Clinician confidence and practices for evaluating bone health in male and female adolescents and young adults with an eating disorder.

Extensive literature exists on bone health in females with an eating disorder, yet few have studied males. Our study assessed clinician confidence and current practices for assessing bone health in patients with an eating disorder. We also aimed to identify any differences in practice based on patient sex. Our 31-item survey, distributed to adolescent clinicians in the United States via the Society for Adolescent Health and Medicine (SAHM) listserv, assessed clinician confidence and practices for assessing bone mineral density in both male and female adolescents with an eating disorder. Findings showed that clinicians (n = 104) were less confident in assessing bone mineral density in males compared to females (p < .001), yet there was no significant difference in rates of obtaining a DXA (p = .390). Although clinicians are less confident assessing bone health in males with an eating disorder than females, this does not appear to result in screening differences.

Clinician practices assessing hypothalamic-pituitary-gonadal axis suppression in adolescents with an eating disorder.

OBJECTIVE: Although extensive literature exists on hypothalamic-pituitary-gonadal (HPG) axis suppression in females with an eating disorder, there are few studies in males. Our study aimed to determine clinician practices for the assessment of HPG axis suppression and to identify differences in practice based on the sex of the patient. METHOD: Our 31-item survey queried clinicians about confidence level and practices for assessing HPG suppression in male compared to female patients. RESULTS: Findings showed that clinicians (n = 104) were less likely to evaluate HPG suppression in males compared to females, including assessment of sexual maturity rating (p < .050), screening of decreased libido compared to amenorrhea (p < .001) and lab assessment (luteinizing hormone and follicular-stimulating hormone: p < .001; estradiol/testosterone: p < .010; TSH: p < .050). Participants also felt less confident evaluating male patients (p < .001) and requested better screening tools for males (p < .001). DISCUSSION: Our data suggest that clinician practices differ based on patient sex and that clinicians request tools for HPG suppression assessment in males. This is the first study examining specific practices and comfort levels of clinicians when assessing HPG axis suppression. Findings suggest that more guidance on the management of male patients may be needed to standardize care and to prevent short and long-term sequela of malnutrition.

Attitudes of Members of Genetics Professional Societies Toward Human Gene Editing.

Gene-editing technologies have improved in ease, efficiency, and precision. Although discussions are occurring around acceptable uses of human gene editing, limited data exist on the views of genetics-trained individuals. In 2017, we distributed an anonymous online survey to assess the attitudes of members of genetics professional societies toward gene editing (N = 500). Virtually all respondents were supportive of somatic editing in basic-science (99.2%) and clinical (87.4%) research on nonreproductive human cells. Only 57.2% were supportive of germline-editing basic-science research; 31.9% supported the transfer of viable embryos to humans for clinical research. While most favored future therapeutic uses of somatic (96.6%) and germline (77.8%) editing, there was little support for enhancement in somatic (13.0%) or germline (8.6%) cells. This study describes attitudes toward gene editing from genetics professionals worldwide and contributes to ongoing discourse and policy guidance in this domain.

Health Care Experiences of Youth Living With HIV Who Were Lost to Follow-up in Western Kenya.

HIV is the leading cause of mortality for youth in sub-Saharan Africa. Youth are more likely than any other age group to be lost to follow-up (LTFU) from care. We investigated the health care-related experiences of youth living with HIV (YLWH) who were LTFU (i.e., had not returned to care for at least 4 months), as well as the perceptions of the community health workers who supported them. Data were collected from two focus group discussions with community health workers (n = 18) who worked with YLWH and 27 semistructured interviews with YLWH (ages 15-21 years) who were LTFU. Attitudes toward health care were presented in the context of a social-ecological model. Respondents highlighted the need for improved youth-oriented services, including youth-friendly clinics and training for care providers about specific needs of YLWH. Researchers should develop and test the impact of these interventions to improve retention of YLWH in care.

Adult Connection in Assault Injury Prevention among Male Youth in Low-Resource Urban Environments.

