steady sex partner; correlates of illicit drug use included lack of family contact, increased hours in the street daily, having had an HIV test, and older age.
Latina mother-daughter dyads (living in urban area)
Having a mother who used drugs during the participants’ childhood or adolescence was significantly related to age of sexual debut; younger ages of sexual debut were associated with drug abuse and more sexual risk behaviors.
Young adults and adolescents receiving voluntary HIV testing
HIV was associated with drug use and sexual debut with a casual/unknown person among males and suspected/confirmed STI and years of sexual activity among females. Among males, sexual debut >16 years old was positively associated with HIV-infection. Later sexual debut was not protective from HIV in women or men.
HIV seroprevalences per 100 adults 15–49 years old and number of children (younger than 15 years of age) living with HIV infection for the beginning of the year 2000 from the Joint United Nations Programme on HIV
Countries with earlier ages at first sex, higher teenage birth rates, and higher fertility rates had higher HIV seroprevalence.
Factors significantly associated with adolescent initiation of IDU included race other than African American and practices prior to initiating injection including condom use, lack of cocaine use, exclusive crack smoking just prior to initiation, and smoking marijuana.
Adolescent-initiating IDUs were less likely than adult-initiating IDUs to report high-risk sex and injection behaviors and more likely to report high-risk networks. African American IDUs from neighborhoods with large percentages of minority residents and low adult educational levels were more likely to initiate injection during adolescence than White IDUs from neighborhoods with low percentages of minority residents and high adult education levels.
Age at first sex declined among males over the past 30 years but increased recently among females; early sexual debut before marriage precedes a lifetime of greater sexual activity but with more consistent condom use; women who begin to have sex earlier than others of their age are more likely to be infected with HIV.
Women who initiated smoking early (before age 15) and later (at 15 or later) and never smokers
Adult women who initiated smoking early reported more lifetime and recent sexual partners and less condom use and had lower debut ages for coitus, pregnancy, and alcohol consumption.
Men with sexual debut at less age than 15 were more likely to report risk behaviors at first sexual experience: no condom use (19%), a casual partner (26.8%), and not feeling they had been “ready and wanted to have sex” (19.5%); early sexual debut was strongly associated with >3 partners in the past 3 years.
Adolescents and Young Adults (participants in two cohorts, born 12 years apart)
Strong association between substance use and sexual risk behavior during early and late adolescence; significant between-cohort difference was a stronger association between female early adolescent smoking and early sexual initiation in the later cohort. Also, relationships between illicit drug use and both early sexual initiation and multiple sexual partners in late adolescence were significantly stronger among girls.
Adolescents and young adults with STIs in wave 3 of National Longitudinal Study of Adolescent Health
Younger ages at first intercourse were associated with higher odds of STI in comparison with older ages, but the effect diminished with increasing current age. The association between timing of first intercourse and STIs did not vary by gender, race, ethnicity, or parental education.
Early vaginal intercourse was associated with not using a condom at last intercourse, unplanned intercourse in the previous year due to substance use, having a casual partner at last intercourse, and having three or more partners for vaginal intercourse in the previous year.
Sexual initiation was associated with using alcohol or methamphetamine; for males, initiation was associated with friend as a confidant, tobacco use, high perceived risk for HIV, and high STI knowledge; for females, other factors associated with earlier initiation were younger age at interview, living away from family, lacking a family member as a confidant, high-perceived risk for STIs, and ever having smoked marijuana.
HIV-positive men were found to be significantly younger on average when they first had anal intercourse compared with HIV-negative men; men with a history of other STIs were significantly younger; engaging in higher risk sexual behavior was a likely factor, with AFAI generally younger among men who reported >10 sexual partners in the past year and who engaged in group sex and receptive anal intercourse or were drug or alcohol affected during their most recent sexual encounter.
Fertile women (participants of the 2006–2008 National Survey of Family Growth)
Compared with women who were 18 or older at first intercourse, women who were <15 years of age at the time of first intercourse were nearly two times as likely to report a gap in contraceptive use.
High school students (participants of the 2009 Mississippi Youth Risk Behavior Survey)
Older age, being a black, drinking alcohol, or using marijuana or other drugs were associated with early sexual initiation and having multiple sexual partners; heavy smoking was associated with early sexual initiation.
FSWs (participants in Integrated Biological Behavioural Assessment study)
Initiating sexual intercourse before the age of 15, more than 2 years of sex work, testing positive for more than 1 STIs, lifetime IDU history, exchange sex for drugs, and having IDU sexual partners were all associated with HIV seropositivity. Sexual debut <15 was independently associated with HIV.
