Effects of a parent-child communications intervention on young adolescents' risk for early onset of sexual intercourse

CONTEXT: The quality of parent-child communications about sex and sexuality appears to be a strong determinant of adolescents' sexual behavior. Evaluations of interventions aimed at improving such communications can help identify strategies for preventing early onset of sexual behavior. METHODS: A school-based abstinence-only curriculum was implemented among 351 middle school students, who were randomly assigned to receive either the classroom instruction alone or the classroom instruction enhanced by five homework assignments designed to be completed by the students and their parents. An experimental design involving pretest and posttest surveys was used to assess the relative efficacy of the curriculum delivered with and without the parent-child homework assignments. RESULTS: In analyses of covariance controlling for baseline scores, immediately after the intervention, adolescents who received the enhanced curriculum reported greater self-efficacy for refusing high-risk behaviors than did those who received the classroom instruction only (mean scores, 16.8 vs. 15.8). They also reported less intention to have sex before finishing high school (0.4 vs. 0.5), and more frequent parent-child communications about prevention (1.6 vs. 1.0) and sexual consequences (1.6 vs. 1.1). In all significant comparisons, the direction of the findings favored adolescents who received the enhanced curriculum. Dose-response relationships supported the findings. CONCLUSIONS: Parent-child homework assignments designed to reinforce and support school-based prevention curricula can have an immediate impact on several key determinants of sexual behavior among middle school adolescents.     

清晨皮质醇与体脂水平在同伴欺凌与乳房早发育关联间的中介效应

  目的  探讨同伴欺凌与女童乳房早发育间的关联及潜在机制,为预防女童性早熟提供新策略。  方法  选取来自马鞍山市市区3所小学950名女童[平均年龄为(9.0±1.2)岁]进行研究,使用修订版《欺凌/受害者调查问卷》(BVQ)评估同伴欺凌,由1名儿童内分泌女医生评估受试女童乳房Tanner分期。使用Salivette?唾液采集器采集所有女童清晨起床唾液样本,体脂率使用生物电阻抗分析法测量。通过逐步Logistic回归分析同伴欺凌与乳房早发育之间的关联,用Logistic回归估算中介系数。  结果  受试女童中,23.2%(220/950)报告自今年年初以来在学校经历过同伴欺凌。同伴欺凌组的乳房早发育女童占比(24.1%,53名)高于未经历过同伴欺凌组(13.7%,100名)。Logistic回归分析表明,调整体脂率和清晨皮质醇水平后,同伴欺凌与乳房早发育相关(OR=1.74,95%CI=1.16~2.59)。中介分析表明,高皮质醇水平和高体脂率在同伴欺凌和乳房早发育之间都有间接影响,中介效应值分别为0.37,0.45。  结论  在女童中,同伴欺凌与乳房早发育显著相关,可能与HPA轴异常活动和高体脂水平有关。     

Friends' influence on adolescents' first sexual intercourse

CONTEXT: Social-psychological theories of health behavior suggest that adolescents' sexual behaviors are influenced by the sexual attitudes and behaviors of their friends. METHODS: Data on 2,436 participants in the National Longitudinal Study of Adolescent Health (Add Health) who were sexually inexperienced at Wave 1 (1994-1995) were analyzed to examine whether friend-related variables predicted initiation of vaginal intercourse by Wave 2 (1996). Analyses also assessed whether predictive relationships varied by level of involvement with friends. Odds ratios were generated by logistic regression analysis. RESULTS: In the 9-18 months between Waves 1 and 2, 18% of participants initiated intercourse. In analyses controlling for gender, family structure and romantic relationships, the higher the proportion of a youth's friends who were sexually experienced, the greater the odds of sexual debut (odds ratio, 1.01); the odds also were elevated among youth who believed that they would gain their friends' respect by having sex (1.2). Relationships between friend variables and sexual initiation did not vary by level of involvement with friends. CONCLUSIONS: To maximize the likelihood of success, programs focused on delaying teenage sexual intercourse should address norms for sexual behavior among adolescents' close friends as well as the perceptions, skills and behaviors of individual youth.     

