Reference Values and Factors Associated With Renal Resistive Index in a Family-Based Population Study

Increased renal resistive index (RRI) has been recently associated with target organ damage and cardiovascular or renal outcomes in patients with hypertension and diabetes mellitus. However, reference values in the general population and information on familial aggregation are largely lacking. We determined the distribution of RRI, associated factors, and heritability in a population-based study. Families of European ancestry were randomly selected in 3 Swiss cities. Anthropometric parameters and cardiovascular risk factors were assessed. A renal Doppler ultrasound was performed, and RRI was measured in 3 segmental arteries of both kidneys. We used multilevel linear regression analysis to explore the factors associated with RRI, adjusting for center and family relationships. Sex-specific reference values for RRI were generated according to age. Heritability was estimated by variance components using the ASSOC program (SAGE software). Four hundred women (mean age±SD, 44.9±16.7 years) and 326 men (42.1±16.8 years) with normal renal ultrasound had mean RRI of 0.64±0.05 and 0.62±0.05, respectively (P<0.001). In multivariable analyses, RRI was positively associated with female sex, age, systolic blood pressure, and body mass index. We observed an inverse correlation with diastolic blood pressure and heart rate. Age had a nonlinear association with RRI. We found no independent association of RRI with diabetes mellitus, hypertension treatment, smoking, cholesterol levels, or estimated glomerular filtration rate. The adjusted heritability estimate was 42±8% (P<0.001). In a population-based sample with normal renal ultrasound, RRI normal values depend on sex, age, blood pressure, heart rate, and body mass index. The significant heritability of RRI suggests that genes influence this phenotype.

The Role of Cell Sterilization in Population Based Studies of Radiogenic Second Cancers Following Radiation Therapy

Advances in radiotherapy have generated increased interest in comparative studies of treatment techniques and their effectiveness. In this respect, pediatric patients are of specific interest because of their sensitivity to radiation induced second cancers. However, due to the rarity of childhood cancers and the long latency of second cancers, large sample sizes are unavailable for the epidemiological study of contemporary radiotherapy treatments. Additionally, when specific treatments are considered, such as proton therapy, sample sizes are further reduced due to the rareness of such treatments. We propose a method to improve statistical power in micro clinical trials. Specifically, we use a more biologically relevant quantity, cancer equivalent dose (DCE), to estimate risk instead of mean absorbed dose (DMA). Our objective was to demonstrate that when DCE is used fewer subjects are needed for clinical trials. Thus, we compared the impact of DCE vs. DMA on sample size in a virtual clinical trial that estimated risk for second cancer (SC) in the thyroid following craniospinal irradiation (CSI) of pediatric patients using protons vs. photons. Dose reconstruction, risk models, and statistical analysis were used to evaluate SC risk from therapeutic and stray radiation from CSI for 18 patients. Absorbed dose was calculated in two ways: with (1) traditional DMA and (2) with DCE. DCE and DMA values were used to estimate relative risk of SC incidence (RRCE and RRMA, respectively) after proton vs. photon CSI. Ratios of RR for proton vs. photon CSI (RRRCE and RRRMA) were then used in comparative estimations of sample size to determine the minimal number of patients needed to maintain 80% statistical power when using DCE vs. DMA. For all patients, we found that protons substantially reduced the risk of developing a second thyroid cancer when compared to photon therapy. Mean RRR values were 0.052±0.014 and 0.087±0.021 for RRRMA and RRRCE, respectively. However, we did not find that use of DCE reduced the number of patents needed for acceptable statistical power (i.e, 80%). In fact, when considerations were made for RRR values that met equipoise requirements and the need for descriptive statistics, the minimum number of patients needed for a micro-clinical trial increased from 17 using DMA to 37 using DCE. Subsequent analyses revealed that for our sample, the most influential factor in determining variations in sample size was the experimental standard deviation of estimates for RRR across the patient sample. Additionally, because the relative uncertainty in dose from proton CSI was so much larger (on the order of 2000 times larger) than the other uncertainty terms, it dominated the uncertainty in RRR. Thus, we found that use of corrections for cell sterilization, in the form of DCE, may be an important and underappreciated consideration in the design of clinical trials and radio-epidemiological studies. In addition, the accurate application of cell sterilization to thyroid dose was sensitive to variations in absorbed dose, especially for proton CSI, which may stem from errors in patient positioning, range calculation, and other aspects of treatment planning and delivery.