Strengths-based strategies to reduce youth violence in low-resource urban communities are urgently needed. Supportive adolescent-adult relationships may confer protection, but studies have been limited by self-reported composite outcomes. We conducted a population-based case-control study among 10- to 24-year-old males in low-resource neighborhoods to examine associations between supportive adult connection and severe assault injury. Cases were victims of gunshot assault injury (n = 143) and non-gun assault injury (n = 206) from two level I trauma centers. Age- and race-matched controls (n = 283) were recruited using random digit dial from the same catchment. Adolescent-adult connections were defined by: (1) brief survey questions and (2) detailed family genograms. Analysis used conditional logistic regression. There were no significant associations between positive adult connection, as defined by brief survey questions, and either gunshot or non-gun assault injury among adolescents with high prior violence involvement (GSW OR = 2.46, 95% CI 0.81-7.49; non-gun OR = 1.59, 95% CI 0.54-4.67) or low prior violence involvement (GSW OR = 0.92, 95% CI 0.34-2.44; non-gun OR = 1.96, 95% CI 0.73-5.28). In contrast, among adolescents with high levels of prior violence involvement, reporting at least one supportive adult family member in the family genogram was associated with higher odds of gunshot assault injury (OR = 4.01, 95% CI 1.36-11.80) and non-gun assault injury (OR = 4.22, 95% CI 1.48-12.04). We were thus unable to demonstrate that positive adult connections protected adolescent males from severe assault injury in this highly under-resourced environment. However, at the time of injury, assault-injured adolescents, particularly those with high prior violence involvement, reported high levels of family support. The post-injury period may provide opportunities to intervene to enhance and leverage family connections to explore how to better safeguard adolescents.

The effectiveness of an adolescent reproductive health education intervention in Uganda.

Ugandan adolescents lack sufficient reproductive health knowledge, which accounts in part for the staggering rates of teen pregnancies and sexually transmitted (STI) infections in this population. This study aimed to (1) examine Ugandan adolescents' baseline STI and contraceptive knowledge; (2) determine whether this knowledge varies by demographic factors, prior sexual experience or school grade; and (3) evaluate the effectiveness of an educational program to increase and retain STI and contraceptive knowledge among Ugandan adolescents. This study surveyed 129 adolescents (ages 15-19) regarding knowledge of STIs and contraceptive methods at schools and community non-governmental organizations at three time points. Findings demonstrated that at baseline the mean test scores for contraceptive knowledge and STI knowledge were 44% and 72%, respectively. Participants in higher secondary school grade-levels had greater odds of having prior STI knowledge (OR=19.6, 95% CI 2.0-187.6); participants who had previously engaged in sex had greater odds of having prior contraceptive knowledge (OR=4.62, 95% CI 1.45-14.72). A higher grade level was not associated with better knowledge of contraception; and being sexually active was not associated with better knowledge of STI information. Participants' knowledge of STIs and contraceptives improved after the education session (p<0.001), and knowledge was retained 3-weeks later (p<0.001). Findings suggest that Ugandan adolescents do not have adequate education regarding contraceptive methods and that implementation of reproductive health modules by an outside party can be effective in improving knowledge.

A Longitudinal Study of Adolescents' Optimistic Bias about Risks and Benefits of Cigarette Smoking.

OBJECTIVES: Optimistic bias, a perception that one's own risks are lower than others', can help explain why adolescents smoke cigarettes despite knowing their risks. We examined the extent and changes over time of adolescents' optimistic bias for various smoking-related perceptions of risks and benefits on the aggregate and individual level. METHODS: Longitudinal study (6 measurements over 3 years) of 395 adolescents (mean age 14 years, SD=0.4, at baseline) who rated the chance of occurrence of 19 short- and long-term heath risks, social risks, addiction, and benefits related to cigarette smoking for self and comparable others. RESULTS: Optimistic bias was consistently found only for addiction (83% of comparisons; 37%- 60% of adolescents). Addiction-related optimistic bias decreased significantly with time for "still be smoking in 5 years" (ß = -2.44, p < .001) and for "become addicted" (ß = -1.71, p < .001). This reduction resulted from a greater decrease in perceived risks for others rather than an increase in the adolescent's own perceived risk. For other risks and benefits, adolescents were either realistic or pessimistically biased. CONCLUSIONS: Smoking-related optimistic bias in adolescents was not as prevalent as past studies showed. Anti-smoking interventions targeting adolescents should emphasize the risk of addiction and personal relevance of addiction.

Adolescent (Mis)Perceptions About Nicotine Addiction: Results From a Mixed-Methods Study.

