Neurophysiological correlates of laboratory-induced aggression in young men with and without a history of violence

In order to further understand the mechanisms involved in planning an aggressive act, we conducted an event-related potential (ERP) study of young men with and without a history of violence. Participants completed a competitive reaction time task (based on the Taylor aggression paradigm) against a virtual opponent. In "passive" blocks, participants were punished by the opponent when losing the trial but could not punish, when winning, whereas in "active" blocks, participants were able to punish the opponent when winning, but were not punished when losing. Participants selected punishment strength in a decision phase prior to each reaction time task and were informed whether they had won or lost in the outcome phase. Additionally, a flanker task was conducted to assess basic performance monitoring. Violent participants selected stronger punishments, especially in "active" blocks. During the decision phase, a frontal P200 was more pronounced for violent participants, whereas non-violent participants showed an enhanced frontal negativity around 300 ms. The P200 might reflect the decision to approach the opponent at a very early state, the latter negativity could reflect inhibition processes, leading to a more considerate reaction in non-violent participants. During the outcome phase, a Feedback-Related Negativity was seen in both groups. This effect was most pronounced when losing entailed a subsequent inability to retaliate. The groups did not differ in the flanker task, indicating intact basic performance monitoring. Our data suggest that the planning of an aggressive act is associated with distinct brain activity and that such activity is differentially represented in violent and non-violent individuals.     

Comparison of variations between percentage of body fat, body mass index and daily physical activity among young Japanese and Thai female students

ABSTRACT: BACKGROUND: In our series of investigations concerning the causes of seasonal change in fat accumulation in young university students, we could not find any contribution of seasonal variation in the ratio of carbohydrate and fat metabolism to that of body fat percentage in Japanese and Thai participants. After our previous study, we examined the effect of daily physical activity on body fat percentage to look for the major causes of seasonal change in fat accumulation in young university students. FINDINGS: In this study, we measured participants' (young Japanese and Thai university students) daily physical activity by a uniaxial accelerometer in addition to the measurements of body fat percentage and body mass index by a bioelectrical impedance meter. We found that there was significant and moderate negative correlation between body fat percentage and daily step counts among Japanese but not Thai participants. We observed significant, moderate and positive correlations between the percentage of body fat and body mass index among Japanese and Thai participants. CONCLUSIONS: Daily physical activity plays an important role in the seasonal variation of body fat percentage of Japanese female students. Our present study also confirmed the importance of daily physical activity for controlling body mass index and for the prevention of obesity.     

Soccer vs. running training effects in young adult men: which programme is more effective in improvement of body composition? Randomized controlled trial

The aims of this study were: 1) To determine the effects of a 12-week recreational soccer training programme and continuous endurance running on body composition of young adult men and 2) to determine which of these two programmes was more effective concerning body composition. Sixty-four participants completed the randomized controlled trial and were randomly assigned to one of three groups: a soccer training group (SOC; n=20), a running group (RUN; n=21) or a control group performing no physical training (CON; n=23). Training programmes for SOC and RUN lasted 12-week with 3 training sessions per week. Soccer sessions consisted of 60 min ordinary five-a-side, six-a-side or seven-a-side matches on a 30-45 m wide and 45-60 m long plastic grass pitch. Running sessions consisted of 60 min of continuous moderate intensity running at the same average heart rate as in SOC (~80% HR_max). All participants, regardless of group assignment, were tested for each of the following dependent variables: body weight, body height, body mass index, percent body fat, body fat mass, fat-free mass and total body water. In the SOC and RUN groups there was a significant decrease (p < 0.05) in body composition parameters from pre- to post-training values for all measures with the exception of fat-free mass and total body water. Body mass index, percent body fat and body fat mass did not differ between groups at baseline, but by week 12 were significantly lower (p < 0.05) in the SOC and RUN groups compared to CON. To conclude, recreational soccer training provides at least the same changes in body composition parameters as continuous running in young adult men when the training intensity is well matched.     

