title: Epidemiological evidence that can help to improve timely diagnosis of colorectal cancer in New Zealand.

authors: Hirsz, Malgorzata

subjects: Colorectal cancer

abstract: Incidence rates of colorectal cancer (CRC) in New Zealand (NZ) are among the highest in the world. The long-term survival rates in NZ are poor, which has partially been attributed to late diagnosis. Considering that CRC is a curable disease if diagnosed early, conducting research targeted at the improvement of early diagnosis is therefore important. This thesis provides statistical models for the calculation of CRC incidence rates in the entire NZ population and population strata defined by age, gender, ethnicity and diabetes status, and a model for CRC risk in individual patients referred to the secondary care. The models presented here could assist health professionals in the selection of patients for further investigation to facilitate earlier diagnosis. The empirical part consists of three independent observational studies, briefly described below.

Sub-study 1. The objectives were, first, to describe trends in CRC incidence in the NZ population and, second, to investigate whether there are any strata defined by gender and ethnicity with especially increased incidence rates of CRC. To address these objectives, I analysed data from the New Zealand Cancer Registry (years 1994–2018) using an age- period-cohort (APC) model. The overall CRC incidence rates in NZ decreased between 1994 and 2018 by an average of 1.31% per year. However, the decrease was observed only in patients 50 years and older. In those 30-<50 years old, the incidence rates increased between 1994 and 2018 regardless of gender and ethnicity. The increase was similar for proximal, distal and rectal cancers. The APC analyses revealed very strong cohort effects that could explain nearly the entire trends in CRC incidence, pointing out generations born in the 1970s and 80s being affected by the increased incidence rates, rather than individuals 30-<50 years old. The cohort effects were different in Ma ̄ori and non-Ma ̄ori populations. In non-Ma ̄ori born between approximately 1939 and 1955, incidence rates decreased sharply. By contrast, those Ma ̄ori generations have not benefitted from the sharp decrease in rates. However, CRC incidence increased substantially in both M ̄aori and non-M ̄aori groups born in the 1970s and 80s.

Sub-study 2. The objective was to estimate the IRR for CRC in patients with diabetes compared to those without diabetes, with relation to diabetes duration and use of insulin for diabetes control. Registration in the Virtual Diabetes Register (VDR) in the years 2014–2018 was used as a marker of a diabetes diagnosis. Tables with counts of the entire NZ population stratified by age, gender, and ethnicity were obtained from Statistics NZ. In total, data from 310,710 patients with diabetes, corresponding to 1,277,284 person- years and 2512 incident CRC cases were analysed using a Poisson regression model. Diabetes was associated with an overall increased CRC incidence of 13% compared to non-diabetes [IRR=1.13 (95% CI: 1.08, 1.18)]. The IRR was especially high in the first three months after diabetes diagnosis [IRR=2.55 (95% CI 2.02, 3.21)], likely due to detection bias. The association was equally strong in males and females. However, in the analysis by ethnicity, the incidence of CRC was increased only in non-Ma ̄ori patients and restricted only to those younger than 75 years.

Sub-study 3. The objective was to develop a predictive model for CRC risk in individual patients referred to secondary care. To develop such a model, I extracted information from free text included in e-referrals from GPs’ to the Gastroenterology and General Surgery departments in the Waikato Hospital from 2015-2018, including: symptoms; test results; and family history of CRC. The reference test was a full colonoscopy with visualisation of the cecum. Data from 3015 patients, 20-<90 years old were analysed using a logistic regression model. The final model included the following predictors associated with increased CRC risk: anaemia, rectal bleeding, palpable mass in abdomen or rectum, weight loss, age and gender, and a decreased CRC risk: family history of CRC, abdominal pain, and inflammatory bowel disease. The model discriminates patients with low CRC risk well. According to the final cross-validated model, around 20% of patients from our cohort had performed colonoscopy despite a very low CRC risk (less than 1.5%).

