Exposure Reconstruction for the TCDD-Exposed NIOSH Cohort Using a Concentration- and Age-Dependent Model of Elimination

Recent studies demonstrating a concentration dependence of elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suggest that previous estimates of exposure for occupationally exposed cohorts may have underestimated actual exposure, resulting in a potential overestimate of the carcinogenic potency of TCDD in humans based on the mortality data for these cohorts. Using a database on U.S. chemical manufacturing workers potentially exposed to TCDD compiled by the National Institute for Occupational Safety and Health (NIOSH), we evaluated the impact of using a concentration- and age-dependent elimination model (CADM) (Aylward et al., 2005) on estimates of serum lipid area under the curve (AUC) for the NIOSH cohort. These data were used previously by Steenland et al. (2001) in combination with a first-order elimination model with an 8.7-year half-life to estimate cumulative serum lipid concentration (equivalent to AUC) for these workers for use in cancer dose-response assessment. Serum lipid TCDD measurements taken in 1988 for a subset of the cohort were combined with the NIOSH job exposure matrix and work histories to estimate dose rates per unit of exposure score. We evaluated the effect of choices in regression model (regression on untransformed vs. ln-transformed data and inclusion of a nonzero regression intercept) as well as the impact of choices of elimination models and parameters on estimated AUCs for the cohort. Central estimates for dose rate parameters derived from the serum-sampled subcohort were applied with the elimination models to time-specific exposure scores for the entire cohort to generate AUC estimates for all cohort members. Use of the CADM resulted in improved model fits to the serum sampling data compared to the first-order models. Dose rates varied by a factor of 50 among different combinations of elimination model, parameter sets, and regression models. Use of a CADM results in increases of up to five-fold in AUC estimates for the more highly exposed members of the cohort compared to estimates obtained using the first-order model with 8.7-year half-life. This degree of variation in the AUC estimates for this cohort would affect substantially the cancer potency estimates derived from the mortality data from this cohort. Such variability and uncertainty in the reconstructed serum lipid AUC estimates for this cohort, depending on elimination model, parameter set, and regression model, have not been described previously and are critical components in evaluating the dose-response data from the occupationally exposed populations.     

Development and Consideration of Global Policies for Managing the Future Risks of Poliovirus Outbreaks: Insights and Lessons Learned Through Modeling

The success of the Global Polio Eradication Initiative promises to bring large benefits, including sustained improvements in quality of life (i.e., cases of paralytic disease and deaths avoided) and costs saved from cessation of vaccination. Obtaining and maintaining these benefits requires that policymakers manage the transition from the current massive use of oral poliovirus vaccine (OPV) to a world without OPV and free of the risks of potential future reintroductions of live polioviruses. This article describes the analytical journey that began in 2001 with a retrospective case study on polio risk management and led to development of dynamic integrated risk, economic, and decision analysis tools to inform global policies for managing the risks of polio. This analytical journey has provided several key insights and lessons learned that will be useful to future analysts involved in similar complex decision-making processes.     

Risk Management in a Polio-Free World

Inherent in the decision to launch the Global Polio Eradication Initiative in 1988 was the expectation for many people that immunization against poliomyelitis would eventually simply stop, as had been the case with smallpox following its eradication in 1977. However, the strategies for managing the risks associated with a "polio-free" world must be continuously refined to reflect new developments, particularly in our understanding of the live polioviruses in the oral poliovirus vaccine (OPV) and in the international approach to managing potential biohazards. The most important of these developments has been the confirmation in 2000 that vaccine-derived polioviruses (VDPVs) can circulate and cause polio outbreaks, making the use of OPV after interruption of wild poliovirus transmission incompatible with a polio-free world. A comprehensive strategy has been developed to minimize the risks associated with eventual OPV cessation, centered on appropriate long-term biocontainment of poliovirus stocks (whether for vaccine production, diagnosis, or research), the controlled reintroduction of any live poliovirus vaccine (i.e., from an OPV stockpile), and appropriate use of the inactivated poliovirus vaccine (IPV). Although some aspects of this risk management strategy are still debated, there is wide agreement that no strategy would entirely eliminate the potential risks to a polio-free world. The current strategy for risk management in a polio-free world will continue to evolve with better characterization of these risks and the development of more effective approaches both to reduce those risks and to limit their consequences should they occur.     

