An "epidemic" model of sexual intercourse prevalences for black and white adolescents

In adolescence (12-16 years), the prevalence of sexual intercourse increases each year. To explain the increasing yearly prevalences, we propose a recursive equation model of onset of adolescent sexual intercourse. The model allows for an "epidemic" process (the transmission of sexuality from a nonvirgin to a virgin) and a nonepidemic process (two virgins progressing to sexual intercourse). The model also requires that virgin females be pubertally mature before they will progress to sexual intercourse. Adequate fits were obtained to the intercourse prevalences for both black and white respondents. Comparisons of alternative models established that the full model was superior to models that omitted either the nonepidemic process or the requirement of females' pubertal maturation. The model was able to fit both white and blacks simultaneously, assuming equal transition probabilities in both races. Hence, we propose the hypothesis that race differences in sexual intercourse prevalence may be strongly influenced by the age of initiation of the "epidemic" process and by race difference in females' rates of pubertal maturation. The results suggested that most new cases of sexual intercourse arose from the epidemic process and that males were more prone to progress to intercourse, given an opportunity.     

Nature, nurture and first sexual intercourse in the USA: fitting behavioural genetic models to NLSY kinship data

Fisher (1930) presented both theoretical and empirical results concerning genetic influences on fertility. Since then, only sparse research has been done on the genetics of fertility, although more sophisticated methodogy and data now exist than were available to Fisher. This paper presents a behavioural genetic analysis of age at first intercourse, accounting for genetic, shared environmental, and selected non-shared environmental influences. The data came from the nationally representative National Longitudinal Survey of Youth (NLSY). A newly developed kinship linking procedure was used that identifies links for cousins, half-siblings, full-siblings and twins in the NLSY. The results suggest a genetic influence in the overall dataset, and also among whites and in male-male and opposite-sex pairs. Genetic influences were extremely small or non-existent for blacks and for female-female pairs. Shared environmental influences were small for most subsets of the data, but moderate for female-female pairs. Two specific non-shared environmental influences--self-esteem and locus of control--were ruled out as accounting for any meaningful variance, although other general sources of non-shared environmental influence appear potentially important. Analysis of selected samples from upper and lower tails suggested that genetic influences are important in accounting for both early and late non-virginity. These findings are consistent with work reported by Miller et al. (1999), who used molecular genetic methods. Generally, these findings support the existence of genetic influences and implicate non-shared environmental influences as being important determinants of the timing of loss of virginity among US adolescents and young adults.     

Female sexual arousal: genital anatomy and orgasm in intercourse

In men and women sexual arousal culminates in orgasm, with female orgasm solely from sexual intercourse often regarded as a unique feature of human sexuality. However, orgasm from sexual intercourse occurs more reliably in men than in women, likely reflecting the different types of physical stimulation men and women require for orgasm. In men, orgasms are under strong selective pressure as orgasms are coupled with ejaculation and thus contribute to male reproductive success. By contrast, women's orgasms in intercourse are highly variable and are under little selective pressure as they are not a reproductive necessity. The proximal mechanisms producing variability in women's orgasms are little understood. In 1924 Marie Bonaparte proposed that a shorter distance between a woman's clitoris and her urethral meatus (CUMD) increased her likelihood of experiencing orgasm in intercourse. She based this on her published data that were never statistically analyzed. In 1940 Landis and colleagues published similar data suggesting the same relationship, but these data too were never fully analyzed. We analyzed raw data from these two studies and found that both demonstrate a strong inverse relationship between CUMD and orgasm during intercourse. Unresolved is whether this increased likelihood of orgasm with shorter CUMD reflects increased penile–clitoral contact during sexual intercourse or increased penile stimulation of internal aspects of the clitoris. CUMD likely reflects prenatal androgen exposure, with higher androgen levels producing larger distances. Thus these results suggest that women exposed to lower levels of prenatal androgens are more likely to experience orgasm during sexual intercourse.     

Make love to forget: two cases of transient global amnesia triggered by sexual intercourse

Transient global amnesia (TGA) is characterized by a sudden onset and by a typical resolution within several hours. Several precipitating events have been proposed: physical exertion, emotional experiences, etc. The aim of this paper was to present two cases of TGA triggered by sexual intercourse and to suggest a possible mechanism for the development of TGA. In both patients, clinical examination revealed elevated blood pressure. Laboratory examinations and brain CTs were normal. EEG demonstrated diffuse dysrhythmia and slow spike-waves, respectively. SPECT revealed hypoperfusion in the left frontal and right medial temporal regions. Various explanations of the mechanism of TGA are discussed. Based on the observed hypoperfusion in the medial temporal regions, a new hypothesis is advanced, suggesting the possibility that TGA occurs due to a pathologically changed or less adaptable anterior chorioid artery, initially constricted by hypotension following a blood shift from the center towards periphery.     