Predictors of early first sexual intercourse among adolescents in Cape Town, South Africa

Early coital debut is a risk factor for HIV. In this paper weinvestigate the predictors of young adolescents' transitionto first intercourse using a social cognition theoretical framework.The analyses reported here were based on a longitudinal studyof 2360 students in the schools allocated to the control armof a cluster-randomized controlled trial to investigate theeffect of a school-based HIV prevention programme among Grade8 students in Cape Town. Structural equation modelling was performedwith Mplus version 3.11. Of the 1440 students who were virginsat baseline, 1144 remained virgins 15 months later and 296 (20.6%)reported having had their first sexual intercourse. Transitionto first sexual intercourse was more likely among males thanfemales, among older students and among students with a lowersocio-economic status. Transition to first sexual intercoursewas significantly associated with intentions to have sexualintercourse, poor self-efficacy to negotiate delayed sex andintimate partner violence. The model predicted 35% of the variancein intentions and 16% of the variance in transition. These findingsindicate some of the factors that influence young adolescent'stransition to first intercourse and that need to be addressedwhen designing effective interventions. Received on June 1, 2007; accepted on October 26, 2007     

Correlates of age at onset of sexual intercourse in African American adolescents living in urban public housing

Research has found the early onset of sexual activity (having sexual intercourse before age 13) among adolescents to be related to teen pregnancy and a range of health-risk behaviors and higher rates of sexually transmitted infections (STIs) and HIV/AIDS. These findings are most prevalent in urban African American adolescents. Using a sample of 299 sexually active African American adolescents living in public housing developments in a large Northeast and a large Mid-Atlantic city, this study assesses the influence of family, peers, and the individual on the age of onset of sexual intercourse. All participants completed surveys in their housing developments. Results indicate an average age of onset of 14. Males reported a significantly younger age of onset and more sexual partners than females. Exposure to delinquent peers and self-efficacy were significant predictors of age of onset. Implications for practice are discussed.     

The frequency of sexual intercourse during pregnancy

Reports of day-by-day sexual activity for the previous week were collected from a total community sample of over 900 pregnant and nonpregnant Thai women of childbearing age during a fertility survey in 1967–1968. About 13% of the women were pregnant. Examination of the women's intercourse frequencies at various stages of pregnancy revealed a downward trend as pregnancy progressed. However, a difference between the mean frequency for age-matched, nonmenstruating, nonpregnant women and that during any stage of pregnancy was not statistically significant at the p =0.05 level (t test, two-tailed) until the seventh month. Much individual variation existed among the women. Complete abstinence from intercourse during the previous week reached a peak of 72.7% in the ninth month. The increase in abstinence with the progression of pregnancy appeared linear. The importance of these data lies in two methodological facts: they were collected from a total population sample and are therefore unbiased by sample selection; the women were not asked to report their average frequencies for some time period in the past. Reports of behavior on each day of only the preceding week were the basis for the conclusion. Although the women are from a different culture, lay and professional advice concerning intercourse during pregnancy is similar to that in the United States. Because intercourse may be discouraged, particularly in the third trimester, it is difficult to attribute the observation of the gradual decline in frequency to a physiological reason. This tempting hypothesis, however, is worthy of further study. Research supported by a grant from the Rockefeller Foundation to the Carolina Population Center.     

Predictors of sixth graders engaging in sexual intercourse

Researchers explored factors related to sixth graders' sexual behavior. First, level of sexual behavior and sexual behavior intentions were examined. Second, health-related risk behaviors and constructs from Social Support and Social Cognitive theories were analyzed based on race and gender to determine their predictive value for sixth graders engaging in sexual intercourse. Findings indicated that very few sixth graders engaged in sexual intercourse or in high-risk behaviors such as smoking. Of the risk factors examined, smoking was the highest predictor of engaging in sexual intercourse for all categories of race and gender. Of the constructs, Efficacy Expectations consistently predicted engaging in sexual intercourse for all race and gender categories.     

