Paediatrics (RCH) - Theses
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ItemRespiratory function tracking in survivors of prematurity and low birth weightGIBSON, ANNE-MARIE ( 2009)INTRODUCTION: To investigate longitudinal ‘tracking’ in lung growth, decline or stability of adult preterm/very low birth weight survivors over the study period. To investigate whether those who have clinically abnormal lung function fall further behind their contemporaries or demonstrate evidence of ‘catch-up’ growth. METHODS: 210 babies born ≤34 weeks’ gestation and with birth weights ≤ 1500g in 1977-1982 were followed up at 8, 11, 14, 18 and 25 years of age. Respiratory outcome was evaluated using Spirometry. Spirometry was performed at each of the follow-up periods. Mixed model regression was used to assess longitudinal lung function trajectories and the influence of Bronchopulmonary dysplasia, being small for gestational age and abnormal lung function. Restricted maximum likelihood modelling was used for longitudinal FEV1 z-score as it allows for analysis of data from different time points that are not necessarily evenly spaced, without being affected by missing data. RESULTS: 137 VLBW children completed lung function testing at 8 years of age. Twenty VLBW children (14.6%) had abnormal FEV1 z-scores and 26 (21.0%) [Defined as >2 standard deviation’s below the mean]. VLBW survivors showed minimal ‘catch-up’ in FEV1 z-score over the 13 years of the study; those without BPD (Bronchopulmonary dysplasia) FEV1 improved 0.034 (p=0.014) z-scores, those with BPD FEV1 improved 0.033 (p=0.039) z-scores. VLBW with BPD survivors did not return to within normal limits; those with abnormal FEF25-75 z-scores did not show significant ‘catch-up’ growth (p=0.41) and remained abnormal. CONCLUSIONS: Mixed models do not reveal any significant effects from being born with VLBW and its interaction with age; it does lead to a reduction in FEV1/FVC mean z-score. Although those VLBW individuals who were small for gestational age had significantly reduced FEV1, FVC and FEV1/FVC mean z-scores and these small for gestational age individuals show evidence of ‘catch-up’ growth in terms of lung function, with the exception of FEV1/FVC z-score which falls further from their contemporaries. This effect on FEV1 and FVC z-scores may suggest some protective element or compensatory mechanism of being born small for gestational age. Reassuringly, Bronchopulmonary dysplasia as a neonate did not significantly affect lung function variables as these individuals as they age. Those with clinically abnormal lung function show a progressive failure to achieve optimal lung function whether or not they had Bronchopulmonary dysplasia.
ItemAttitudes towards newborn screening for Pompe disease among affected adults, family members and parents of ‘healthy’ childrenCurlis, Yvette M. ( 2009)Pompe disease is a rare autosomal recessive condition caused by a deficiency in lysosomal alpha glucosidase. It is a progressive and often fatal muscular disease with wide variation in clinical presentation. Two broad clinical categories of Pompe disease have been identified; infantile- and late- onset. In the past decade, enzyme replacement therapy has shown promising results in treating the underlying pathology, resulting in improved clinical outcome. Clinical trials indicating that initiation of treatment at an earlier disease stage leads to a higher chance of preventing permanent damage have led to the proposition of introducing newborn screening for Pompe disease. All forms of Pompe disease are caused by the same pathology, and thus newborn screening has the potential to identify those affected with the more severe infantile-onset form as well as those with late-onset disease who may not present with symptoms until late in life. The aim of this study was to investigate attitudes towards newborn screening for Pompe disease among affected adults, their family members and parents of ‘healthy’ children. Affected adults were recruited through support groups in Australia, the United Kingdom and United States; family members of affected adults were recruited from Australia; and parents of ‘healthy’ children were recruited through maternal child health clinics in Victoria, Australia. Participants completed questionnaires exploring their experiences of Pompe disease and/or newborn screening and their attitudes towards newborn screening for Pompe disease. Support for newborn screening for Pompe disease was high among adults with Pompe disease (85.4%), parents of ‘healthy’ children (93.9%) and all three family members of affected adults who participated in this study. However, when offered a theoretical screening test that would only identify infantile-onset Pompe disease, 42.1% of adults with Pompe disease and 53.1% of parents of ‘healthy’ children preferred this screen, indicating that these stakeholders have some concerns regarding detection of late-onset disease in infancy. Factors influencing attitudes were investigated and support for newborn screening in affected adults was highly correlated with age of onset of disease; a preference to have been diagnosed in infancy; a belief that an earlier diagnosis would have made symptoms easier to cope with; and a stronger confidence in the efficacy of enzyme replacement therapy. Potential benefits of diagnosis of late-onset disease in infancy were identified as being able to avoid the diagnosis odyssey, access enzyme replacement therapy at the optimal time, and allow individuals to make appropriate life choices. Participants identified increased anxiety in parents and the potential for over-protectiveness, in addition to possible discrimination, as harms of newborn screening for Pompe disease. Families in which an infant is identified with the potential for late-onset Pompe disease will need assistance to adapt to and manage this diagnosis, so that anxiety is minimised and unnecessary limitations are not placed on the child. Whilst potential medical and psychosocial benefits can result from newborn screening, it is important to carefully consider the potential for harm and the resources required to appropriately manage these so that ultimately benefit outweighs harm.
ItemExploring the experiences of people who have consented to tumour testing for a hereditary disposition to cancerOpat, Annette ( 2009)Due to the costly and technically challenging nature of genetic testing, methods have been developed to target more specifically those who are at increased risk of carrying the Hereditary Non-Polyposis Colorectal Cancer (HNPCC) mutation. HNPCC is an inherited colorectal cancer syndrome. Testing of tumour material (which has previously been removed during surgery) for features of HNPCC has been found to be an effective and economic method of identifying those at higher risk of having a mutation. Only those at higher risk of having a mutation will undergo genetic testing. This practice of “tumour testing” has become widespread. There is currently no clarity about requirements for consent prior to testing of stored tumour tissue. The person giving consent to tumour testing does not always have an appointment with a genetics service prior to giving consent. This can be contrasted to genetic testing on blood samples where laws and guidelines state that informed consent is required prior to genetic testing and that comprehensive genetic counselling and support should be provided as part of this process. Protocols for genetic testing have been developed as a result of extensive research around the impact and implications of genetic testing. Consumer opinion and participation through research is an important aspect of health policy and guideline development. Accordingly the purpose of this study was to contribute to such development by gaining insight into the experiences, understandings, decision making processes and opinions of those who had given consent to have their own or their relatives tumour tested. Seventeen people who had given consent for tumour testing either for themselves, or on behalf of a deceased relative were recruited through a Familial Cancer Centre and in-depth interviews conducted. The interviews were transcribed and analysed using thematic analysis. Some participants had no memory of consenting to tumour testing. Others remembered basic concepts. Negative implications of testing were unknown or viewed as unimportant. Participants did not understand the difference between tumour testing and germline testing. Despite lack of memory or understanding participants did not want additional or more detailed pre-test information although they did want more follow-up and support after receipt of results. The decision to consent to testing was made as soon as participants were informed of the availability of tumour testing - the major reason being to provide information for the family that would aid in cancer prevention. Participants were more concerned with accessibility to testing than pre test information and counselling. Findings in this study indicated participants made decisions heuristically rather than systematically and this as well as participants’ opinions and other decision-making research has implications for the traditional view of informed consent around genetic related decisions. This in turn has implications for policy and guidelines in the area. Implications for current practise as a result of findings from this study include ensuring participants understand negative implications of testing and follow up and support of those with negative as well as positive results to tumour testing.