Tracking of sedentary behaviours of young people : a systematic review

Objective : To review the empirical evidence concerning the strength of tracking of sedentary behaviours from childhood and adolescence.

Methods : Published English language studies were located from computerised and manual searches in 2009. Included studies were prospective, longitudinal studies with at least one sedentary behaviour for at least two time-points, with tracking coefficients reported, and included children (aged 3–11 years) and adolescents (12–18 years) at baseline.

Results : Based on data from 21 independent samples, tracking coefficients (r) ranged from 0.08 (over 16 years) to 0.73 (over 2 years) for TV viewing, from 0.18 (boys over 3 years) to 0.52 (over 2 years) for electronic game/computer use, from 0.16 (girls over 4 years) to 0.65 (boys over 2 years) for total screen time, and from −0.15 (boys over 2 years) to 0.48 (over 1 year) for total sedentary time. Study follow-up periods ranged from 1 to up to 27 years, and tracking coefficients tended to be higher with shorter follow-ups.

Conclusions : Sedentary behaviours track at moderate levels from childhood or adolescence. Data suggest that sedentary behaviours may form the foundation for such behaviours in the future and some may track slightly better than physical activity.

Differentiating three conceptualisations of the relationship between positive development and psychopathology during the transition to adulthood

The transition to adulthood is characterised by both great potential for positive change and a relatively high incidence of problem outcomes. A multidimensional model of positive development during the transition to adulthood (at 19-20 years) has recently been proposed. However, an unresolved question regarding the nature of positive development during this time is how best to conceptualise its relationship to psychopathology. We drew on data from 1158 participants in the Australian Temperament Project, a large longitudinal community-based study that has followed young people's psychosocial adjustment from infancy to early adulthood. Using structural equation modelling, we compared three models reflecting different conceptualisations of the relationship between positive development and psychopathology. The results suggest that positive development and psychopathology are best modelled as separate but correlated constructs. Hence, development in one domain is likely to influence the other, although separate and specific developmental pathways are also likely to be operating.

Self-assessed sexuality in young adults with High-Functioning Autism

The literature has revealed that autistic persons of all ages show an interest in sexuality and relationships, but the poor social and communication skills found among those with autism hinders the experience of this. Unfortunately, most research to date in this domain has relied exclusively upon parental or caregiver reports. Thus there remains a need for research to be undertaken in this area based on direct reports from autistic individuals. We hypothesised that compared to Typically Developing (TD) persons, persons with High-Functioning Autism (HFA) would reveal lesser levels of sexual experience, lower levels of sexual and social behaviour, and less understanding of privacy on various subscales of the Sexualised Behaviour Scale. The results of this present study supported the hypothesis on all scales except Privacy and Sexualised Behaviour. Overall, compared to TD individuals, HFA individuals engaged in fewer social behaviours, had less sex education and fewer sexual experiences, had more pronounced concerns for the future, and showed similar levels of privacy knowledge and public sexualised behaviour. These findings suggest a need for specialised sex education programs for autistic populations; further, since social behaviour was significantly lower for autistic individuals and future concerns were higher, this suggests that sex education programs need to incorporate education about social rules to enhance social communication and understanding.

Descriptive model of the offence process of women violent offenders : distal background variables

The literature indicates two areas of growing concern in regard to the perpetration of violence by women. One is that the incidence of violence perpetrated by women is increasing across jurisdictions. The other is that despite their growing numbers the knowledge and understanding of violent women has been greatly hindered by the general lack of empirical investigation of this population. The present study uses a grounded theory approach to develop a preliminary descriptive model of the offence process of women violent offenders. The women's violent offence model (WVOM) has four distinct levels or phases. The current article addresses the first of these in detail, consisting of the distal background variables. This phase of the model includes experiences of childhood and adolescence, providing preliminary insight into the more stable distal predispositional factors underlying women's violent offending.