The smell of age: perception and discrimination of body odors of different ages

Our natural body odor goes through several stages of age-dependent changes in chemical composition as we grow older. Similar changes have been reported for several animal species and are thought to facilitate age discrimination of an individual based on body odors, alone. We sought to determine whether humans are able to discriminate between body odor of humans of different ages. Body odors were sampled from three distinct age groups: Young (20-30 years old), Middle-age (45-55), and Old-age (75-95) individuals. Perceptual ratings and age discrimination performance were assessed in 41 young participants. There were significant differences in ratings of both intensity and pleasantness, where body odors from the Old-age group were rated as less intense and less unpleasant than body odors originating from Young and Middle-age donors. Participants were able to discriminate between age categories, with body odor from Old-age donors mediating the effect also after removing variance explained by intensity differences. Similarly, participants were able to correctly assign age labels to body odors originating from Old-age donors but not to body odors originating from other age groups. This experiment suggests that, akin to other animals, humans are able to discriminate age based on body odor alone and that this effect is mediated mainly by body odors emitted by individuals of old age.     

Obesity in middle age and future risk of dementia: a 27 year longitudinal population based study

Objective To evaluate any association between obesity in middle age, measured by body mass index and skinfold thickness, and risk of dementia later in life.Design Analysis of prospective data from a multiethnic population based cohort.Setting Kaiser Permanente Northern California Medical Group, a healthcare delivery organisation.Participants 10 276 men and women who underwent detailed health evaluations from 1964 to 1973 when they were aged 40-45 and who were still members of the health plan in 1994.Main outcome measures Diagnosis of dementia from January 1994 to April 2003. Time to diagnosis was analysed with Cox proportional hazard models adjusted for age, sex, race, education, smoking, alcohol use, marital status, diabetes, hypertension, hyperlipidaemia, stroke, and ischaemic heart disease.Results Dementia was diagnosed in 713 (6.9%) participants. Obese people (body mass index ≥ 30) had a 74% increased risk of dementia (hazard ratio 1.74, 95% confidence interval 1.34 to 2.26), while overweight people (body mass index 25.0-29.9) had a 35% greater risk of dementia (1.35, 1.14 to 1.60) compared with those of normal weight (body mass index 18.6-24.9). Compared with those in the lowest fifth, men and women in the highest fifth of the distribution of subscapular or tricep skinfold thickness had a 72% and 59% greater risk of dementia, respectively (1.72, 1.36 to 2.18, and 1.59, 1.24 to 2.04).Conclusions Obesity in middle age increases the risk of future dementia independently of comorbid conditions.     

Sleep Duration Trajectories and Body Composition in Adolescents: Prospective Birth Cohort Study

We aimed to estimate the association between sleep duration trajectories and body composition in adolescents. We used data from participants of the 1993 Pelotas (Brazil) Birth Cohort Study who were later followed up at age 18 years (response rate of 81.3%). At the time, 3974 adolescents had complete data on body composition, which was assessed by air displacement plethysmography. Sleep duration was self-reported by participants at ages 11 and 18 years. Analyses were sex-stratified. The mean sleep duration at 11 years was 9.7 (SD 1.4) and 8.4 (SD 1.9) at 18 years. Sleep duration was dichotomized as inadequate (<8 hours/day) or adequate (≥8 hours/day). Mean body mass, fat mass, and fat-free mass indices at 18 years were 23.4 kg/m² (SD 4.5), 6.1 kg/m² (SD 3.9) and 17.3 kg/m² (SD 2.5), respectively. Girls who reported inadequate sleep duration at 11 years of age, but adequate sleep duration at 18, on average experienced an increase in body mass index (β = 0.39 z-scores; 95% CI 0.13, 0.65), fat mass index (β = 0.30 z-scores; 95% CI 0.07, 0.53), and fat-free mass index (β = 0.24 z-scores; 95% CI 0.08, 0.39) compared to those who had adequate sleep duration at both time points. The results suggest that changes in sleep duration across adolescence may impact body composition in later adolescence and that this may differ by sex.     

Reaction time: Does it relate to weight status in children?