In conclusion, the APC analysis revealed an alarming pattern. According to the fitted APC model, the combination of increasing age and cohort effect in generations born in the 1970s and 80s will bring a wave of CRC diagnoses in the near future when the young generations with high CRC incidence rates will replace the old generations with low CRC incidence. The results from this study could therefore help policy-makers to plan the needs for gastroenterology services.
Secondly, CRC incidence rates in diabetes have been found to be slightly increased com- pared to non-diabetes but only in non-Ma ̄ori individuals younger than 75 years.
Third, the results suggest that males underutilise health services. As shown in sub- study 3, males underwent fewer colonoscopies than females, despite having a higher risk of CRC. The higher detection bias in males than in females (sub-study 2) could also suggest underuse of health services by males, but the difference was not statistically significant.
Finally, based on the fitted models for CRC incidence in sub-studies 1 and 2, population- wide CRC screening for Ma ̄ori and patients with diabetes, based on the incidence, instead of age alone, would be proposed to start at age 57.5 years if the screening in the general population starts at age 60 years.

text: Epidemiological evidence that can help to improve timely diagnosis of colorectal cancer in New Zealand. Incidence rates of colorectal cancer (CRC) in New Zealand (NZ) are among the highest in the world. The long-term survival rates in NZ are poor, which has partially been attributed to late diagnosis. Considering that CRC is a curable disease if diagnosed early, conducting research targeted at the improvement of early diagnosis is therefore important. This thesis provides statistical models for the calculation of CRC incidence rates in the entire NZ population and population strata defined by age, gender, ethnicity and diabetes status, and a model for CRC risk in individual patients referred to the secondary care. The models presented here could assist health professionals in the selection of patients for further investigation to facilitate earlier diagnosis. The empirical part consists of three independent observational studies, briefly described below.

Sub-study 1. The objectives were, first, to describe trends in CRC incidence in the NZ population and, second, to investigate whether there are any strata defined by gender and ethnicity with especially increased incidence rates of CRC. To address these objectives, I analysed data from the New Zealand Cancer Registry (years 1994–2018) using an age- period-cohort (APC) model. The overall CRC incidence rates in NZ decreased between 1994 and 2018 by an average of 1.31% per year. However, the decrease was observed only in patients 50 years and older. In those 30-<50 years old, the incidence rates increased between 1994 and 2018 regardless of gender and ethnicity. The increase was similar for proximal, distal and rectal cancers. The APC analyses revealed very strong cohort effects that could explain nearly the entire trends in CRC incidence, pointing out generations born in the 1970s and 80s being affected by the increased incidence rates, rather than individuals 30-<50 years old. The cohort effects were different in Ma ̄ori and non-Ma ̄ori populations. In non-Ma ̄ori born between approximately 1939 and 1955, incidence rates decreased sharply. By contrast, those Ma ̄ori generations have not benefitted from the sharp decrease in rates. However, CRC incidence increased substantially in both M ̄aori and non-M ̄aori groups born in the 1970s and 80s.

Sub-study 2. The objective was to estimate the IRR for CRC in patients with diabetes compared to those without diabetes, with relation to diabetes duration and use of insulin for diabetes control. Registration in the Virtual Diabetes Register (VDR) in the years 2014–2018 was used as a marker of a diabetes diagnosis. Tables with counts of the entire NZ population stratified by age, gender, and ethnicity were obtained from Statistics NZ. In total, data from 310,710 patients with diabetes, corresponding to 1,277,284 person- years and 2512 incident CRC cases were analysed using a Poisson regression model. Diabetes was associated with an overall increased CRC incidence of 13% compared to non-diabetes [IRR=1.13 (95% CI: 1.08, 1.18)]. The IRR was especially high in the first three months after diabetes diagnosis [IRR=2.55 (95% CI 2.02, 3.21)], likely due to detection bias. The association was equally strong in males and females. However, in the analysis by ethnicity, the incidence of CRC was increased only in non-Ma ̄ori patients and restricted only to those younger than 75 years.

Sub-study 3. The objective was to develop a predictive model for CRC risk in individual patients referred to secondary care. To develop such a model, I extracted information from free text included in e-referrals from GPs’ to the Gastroenterology and General Surgery departments in the Waikato Hospital from 2015-2018, including: symptoms; test results; and family history of CRC. The reference test was a full colonoscopy with visualisation of the cecum. Data from 3015 patients, 20-<90 years old were analysed using a logistic regression model. The final model included the following predictors associated with increased CRC risk: anaemia, rectal bleeding, palpable mass in abdomen or rectum, weight loss, age and gender, and a decreased CRC risk: family history of CRC, abdominal pain, and inflammatory bowel disease. The model discriminates patients with low CRC risk well. According to the final cross-validated model, around 20% of patients from our cohort had performed colonoscopy despite a very low CRC risk (less than 1.5%).

