The utility of survey and administrative data to generate information for research and outcomes-based oral health services development

The aim of this research, which focused on the Irish adult population, was to generate information for policymakers by applying statistical analyses and current technologies to oral health administrative and survey databases. Objectives included identifying socio-demographic influences on oral health and utilisation of dental services, comparing epidemiologically-estimated dental treatment need with treatment provided, and investigating the potential of a dental administrative database to provide information on utilisation of services and the volume and types of treatment provided over time. Information was extracted from the claims databases for the Dental Treatment Benefit Scheme (DTBS) for employed adults and the Dental Treatment Services Scheme (DTSS) for less-well-off adults, the National Surveys of Adult Oral Health, and the 2007 Survey of Lifestyle Attitudes and Nutrition in Ireland. Factors associated with utilisation and retention of natural teeth were analysed using count data models and logistic regression. The chi-square test and the student’s t-test were used to compare epidemiologically-estimated need in a representative sample of adults with treatment provided. Differences were found in dental care utilisation and tooth retention by Socio-Economic Status. An analysis of the five-year utilisation behaviour of a 2003 cohort of DTBS dental attendees revealed that age and being female were positively associated with visiting annually and number of treatments. Number of adults using the DTBS increased, and mean number of treatments per patient decreased, between 1997 and 2008. As a percentage of overall treatments, restorations, dentures, and extractions decreased, while prophylaxis increased. Differences were found between epidemiologically-estimated treatment need and treatment provided for those using the DTBS and DTSS. This research confirms the utility of survey and administrative data to generate knowledge for policymakers. Public administrative databases have not been designed for research purposes, but they have the potential to provide a wealth of knowledge on treatments provided and utilisation patterns.

Analysing energy detector diversity receivers for spectrum sensing

The analysis of energy detector systems is a well studied topic in the literature: numerous models have been derived describing the behaviour of single and multiple antenna architectures operating in a variety of radio environments. However, in many cases of interest, these models are not in a closed form and so their evaluation requires the use of numerical methods. In general, these are computationally expensive, which can cause difficulties in certain scenarios, such as in the optimisation of device parameters on low cost hardware. The problem becomes acute in situations where the signal to noise ratio is small and reliable detection is to be ensured or where the number of samples of the received signal is large. Furthermore, due to the analytic complexity of the models, further insight into the behaviour of various system parameters of interest is not readily apparent. In this thesis, an approximation based approach is taken towards the analysis of such systems. By focusing on the situations where exact analyses become complicated, and making a small number of astute simplifications to the underlying mathematical models, it is possible to derive novel, accurate and compact descriptions of system behaviour. Approximations are derived for the analysis of energy detectors with single and multiple antennae operating on additive white Gaussian noise (AWGN) and independent and identically distributed Rayleigh, Nakagami-m and Rice channels; in the multiple antenna case, approximations are derived for systems with maximal ratio combiner (MRC), equal gain combiner (EGC) and square law combiner (SLC) diversity. In each case, error bounds are derived describing the maximum error resulting from the use of the approximations. In addition, it is demonstrated that the derived approximations require fewer computations of simple functions than any of the exact models available in the literature. Consequently, the regions of applicability of the approximations directly complement the regions of applicability of the available exact models. Further novel approximations for other system parameters of interest, such as sample complexity, minimum detectable signal to noise ratio and diversity gain, are also derived. In the course of the analysis, a novel theorem describing the convergence of the chi square, noncentral chi square and gamma distributions towards the normal distribution is derived. The theorem describes a tight upper bound on the error resulting from the application of the central limit theorem to random variables of the aforementioned distributions and gives a much better description of the resulting error than existing Berry-Esseen type bounds. A second novel theorem, providing an upper bound on the maximum error resulting from the use of the central limit theorem to approximate the noncentral chi square distribution where the noncentrality parameter is a multiple of the number of degrees of freedom, is also derived.

The association between parental attitudes and alcohol consumption and adolescent alcohol consumption in Southern Ireland: a cross-sectional study

Background: Alcohol plays a complex role in society. A recent study showed that over half of Irish adults drink hazardously. Adolescents report increased levels of alcohol consumption. Previous research has inferred the influence of the parent on their adolescent. Thus, the aim of the current study was to investigate the association between adolescent alcohol consumption and their parent’s consumption pattern and attitude toward alcohol use in Southern Ireland. Methods: A cross-sectional survey was undertaken in November 2014. This involved distributing a survey to adolescents (n = 982) in their final two years of second level education and at least one of their parents from a local electorate area in Southern Ireland. This survey included: alcohol use, self- reported height and weight, smoking status, mental health and well-being along with attitudinal questions. Chi-square tests and multivariate logistic regression were utilised. Results: A 37 % response rate was achieved. Over one-third (34.2 %) of adolescents and 47 % of parents surveyed reported hazardous drinking. Over 90 % of parents disagreed with allowing their adolescent to get drunk and rejected the idea that getting drunk is part of having fun as an adolescent. The majority (79.5 %) of parents surveyed believed that their alcohol consumption pattern set a good example for their adolescent. Multivariate logistic regression highlights the association between adolescent hazardous alcohol consumption and hazardous drinking by the father. Furthermore either parent permitting their adolescent to drink alcohol on special occasions was associated with hazardous alcohol consumption in the adolescent. Conclusion: The findings of this research notes a liberal attitude to alcohol and increased levels of consumption by the parent are linked to hazardous adolescent drinking behaviour. Future action plans aimed at combatting adolescent hazardous alcohol consumption should also be aimed at tackling parents’ attitudes towards and consumption of alcohol.