IDUs (participants of the Vancouver Injection Drug Users Study)
Proportion of young initiators was greater among, females, sex workers, binge drug users, and those who have been in juvenile detention or jail; early initiates were more likely to be infected with HIV and hepatitis C virus.
Cohorts of American Indian youths (participants of The Voices of Indian Teens (VOICES, 1993–1995; Waves 1–3) and Pathways of Choices (CHOICES, 1996–1999; Waves 4–7)
For young men, younger initiation of sex was predicted by a greater likelihood of having used alcohol or drugs at first sex; for young women, earlier initiation was related to having mothers who had their first child at an early age and using alcohol/drugs at first sex; higher cumulative risk was associated with elevated risk of sexual initiation.
Having no access to Internet, feeling regretful at sexual debut, having one sexual partner in lifetime, and lower knowledge of condoms predictors of condom nonuse; older age, using alcoholic drinks, early sexual debut, and poor knowledge of reproductive physiology are predictors of multiple sexual partners.
Female teens using 2 illicit substances were 12 times more likely to report early debuts than abstinent teens; females using 3 illicit substances were 44 times more likely to report early debuts.
Young urban IDUs (participants of the REACH III study)
Adjusting for race, gender, and homelessness, following variables independently associated with recent receptive syringe sharing: age at first hit, self-injection at initiation, and using a syringe that had previously been used by someone else at first hit.
Early initiators had an increased likelihood of having had multiple sex partners, forced a partner to have sex, had frequent intercourse, and had sex while drunk or high.
OR of reporting >10 lifetime sexual partners was almost four times higher among women who reported a young age at first intercourse; women who were young at first intercourse were more likely to report two or more recent partners and to have a history of STIs; young age at first intercourse was associated with current smoking and binge drinking.
USA: New York, North Carolina, Michigan, Texas, and California
N = 363 (M; 13–24)
Cross-sectional
Non-White MSM
Participants having a MSM sexual debut before the age of 16 reported more exchange sex, drug use, and emotional/psychological problems related to substance use.
Younger age of first injection was associated with subsequent receptive needle sharing. 47% of respondents shared needles and 22% had sexual intercourse—of whom 7% used condoms. No respondents cleaned needles with bleach.
Participants with early sexual debut (<14) more likely to report lifetime use of marijuana and powder and crack cocaine; early sexual debut was associated with past year sexual risk behaviors, including having sex while high and having two or more sex partners.
HIV seropositivity among ethnic Thai was independently correlated with past history of needle sharing, injecting immediately at drug onset, and starting first injection at younger age.
Sexually active women (from public sector family planning clinic)
Women with early coital debut had a significantly higher risk profile, including multiple lifetime partners; HIV risk was increased for women reporting early age of coital debut.
Lack of condom use at first sex associated with early coital debut and forced sex for males; among females, the likelihood of nonuse elevated for respondents who had an early debut but had not had forced sex, and among those who had had both a later debut and forced sex.
Larger proportion with high intrapersonal risk for unsafe sex (irrespective of ecodevelopmental risk) report early sex initiation and sexually transmitted disease incidence.
Age at first sex decreased linearly with decreasing age at first drink for all adolescents; significant positive trends between age at first drink and age at first sex were observed for all race and ethnic subgroups.
US adult population (participants of the 1996 National Sexual Health Survey)
Early initiation of sexual intercourse was associated with various sexual risk factors, whereas late initiation was associated with fewer risk factors.
African American and Hispanic youths at 7th and 8th grade
Early drinking was associated with alcohol and sexual risks through midadolescence; more likely to report subsequent alcohol problems, unprotected sexual intercourse, multiple partners, being drunk or high during sexual intercourse.
Roughly 50% injection heroin users reported sharing injection equipment/paraphernalia and 40% of total sample (opioid and heroin users) engaged in HIV-sexual risk behaviors.
Being 44 years or younger; not holding regular job; initiating drug use at age 23 or younger; being a morphine user; sharing injecting equipment and having multiple-sex partners were all risk factors associated with HIV seropositivity, though only last 2 remained significant in multivariate analysis.
Sexually active women (participants of MIRA study)
Lowest quintiles of age at sexual debut, a higher number of lifetime sexual partners, and being diagnosed as having STIs were significantly associated with prevalent HIV infection.
Adolescents (participants of the 2004 National Surveys of Adolescents)
Initiation of sexual activity <14 years of age was more likely to be associated with having a casual sex partner and less likely to be associated with condom use at first sexual relation or with systematic condom use in the past 12 months.