In conclusion, the APC analysis revealed an alarming pattern. According to the fitted APC model, the combination of increasing age and cohort effect in generations born in the 1970s and 80s will bring a wave of CRC diagnoses in the near future when the young generations with high CRC incidence rates will replace the old generations with low CRC incidence. The results from this study could therefore help policy-makers to plan the needs for gastroenterology services.
Secondly, CRC incidence rates in diabetes have been found to be slightly increased com- pared to non-diabetes but only in non-Ma ̄ori individuals younger than 75 years.
Third, the results suggest that males underutilise health services. As shown in sub- study 3, males underwent fewer colonoscopies than females, despite having a higher risk of CRC. The higher detection bias in males than in females (sub-study 2) could also suggest underuse of health services by males, but the difference was not statistically significant.
Finally, based on the fitted models for CRC incidence in sub-studies 1 and 2, population- wide CRC screening for Ma ̄ori and patients with diabetes, based on the incidence, instead of age alone, would be proposed to start at age 57.5 years if the screening in the general population starts at age 60 years.

year: 2021

title: Making the invisible visible: Exploring the complex pathways between childhood experiences of maltreatment and the perpetration of family harm

authors: Dempster-Rivett, Kirsty

subjects: Childhood maltreatment

abstract: Preventing family harm and providing care for those affected is a high priority for governments and social services worldwide. Adverse consequences of family harm continue to place demands on justice, mental health and care and protection services. The costs to individuals, families and communities are beyond measure, given that rates of family harm are under-reported. Quantitative researchers have demonstrated a link between childhood maltreatment and family harm perpetration with existing psychological theories used to explain this link. However, mainstream theories were first developed many decades ago, at a time when the notion of gender was not inclusively factored into theory development. Neither were they developed with or by Indigenous peoples, calling into question the translatability of mainstream theories for stopping the intergenerational transmission of trauma and violence. 
The main aim of this thesis was to explore the relationship between childhood maltreatment and the perpetration of family harm by investigating two research questions. How could psychological theories better explain the pathways between childhood experiences of maltreatment and family harm perpetration? And, to what extent do psychological theories about the cycle of family harm reflect the experiences of Māori and non-Māori men and women in Aotearoa New Zealand? To answer these questions, interviews were conducted with 16 individuals who self-identified as perpetrating family harm and had childhood histories of maltreatment. (n=8 men, n=8 women). Purposive sampling ensured an equal number of Māori (Indigenous people of Aotearoa New Zealand) and non-Māori participated in the research. Thematic analysis was utilised to examine the personal conceptualisations regarding the association between experiences of childhood maltreatment and subsequent perpetration of family harm. The core corpus of data explored the maltreatment-family harm relationship within and between Māori and non-Māori men and women. This thesis is comprised of three studies that investigate the intergenerational transmission of trauma and violence.

The first study analysed the interviews of the seven participants removed from their families of origin as children. All described ongoing experiences of poly-victimisation in subsequent placements, whether through adoption, foster or residential settings. When examined alongside all women interviewed in this thesis, men more often reported that their childhood maltreatment was overlooked by professionals. The findings of this study highlighted a relationship between the perpetration of family harm and limited relational and emotional experiences during childhood. Intervention points across the life span were identified to stop the intergenerational transmission of trauma and violence for people removed from their family of origin as children.

The second study focused on the experiences of the eight Māori men and women interviewed. A culture of silence surrounding childhood maltreatment pervaded all interviewees’ childhood experiences. However, additional issues, including cultural isolation, were evident for Māori from the adults and professionals charged with their care. Māori interviewees identified three core Indigenous concepts that facilitated healing and intergenerational wellbeing: Wairua (spiritual connection), Pou (becoming a symbol of strength and support for self and others), and Tūrangawaewae (finding a sense of belonging). A return to Indigenous knowledge and practices was integral to stopping the intergenerational transmission of trauma and violence. This highlights the importance of privileging Indigenous knowledge in existing theoretical understanding of the cycle of family harm and incorporation in prevention initiatives.

The final study explored the impact of psychological distress within the cycle of family harm. Everyone interviewed experienced severe adverse trauma reactions linked to mental health and addiction issues, self-harm and suicidality, and instances of family harm. A significant barrier to psychological and familial wellbeing was the lack of access to integrated models of care capable of responding to complex and intertwined issues in trauma informed and Indigenous informed ways. Thus, family harm, trauma and mental health and addiction services need to work together to tailor and deliver treatment according to the individual and family needs to break the cycle of family harm and ongoing adverse life course trajectories. 

This research identifies significant limitations in the psychological theories that usually contribute to thinking about family harm. There has been a particular failure to develop a theory that accounts for the heterogeneous cultural and gendered experiences of the cycle of family harm. Going forward, expanding the? view of traditional psychological theories of intergenerational trauma and violence is required to account for the historical trauma of colonisation and the ongoing adverse consequences for Indigenous communities. Family harm prevention initiatives must be led by and/or developed in partnership with and by Indigenous peoples to ensure responsivity through active incorporation of traditional practices for intergenerational healing and wellbeing.