PURPOSE: Despite evidence that adolescents become addicted to nicotine even after limited use, adolescents believe they can experiment with or smoke cigarettes for a few years and easily quit. The goal of this study was to examine adolescents' understanding of the definition and process of nicotine addiction using a mixed-methods approach.Method A total of 367 adolescents with and without smoking experience rated the perceived risk for addiction, still being a smoker in 5 years, and ability to quit smoking. A subsample of adolescents (N= 41) were interviewed about their conceptualization and understanding of nicotine addiction. Within-participants analyses of variance were conducted to assess differences in perceptions of addiction across the three scenarios; thematic analyses of interviews were conducted to assess adolescents' understanding of addiction.Results Adolescents rated their perceived risk for addiction, still being a smoker in 5 years, and ability to quit as significantly different from one another for three different scenarios (F= 7.81, 47.78, and 70.27, respectively;p< .001). Seven themes describing how youth conceptualize and understand addiction emerged from the interview data, including skepticism and uncertainty about addiction, how smoking makes a person feel, and family and friends' experiences. CONCLUSION: While adolescents have received the message that cigarettes are addictive, they are uncertain regarding the definition of addiction and have not recognized that addiction means experiencing difficulty quitting and continuing to smoke longer than expected. Findings suggest the need for comprehensive messaging regarding nicotine addiction in educational, clinical, and intervention settings and for product warning messages aimed at reducing and preventing tobacco use.

Health care providers' comfort with and barriers to care of transgender youth.

PURPOSE: To explore providers' clinical experiences, comfort, and confidence with and barriers to providing care to transgender youth. METHODS: An online survey was administered to members of the Society for Adolescent Health and Medicine and the Pediatric Endocrine Society with items querying about clinical exposure to transgender youth, familiarity with and adherence to existing clinical practice guidelines, perceived barriers to providing transgender-related care, and comfort and confidence with providing transgender-related care. The response rate was 21.9% (n = 475). RESULTS: Of the respondents, 66.5% had provided care to transgender youth, 62.4% felt comfortable with providing transgender medical therapy, and 47.1% felt confident in doing so. Principal barriers to provision of transgender-related care were lack of the following: training, exposure to transgender patients, available qualified mental health providers, and insurance reimbursement. CONCLUSIONS: This study suggests that more training in transgender-related care, available qualified mental health providers, and insurance reimbursement for transgender-related care are needed.

Neighborhood Characteristics and ADHD: Results of a National Study.

OBJECTIVE: We examined the association of neighborhood social and physical characteristics with ADHD, accounting for individual and family factors. METHOD: The 2007 National Survey of Child Health, a nationally representative data set, was used (N = 64,076). Three neighborhood scales were generated: social support, amenities, and disorder. Logistic and ordinal logistic regressions were conducted to examine the association of these scales with ADHD diagnosis and severity while adjusting for individual and family characteristics. RESULTS: Eight percent had a child with ADHD: 47% described as mild, 40% moderate, and 13% severe. In adjusted models, lower neighborhood support was associated with increased ADHD diagnosis (odds ratio [OR] = 1.66 [1.05, 2.63]) and severity (OR = 3.74 [1.71, 8.15]); neighborhood amenities or disorder were not significantly associated. Poor parental mental health was associated with ADHD prevalence and severity. CONCLUSION: Neighborhood social support is a potential area of intervention for children with ADHD and their caregivers. Research challenges and opportunities are discussed.

"It is all about the fear of being discriminated [against] the person suffering from HIV will not be accepted": a qualitative study exploring the reasons for loss to follow-up among HIV-positive youth in Kisumu, Kenya.

BACKGROUND: Youth represent 40% of all new HIV infections in the world, 80% of which live in sub-Saharan Africa. Youth living with HIV (YLWH) are more likely to become lost to follow-up (LTFU) from care compared to all other age groups. This study explored the reasons for LTFU among YLWH in Kenya. METHODS: Data was collected from: (1) Focus group Discussions (n = 18) with community health workers who work with LTFU youth. (2) Semi-structured interviews (n = 27) with HIV + youth (15-21 years old) that had not received HIV care for at least four months. (3) Semi-structured interviews (n = 10) with educators selected from schools attended by LTFU interview participants. Transcripts were coded and analyzed employing grounded theory. RESULTS: HIV-related stigma was the overarching factor that led to LTFU among HIV + youth. Stigma operated on multiple levels to influence LTFU, including in the home/family, at school, and at the clinic. In all three settings, participants' fear of stigma due to disclosure of their HIV status contributed to LTFU. Likewise, in the three settings, the dependent relationships between youth and the key adult figures in their lives were also adversely impacted by stigma and resultant lack of disclosure. Thus, at all three settings stigma influenced fear of disclosure, which in turn impacted negatively on dependent relationships with adults on whom they rely (i.e. parents, teachers and clinicians) leading to LTFU. CONCLUSIONS: Interventions focusing on reduction of stigma, increasing safe disclosure of HIV status, and improved dependent relationships may improve retention in care of YLWH.

