Vulnerability or resilience? Psycho-social factors associated with deliberate self-harm among adolescents

Background: Deliberate self-harm (DSH) is common among adolescents in Ireland and internationally. Psychological factors, negative life events and lifestyle factors have been found to be associated with self-harm in this group. However, large scale population-based studies of adolescent selfharm and its correlates have been lacking, and internationally a standardised methodology was needed to facilitate comparative studies. The focus on vulnerability which has been prevalent in this field has meant that research has failed to examine resilient adaptation among at-risk adolescents. Method: Data were obtained from a cross-sectional school-based study conducted in Ireland and in each of the six other centres which participated in the Child and Adolescent Self-harm in Europe (CASE) study. In Ireland, 3,881 adolescents in 39 schools in completing the anonymous questionnaire, while across all 7 centres, over 30,000 young people participated. Data were gathered on health and lifestyle, self-harm thoughts and behaviour, a wide range of life events, psychological characteristics (anxiety and depressive symptoms, self-esteem, impulsivity and coping style), and support available to young people. Results: This thesis reports the findings of the Irish CASE centre as well as one international study. The factors associated with DSH among Irish adolescents differed by gender, but among both genders drug use and knowing a friend who had engaged in self-harm were associated with DSH. Among Irish boys, strong associations were found between bullying and poor mental health and DSH. Among boys who had been bullied, psychological and school factors were associated with DSH, while family support was protective. Links between stressful life events, psychological characteristics and DSH within the international CASE sample were examined. Increased history of self-harm thoughts and acts was associated with greater depression, anxiety and impulsivity, lower self esteem and an increased prevalence of ten different negative life events, supporting the hypothesis of a “dose-response” relationship between these risk factors and the self-harm process. Associations between coping style, mental health factors (depressive symptoms, anxiety and self-esteem) and self-harm were examined among Irish adolescents. Emotion-oriented coping was strongly associated with poorer mental health and self-harm thoughts and acts. A mediating effect of emotion-oriented coping on associations between mental health factors and DSH was found for both genders and between problem-oriented coping and mental health factors for girls. Similar mediating effects of coping style were found when risk of self-harm thoughts was examined. Resilient adaptation among adolescents exposed to suicidal behaviour of others was examined. Self-harm thoughts were common in these adolescents. Among those exposed to suicidal behaviour of others, vulnerability factors were drug use and higher levels of anxiety among boys, while for girls drug use, bullying and abuse were vulnerability factors, while resilience was associated with higher self-esteem and use of problem-oriented coping. Conclusion: These findings can aid in the identification of young people at risk of self-harm in the school setting and highlight the importance of mental health, peer-related and lifestyle factors in the development of DSH. High-risk groups of young people such as bullying victims and those exposed to suicidal behaviour of others have distinctive profiles of risk factors which differ from those of their peers. Findings relating to the importance of positive coping skills can inform positive mental health programmes, many of which aim to enhance life skills and build resilience among young people. Knowledge of the factors associated with positive adaptation among at-risk adolescents can inform prevention efforts among this group.

Childhood obesity in Ireland: recent trends and modifiable determinants

Background: Childhood obesity is a global epidemic posing a significant threat to the health and wellbeing of children. To reverse this epidemic, it is essential that we gain a deeper understanding of the complex array of driving factors at an individual, family and wider ecological level. Using a social-ecological framework, this thesis investigates the direction, magnitude and contribution of risk factors for childhood overweight and obesity at multiple levels of influence, with a particular focus on diet and physical activity. Methods: A systematic review was conducted to describe recent trends (from 2002-2012) in childhood overweight and obesity prevalence in Irish school children from the Republic of Ireland. Two datasets (Cork Children’s Lifestyle [CCLaS] Study and the Growing Up in Ireland [GUI] Study) were used to explore determinants of childhood overweight and obesity. Individual lifestyle factors examined were diet, physical activity and sedentary behaviour. The determinants of physical activity were also explored. Family factors examined were parental weight status and household socio-economic status. The impact of food access in the local area on diet quality and body mass index (BMI) was investigated as an environmental level risk factor. Results: Between 2002 and 2012, the prevalence of childhood overweight and obesity in Ireland remained stable. There was some evidence to suggest that childhood obesity rates may have decreased slightly though one in four Irish children remained either overweight or obese. In the CCLaS study, overweight and obese children consumed more unhealthy foods than normal weight children. A diet quality score was constructed based on a previously validated adult diet score. Each one unit increase in diet quality was significantly associated with a decreased risk of childhood overweight and obesity. Individual level factors (including gender, being a member of a sports team, weight status) were more strongly associated with physical activity levels than family or environmental factors. Overweight and obese children were more sedentary and less active than normal weight children. There was a dose response relationship between time spent at moderate to vigorous physical activity (MVPA) and the risk of childhood obesity independent of sedentary time. In contrast, total sedentary time was not associated with the risk of childhood obesity independent of MVPA though screen time was associated with childhood overweight and obesity. In the GUI Study, only one in five children had 2 normal weight parents (or one normal weight parent in the case of single parent families). Having overweight and obese parents was a significant risk factor for overweight and obesity regardless of socio-economic characteristics of the household. Family income was not associated with the odds of childhood obesity but social class and parental education were important risk factors for childhood obesity. Access to food stores in the local environment did not impact dietary quality or the BMI of Irish children. However, there was some evidence to suggest that the economic resources of the family influenced diet and BMI. Discussion: Though childhood overweight and obesity rates appear to have stabilised over the previous decade, prevalence rates are unacceptably high. As expected, overweight and obesity were associated with a high energy intake and poor dietary quality. The findings also highlight strong associations between physical inactivity and the risk of overweight and obesity, with effect sizes greater than what have been typically found in adults. Important family level determinants of childhood overweight and obesity were also identified. The findings highlight the need for a multifaceted approach, targeting a range of modifiable determinants to tackle the problem. In particular, policies and interventions at the shared family environment or community level may be an effective mean of tackling this current epidemic.

Peanut Allergen Threshold Study (PATS): validation of eliciting doses using a novel single-dose challenge protocol

Background: The eliciting dose (ED) for a peanut allergic reaction in 5% of the peanut allergic population, the ED05, is 1.5 mg of peanut protein. This ED05 was derived from oral food challenges (OFC) that use graded, incremental doses administered at fixed time intervals. Individual patients’ threshold doses were used to generate population dose-distribution curves using probability distributions from which the ED05 was then determined. It is important to clinically validate that this dose is predictive of the allergenic response in a further unselected group of peanut-allergic individuals. Methods/Aims: This is a multi-centre study involving three national level referral and teaching centres. (Cork University Hospital, Ireland, Royal Children’s Hospital Melbourne, Australia and Massachusetts General Hospital, Boston, U.S.A.) The study is now in process and will continue to run until all centres have recruited 125 participates in each respective centre. A total of 375 participants, aged 1–18 years will be recruited during routine Allergy appointments in the centres. The aim is to assess the precision of the predicted ED05 using a single dose (6 mg peanut = 1.5 mg of peanut protein) in the form of a cookie. Validated Food Allergy related Quality of Life Questionnaires-(FAQLQ) will be self-administered prior to OFC and 1 month after challenge to assess the impact of a single dose OFC on FAQL. Serological and cell based in vitro studies will be performed. Conclusion: The validation of the ED05 threshold for allergic reactions in peanut allergic subjects has potential value for public health measures. The single dose OFC, based upon the statistical dose-distribution analysis of past challenge trials, promises an efficient approach to identify the most highly sensitive patients within any given food-allergic population.