The impact of cancer on the population of Salvador-Bahia, Brazil

The impact of cancer on the population of Salvador-Bahia, Brazil was studied using mortality data available from the Brazilian National Bureau of Vital Statistics. Average annual site, age, and gender specific and adjusted cancer mortality rates were determined for the years 1977-83 and contrasted with United States cancer mortality rates for the year of 1977. The accuracy of the cancer mortality rates generated by this research was determined by comparing the underlying causes of death as coded on death certificates to pathology reports and to hospital diagnosis of a sample of 966 deaths occurring in Salvador during the year of 1983. To further explore the information available on the death certificate, a population based decedent case control study was used to determine the relationship between type of occupation (proxy for exposure) and mortality by cancer sites known to be occupationally related.^ The rates in Salvador for cancer of the stomach, oral cavity, and biliary passages are, on average, two fold higher than the U.S. rates.^ The death certificate was found to be accurate for 65 percent of the 485 cancer deaths studied. Thirty five histologically confirmed cancer deaths were found in a random sample of 481 deaths from other causes. This means that, approximately 700 more deaths may be lost among the remainder 10,073 death certificates stating a cause other than cancer.^ In addition, despite the known limitations of decedent case-control studies, cancers of the oral cavity OR = 2.44, CI = 1.17-5.09, stomach OR = 2.31, CI = 1.18-4.52, liver OR = 4.06, CI = 1.27-12.99, bladder OR = 6.77, CI = 1.5-30.67, and lymphoma OR = 2.55, CI = 1.04-6.25 had elevated point estimates, for different age strata indicating an association between these cancers and occupations that led to exposure to petroleum and its derivates. ^

Evaluation of androgenicity, abdominal adiposity, blood pressure and types of ovulatory patterns in a sample of women with menstrual irregularities

Objective: To determine the prevalence of and the relationships between the degree and source of hyperandrogenemia, ovulatory patterns and cardiovascular disease risk indicators (blood pressure, indices or amount of obesity and fat distribution) in women with menstrual irregularities seen at endocrinologists' clinic. Design: A cross-sectional study design. Participants: A sample of 159 women with menstrual irregularities, aged 15-44, seen at endocrinologists' clinic. Main Outcome Measures: androgen levels, body mass index (BMI), waist-hip ratio (WHR), systolic and diastolic blood pressure (SBP & DBP), source of androgens, ovulatory activity. Results: The prevalence of hyperandrogenemia was 54.7% in this study sample. As expected, women with acne or hirsutism had an odds ratio 12.5 (95%CI = 5.2-25.5) times and 36 (95%CI = 12.9-99.5) times more likely to have hyperandrogenemia than those without acne or hirsutism. The main findings of this study were the following: Hyperandrogenemic women were more likely to have oligomenorrheic cycles (OR = 3.8, 95%CI = 1.5-9.9), anovulatory cycles (OR = 6.6, 95%CI = 2.8-15.4), general obesity (BMI $\ge$ 27) (OR = 6.8, 95%CI = 2.2-27.2) and central obesity (WHR $\ge$ 127) (OR = 14.5, 95%CI = 6.1-38.7) than euandrogenemic women. Hyperandrogenemic women with non-suppressible androgens had a higher mean BMI (29.3 $\pm$ 8.9) than those with suppressible androgens (27.9 $\pm$ 7.9); the converse was true for abdominal adiposity (WHR). Hyperandrogenemic women had a 2.4 odds ratio (95%CI = 1.0-6.2) for an elevated SBP and a 2.7 odds ratio (95%CI = 0.8-8.8) for elevated DBP. When age differences were accounted for, this relationship was strengthened and further strengthened when sources of androgens were controlled. When the differences in BMI were controlled, the odds ratio for elevated SBP in hyperandrogenemic women increased to 8.8 (95%CI = 1.1-69.9). When the age, the source of androgens, the amount of obesity and the type of obesity were controlled, hyperandrogenemic women had 13.5 (95%CI = 1.1-158.9) odds ratio for elevated SBP. Conclusions: In this study population, the presence of menstrual irregularities are highly predictive for the presence of elevated androgens. Women with elevated androgens have a high risk for obesity, more specifically for central obesity. The androgenemic status is an independent predictor of blood pressure elevation. It is probable that in the general population, the presence of menstrual irregularities are predictive of hyperandrogenemia. There is a great need for a population study of the prevalence of hyperandrogenemia and for longitudinal studies in hyperandrogenemic women (adrenarche to menopause) to investigate the evolution of these relationships. ^