Use of recall data in survey research on human sexual behavior

Abstract

A critical, but often neglected, concern in survey research is the use of recall data. This article identifies two sources of possible error in restrospective accounts, particularly of human sexual behavior. “Faulty recall” is unintentional false reporting due to poor memory or changing perception of past reality. “Falsified accounts” involve intentional false reporting due to a fear of being honest with the interviewer or a desire to present a false image for ego enhancement. Previous warnings about the use of recall data are reviewed. The variety of ways and the circumstances under which faulty recall and falsified accounts can influence research findings are elaborated. However, with care in data collection and analysis, these problems need not preclude the use of recall data in survey research.     

Influence of sexual intercourse on genital tract microbiota in infertile couples

Several studies have suggested the association of disturbed genital tract microbiota with infertility. Our aim was to clarify the influence of sexual intercourse on partner’s genital tract microbiota in infertile couples. Seventeen couples were studied, and in 5 men inflammatory prostatitis (IP) was diagnosed. Semen samples were collected during menstruation of the female counterpart, two self-collected vaginal samples were taken 3–5 days later – before intercourse and 8–12 h after intercourse. Ureaplasma parvum was found in 59% of women, its prevalence was higher in women whose partner had IP, as well as in half of their male partners. Sexual intercourse caused significant shifts in vaginal microbiota – increase of Nugent score and shifts in cultured microbiota (emergence and disappearance of several species). These changes were less expressed in the presence of normal vaginal microbiota but more prominent in the partners of IP men. These changes may interfere with fertilization.     

A survey on growth and sexual development of adolescent students in Changhua City: growth of body height and weight

In order to understand the physical growth and sexual development of contemporary adolescents, a cross-sectional survey was conducted during the period September 1983 to May 1984. The population came from all the pupils from 4th grade up, and all the junior and senior high students of Changhua City. By using stratified cluster sampling, 1419 boys and 1599 girls participated, ranging in age from 8 to 19 years. Body weight and height were measured. Growth spurt is a unique event during adolescence. It is well shown in the distance curves and pseudo-velocity curves of body height and weight. In boys, the growth spurt of height spanned from 12.0 to 14.8 years, with peak height velocity (PHV) at 13.5 years. In girls it was from 10.0 to 12.6 years and peaked at 11.5 years. The growth spurt of weight occurred from 12.0 to 15.9 years in boys with peak weight velocity (PWV) at 14.5 years, while girls had a growth spurt at 10.0-12.7 years with PWV at 11.5 years. Girls entered into the growth spurt about 2 years earlier, and also entered into PHV, PWV, two and three years earlier respectively than boys, while boys had a more intense and longer growth during the growth spurt than girls. Between 10.0-13.0 years girls were taller than boys, and between 12.0-13.0 years they were heavier than boys. However, from 13.5 years onward girls were soon surpassed by boys both in height and weight. Growth in height after 16.5 years in boys and after 15.5 in girls was minimal. Growth in weight in boys also became minimal after 16.5 years while girls weight even dropped a little bit after 16.5 years. At the mean age of 17.5 years, boys were 168.1 cm, girls were 156.2 cm in average, boys being 12 cm taller than girls after reaching their final height.     

The dynamics of condom use with regular and casual partners: analysis of the 2006 national sexual behavior survey of Thailand

Objective

This study aims to determine factors associated with levels of condom use among heterosexual Thai males in sex with regular partners and in sex with casual partners.

Methods

The data used in this study are from the national probability sample of the 2006 National Sexual Behavior Study, the third nationally representative cross-sectional survey in Thailand. A subtotal of 2,281 men were analyzed in the study, including young (18–24) and older (25–59) adults who were residents of rural areas of Thailand, non-Bangkok urban areas, and Bangkok. Two outcomes of interest for this analysis are reported condom use in the past 12 months by males in relationships with the most recent regular and casual partners who were not sex workers. Chi-square statistics, bivariate regressions and the proportional odds regression models are used in the analysis.

Results

Condom use for men with their regular partner is revealed to be positively related to education, knowledge of condom effectiveness, and pro-condom strategy, and negatively related to non-professional employment, status of registered marriage, and short relationship duration. Condom use with casual partner is positively determined by education, condom knowledge, non-professional occupation, short relationship duration, and lack of history of paid sex.