It has been recently reported that reaction time (RT) is related to weight status [measured by body mass index (BMI)] in young, adult and older people. However, there is little evidence for children, and the similar studies included small sample of participants. The aim of this study was to evaluate the relationship between a new RT test and weight status among a sample of 7–11 year old schoolboys. Therefore, 533 apparently healthy schoolboys underwent clinical reaction time (RT_clin) measurements and standard anthropometry. Participants according to different obesity indices [waist circumference (WC), waist to height ratio (WHtR), BMI and fat%] were assigned to different weight status categories. Results indicated that time of RT_clin decreased as age of the boys increased (F = 63; P < 0.01). No significant difference was observed for RT_clin among the BMI, WC, WHtR and fat% categories after controlling for age (P > 0.05). In conclusion, it seems that there is no relationship between simple RT (measured by RT_clin) and weight status in the boys. Additional studies for finding relationship between RT and weight status are needed by including larger samples of participants, various age groups and various RT tests.     

Body Characteristics,Dietary Protein and Body Weight Regulation. Reconciling Conflicting Results from Intervention and Observational Studies?

Background/Objectives

Physiological evidence indicates that high-protein diets reduce caloric intake and increase thermogenic response, which may prevent weight gain and regain after weight loss. Clinical trials have shown such effects, whereas observational cohort studies suggest an association between greater protein intake and weight gain. In both types of studies the results are based on average weight changes, and show considerable diversity in both directions. This study investigates whether the discrepancy in the evidence could be due to recruitment of overweight and obese individuals into clinical trials.

Subjects/Methods

Data were available from the European Diet, Obesity and Genes (DiOGenes) post-weight-loss weight-maintenance trial and the Danish Diet, Cancer and Health (DCH) cohort. Participants of the DCH cohort were matched with participants from the DiOGenes trial on gender, diet, and body characteristics. Different subsets of the DCH-participants, comparable with the trial participants, were analyzed for weight maintenance according to the randomization status (high or low protein) of the matched trial participants.

Results

Trial participants were generally heavier, had larger waist circumference and larger fat mass than the participants in the entire DCH cohort. A better weight maintenance in the high-protein group compared to the low protein group was observed in the subgroups of the DCH cohort matching body characteristics of the trial participants.

Conclusion

This modified observational study, minimized the differences between the RCT and observational data with regard to dietary intake, participant characteristics and statistical analysis. Compared with low protein diet the high protein diet was associated with better weight maintenance when individuals with greater body mass index and waist circumference were analyzed. Selecting subsets of large-scale observational cohort studies with similar characteristics as participants in clinical trials may reconcile the otherwise conflicting results.     

Screening for obesity in the offspring of first-cousin consanguineous couples: A Phase-I study in Saudi Arabia

Consanguineous or cousin marriages are very common in Saudi Arabia. However, owing to limited studies and insufficient knowledge about genetic diseases/disorders, many couples are unaware of the increased health risks for their offspring. Among the inherited and complex diseases from parents’ consanguinity, obesity is common; therefore, we examined the prevalence of obesity in the offspring of first-cousin consanguineous couples in Saudi Arabia. In this questionnaire-based study, 657 individuals (mean age = 18.7 ± 10.2 years; age range = 2–65 years) who were residing in Riyadh, Saudi Arabia participated. Among them, almost 90% were native Saudis. Participants mean body mass index (BMI) was 24.5 ± 9.1 kg/m2. Sex- stratified demographic details confirmed a significant association between age and BMI (p < .001). We confirmed that adolescents and adults were more prone to develop obesity. Adults and non-Saudi participants were three times more likely to develop obesity if they had first-cousin consanguineous parents than those who did not. Of the 30% of participants who were obese, 100 will be selected for Phase II, in which we plan to perform exome sequencing.     

Anthropometry and body composition in soccer and volleyball players in West Bengal, India

50 sedentary males and 128 sports persons (volleyball=82, soccer=46) of 20-24 years were selected from West Bengal, India, to evaluate and compare their anthropometry and body composition. Skinfolds, girth measurements, body fat percentage (%fat), and endomorphy were significantly higher among sedentary individuals, but lean body mass (LBM) and mesomorphy were significantly (p<0.001) higher among the sports persons. Soccer and volleyball players were found to be ectomorphic mesomorph, whereas sedentary subjects were endomorphic mesomorph. The soccer and volleyball players had higher %fat with lower body height and body mass than their overseas counterparts. %fat exhibited a significant correlation with body mass index (BMI) and thus prediction equations for %fat from BMI were computed in each group. The present data will serve as a reference standard for the anthropometry and body composition of Indian soccer and volleyball players and the prediction norms for %fat will help to provide a first-hand impression of body composition in the studied population.     