Twenty-three per cent of the Swiss adult population are using complementary medicine

Aim of the study: This study investigated the use among the Swiss adult population and the regional dissemination in Switzerland of various methods of complementary medicine (CM). It focused on CM methods that required visiting a physician or therapist and excluded e.g. over-the-counter drugs. Data and Methods: Data of the Swiss Health Survey 2007 were obtained from the Swiss Federal Statistical Office. This survey is performed every 5 years in a sample and is representative of the Swiss resident population from the age of 15 on. It consists of a telephone interview followed by a written questionnaire (2007: 18'760 and 14'432 respondents, respectively) and includes questions about people's state of health, general living conditions, lifestyle, health insurance and usage of health services. Users and non-users of CM were compared using logistic regression models. Results: 23.0 % of the Swiss adult population (women: 30.5 %, men: 15.2 %) used CM during the 12 months before the survey. Homeopathy (6.4 %), osteopathy (5.4 %) and acupuncture (4.9 %) were the most popular methods. The average number of treatments within 12 months for these three methods was 3.1 ± 3.6, 3.5 ± 3.3 and 6.6 ± 5.8, respectively. For treatments with homeopathy and acupuncture, medical practitioners were more commonly consulted than non-medical practitioners, for treatments with osteopathy no difference was found. By means of logistic regression, CM users and non-users were compared. There were significant differences in the use of CM between genders, age groups, levels of education and areas of living. Women, people aged 25 to 64 years, and people with higher levels of education used CM more commonly than men, people below 25 or above 64 years of age, or those with poorer education. Lake Geneva region and central Switzerland had a higher proportion of CM users than the other regions. Discussion: Almost one fourth of the Swiss adult population had used CM within 12 months before the survey. User profiles were comparable to those in other countries. Despite a generally lower self-perceived health status, elderly people were less likely to use CM. Reference: Klein SD, Frei-Erb M, Wolf U. Usage of complementary medicine across Switzerland. Results of the Swiss Health Survey 2007. Swiss Med Wkly. 2012;142:w13666.

Twenty-three per cent of the Swiss adult population are using complementary medicine

Aim of the study Various forms of complementary medicine (CM) play an important role in the Swiss health care system, they are appreciated by a majority of the population and mostly used complementarily rather than alternatively to conventional medicine. This study investigates, how many people in Switzerland are actually being treated with CM, and what the most popular methods of CM are. Data Data of the Swiss Health Survey 2007 were obtained from the Swiss Federal Statistical Office. This survey is performed every 5 years amongst a sample of the Swiss resident population above 15 years of age. It consists of a telephone interview followed by a written questionnaire (2007: 18'760 and 14'432 respondents, respectively) and includes questions about people's state of health, general living conditions, lifestyle, health insurance and usage of health services. Results 23.0% of the Swiss adult population (women: 30.5%, men: 15.2%) used CM during the 12 months before the survey. Homeopathy (6.4%), osteopathy (5.4%) and acupuncture (4.9%) were the most popular methods. The average number of treatments within 12 months for these three methods was 3.1, 3.5 and 6.6, respectively. For treatments with homeopathy and acupuncture, medical practitioners were more commonly consulted than non-medical practitioners, for treatments with osteopathy no difference was found. By means of logistic regression, CM users and non-users were compared. There were significant differences in the use of CM between genders, age groups, levels of education and areas of living. Women, people aged 25 to 64 years, and people with higher education used CM more commonly than men, people below 25 or above 64 years of age, or those with poorer education. Lake Geneva region and central Switzerland had a higher proportion of CM users than the other regions. Discussion While 2 years ago, 67.0% of the Swiss population approved a referendum in favour of CM, we find that 23.0% are in fact using it. Current political discussions focus on effectiveness, cost effectiveness and suitability of CM to decide which methods should be permanently covered by the basic health insurance.

Associations between mood, anxiety or substance use disorders and inflammatory markers after adjustment for multiple covariates in a population-based study.