Management of safety climate and the psychosocial work environment – new challenges for occupational health and safety professionals?

Introduction: The work environment and Occupational Health and Safety (OHS) practice have changed over the last number of years. A holistic OHS approach has been recommended by the authorities in this field (e.g. World Health Organisation (WHO), European Agency for Safety and Health at Work (EU-OSHA) and the International Labour Organisation (ILO)). This involves a unified action engaging elements of the physical and psychosocial workplace with greater focus on prevention and promotion of health and wellbeing. The health and safety practitioner (HSP) has been recognised as one of the main agents for implementation of OHS. Within an organisation they act as a leader of change and a professional who shapes health and safety while safeguarding the wellbeing of individuals at work. Additionally, safety climate (SC) has been developed as an essential concept for OHS of an organisation, its productivity and the wellbeing of its workforce. Scholars and practitioners have recognised the great need for further empirical evidence on the HSP’s role in a changing work environment that increasingly requires the use of preventative measures and the assessment and management of psychosocial work-related risks. This doctoral research brings together the different concepts used in OHS and Public Health including SC, Psychosocial workplace risks, Health Promotion and OHS performance. The associations between these concepts are analysed bearing in mind the WHO Healthy Workplace Framework and three of its main components (physical and psychosocial work environment and health resources). This thesis aims to establish a deeper understanding of the practice and management of OHS in Ireland and the UK, exploring the role of HSPs (employed in diverse sectors of activity) and of SC in the OHS of organisations. Methods: One systematic review and three cross-sectional research studies were performed. The systematic review focussed on the evidence compiled for the association of SC with accidents and injuries at work, clarifying this concept’s definition and its most relevant dimensions. The second article (chapter 3) explored the association of SC with accidents and injuries in a sample of workers (n=367) from a pharmaceutical industry and compared permanent with non-permanent workers. Associations of safety climate with employment status and with self-reported occupational accidents/injuries were studied through logistic regression modelling. The third and fourth papers in this thesis investigated the main tasks performed by HSPs, their perceptions of SC, health climate (HC), psychosocial risk factors and health outcomes as well as work efficacy. Validated questionnaires were applied to a sample of HSPs in Ireland and UK, members of the Institute of Occupational Safety and Health (n=1444). Chi-square analysis and logistic regression were used to assess the association between HSPs work characteristics and their involvement in the management of Psychosocial Risk Factors, Safety Culture and Health Promotion (paper 3). Multiple linear regression analysis was used to determine the association between SC, HC, psychosocial risk factors and health outcomes (general health and mental wellbeing) and self-efficacy. Results: As shown in the systematic review, scientific evidence is unable to establish the widely assumed causal link between SC and accidents and injuries. Nevertheless, the current results suggested that, particularly, the organisational dimensions of SC were associated with accidents and injuries and that SC is linked to health, wellbeing and safety performance in the organisation. According to the present research, contingent workers had lower SC perceptions but showed a lower accident/injury rate than their permanent colleagues. The associations of safety climate with accidents/injuries had opposite directions for the two types of workers as for permanent employees it showed an inverse relationship while for temporary workers, although not significant, a positive association was found. This thesis’ findings showed that HSPs are, to a very small degree, included in activities related to psychosocial risk management and assessment, to a moderate degree, involved in HP activities and, to a large degree, engaged in the management of safety culture in organisations. In the final research study, SC and HC were linked to job demands-control-support (JDCS), health, wellbeing and efficacy. JDCS were also associated with all three outcomes under study. Results also showed the contribution of psychosocial risk factors to the association of SC and HC with all the studied outcomes. These associations had rarely been recorded previously. Discussion & Conclusions: Health and safety climate showed a significant association with health, wellbeing and efficacy - a relationship which affects working conditions and the health and wellbeing of the workforce. This demonstrates the link of both SC and HC with the OHS and the general strength or viability of organisations. A division was noticed between the area of “health” and “safety” in the workplace and in the approach to the physical and psychosocial work environment. These findings highlighted the current challenge in ensuring a holistic and multidisciplinary approach for prevention of hazards and for an integrated OHS management. HSPs have shown to be a pivotal agent in the shaping and development of OHS in organisations. However, as observed in this thesis, the role of these professionals is still far from the recommended involvement in the management of psychosocial risk factors and could have a more complete engagement in other areas of OHS such as health promotion. Additionally, a strong culture of health and safety with supportive management and buy-in from all stakeholders is essential to achieve the ideal unified and prevention-focussed approach to OHS as recommended by the WHO, EU-OSHA and ILO.