Conclusion

The national survey emphasized the importance of risk perceptions and condom motivations variables in explaining condom use among men in Thailand. These factors include not only education and knowledge of condom effectiveness and pro-condom strategy but also types of partners and their relationship context and characteristics. Program intervention to promote condom use in Thailand in this new era of predominant casual sex rather than sex with sex workers has to take into account more dynamic partner-based strategies than in the past history of the epidemics in Thailand.     

The association of sexual interest and sexual behaviors among adolescent women: a daily diary perspective

Theoretical and empirical linkages of adult women's sexual interest and sexual behaviors are relatively well-established, but few data address similar issues in adolescent women. This paper reviews data from published reports of associations of adolescent women's sexual interest and various sexual behaviors. All of the papers reported data collected from a single longitudinal cohort of young women. The primary source of data collection was daily diaries, allowing close temporal pairing of sexual interest with sexual behaviors. Young women's sexual interest on a given day was consistently and independently associated with sexual activity on that day, whether the behavior was first lifetime coitus, coitus, fellatio, cunnilingus, anal intercourse, or coitus during menses. We also found no evidence of influence of hormonal contraceptives on young women's sexual interest. Taken together, these data demonstrate the relevance of sexual interest as a key factor in young women's sexuality and sexual behavior.     

Clustering by soft-constraint affinity propagation: applications to gene-expression data

MOTIVATION: Similarity-measure-based clustering is a crucial problem appearing throughout scientific data analysis. Recently, a powerful new algorithm called Affinity Propagation (AP) based on message-passing techniques was proposed by Frey and Dueck (2007a). In AP, each cluster is identified by a common exemplar all other data points of the same cluster refer to, and exemplars have to refer to themselves. Albeit its proved power, AP in its present form suffers from a number of drawbacks. The hard constraint of having exactly one exemplar per cluster restricts AP to classes of regularly shaped clusters, and leads to suboptimal performance, e.g. in analyzing gene expression data. RESULTS: This limitation can be overcome by relaxing the AP hard constraints. A new parameter controls the importance of the constraints compared to the aim of maximizing the overall similarity, and allows to interpolate between the simple case where each data point selects its closest neighbor as an exemplar and the original AP. The resulting soft-constraint affinity propagation (SCAP) becomes more informative, accurate and leads to more stable clustering. Even though a new a priori free parameter is introduced, the overall dependence of the algorithm on external tuning is reduced, as robustness is increased and an optimal strategy for parameter selection emerges more naturally. SCAP is tested on biological benchmark data, including in particular microarray data related to various cancer types. We show that the algorithm efficiently unveils the hierarchical cluster structure present in the data sets. Further on, it allows to extract sparse gene expression signatures for each cluster.     

A sensitivity analysis for nonrandomly missing categorical data arising from a national health disability survey

Using data from 145,007 adults in the Disability Supplement to the National Health Interview Survey, we investigated the effect of balance difficulties on frequent depression after controlling for age, gender, race, and other baseline health status information. There were two major complications: (i) 80% of subjects were missing data on depression and the missing-data mechanism was likely related to depression, and (ii) the data arose from a complex sample survey. To adjust for (i) we investigated three classes of models: missingness in depression, missingness in depression and balance, and missingness in depression with an auxiliary variable. To adjust for (ii) we developed the first linearization variance formula for nonignorable missing-data models. Our sensitivity analysis was based on fitting a range of ignorable missing-data models along with nonignorable missing-data models that added one or two parameters. All nonignorable missing-data models that we considered fit the data substantially better than their ignorable missing-data counterparts. Under an ignorable missing-data mechanism, the odds ratio for the association between balance and depression was 2.0 with a 95% CI of (1.8, 2.2). Under 29 of the 30 selected nonignorable missing-data models, the odds ratios ranged from 2.7 with 95% CI of (2.3, 3.1) to 4.2 with 95% CI of (3.9, 4.6). Under one nonignorable missing-data model, the odds ratio was 7.4 with 95% CI of (6.3, 8.6). This is the first analysis to find a strong association between balance difficulties and frequent depression.     