Identifying Elements of Patient-Centered Care in Underserved Populations: A Qualitative Study of Patient Perspectives

Patient-centered care is an important goal in the delivery of healthcare. However, many patients do not engage in preventive medical care. In this pilot study, we conducted twenty in depth, semi-structured qualitative interviews at the University of Illinois at Chicago Health Sciences campus in a four month time frame. Many patients were underserved and underinsured, and we wanted to understand their experiences in the healthcare system. Using content analysis, several themes emerged from the interview data. Participants discussed the need for empathy and rapport with their providers. They identified provider behaviors that fostered a positive clinical relationship, including step-by step explanations of procedures, attention to body language and clinic atmosphere, and appropriate time management. Participants identified cost as the most common barrier to engaging in preventive care and discussed children and social support as motivating factors. A long-term relationship with a provider was an important motivator for preventive care, suggesting that the therapeutic alliance was essential to many patients. Conversely, many participants discussed a sense of dehumanization in the healthcare system, reporting that their life circumstances were overlooked, or that they were judged based on insurance status or ethnicity. We discuss implications for provider training and healthcare delivery, including the importance of patient-centered medical homes.     

Changes over four years in body composition and oxygen uptake of young adult males after university graduation

Lifestyle changes and challenges following university graduation often present a sharp contrast to the relatively free and basically pleasant university life enjoyed by the typical college student. Adaptation to a new work environment, relocation to a new community, concerns of marriage and family, personal finances, including income and budgeting (automobile and mortgage payments, savings, etc.), and adjustment to independent living result in an unfamiliar schedule of duties, often too sedentary in nature.The aim of this study was to analyse the changes observed in young working professionals by comparing selected body composition estimates, and physiological working capacity variables at the time of university graduation and four years later.Anthropometric and functional cardio-respiratory exercise test data were collected in 26 physically active (but non-athletic) volunteer males at the time of their university graduation in 2000 and 4 years later in 2004. By the end of this four-year period body weight, body mass index (BMI), the sum of 5 skinfold thicknesses, and relative body fat content increased significantly. Both mean BMI and weight-related body fat content were within the categorized risk range at the time of the second data collection. Parallel with unfavourable changes in body composition, peak minute ventilation, aerobic power, oxygen pulse, and maximum treadmill running distance had decreased significantly during this time. We attributed the significant changes observed mainly to the dramatically changed lifestyle. The subjects could not maintain their previous level of habitual physical activity.     

Sleep supports selective retention of associative memories based on relevance for future utilization

An outstanding question is whether memory consolidation occurs passively or involves active processes that selectively stabilize memories based on future utility. Here, we differentially modulated the expected future relevance of two sets of picture-location associations after learning. Participants first studied two sets of picture-location associations. After a baseline memory test, they were instructed that only one set of associations would be retested after a 14-hour delay. For half of the participants, this test-retest delay contained a night of sleep; for the other half the delay included a normal working day. At retest, participants were re-instructed and against their expectations tested on both sets of associations. Our results show that post-learning instruction about subsequent relevance selectively improves memory retention for specific associative memories. This effect was sleep-dependent; it was present only in the group of subjects for which the test-retest delay contained sleep. Moreover, time spent asleep for participants in this sleep group correlated with retention of relevant but not irrelevant associations; participants who slept longer forgot fewer associations from the relevant category. In contrast, participants that did not sleep forgot more relevant than irrelevant associations across the test-retest delay. In summary, our results indicate that it is possible to modulate the retention of selected memories after learning with simple verbal instructions on their future relevance. The finding that this effect depends on sleep demonstrates this state's active role in memory consolidation and may have utility for educational settings.     