Vaginal laceration and hemorrhagic shock during consensual sexual intercourse

Coital injury causing severe vaginal laceration is not uncommon during first coitus. However, hemorrhagic shock during consensual sexual intercourse is quite rare. In this report, there was one 30-year-old, 20-year-old one, and one 24 year-old women who suffered severe vaginal laceration and bleeding during the process of consensual coitarche. All subjects were transferred to the hospital in the condition of impending shock. We found that the lacerated sites were located at right posterior fornices in all cases. We postulate that these vulnerable sites of vaginal laceration may be due to the dextro-rotation characteristics of the uterus and the distensibility of the vagina in this area. The vaginal fornix can be extremely distended during sexual intercourse, making it vulnerable to laceration in this area. Besides, there was a disproportionate genital size in all three cases which may be a cause of vaginal laceration. It is critical that such patients receive a prompt diagnosis to provide efficient management. It needs only simple surgical skills to cure the injury if the vital signs are stable. However, those survivors may need further psychological consultation to prevent negative impact on their future sexual functioning.     

Child sexual abuse and premarital intercourse among high-risk adolescents

This study examined the extent to which child sexual abuse was associated with an increased likelihood of premarital sex among adolescents at high risk of sexual abuse. The sample consisted of 177 teenage girls who, because of evidence of family dysfunction, had become part of a public child welfare system. Half the sample had been placed in a foster home and the remainder were receiving protective services in their own home. About 40% of the teens in both groups had been sexually abused, although teens still living at home were less likely to have reported abuse. Victims of sexual abuse were found to be more likely to have engaged in voluntary sexual intercourse, even after background factors were controlled. Teens in foster home were somewhat less likely to be sexually active than the teens who remained at home.     

Sexual practices in youth: analysis of lifetime sexual trajectory and last sexual intercourse

This article examines the sexual practices of young Brazilians based on data from the GRAVAD Research Project, a household survey targeting males and females from 18 to 24 years of age (n = 4,634) in three Brazilian State capitals: Porto Alegre, Rio de Janeiro, and Salvador. The set of practices experienced over the course of their sexual careers is characterized by traits of social belonging, elements from individual life histories, and prescribed rules of conduct for men and women. The authors compared the young people's range of lifetime practices and those from last sexual relations in order to discuss the spread and incorporation of practices into life histories. The data point to the hegemony of vaginal sex in both the lifetime repertoire of sexual practices and the last sexual encounters, such that vaginal sex provides the prime definition of heterosexuality.     

Characteristics of adult women who abstain from sexual intercourse

OBJECTIVES: To evaluate demographic and behavioural characteristics of sexually active women compared to those who had abstained from intercourse in the past 6 months. METHODS: The study participants were women of childbearing age from six sites in three states in the USA. Survey questions were asked of women who were not surgically sterile and who had not gone through menopause. The main outcome measures were correlates of sexual abstinence. RESULTS: Of the 1801 respondents, 244 (14%) reported abstaining from intercourse in the past 6 months. Univariate analysis revealed that abstinent women were less likely than sexually active women to have used illicit drugs [odds ratio (OR) 0.47; 95% CI 0.35-0.63], to have been physically abused (OR 0.44, 95% CI 0.31-0.64), to be current smokers (OR 0.59, 95% CI 0.45-0.78), to drink above risk thresholds (OR 0.66, 95% CI 0.49-0.90), to have high Mental Health Inventory-5 scores (OR 0.7, 95% CI 0.54-0.92) and to have health insurance (OR 0.74, 95% CI 0.56-0.98). Abstinent women were more likely to be aged over 30 years (OR 1.98, 95% CI 1.51-2.61) and to have a high school education (OR 1.38, 95% CI 1.01-1.89). Logistic regression showed that age >30 years, absence of illicit drug use, absence of physical abuse and lack of health insurance were independently associated with sexual abstinence. CONCLUSIONS: Prolonged sexual abstinence was not uncommon among adult women. Periodic, voluntary sexual abstinence was associated with positive health behaviours, implying that abstinence was not a random event. Future studies should address whether abstinence has a causal role in promoting healthy behaviours or whether women with a healthy lifestyle are more likely to choose abstinence.     