Longitudinal study of adolescents' attempts to promote and deter friends' smoking behavior.

PURPOSE: Little research has examined the extent to which adolescents directly attempt to influence friends' smoking. This study examines adolescents' reported actions to promote or deter friends' smoking, and whether actions vary by adolescents' smoking experience. METHODS: Data were collected between 2001 and 2004 at four time points across the 9th and 10th grades from an ethnically diverse school-based sample (N = 395; 53% female). RESULTS: Deterrence of smoking was reported by a greater percentage of adolescents than was promotion of smoking, both among those who had ever smoked and never smoked. By the end of the study, over 45% of ever smokers and less than 5% of never smokers had promoted smoking among friends. In contrast, over 70% of ever smokers and roughly 40% of never smokers had deterred smoking. Among adolescents who had ever smoked, positive consequences of smoking by fall of 10th grade predicted attempts to promote smoking by the end of 10th grade (OR = 4.37, p < .05). To a lesser extent, negative consequences of smoking predicted attempts to deter smoking (OR = 2.60, p < .08). These effects were independent of the opposite type of smoking consequences, level of personal smoking experience, having close friends who smoked, prior attempts to influence friends' behavior, and smoker's gender. CONCLUSIONS: Models of peer influence should account for both positive and negative influence of adolescents on friends' health behavior. Adolescents who have engaged in risk-taking and experienced negative consequences may be a resource in designing and delivering interventions; future research should evaluate their ability to change friends' behavior.

Identification and characterization of adolescents' sexual boundaries.

PURPOSE: Adolescents' decisions to have sex may be based on a priori boundaries placed on sex. This study addresses: (1) to what extent adolescents set vaginal sexual boundaries; (2) the types of sexual boundaries most and least likely to be endorsed; and (3) to what extent sexual boundaries vary by sex, race/ethnicity, and sexual experience. METHODS: A cross-sectional study of 518 students attending 10th grade. Survey measures queried about demographics, ever having sex, and existence of sexual boundaries (e.g., being in love, having an attractive partner) that must be in place before having vaginal sex. RESULTS: The most frequently endorsed boundaries were maturity, commitment, trust, love, and marriage. These boundaries were more frequently endorsed than having a safer-sex method. Compared with females, males were more likely to choose boundaries based on partner attractiveness (p < .001) and avoiding trouble (p < .04). Compared with Asians and Pacific Islanders, whites were more likely to endorse wanting to be a certain age to have sex (p < .01 and p < .05, respectively); Asians and Pacific Islanders were more likely to choose sexual boundaries based on marriage (p's < .05). Adolescents who were sexually experienced were more likely than inexperienced adolescents to endorse boundaries related to relationship characteristics and partner attractiveness (OR = 2.5), and less likely to endorse boundaries related to feeling mature (OR = .34) and waiting until marriage (OR = .34). CONCLUSIONS: Identifying adolescents' sexual boundaries should help healthcare professionals better understand under what circumstances adolescents are more or less likely to have sex; and this information should ultimately inform the development of new interventions.

What does it take to be a smoker? Adolescents' characterization of different smoker types.