The influence of social comparison on visual representation of one's face

Can the effects of social comparison extend beyond explicit evaluation to visual self-representation--a perceptual stimulus that is objectively verifiable, unambiguous, and frequently updated? We morphed images of participants' faces with attractive and unattractive references. With access to a mirror, participants selected the morphed image they perceived as depicting their face. Participants who engaged in upward comparison with relevant attractive targets selected a less attractive morph compared to participants exposed to control images (Study 1). After downward comparison with relevant unattractive targets compared to control images, participants selected a more attractive morph (Study 2). Biased representations were not the products of cognitive accessibility of beauty constructs; comparisons did not influence representations of strangers' faces (Study 3). We discuss implications for vision, social comparison, and body image.     

Childhood Growth Trajectories According to Combinations of Pregestational Weight Status and Maternal Smoking during Pregnancy: A Multilevel Analysis

Pregestational weight status and maternal smoking during pregnancy are significantly associated with fetal and childhood growth. However, few studies have examined associations between childhood growth and combinations of these factors using multilevel analysis. This study aimed to describe differences in childhood growth trajectories according to these combinations, using data from a prospective cohort study in Japan. The study participants were 1,973 women and their singletons, who were born between April 1, 1991 and March 31, 2003. Children were categorized according to whether they were born to normal-weight, nonsmoking mothers (NN); normal-weight, smoking mothers (NS); underweight, nonsmoking mothers (UN); underweight, smoking mothers (US); overweight, nonsmoking mothers (ON); or overweight, smoking mothers (OS). Birth weight and anthropometric data were collected from 1,965 children at birth (99.6%), 1,655 aged 3 (83.9%), 1,527 aged 5 (77.4%), 1,497 aged 7–8 (75.9%), and 1,501 aged 9–10 (76.1%). Multilevel analysis examining both individual and age as different level variables according to sex was used to describe the trajectories of body mass index z scores for statistical analyses. Although children of the OS group were the leanest at birth, their body mass indices had increased rapidly by 3 years of age. Moreover, body mass index was also likely to increase in boys in the NS and ON groups. A different trend was observed in girls. Body mass index decreased from 5 years of age in girls in the US group. There were no remarkable differences in body mass index trajectories between children in the other groups. In conclusion, childhood growth trajectories differed according to combinations of pregestational weight status and maternal smoking during pregnancy. Further, there were sex-related differences in the associations between childhood growth and factor combinations.     

Self-Assessment of Sexual Maturation in Children and Adolescents with Diabetes Mellitus

ObjectiveTo evaluate the reliability of a self-assessment tool as a surrogate means for estimating phase of sexual maturation in children and adolescents with diabetes mellitus.MethodsChildren and adolescents between 8 and 16 years of age with the diagnosis of type 1 or type 2 diabetes mellitus were recruited from the pediatric endocrinology clinic at a children’s hospital. Participants were given a series of gender-appropriate drawings representing the 5 Tanner stages of sexual maturation for genital development in boys and breast and genital development in girls and asked to select the illustration that best represented their current maturity stage. The self-assessments were compared with physical examination findings by pediatric endocrinologists. Demographic and clinical data including age, race, hemoglobin A_1c level, type of diabetes, and body mass index were also collected. Agreement rates between participants and physician assessment were compared. A level of agreement greater than 80% and a k coefficient greater than 0.61 were considered substantial.ResultsEighty-seven children and adolescents completed the study. Agreement rates for girls were greater than 80%. Agreement rates for boys were 76%. All k coefficients for boys and girls were greater than 0.61, corresponding to good agreement. However, peripubertal participants overestimated their sexual maturity rating almost half the time. The role of age, metabolic control (as measured by hemoglobin A_1c), race, type of diabetes, and body mass index did not influence a participant’s ability to accurately assess sexual maturity.ConclusionWhile useful in mid- to late-pubertal youth with diabetes, this self-assessment tool does not appear to be helpful in identifying the early stages of puberty. (Endocr Pract. 2008;14:840-845)     

Anthropometric variables accurately predict dual energy x-ray absorptiometric-derived body composition and can be used to screen for diabetes