Inflammation is one possible mechanism underlying the associations between mental disorders and cardiovascular diseases (CVD). However, studies on mental disorders and inflammation have yielded inconsistent results and the majority did not adjust for potential confounding factors. We examined the associations of several pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and high sensitive C-reactive protein (hsCRP) with lifetime and current mood, anxiety and substance use disorders (SUD), while adjusting for multiple covariates. The sample included 3719 subjects, randomly selected from the general population, who underwent thorough somatic and psychiatric evaluations. Psychiatric diagnoses were made with a semi-structured interview. Major depressive disorder was subtyped into "atypical", "melancholic", "combined atypical-melancholic" and "unspecified". Associations between inflammatory markers and psychiatric diagnoses were assessed using multiple linear and logistic regression models. Lifetime bipolar disorders and atypical depression were associated with increased levels of hsCRP, but not after multivariate adjustment. After multivariate adjustment, SUD remained associated with increased hsCRP levels in men (β = 0.13 (95% CI: 0.03,0.23)) but not in women. After multivariate adjustment, lifetime combined and unspecified depression were associated with decreased levels of IL-6 (β = -0.27 (-0.51,-0.02); β = -0.19 (-0.34,-0.05), respectively) and TNF-α (β = -0.16 (-0.30,-0.01); β = -0.10 (-0.19,-0.02), respectively), whereas current combined and unspecified depression were associated with decreased levels of hsCRP (β = -0.20 (-0.39,-0.02); β = -0.12 (-0.24,-0.01), respectively). Our data suggest that the significant associations between increased hsCRP levels and mood disorders are mainly attributable to the effects of comorbid disorders, medication as well as behavioral and physical CVRFs.

Age matters in the prevalence and clinical significance of ultra-high-risk for psychosis symptoms and criteria in the general population: Findings from the BEAR and BEARS-kid studies

Early detection of psychosis is an important topic in psychiatry. Yet, there is limited information on the prevalence and clinical significance of high-risk symptoms in children and adolescents as compared to adults. We examined ultra-high-risk (UHR) symptoms and criteria in a sample of individuals aged 8-40 years from the general population of Canton Bern, Switzerland, enrolled from June 2011 to May 2014. The current presence of attenuated psychotic symptoms (APS) and brief intermittent psychotic symptoms (BLIPS) and the fulfillment of onset/worsening and frequency requirements for these symptoms in UHR criteria were assessed using the Structured Interview for Psychosis Risk Syndromes. Additionally, perceptive and non-perceptive APS were differentiated. Psychosocial functioning and current non-psychotic DSM-IV axis I disorders were also surveyed. Well-trained psychologists performed assessments. Altogether, 9.9% of subjects reported APS and none BLIPS, and 1.3% met all the UHR requirements for APS. APS were related to more current axis I disorders and impaired psychosocial functioning, indicating some clinical significance. A strong age effect was detected around age 16: compared to older individuals, 8-15-year olds reported more perceptive APS, that is, unusual perceptual experiences and attenuated hallucinations. Perceptive APS were generally less related to functional impairment, regardless of age. Conversely, non-perceptive APS were related to low functioning, although this relationship was weaker in those below age 16. Future studies should address the differential effects of perceptive and non-perceptive APS, and their interaction with age, also in terms of conversion to psychosis.

Unresolved Grief in a National Sample of Bereaved Parents: Impaired Mental and Physical Health 4 to 9 Years Later

PURPOSE: To assess unresolved parental grief, the associated long-term impact on mental and physical health, and health service use. PATIENTS AND METHODS: This anonymous, mail-in questionnaire study was performed as a population-based investigation in Sweden between August 2001 and October 2001. Four hundred forty-nine parents who lost a child as a result of cancer 4 to 9 years earlier completed the survey (response rate, 80%). One hundred ninety-one (43%) of the bereaved parents were fathers, and 251 (56%) were mothers. Bereaved parents were asked whether or not, and to what extent, they had worked through their grief. They were also asked about their physical and psychological well-being. For outcomes of interest, we report relative risk (RR) with 95% CIs as well as unadjusted odds ratios and adjusted odds ratios. RESULTS: Parents with unresolved grief reported significantly worsening psychological health (fathers: RR, 3.6; 95% CI, 2.0 to 6.4; mothers: RR, 2.9; 95% CI, 1.9 to 4.4) and physical health (fathers: RR, 2.8; 95% CI, 1.8 to 4.4; mothers: RR, 2.3; 95% CI, 1.6 to 3.3) compared with those who had worked through their grief. Fathers with unresolved grief also displayed a significantly higher risk of sleep difficulties (RR, 6.7; 95% CI, 2.5 to 17.8). Mothers, however, reported increased visits with physicians during the previous 5 years (RR, 1.7; 95% CI, 1.1 to 2.6) as well as a greater likelihood of taking sick leave when they had not worked through their grief (RR, 2.1; 95% CI, 1.2 to 3.5). CONCLUSION: Parents who have not worked through their grief are at increased risk of long-term mental and physical morbidity, increased health service use, and increased sick leave.