The subjective wellbeing of high-school students : validating the personal wellbeing index—school children

The Personal Wellbeing Index—School Children (PWI-SC) is designed as a parallel form of the adult PWI-A, to measure subjective wellbeing. This study examines the psychometric properties of the PWI-SC. Data from 351 students, aged between 12 and 20 years, were collected by two independent studies over the years 2005–2006. Using the combined data, the results indicate good psychometric properties for the PWI-SC. It is also found that females have higher SWB but that both genders show an age-related decline in SWB from early to mid adolescence. Notably, School satisfaction meets the criteria for a new domain for the PWI-SC and should be considered for inclusion in a future revision of the scale. The use of the PWI-SC in schools can provide important information for the development of educational policy.

Family interactions and the development of borderline personality symptoms

This thesis investigated the emergence of borderline personality disorder in adolescence. It found that adolescent sensitivity to, and maternal socialization of, aggressive behaviour is associated with borderline pathology. Change in pathology over time was related to adolescent dysphoric behaviour and sensitivity to inconsistent displays of maternal negative emotion.

Actual/ideal body images of high school girls and how it affects their self-esteem : implications for educational and clinical institutions

Given that adolescence is a critical period for the development of a positive self-concept and body image, it is imperative that educators have an understanding of adolescent students' body image and their dieting practises and behaviours. Negative body image is an issue that is rife within the adolescent student population in Australia and around the world, and is a factor that is commonly associated with and linked to disturbed eating behaviours and chronic eating disorders like Anorexia Nervosa (AN). Despite the intuitive appeal and importance of investigating adolescents' body image in terms of what adolescents would like to look like and what they think that they look like now, very little research has investigated these concepts. Furthermore, very little research has explored whether there is a difference between these two constructs how this may affect adolescents' self-esteem. This study therefore aimed to explore the actual and ideal body images of adolescent high school girls aged between 12 and 18 years in two samples of adolescents, one with eating disorders (n=76, clinical sample) and one without (n=823 high school sample). Additionally, this study investigates these constructs in relation to self-esteem levels. The results of this study have important implications for educators and clinicians within educational and clinical settings.

Targeted exercise against osteoporosis : a systematic review and meta-analysis for optimising bone strength throughout life

Background
Exercise is widely recommended to reduce osteoporosis, falls and related fragility fractures, but its effect on whole bone strength has remained inconclusive. The primary purpose of this systematic review and meta-analysis was to evaluate the effects of long-term supervised exercise (≥6 months) on estimates of lower-extremity bone strength from childhood to older age.

Methods
We searched four databases (PubMed, Sport Discus, Physical Education Index, and Embase) up to October 2009 and included 10 randomised controlled trials (RCTs) that assessed the effects of exercise training on whole bone strength. We analysed the results by age groups (childhood, adolescence, and young and older adulthood) and compared the changes to habitually active or sedentary controls. To calculate standardized mean differences (SMD; effect size), we used the follow-up values of bone strength measures adjusted for baseline bone values. An inverse variance-weighted random-effects model was used to pool the results across studies.

Results
Our quality analysis revealed that exercise regimens were heterogeneous; some trials were short in duration and small in sample size, and the weekly training doses varied considerably between trials. We found a small and significant exercise effect among pre- and early pubertal boys [SMD, effect size, 0.17 (95% CI, 0.02-0.32)], but not among pubertal girls [-0.01 (-0.18 to 0.17)], adolescent boys [0.10 (-0.75 to 0.95)], adolescent girls [0.21 (-0.53 to 0.97)], premenopausal women [0.00 (-0.43 to 0.44)] or postmenopausal women [0.00 (-0.15 to 0.15)]. Evidence based on per-protocol analyses of individual trials in children and adolescents indicated that programmes incorporating regular weight-bearing exercise can result in 1% to8% improvements in bone strength at the loaded skeletal sites. In premenopausal women with high exercise compliance, improvements ranging from 0.5% to 2.5% have been reported.

Conclusions
The findings from our meta-analysis of RCTs indicate that exercise can significantly enhance bone strength at loaded sites in children but not in adults. Since few RCTs were conducted to investigate exercise effects on bone strength, there is still a need for further well-designed, long-term RCTs with adequate sample sizes to quantify the effects of exercise on whole bone strength and its structural determinants throughout life.