INTRODUCTION: Studies have demonstrated that clinical- and research-based definitions of who a smoker is and what constitutes smoking often differ from adolescent-derived definitions, which can be problematic for effective intervention and prevention efforts. We investigated how adolescents define different smoker types (nonsmoker, smoker, regular smoker, addicted smoker, heavy smoker, experimental smoker, casual smoker, and social smoker) using multiple indicators of smoking behaviors, including frequency, amount, place, and length of time cigarette smoking, and whether differences exist by smoking experience. METHODS: Quantitative and qualitative methods were used to analyze data from a cohort of adolescents (N = 372) in northern California. RESULTS: We found differences in how adolescents characterized smoker types based on their own smoking experience. Ever-smokers tended to have a greater flexibility in determining what constituted nonsmoking and heavy smoking, while never-smokers had much narrower definitions. Results also indicated that adolescents may mistakenly associate nicotine addiction with a high frequency and amount of cigarette use as 74.3% characterized an addicted smoker as having smoked for a few years or more. In addition, there was a considerable amount of overlap in definitions between different smoker types, particularly among the smoker-regular smoker, addicted smoker-heavy smoker, and casual smoker-social smoker pairs. CONCLUSION: Health communication strategies for youth smoking prevention need to address the wide variability and overlap in how adolescents define different smoker types. Greater attention should be directed to understanding the nuances of how adolescents define smoking in order to maximize the effectiveness of youth-centered smoking prevention and cessation messages.

Earlier age of smoking initiation may not predict heavier cigarette consumption in later adolescence.

Previous studies suggest that earlier cigarette smoking initiation in adolescence predicts greater cigarette consumption later in adolescence or adulthood. Results from these studies have been used to inform interventions for adolescent smoking. However, previous studies suffer from several important methodological limitations. The objective of the present study was to address these limitations by longitudinally and prospectively examining whether and how age of initiation of smoking among adolescents predicts cigarette consumption by age 16 or 17. Participants completed an in-class survey every 6 months for 2-3 school years. Participants included 395 adolescents (Mean age=14 years at baseline; 53.2% female) from two public high schools in Northern California (Schools A and B) who completed self-report measures of smoking initiation, number of friends who smoke, and number of whole cigarettes smoked by the final survey time point. Adolescents who were older when they first smoked one whole cigarette were 5.3 to 14.6 times more likely in School A and 2.9 to 4.3 times more likely in School B to have smoked a greater number of cigarettes by age 16 or 17. Results suggested that earlier smoking initiation may not lead to heavier cigarette consumption later in time, as has been previously shown. There may be a period of heightened vulnerability in mid- or late adolescence where smoking experimentation is more likely to lead to greater cigarette consumption. Targeting prevention efforts to adolescents aged 14 to 17 years may further reduce smoking initiation among youth, thus limiting subsequent smoking-related morbidity and mortality in adulthood.

Predictive relationship between adolescent oral and vaginal sex: results from a prospective, longitudinal study.

OBJECTIVES: To (1) identify the temporal order between oral and vaginal sex onset; (2) test whether oral sex or vaginal sex is a risk or protective factor for the other; and (3) determine whether the relationship between oral and vaginal sex varies across time. DESIGN: Prospective, longitudinal study with 6-month assessments conducted between 2002 and 2005. SETTING: Self-administered surveys completed during class time. PARTICIPANTS: At baseline, 627 ninth grade high school students from 2 northern California schools were included in the study. MAIN OUTCOME MEASURE: Oral and vaginal sex onset. RESULTS: Among sexually active adolescents, most initiated vaginal sex after or within the same 6-month period of oral sex initiation. Adolescents who initiated oral sex at the end of ninth grade had a 50% chance of initiating vaginal sex by the end of 11th grade. In comparison, adolescents who delayed until the end of 11th grade had a 16% chance of initiating vaginal sex by the end of 11th grade. CONCLUSIONS: The first 2 years of high school may be a critical age period for adolescents' vulnerability to vaginal sex initiation via oral sex behaviors. Comprehensive evidenced-based interventions and provision of preventive services aimed toward reducing sexual risk should be expanded to include the role oral sex plays in adolescent sex behavior.

Predicting adolescent perceptions of the risks and benefits of cigarette smoking: a longitudinal investigation.

OBJECTIVE: To evaluate developmental changes, personal smoking experiences, and vicarious smoking experiences as predictors of adolescents' perceptions of the risks and benefits of cigarette smoking over time, and to identify new and effective targets for youth smoking prevention programs. DESIGN: There were 395 adolescents surveyed every 6 months for two school years, from the beginning of 9th grade to the end of 10th grade. MAIN OUTCOME MEASURES: Time, participant smoking, friend smoking, parental smoking, and sex were evaluated as predictors of smoking-related short-term risk perceptions, long-term risk perceptions, and benefits perceptions using multilevel modeling techniques. RESULTS: Perceptions of benefits did not change over time. Perceptions of risk decreased with time, but not after sex and parental smoking were included in the model. Adolescents with personal smoking experience reported decreasing perceptions of risk and increasing perceptions of benefits over time. Adolescents with more than 6 friends who smoked also reported increasing perceptions of benefits over time. CONCLUSIONS: Changes in risk perceptions may not purely be the result of developmental processes, but may also be influenced by personal and vicarious experience with smoking. Findings highlight the importance of identifying and targeting modifiable factors that may influence perceptions.

