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.

Nutrition, growth and body composition in infancy

This thesis is presented in two parts. Data for this research is from the Cork BASELINE (Babies after SCOPE, Evaluating Longitudinal Impact using Neurological and Nutritional Endpoints) Birth Cohort Study (n = 2137). In this prospective birth cohort study, pediatric follow-up with in-person appointments were repeated from the time of birth through to 2, 6 and 12 months, and at 2 years. Body composition was measured by air displacement plethysmography at birth and at 2 months using the PEA POD Infant Body Composition Tracking System. This thesis provides the first extensive report on the study’s 2 year assessment. In part one, the aims were to investigate potential early-life risk factors for childhood overweight and obesity, including rapid growth and body composition in infancy and umbilical cord concentrations of leptin and high molecular weight (HMW) adiponectin. This research is the first to describe rapid growth in early infancy in terms of changes in direct measures of body composition. These are also the first data to examine associations between umbilical cord leptin and HMW adiponectin concentrations and changes in fat and lean mass in early infancy. These data provide additional insight into characterising the growth trajectory in infancy and into the role of perinatal factors in determining infant growth and subsequent overweight/obesity risk. In part two of this thesis, the aims were to quantify vitamin D intake and status at 2 years and to investigate whether 25-hydroxyvitamin D [25(OH)D] concentrations in early pregnancy and in umbilical cord blood are associated with infant growth and body composition. There was a low prevalence of vitamin D deficiency among Irish 2 year olds (n = 742) despite a high prevalence of inadequate intakes and high latitude (51°N). Maternal 25(OH)D concentrations at 15 weeks gestation and cord 25(OH)D concentrations at delivery were not associated with infant growth or adiposity.

Parents' concerns about future pregnancy after stillbirth: a qualitative study

Objectives: As stillbirth has a devastating impact, it is imperative to understand the importance of clinical and emotional care after stillbirth and how it influences subsequent pregnancies. The aim of the study was to gain insight into the consideration and planning of a subsequent pregnancy by parents in the weeks following stillbirth. Design: A qualitative semi-structured interview format was utilized. Interpretative phenomenological analysis was employed as the analytic strategy. Participants and setting: The recruitment strategy focused on couples whereby the parents of ten stillborn babies were contacted; however, five men declined to participate in the study. The final sample of 15 parents were all Irish: ten of whom were female and five of whom were male. Results: Findings revealed two superordinate themes relating to a subsequent pregnancy after stillbirth: aspirations for future pregnancy and expectations of future care. Parents disclosed how the prospect of a subsequent pregnancy was daunting with fears about the potential loss of another child. Despite these fears, parentsâ aspirations differed in the days following stillbirth; mothers wished to plan a future pregnancy while fathers were reluctant to consider any pregnancies. Parents were unsure of what to expect in terms of the level of care that would be provided to them in a subsequent pregnancy. Additional appointments at the maternity hospital were considered crucial to provide reassurance during a subsequent pregnancy. Conclusions: These findings underscore the far-reaching and contrasting effects of stillbirth on parents. These complex needs highlight the importance of the multidisciplinary team approach.Objectives: As stillbirth has a devastating impact, it is imperative to understand the importance of clinical and emotional care after stillbirth and how it influences subsequent pregnancies. The aim of the study was to gain insight into the consideration and planning of a subsequent pregnancy by parents in the weeks following stillbirth. Design: A qualitative semi-structured interview format was utilized. Interpretative phenomenological analysis was employed as the analytic strategy. Participants and setting: The recruitment strategy focused on couples whereby the parents of ten stillborn babies were contacted; however, five men declined to participate in the study. The final sample of 15 parents were all Irish: ten of whom were female and five of whom were male. Results: Findings revealed two superordinate themes relating to a subsequent pregnancy after stillbirth: aspirations for future pregnancy and expectations of future care. Parents disclosed how the prospect of a subsequent pregnancy was daunting with fears about the potential loss of another child. Despite these fears, parentsâ aspirations differed in the days following stillbirth; mothers wished to plan a future pregnancy while fathers were reluctant to consider any pregnancies. Parents were unsure of what to expect in terms of the level of care that would be provided to them in a subsequent pregnancy. Additional appointments at the maternity hospital were considered crucial to provide reassurance during a subsequent pregnancy. Conclusions: These findings underscore the far-reaching and contrasting effects of stillbirth on parents. These complex needs highlight the importance of the multidisciplinary team approach.