Feedback reporting of survey data to healthcare aides

ABSTRACT: BACKGROUND: This project occurred during the course of the Translating Research in Elder Care (TREC) program of research. TREC is a multilevel and longitudinal research program being conducted in the three Canadian Prairie Provinces of Alberta, Saskatchewan, and Manitoba. The main purpose of TREC is to increase understanding about the role of organizational context in influencing knowledge use in residential long-term care settings. The purpose of this study was to evaluate healthcare aides' (HCAs) perceptions of a one-page poster designed to feed back aggregated data (including demographic information and perceptions about influences on best practice) from the TREC survey they had recently completed. METHODS: A convenience sample of 7 of the 15 nursing homes participating in the TREC research program in Alberta were invited to participate. Specific facility-level summary data were provided to each facility in the form of a one-page poster report. Two weeks following delivery of the report, a convenience sample of HCAs was surveyed using one-to-one structured interviews. RESULTS: One hundred twenty-three HCAs responded to the evaluation survey. Overall, HCAs' opinions about presentation of the feedback report and the understandability, usability, and usefulness of the content were positive. For each report, analysis of data and production and inspection of the report took up to one hour. Information sessions to introduce and explain the reports averaged 18 minutes. Two feedback reports (minimum) were supplied to each facility at a cost of CAN$2.39 per report, for printing and laminating. CONCLUSIONS: This study highlights not only the feasibility of producing understandable, usable, and useful feedback reports of survey data but also the value and importance of providing feedback to survey respondents. More broadly, the findings suggest that modest strategies may have a positive and desirable effect in participating sites.     

Feedback reporting of survey data to healthcare aides

Background

Modifying the format and content of guidelines may facilitate their use and lead to improved quality of care. We reviewed the medical literature to identify features desired by different users and associated with guideline use to develop a framework of implementability and found that most guidelines do not contain these elements. Further research is needed to develop and evaluate implementability tools.

Methods

We are launching the Guideline Implementability Research and Application Network (GIRAnet) to enable the development and testing of implementability tools in three domains: Resource Implications, Implementation, and Evaluation. Partners include the Guidelines International Network (G-I-N) and its member guideline developers, implementers, and researchers. In phase one, international guidelines will be examined to identify and describe exemplar tools. Indication-specific and generic tools will populate a searchable repository. In phase two, qualitative analysis of cognitive interviews will be used to understand how developers can best integrate implementability tools in guidelines and how health professionals use them for interpreting and applying guidelines. In phase three, a small-scale pilot test will assess the impact of implementability tools based on quantitative analysis of chart-based behavioural outcomes and qualitative analysis of interviews with participants. The findings will be used to plan a more comprehensive future evaluation of implementability tools.

Discussion

Infrastructure funding to establish GIRAnet will be leveraged with the in-kind contributions of collaborating national and international guideline developers to advance our knowledge of implementation practice and science. Needs assessment and evaluation of GIRAnet will provide a greater understanding of how to develop and sustain such knowledge-exchange networks. Ultimately, by facilitating use of guidelines, this research may lead to improved delivery and outcomes of patient care.     

Patient-physician sexual involvement: a Canadian survey of obstetrician-gynecologists.

OBJECTIVE: To determine obstetrician-gynecologists'' (ob-gyns'') awareness of and experience with sexual abuse of patients and former patients and their opinions about appropriate consequences. DESIGN: Mailed survey. SETTING: Canada. PARTICIPANTS: All 792 members of the Society of Obstetricians and Gynaecologists of Canada (SOGC); 618 (78%) responded. Approximately half of all ob-gyns in Canada belong to the SOGC. MAIN OUTCOME MEASURES: Knowledge of sexual involvement by an ob-gyn colleague with a patient or former patient (as defined by the respondents and by the College of Physicians and Surgeons of Ontario [CPSO]), self-report of such involvement, attitudes toward physician sexual abuse, desirable length of time a physician should wait before seeing a former patient in a situation that could lead to a sexual encounter, suggested consequences of sexual abuse. RESULTS: Overall, 10% of the respondents indicated that they knew about another ob-gyn who at some time had been sexually involved with a patient. In all, 3% of the male respondents and 1% of the female respondents reported sexual involvement with a patient; the corresponding proportions of those who reported having been accused of sexual abuse by a patient were 4% and 2%. Significantly more of the female ob-gyns than of their male counterparts (37% v. 19%) reported awareness of a colleague''s sexual involvement with a patient that would meet the CPSO''s definition of sexual impropriety, transgression or violation. Most of the respondents felt that the consequence of proven sexual impropriety should be reprimand and fine (chosen by 33%) or rehabilitation without loss of licence (28%). Most of the physicians supported loss of licence for proven sexual transgression (57%) or proven sexual violation (74%), but fewer felt that loss of licence should be permanent for these types of abuse (4% and 24% respectively). The female ob-gyns supported stronger sanctions against sexual transgression and sexual violation than the male ob-gyns. A wide range of opinion was seen regarding the propriety of sexual relationships with former patients. CONCLUSIONS: Ob-gyns have varied opinions about how sexual abuse of patients should be defined and how it should be sanctioned. There is a discrepancy between proposed public policy and the beliefs of physicians to whom the policy is to be applied.