Magnetic resonance imaging of sexual intercourse: initial experience

The objective of this study was to investigate sexual intercourse with magnetic resonance imaging (MRI). A volunteer couple (30 year-old male, 27-year-old female) with a normal sex life, had face-to-face sexual intercourse (reversed missionary position) under MRI. Static and dynamic T2-weighted sagittal sequencies were acquired on the midline before and during vaginal penetration. In this position, before penetration, the vagina was parallel to the pubococcygeal line and had normal anterior convexity. After penetration, accentuation of the vaginal convexity was observed, produced by the penile gland reaching the anterior cul-de-sac and contact with the anterior vaginal wall. The posterior bladder wall was pushed forward and upward, the uterus upward and backward. In this initial experience, we observed a preferential contact of the penis in erection with the anterior vaginal wall and the anterior cul-de-sac in the face-to-face sexual position. MRI allows a noninvasive assessment of sexual intercourse.     

The determinants of sexual intercourse before age 16.

PURPOSE: To identify risk and protective factors for initiation of sexual intercourse before age 16 years at the level of the individual, family, and school. METHODS: A longitudinal study based on a cohort of 1020 people born in Dunedin, New Zealand in 1972/73 and followed up to age 21 years. Demographic characteristics of the sample were similar to the New Zealand population of that age, except that a smaller proportion (3%) were Maori or Pacific Island Polynesian. Information on individual, family and school factors was collected by interview with parents at ages 3, 5, 7 and 9 years and then by postal questionnaire two-yearly up to 15 years. Subjects were assessed two-yearly from age 3 years and interviewed about their behaviours and ambitions at ages 11, 13, and 15 years. Questions about age at first intercourse were asked by computer at age 21 years. Multivariate logistic regression was used to model associations with age of first intercourse less than 16 years. RESULTS: Data on age at first intercourse were available for 926/1020 (91%) of surviving members of the cohort assembled at age 3 years. Overall 27.5% of males and 31.7% of females reported sexual intercourse before age 16 years. In multivariate analyses the independent predictors for early sexual initiation for males were: not having outside home interests at age 13 years, no religious activity at age 11 years, not being attached to school at age 15 years, a low reading score, and a diagnosis of conduct disorder in early adolescence. For females, independent predictors were: socioeconomic status in the middle range, mother having her first child before age 20 years, IQ in the middle range, not being attached to school, being in trouble at school, planning to leave school early, cigarette smoking and higher self-esteem score. CONCLUSIONS: Individual and school factors appear to be more important than family composition or socioeconomic status in the decision to have sexual intercourse before age 16 years. The lowering of age at first intercourse may be partly a cohort effect related to high rates of teenage childbearing in the mothers' generation, and to changes in social acceptability of early sexual behaviour.     

3441名普通高校大学生艾滋病知识及性行为调查

目的 了解我国普通高校大学生艾滋病相关知识的掌握情况及性行为状况,探讨适合我国大学生特点的艾滋病健康教育和行为策略并提供依据。方法 采用自行设计问卷,对全国5所普通高校共3441名大学生进行了问卷调查,内容包括艾滋病相关知识的掌握情况、性行为发生率、艾滋病健康教育需求及高校开展艾滋病健康教育的现状。结果 大学生对艾滋病相关知识的总知晓率为76.2%。艾滋病相关知识的掌握情况在不同性别和年级间存在统计学差异（P〈0.05）。性行为发生率为9.5%;发生过性行为的大学生中,只有20.1%每次都用安全套。87.6%的大学生希望了艾滋病相关知识,只有21.5%的学生表示满意学校当前的艾滋病健康教育活动。结论 应进一步改进高校的健康教育模式和内容,注重艾滋病预防技能的培养。     

Effects of abstinence-only education on adolescent attitudes and values concerning premarital sexual intercourse

This article compares the values and attitudes of two groups of 7th and 8th grade adolescents toward premarital sexual activity. One group received state-funded, abstinence-only education; the other group did not receive that education. Abstinence-only education did not significantly change adolescents' values and attitudes about premarital sexual activity, nor their intentions to engage in premarital sexual activity. The majority of both the treatment and control group subjects expressed disagreement with the statement: "It is okay for people my age to have sexual intercourse," and they did not intend to have sexual intercourse while an unmarried teenager.