Effects of lifetime loading history on cortical bone density and its distribution in middle-aged and older men

We have reported previously that long-term participation of weight-bearing exercise is associated with increased QCT-derived cortical bone size and strength in middle-aged and older men, but not whole bone cortical volumetric BMD. However, since bone remodeling and the distribution of loading-induced strains within cortical bone are non-uniform, the aim of this study was to examine the effects of lifetime loading history on cortical bone mass distribution and bone shape in healthy community dwelling middle-aged and older men. We used QCT to assess mid-femur and mid-tibia angular bone mass distribution around its center (polar distribution), the bone density distribution through the cortex (radial distribution), and the ratio between the maximum and minimum moments of inertia (I_max/I_min ratio) in 281 men aged 50 to 79 years. Current (> 50 years) and past (13–50 years) sport and leisure time activity was assessed by questionnaire to calculate an osteogenic index (OI) during adolescence and adulthood. All men were then categorized into a high (H) or low/non impact (L) group according to their OI scores in each period. Three contrasting groups were then formed to reflect weight-bearing impact categories during adolescence and then adulthood: H–H, H–L and L–L. For polar bone mass distribution, bone deposition in the anterolateral, medial and posterior cortices were 6–10% greater at the mid-femur and 9–24% greater at mid-tibia in men in the highest compared to lowest tertile of lifetime loading (p < 0.01– < 0.001). When comparing the influence of contrasting loading history during adolescence and adulthood, there was a graded response between the groups in the distribution of bone mass at the anterior-lateral and posterior regions of the mid-tibia (H–H > H–L > L–L). For radial bone density distribution, there were no statistically significant effects of loading at the mid-femur, but a greater lifetime OI was associated with a non-significant 10–15% greater bone density near the endocortical region of the mid-tibia. In conclusion, a greater lifetime loading history was associated with region-specific adaptations in cortical bone density.

Young adults’ management of Type 1 diabetes during life transitions

Aim. To identify life transitions likely to impact diabetes self-care among young adults with Type 1 diabetes and their coping strategies during transition events.
Background. Relationships among psychosocial stress, adjustment, coping and metabolic control affect clinical outcomes and mental health. Life transitions represent major change and are associated with stress that temporarily affects individuals’ problem-solving, coping abilities and blood glucose levels.
Design. A qualitative interpretive inquiry.
Method. Semi-structured interviews were conducted with 20 young adults with Type 1 diabetes and a constant comparative analysis method. Data and analysis was managed using QSR NVIVO 7 software.
Results. Participants identified two significant transition groups: life development associated with adolescence, going through the education system, entering new relationships, motherhood and the workforce and relocating. Diabetes-related transitions included being diagnosed, developing diabetes complications, commencing insulin pump treatment and going on diabetes camps. Participants managed transitions using ‘strategic thinking and planning’ with strategies of ‘self-negotiation to minimise risks’; ‘managing diabetes using previous experiences’; ‘connecting with others with diabetes’; ‘actively seeing information to ‘patch’ knowledge gaps’; and ‘putting diabetes into perspective’.
Conclusions. Several strategies are used to manage diabetes during transitions. Thinking and planning strategically was integral to glycaemic control and managing transitions. The impact of transitions on diabetes needs to be explored in larger and longitudinal studies to identify concrete strategies that assist diabetes care during life transitions.
Relevance to clinical practice. It is important for health professionals to understand the emotional, social and cognitive factors operating during transitions to assist young adults with Type 1 diabetes to achieve good health outcomes by prioritising goals and plan flexible, timely, individualised and collaborative treatment.