Heritability of ambulatory and office blood pressure in the Swiss population

BACKGROUND Blood pressure (BP) is known to aggregate in families. Yet, heritability estimates are population-specific and no Swiss data have been published so far. We estimated the heritability of ambulatory and office BP in a Swiss population-based sample. METHODS The Swiss Kidney Project on Genes in Hypertension is a population-based family study focusing on BP genetics. Office and ambulatory BP were measured in 1009 individuals from 271 nuclear families. Heritability was estimated for SBP, DBP, and pulse pressure using a maximum likelihood method implanted in the Statistical Analysis in Genetic Epidemiology software. RESULTS The 518 women and 491 men included in this analysis had a mean (±SD) age of 48.3 (±17.4) and 47.3 (±17.7) years, and a mean BMI of 23.8 (±4.2) and 25.9 (±4.1) kg/m, respectively. Narrow-sense heritability estimates (±standard error) for ambulatory SBP, DBP, and pulse pressure were 0.37 ± 0.07, 0.26 ± 0.07, and 0.29 ± 0.07 for 24-h BP; 0.39 ± 0.07, 0.28 ± 0.07, and 0.27 ± 0.07 for day BP; and 0.25 ± 0.07, 0.20 ± 0.07, and 0.30 ± 0.07 for night BP, respectively (all P < 0.001). Heritability estimates for office SBP, DBP, and pulse pressure were 0.21 ± 0.08, 0.25 ± 0.08, and 0.18 ± 0.07 (all P < 0.01). CONCLUSIONS We found significant heritability estimates for both ambulatory and office BP in this Swiss population-based study. Our findings justify the ongoing search for the genetic determinants of BP.

Contextualizing local-scale point sample data using global-scale spatial datasets: Lessons learnt from the analysis of large-scale land acquisitions

This paper examines how the geospatial accuracy of samples and sample size influence conclusions from geospatial analyses. It does so using the example of a study investigating the global phenomenon of large-scale land acquisitions and the socio-ecological characteristics of the areas they target. First, we analysed land deal datasets of varying geospatial accuracy and varying sizes and compared the results in terms of land cover, population density, and two indicators for agricultural potential: yield gap and availability of uncultivated land that is suitable for rainfed agriculture. We found that an increase in geospatial accuracy led to a substantial and greater change in conclusions about the land cover types targeted than an increase in sample size, suggesting that using a sample of higher geospatial accuracy does more to improve results than using a larger sample. The same finding emerged for population density, yield gap, and the availability of uncultivated land suitable for rainfed agriculture. Furthermore, the statistical median proved to be more consistent than the mean when comparing the descriptive statistics for datasets of different geospatial accuracy. Second, we analysed effects of geospatial accuracy on estimations regarding the potential for advancing agricultural development in target contexts. Our results show that the target contexts of the majority of land deals in our sample whose geolocation is known with a high level of accuracy contain smaller amounts of suitable, but uncultivated land than regional- and national-scale averages suggest. Consequently, the more target contexts vary within a country, the more detailed the spatial scale of analysis has to be in order to draw meaningful conclusions about the phenomena under investigation. We therefore advise against using national-scale statistics to approximate or characterize phenomena that have a local-scale impact, particularly if key indicators vary widely within a country.

Psychometric properties of the Trauma and Distress Scale, TADS, in an adult community sample in Finland

BACKGROUND: There is increasing evidence that a history of childhood abuse and neglect is not uncommon among individuals who experience mental disorder and that childhood trauma experiences are associated with adult psychopathology. Although several interview and self-report instruments for retrospective trauma assessment have been developed, many focus on sexual abuse (SexAb) rather than on multiple types of trauma or adversity. METHODS: Within the European Prediction of Psychosis Study, the Trauma and Distress Scale (TADS) was developed as a new self-report assessment of multiple types of childhood trauma and distressing experiences. The TADS includes 43 items and, following previous measures including the Childhood Trauma Questionnaire, focuses on five core domains: emotional neglect (EmoNeg), emotional abuse (EmoAb), physical neglect (PhyNeg), physical abuse (PhyAb), and SexAb.This study explores the psychometric properties of the TADS (internal consistency and concurrent validity) in 692 participants drawn from the general population who completed a mailed questionnaire, including the TADS, a depression self-report and questions on help-seeking for mental health problems. Inter-method reliability was examined in a random sample of 100 responders who were reassessed in telephone interviews. RESULTS: After minor revisions of PhyNeg and PhyAb, internal consistencies were good for TADS totals and the domain raw score sums. Intra-class coefficients for TADS total score and the five revised core domains were all good to excellent when compared to the interviewed TADS as a gold standard. In the concurrent validity analyses, the total TADS and its all core domains were significantly associated with depression and help-seeking for mental problems as proxy measures for traumatisation. In addition, robust cutoffs for the total TADS and its domains were calculated. CONCLUSIONS: Our results suggest the TADS as a valid, reliable, and clinically useful instrument for assessing retrospectively reported childhood traumatisation.