The current world-wide epidemic of obesity has stimulated interest in developing simple screening methods to identify individuals with undiagnosed diabetes mellitus type 2 (DM2) or metabolic syndrome (MS). Prior work utilizing body composition obtained by sophisticated technology has shown that the ratio of abdominal fat to total fat is a good predictor for DM2 or MS. The goals of this study were to determine how well simple anthropometric variables predict the fat mass distribution as determined by dual energy x-ray absorptometry (DXA), and whether these are useful to screen for DM2 or MS within a population. To accomplish this, the body composition of 341 females spanning a wide range of body mass indices and with a 23% prevalence of DM2 and MS was determined using DXA. Stepwise linear regression models incorporating age, weight, height, waistline, and hipline predicted DXA body composition (i.e., fat mass, trunk fat, fat free mass, and total mass) with good accuracy. Using body composition as independent variables, nominal logistic regression was then performed to estimate the probability of DM2. The results show good discrimination with the receiver operating characteristic (ROC) having an area under the curve (AUC) of 0.78. The anthropometrically-derived body composition equations derived from the full DXA study group were then applied to a group of 1153 female patients selected from a general endocrinology practice. Similar to the smaller study group, the ROC from logistical regression using body composition had an AUC of 0.81 for the detection of DM2. These results are superior to screening based on questionnaires and compare favorably with published data derived from invasive testing, e.g., hemoglobin A1c. This anthropometric approach offers promise for the development of simple, inexpensive, non-invasive screening to identify individuals with metabolic dysfunction within large populations.     

Prospective time estimation over a night without sleep

The aim of the present study was to investigate the time of night effect on prospective time estimation efficiency. Fifty-four participants took part in six consecutive experimental sessions from 10:00 p.m. to 8:00 a.m. at intervals of 2 h, during which they had to carry out two kinds of tasks (simple reaction time and prospective time estimation), give an evaluation of their subjective alertness, and record body temperature. In agreement with previous data on body temperature, subjective alertness and performance in simple reaction time showed a significant decrease during the night, while performance in prospective time estimation did not change over the night. Taking into account circadian typology we found that morning-types tended to produce significantly shorter time intervals and less time estimation accuracy than evening-types. With reference to recent cognitive timing models and data derived from free-running conditions, it is hypothesised that internal pace-makers pulse at different rates between the extreme chronotypes.     

Evaluating the validity of using unverified indices of body condition

Condition indices are commonly used in an attempt to link body condition of birds to ecological variables of interest, including demographic attributes such as survival and reproduction. Most indices are based on body mass adjusted for structural body size, calculated as simple ratios or residuals from regressions. However, condition indices are often applied without confirming their predictive value (i.e., without being validated against measured values of fat and protein), which we term 'unverified' use. We evaluated the ability of a number of unverified indices frequently found in the literature to predict absolute and proportional levels of fat and protein across five species of waterfowl. Among indices we considered, those accounting for body size never predicted absolute protein more precisely than body mass, however, some indices improved predictability of fat, although the form of the best index varied by species. Further, the gain in precision by using a condition index to predict either absolute or percent fat was minimal (rise in r²≤0.13), and in many cases model fit was actually reduced. Our data agrees with previous assertions that the assumption that indices provide more precise indicators of body condition than body mass alone is often invalid. We strongly discourage the use of unverified indices, because subjectively selecting indices likely does little to improve precision and might in fact decrease predictability relative to using body mass alone.     

Concept formation based on value relations evaluated with a matching-to-sample procedure

To study concept formation based on relations, adults were taught and tested on complex discriminations involving figures that varied in colors, forms, and orientations. In Experiment 1, participants learned to select figures with values A1 and B1 or values B1 and C1; thereafter, they consistently selected figures with values A1 and C1. Selections were based on the relations among the values, rather than on perceptual properties. Experiments 2 and 3 studied generalization with a matching-to-sample procedure: participants learned to select "yes" in the presence of the positive figures, such as A1B1, and "no" in the presence of the negative figures. Thereafter, all figures that resulted from combining three values of the three relevant dimensions were probed. Participants typically selected "yes" in the presence of the novel figures that had two or three values related to one another and selected "no" in the presence of the other figures. Finally, two participants learned a simple discrimination. They did not generalize responding to other figures with the same values; instead, their performance in the generalization test remained almost unaltered. Thus, the concept based on relations was not affected by the simple discrimination. These results showed some unique properties of the concept based on relations and challenge previous theories on concept formation.