Modeling gene-environment interaction in longitudinal data : risk for neuroticism due to interaction between maternal care and the Dopamine 4 Receptor gene (DRD4)

The purpose of this study was to investigate risk for neuroticism due to the joint action of low maternal care and compromised mesocorticolimbic ‘reward’ system function linked to a variable number tandem repeat (VNTR) in the dopamine 4 receptor gene (DRD4). Data were drawn from the Victorian Adolescent Health Cohort Study, a longitudinal study of the health and well-being of 2,000 young Australians followed from adolescence to young adulthood across 8 waves from 14- to 28-years. Genetic risk was defined by carriage of at least one copy of the 7-repeat allele or derivative alleles 5, 6, and 8 (labeled 7R+). Neuroticism was assessed in adolescence and young adulthood. We observed an approximately fourfold increase in the odds of reporting neurotic symptoms in carriers of the 7R+ disposition who reported low maternal care compared with non-carriers who reported high maternal care. The percentage of risk attributable to mechanisms in which both factors played a role was 35%. Findings are discussed in terms of implications for prevention.

Risk-taking in young people: the role of impulsivity

This study investigated rash impulsivity, reward sensitivity and a range of adolescent risk-taking behaviours using both self-report and behavioural measures of each of these variables. It found that (a) rash impulsivity and reward sensitivity were related dimensions of the impulsivity construct, (b) self-report and behavioural measures were not correlated even when theoretically assessing the same dimension of impulsivity, and (c) of all the risk-taking behaviours examined, rash impulsivity and reward sensitivity were significantly correlated with riding without a seatbelt.

Risk and protective factors for adolescent substance use in Washington State, the United States and Victoria, Australia : a longitudinal study

Purpose
To compare the levels of risk and protective factors and the predictive influence of these factors on alcohol, tobacco, and cannabis use over a 12-month follow-up period in Washington State in the United States and in Victoria, Australia.

Method
The study involved a longitudinal school-based survey of students drawn as a two-stage cluster sample recruited through schools, and administered in the years 2002 and 2003 in both states. The study used statewide representative samples of students in the seventh and ninth grades (n = 3,876) in Washington State and Victoria.

Results
Washington State students, relative to Victorian students, had higher rates of cannabis use but lower rates of alcohol and tobacco use at time 1. Levels of risk and protective factors showed few but important differences that contribute to the explanation of differences in substance use; Washington State students, relative to Victorian students, reported higher religiosity (odds ratio, .96 vs. .79) and availability of handguns (odds ratio, 1.23 vs. 1.18), but less favorable peer, community, and parental attitudes to substance use. The associations with substance use at follow-up are generally comparable, but in many instances were weaker in Washington State.

Conclusions
Levels of risk and protective factors and their associations with substance use at follow-up were mostly similar in the two states. Further high-quality longitudinal studies to establish invariance in the relations between risk and protective factors and substance use in adolescence across diverse countries are warranted.

A prospective study of diet quality and mental health in adolescents

Objectives: A number of cross-sectional and prospective studies have now been published demonstrating inverse relationships between diet quality and the common mental disorders in adults. However, there are no existing prospective studies of this association in adolescents, the onset period of most disorders, limiting inferences regarding possible causal relationships.
Methods: In this study, 3040 Australian adolescents, aged 11–18 years at baseline, were measured in 2005–6 and 2007–8. Information on diet and mental health was collected by self-report and anthropometric data by trained researchers.
Results: There were cross-sectional, dose response relationships identified between measures of both healthy (positive) and unhealthy (inverse) diets and scores on the emotional subscale of the Pediatric Quality of Life Inventory (PedsQL), where higher scores mean better mental health, before and after adjustments for age, gender, socio-economic status, dieting behaviours, body mass index and physical activity. Higher healthy diet scores at baseline also predicted higher PedsQL scores at follow-up, while higher unhealthy diet scores at baseline predicted lower PedsQL scores at follow-up. Improvements in diet quality were mirrored by improvements in mental health over the follow-up period, while deteriorating diet quality was associated with poorer psychological functioning. Finally, results did not support the reverse causality hypothesis.
Conclusion: This study highlights the importance of diet in adolescence and its potential role in modifying mental health over the life course. Given that the majority of common mental health problems first manifest in adolescence, intervention studies are now required to test the effectiveness of preventing the common mental disorders through dietary modification.