Age, Growth and Population Structure of Jumbo Flying Squid, Dosidicus Gigas, Based on Statolith Microstructure Off the Exclusive Economic Zone of Chilean Waters

The jumbo flying squid, Dosidicus gigas, support an important squid fishery off the Exclusive Economic Zone of Chilean waters. However, we only have limited information about their biology. In this study, age, growth and population structure of D. gigas were studied using statoliths from 333 specimens (386 females and 147 males) randomly sampled in the Chinese squid jigging surveys from 2007 to 2008 off the Exclusive Economic Zone of Chile. Mantle lengths (MLs) of the sample ranged from 206 to 702 mm, and their ages were estimated from 150 to 307 days for females and from 127 to 302 days for males. At least two spawning groups were identified, the main spawning peak tended to occur between August and November (austral spring group), and the secondary peak appeared during March to June (austral autumn group). The ML-age relationship was best modelled by a linear function for the austral spring group and a power function for the austral autumn group, and the body weight (BW)-age relationship was best described by an exponential function for both the groups. Instantaneous relative growth rates and absolute growth rates for ML and BW did not differ significantly between the two groups. The growth rate of D. gigas tended to be high at young stages, and then decreased after the sub-adult stage (>180 days old). This study suggests large spatial and temporal variability in key life history parameters of D. gigas, calling for the collection of more data with fine spatial and temporal scales to further improve our understanding of the fishery biology of D. gigas.

Sleep Disturbance in the Homeless Population: The Relationship between Homelessness, Sleep and Health

Little is known about how sleep disruption impacts physical health among the homeless. The association between homelessness, quality of sleep and physical health were investigated in the current study. Convenience sampling was used to select participants from a pool of people attending the programs of Ecclesia Ministries. Interviews were conducted with 32 persons from the Boston metropolitan area, of whom 23 were currently homeless. The researcher assessed level of sleep disturbance, number of health problems and degree of homelessness using a standard demographic questionnaire, the General Health Questionnaire-12 (GHQ-12) and the Pittsburgh Sleep Quality Index (PSQI). Our results found evidence of significant sleep disturbance as well as significant mental and physical health problems in the sample. Correlational analyses provided partial support for the hypothesis that degree of homelessness impacts both sleep quality and physical health. Future work should investigate whether change in homelessness status alters sleep quality and physical health and also whether interventions may be utilized in this understudied and vulnerable population.

An assessment of self-concept and violence within a delinquent adolescent population

The purpose of this study was to provide further data on the relationship between self-concept and violence focusing on a delinquent adolescent population. Recent research has explored the relationship between self-concept and violence with most of the research being done with adult populations. Within the literature, there are two opposing views on the question of this relationship. The traditional view supports the idea that low self-esteem is a cause of violent behavior while the non-traditional view supports the idea that high self-esteem may be a contributor to violent behavior. ^ Using a sample of 200 delinquent adolescents 100 of whom had committed acts of violence and 100 who had not, a group comparison study was done which addressed the following questions, (1) within a delinquent population of violent and non-violent adolescents, is there a relationship between violence and self-concept? (2) what is that relationship; (3) using the Piers-Harris Children's Self-Concept Scale, can it be determined that attributes such as behavior, anxiety, popularity, happiness, and physical appearance as they relate to self-concept are more predictive than others in determining who within a delinquent population will commit acts of violence. For the purposes of this study, delinquent adolescents were those who had official records of misconduct with either the school or juvenile authorities. Adolescents classified as violent were those who had committed acts such as assault, use of a weapon, use of deadly force, and sexual assault while adolescents classified as non-violent had committed anti-social acts such as, truancy, talking back and rule breaking. ^ The study concluded that there is a relationship between adolescent violence and self-concept. However, there was insufficient statistical evidence that self-concept is a predictor of violence. ^