The impact of poly-victimisation in childhood had severe and ongoing adverse consequences for both men and women that outweighed any obvious gender difference. For people who have experienced childhood maltreatment, it is essential to imbue initiatives with opportunities to understand emotions in relational contexts. Children who are placed in the care of the state must be cared for and, unlike the interviewees in this thesis, free from further childhood maltreatment. A therapeutic web should be established to stop the systemic issues identified in this thesis by providing cohesive and coherent services in a timely fashion for children and adults affected by the cycle of family harm. In conclusion, adopting practices that are informed by understandings of trauma, gender, and Indigenous knowledge are needed to replace the intergenerational transmission of trauma and violence with hope and wellbeing.

text: Making the invisible visible: Exploring the complex pathways between childhood experiences of maltreatment and the perpetration of family harm Preventing family harm and providing care for those affected is a high priority for governments and social services worldwide. Adverse consequences of family harm continue to place demands on justice, mental health and care and protection services. The costs to individuals, families and communities are beyond measure, given that rates of family harm are under-reported. Quantitative researchers have demonstrated a link between childhood maltreatment and family harm perpetration with existing psychological theories used to explain this link. However, mainstream theories were first developed many decades ago, at a time when the notion of gender was not inclusively factored into theory development. Neither were they developed with or by Indigenous peoples, calling into question the translatability of mainstream theories for stopping the intergenerational transmission of trauma and violence. 
The main aim of this thesis was to explore the relationship between childhood maltreatment and the perpetration of family harm by investigating two research questions. How could psychological theories better explain the pathways between childhood experiences of maltreatment and family harm perpetration? And, to what extent do psychological theories about the cycle of family harm reflect the experiences of Māori and non-Māori men and women in Aotearoa New Zealand? To answer these questions, interviews were conducted with 16 individuals who self-identified as perpetrating family harm and had childhood histories of maltreatment. (n=8 men, n=8 women). Purposive sampling ensured an equal number of Māori (Indigenous people of Aotearoa New Zealand) and non-Māori participated in the research. Thematic analysis was utilised to examine the personal conceptualisations regarding the association between experiences of childhood maltreatment and subsequent perpetration of family harm. The core corpus of data explored the maltreatment-family harm relationship within and between Māori and non-Māori men and women. This thesis is comprised of three studies that investigate the intergenerational transmission of trauma and violence.

The first study analysed the interviews of the seven participants removed from their families of origin as children. All described ongoing experiences of poly-victimisation in subsequent placements, whether through adoption, foster or residential settings. When examined alongside all women interviewed in this thesis, men more often reported that their childhood maltreatment was overlooked by professionals. The findings of this study highlighted a relationship between the perpetration of family harm and limited relational and emotional experiences during childhood. Intervention points across the life span were identified to stop the intergenerational transmission of trauma and violence for people removed from their family of origin as children.

The second study focused on the experiences of the eight Māori men and women interviewed. A culture of silence surrounding childhood maltreatment pervaded all interviewees’ childhood experiences. However, additional issues, including cultural isolation, were evident for Māori from the adults and professionals charged with their care. Māori interviewees identified three core Indigenous concepts that facilitated healing and intergenerational wellbeing: Wairua (spiritual connection), Pou (becoming a symbol of strength and support for self and others), and Tūrangawaewae (finding a sense of belonging). A return to Indigenous knowledge and practices was integral to stopping the intergenerational transmission of trauma and violence. This highlights the importance of privileging Indigenous knowledge in existing theoretical understanding of the cycle of family harm and incorporation in prevention initiatives.

The final study explored the impact of psychological distress within the cycle of family harm. Everyone interviewed experienced severe adverse trauma reactions linked to mental health and addiction issues, self-harm and suicidality, and instances of family harm. A significant barrier to psychological and familial wellbeing was the lack of access to integrated models of care capable of responding to complex and intertwined issues in trauma informed and Indigenous informed ways. Thus, family harm, trauma and mental health and addiction services need to work together to tailor and deliver treatment according to the individual and family needs to break the cycle of family harm and ongoing adverse life course trajectories. 

This research identifies significant limitations in the psychological theories that usually contribute to thinking about family harm. There has been a particular failure to develop a theory that accounts for the heterogeneous cultural and gendered experiences of the cycle of family harm. Going forward, expanding the? view of traditional psychological theories of intergenerational trauma and violence is required to account for the historical trauma of colonisation and the ongoing adverse consequences for Indigenous communities. Family harm prevention initiatives must be led by and/or developed in partnership with and by Indigenous peoples to ensure responsivity through active incorporation of traditional practices for intergenerational healing and wellbeing.