Unpredicted trajectories: the relationship between race/ethnicity, pregnancy during adolescence, and young women's outcomes.

PURPOSE: Adolescents who become pregnant in the United States are at higher risk for a myriad of health concerns. One would predict even more adverse health outcomes among pregnant adolescents who are from disadvantaged racial/ethnic groups; however, previous studies indirectly suggest the opposite. This study examines whether adolescents from racial/ethnic minority groups are less affected by adolescent pregnancy compared to white adolescents. METHODS: We used data from 1,867 adolescents participating in the National Longitudinal Study of Adolescent Health (1995-2001). Our predictor variable was self-reported race/ethnicity. Self-perception of health, educational attainment, and public assistance use in young adulthood were outcome measures. We conducted weighted multivariate logistic regressions and analyzed how adolescent pregnancy modified the relationship between our predictor and outcome variables. RESULTS: Black and American Indian young women had significantly higher odds than white young women of receiving public assistance (OR, 2.6 and 2.7, respectively; p <.01) and even higher odds if ever pregnant in adolescence (OR, 4.2 and 19.0, respectively; p = .03). White young women had significantly lower odds of high educational attainment if they had a live birth in adolescence as compared to those who had not (OR, 0.1; CI = 0.1-0.4). CONCLUSIONS: These findings support studies that found adolescent pregnancy increases the risk of public assistance use and low educational attainment. The study shows that, for educational attainment, black young women who become pregnant may not be as disadvantaged as their peers, whereas white young women who become pregnant are more disadvantaged.

Adolescents and driving: a position paper of the Society for Adolescent Health and Medicine.

Motor vehicle crashes continue to be the leading cause of mortality and severe morbidity among adolescents and young adults. All states have changed their drivers' licensure laws to make the process of obtaining a license more protracted and focused on the development of safe driving skills. Health care providers who counsel children and adolescents should actively address safe driving with them, and also involve their parents in this discussion. Additionally, they should also advocate for strict and uniform graduated licensure laws.

Longitudinal development of secondary sexual characteristics in girls and boys between ages 91/2 and 151/2 years.

OBJECTIVES: To identify ages when adolescents were in sexual maturity stages 2 through 5; to explain the relations between breast (girls), genital (boys), and pubic hair (girls and boys) development between ages 9(1/2) and 15(1/2) years; and to evaluate synchrony of pubertal development across characteristics. DESIGN: Annual pubertal assessments. SETTING: Ten locations in the United States. PARTICIPANTS: A total of 859 adolescents (427 boys [49.7%] and 432 girls [50.3%]; 737 white [85.8%] and 122 black [14.2%]). MAIN OUTCOME MEASURES: Changes in the 5 stages of breast, genital, and pubic hair development. RESULTS: Girls were in breast maturity stages 2 and 3 earlier than comparable pubic hair stages. Although breast development in girls started earlier than pubic hair development, girls completed breast and pubic hair development at approximately the same age. Black girls were in all stages of breast and pubic hair development earlier than white girls. Boys were in stages 2, 3, 4, and 5 of genital development before the comparable pubic hair stage. In boys, genital development started earlier than pubic hair development, but pubic hair development was completed in less time. Black boys were in genital and pubic hair development about 7 months earlier than white boys. Black and white boys completed genital development in approximately 4(1/2) years, but black boys took approximately 6 months longer than white boys to complete pubic hair development. At stage 2, for 66.2% of girls, breast development preceded their pubic hair development; for 91.1% of boys, genital development preceded their pubic hair development. CONCLUSIONS: The results of this study are useful in understanding normative variation in the timing and change in the development of secondary sexual characteristics at puberty. They will help identify adolescents with atypical changes in sexual maturation and unusual progression of sexual maturation and growth disorders.