The influence of the birthplace and models of care on midwifery practice for the management of women in labour

This paper will examine how the settings in which midwives practice (the birthplace) and models of care affect midwives’ decision making during the management of labour. One-hundred-and-four independent, team and hospital based midwives and 100 low obstetric risk nulliparous women to whom labour care was provided were surveyed. These midwives and women resided in the Auckland metropolitan area of New Zealand. The majority of midwives who participated worked in models of care which provided women with continuity of carer and care, however, this was not found to influence the way the midwives provided labour care. Instead, practice was found to be relatively homogenous regardless of whether the midwives worked in independent, team, or hospital-based practice. The birthplace setting in which the labour care took place did influence midwifery practice. The majority of midwives provided labour care in large obstetric hospitals and identified practices dominated by the medical model of care. Practice was described as being influenced by intervention and the need for technology, however, this did not prevent the majority of women from perceiving they were actively involved in the decision making process and that they worked in partnership with their midwives. Closer examination of the midwives’ decision making processes whilst providing the labour care revealed that the midwives’ individual decisions were influenced by the needs of the women rather than the hospital protocols. What became evident was that the midwives in this study had adopted a humanistic approach to care whereby technology was used alongside relationship-centred care.     

Barriers children face complaining about social work practice: A study in one English local authority

Despite the introduction of guidelines and procedures aimed at encouraging and supporting children and young people to complain about the services they receive, children in care still face barriers to doing so in practice. This paper explores what happens when children in care are dissatisfied with the services they receive. Specifically, this study examines the complaints procedure for children in care. The findings are based on semistructured interviews with children in care, social workers, senior managers, and independent reviewing officers from one English local authority. Thematic analysis of these data identified five emergent themes: (a) complaints by children in care are managed at the lowest possible level, (b) senior managers have an overly optimistic view about children in care being informed of complaint procedures and being encouraged to do so, (c) children in care are worried about complaining, which is recognized by professionals, (d) children's voices are often not heard, and (e) when issues are clearly defined, independent reviewing officers have some degree of success in resolving complaints from children in care.     

Enhancing the midwife-woman relationship through shared decision making and clinical guidelines

The active and passive voice allocated to women within maternity service guidelines helps construct the nature of decision making. The aim of this paper is to demonstrate that by allocating women an active voice within practice guidelines serves the interest of all parties within the health care relationship. Clinical guidelines were reviewed, and electronic databases and text were searched. The findings of this paper support that applying the principles of a shared decision making framework, within clinical practice guidelines, can assist the development of a partnership relationship between midwives and women.     

‘Next Steps’ for Equality?: The Impact of Organizational Change on Opportunities for Women in the Civil Service

The ‘Next Steps’ restructuring programme (1988) has had a fundamental impact on the management and organization of the Civil Service, and on the practice of equal opportunities. The fragmentation of the service into semi-autonomous agencies has resulted in greater managerial autonomy in relation to staffing issues. Equality initiatives such as part-time and flexible working patterns, ‘family friendly’ policies, women-only training programmes and the provision of nurseries are coming under threat due to increased discretion over decision-making in these areas. Other aspects of restructuring — such as ‘downsizing’— have resulted in a reduction of the middle management layer, making it more difficult for women to breach the ‘glass ceiling’ and access senior posts. The persistence of a hostile managerial sub-culture to equal opportunities has been instrumental in pushing equality issues to the bottom of the agenda in the current climate of change because of ‘more important’ organizational pressures. Within this context, equality of opportunity for women in the Civil Service has reached a critical stage.