The impact of poly-victimisation in childhood had severe and ongoing adverse consequences for both men and women that outweighed any obvious gender difference. For people who have experienced childhood maltreatment, it is essential to imbue initiatives with opportunities to understand emotions in relational contexts. Children who are placed in the care of the state must be cared for and, unlike the interviewees in this thesis, free from further childhood maltreatment. A therapeutic web should be established to stop the systemic issues identified in this thesis by providing cohesive and coherent services in a timely fashion for children and adults affected by the cycle of family harm. In conclusion, adopting practices that are informed by understandings of trauma, gender, and Indigenous knowledge are needed to replace the intergenerational transmission of trauma and violence with hope and wellbeing.

year: 2022

title: Agricultural land management strategies to reduce phosphorus loads in the Gippsland Lakes, Australia

authors: Roberts, Anna M.

subjects: Benefit:Cost analysis

abstract: A target to reduce phosphorus flows into the Gippsland Lakes in south-eastern Australia by 40% in order to improve water quality has previously been established by stakeholders. This target, like many others worldwide, has been set mostly on the basis of environmental concerns, with limited consideration of issues such as technical feasibility, socio-economic constraints, political factors and associated costs and benefits. An integrated analysis at the catchment scale is undertaken to assess the agricultural land management changes required to achieve this target, and to evaluate the cost-effectiveness of these changes. Based on assumptions used, it appears technically feasible to achieve a 40% reduction in P load entering the Lakes. However, the least-costly way of doing so would require around A$1 billion over 25 years, a dramatic increase in the current levels of funding provided for management. Results of a sensitivity analysis indicate that there is little or no chance of investment in a 40% reduction being cost-effective. On the other hand, a 20% P reduction could be achieved at much lower cost: around $80 million over 25 years and requiring more modest land-management changes. Reliance on voluntary adoption of ‘Current Recommended Practices’ is unlikely to deliver changes in management practices at the scale required to have sufficient environmental impacts. Enforcement of existing regulations for the dairy industry would be amongst the most cost-effective management strategies. The major implications of this work for agriculturally induced diffuse-source pollution include the need for feedback between goal setting and program costs, and consideration of factors such as the levels of landholder adoption of new practices that are required and the feasibility of achieving those adoption levels. Costs, landholder adoption of new practices and socio-political risks appear neglected in the formulation of many water quality programs. The study provides a demonstration of an approach to integrated multidisciplinary research addressing complex environmental problems with multiple decision makers, multiple stakeholders, and high uncertainty. On the evidence of experience in this study, the approach deserves consideration in other contexts.

text: Agricultural land management strategies to reduce phosphorus loads in the Gippsland Lakes, Australia A target to reduce phosphorus flows into the Gippsland Lakes in south-eastern Australia by 40% in order to improve water quality has previously been established by stakeholders. This target, like many others worldwide, has been set mostly on the basis of environmental concerns, with limited consideration of issues such as technical feasibility, socio-economic constraints, political factors and associated costs and benefits. An integrated analysis at the catchment scale is undertaken to assess the agricultural land management changes required to achieve this target, and to evaluate the cost-effectiveness of these changes. Based on assumptions used, it appears technically feasible to achieve a 40% reduction in P load entering the Lakes. However, the least-costly way of doing so would require around A$1 billion over 25 years, a dramatic increase in the current levels of funding provided for management. Results of a sensitivity analysis indicate that there is little or no chance of investment in a 40% reduction being cost-effective. On the other hand, a 20% P reduction could be achieved at much lower cost: around $80 million over 25 years and requiring more modest land-management changes. Reliance on voluntary adoption of ‘Current Recommended Practices’ is unlikely to deliver changes in management practices at the scale required to have sufficient environmental impacts. Enforcement of existing regulations for the dairy industry would be amongst the most cost-effective management strategies. The major implications of this work for agriculturally induced diffuse-source pollution include the need for feedback between goal setting and program costs, and consideration of factors such as the levels of landholder adoption of new practices that are required and the feasibility of achieving those adoption levels. Costs, landholder adoption of new practices and socio-political risks appear neglected in the formulation of many water quality programs. The study provides a demonstration of an approach to integrated multidisciplinary research addressing complex environmental problems with multiple decision makers, multiple stakeholders, and high uncertainty. On the evidence of experience in this study, the approach deserves consideration in other contexts.

year: 2012