Mandatory fortification with folic acid for the prevention of neural tube defects: a case study of Australia and New Zealand.

PURPOSE: To present a case study of the considerations of mandatory fortification with folic acid in Australia and New Zealand. METHODS: Review of published reports and consumer advocacy views. RESULTS: Australia and New Zealand jointly approved mandatory fortification of flour with folic acid to prevent neural tube defects in 2007. Fortification was fully implemented in Australia in 2009 and has resulted in reduction in NTD. At the last minute, industry lobbying led to the New Zealand government not proceeding with fortification. With continued consumer advocacy, mounting scientific evidence, and a change of government, approval was given in 2021 for mandatory fortification of flour with folic acid. CONCLUSION: In large part as a response to consumer pressure, New Zealand has now joined with Australia (and around 70 other countries) in fortifying flour with folic acid for the prevention of NTD.

A New Zealand regional work-related sprains and strains surveillance, management and prevention programme: study protocol.

BACKGROUND: The impact and costs associated with work-related sprains and strains in New Zealand and globally are substantial and a major occupational and public health burden. In New Zealand around one-third of all sprains and strains workers compensation (ACC) claims (2019) are for back injuries, but shoulder and arm injuries are increasing at a faster rate than other sprain and strain injuries (ACC, 2020). A need exists for a change to current approaches to sprains and strains prevention, to more effectively manage this significant and persistent problem in workplaces. Designing out hazards is one of the most effective means of preventing occupational injuries and illnesses. This paper outlines the study protocol of the surveillance, management and prevention programme and describes the utilisation of prevention through design principles in the prevention of work-related sprains and strains in agriculture/horticulture/food production in the Hawkes Bay region of New Zealand. METHODS: This is a prospective mixed methods study incorporating the collection of quantitative data to describe the epidemiology of work related sprains and strains injuries presenting to the regional health centre (Hastings Health Centre) over a period of 24 months and qualitative data from participants presenting at the health centre to identify high risk industry sectors/ occupations/ workplaces and tasks and design, develop and apply prevention through design principles/ solutions/interventions to critical features of the work and work environment and undertake an outcome evaluation during the last 6 months of the project. DISCUSSION: The purpose of this project is to establish an epidemiological surveillance programme to assess the incidence and prevalence of work-related sprains and strains according to age, sex, industry sector and occupation to target efforts to prevent work-related sprains and strains, by applying prevention through design (PtD) principles in selected workplaces in agriculture. The collection of more detailed case, occupational and work history data from a sample of patients presenting at the HHC clinic will identify high risk industry sectors/occupations/workplaces and tasks. Assessment techniques will include comprehensive design, design thinking and human factors/ergonomics methodologies through co-design and participatory ergonomics techniques. The PtD solutions/ interventions implemented will be evaluated using a quasi-experimental design consisting of a pre-test/ post-test with-in subjects design with control groups that do not receive the intervention.

Did new treatments contribute to a decrease in melanoma deaths?

Melanoma is one of the most common cancers diagnosed in New Zealand, and New Zealand has one of the highest rates of melanoma incidence and mortality in the world. Monitoring by Environmental Health Intelligence NZ (EHINZ) has found a recent sharp decline in melanoma mortality rates in New Zealand. Since 2014 and 2015 (with 376 and 378 melanoma deaths, respectively), melanoma deaths have declined to 362 deaths in 2016, 308 deaths in 2017, and 296 deaths in 2018. We believe that two new PD-1 inhibitor drug treatments introduced in New Zealand in 2016-nivolumab (Opdivo, BMS) and pembrolizumab (Keytruda, MSD)-may have contributed to this decrease in melanoma mortality. Other factors are unlikely to have had such a major effect, with the drop unlikely due to random variation, and no major changes in melanoma registrations or melanoma thickness at diagnosis over the past decade. While our monitoring of the time trend is descriptive only, and cannot attribute causality, it does suggest a recent decrease in melanoma mortality rates at the population level. These national-level statistics reflect both what might be expected in the New Zealand situation with the introduction of PD-1 inhibitor treatments, based on clinical trials, and what oncologists are seeing at an individual level. Further studies could investigate this observational finding, to confirm whether PD-1 inhibitor drug treatments are having an impact on melanoma mortality and survival rates in New Zealand.

Assessing youth empowerment and co-design to advance Pasifika health: a qualitative research study in New Zealand.

OBJECTIVES: The Pasifika Prediabetes Youth Empowerment Programme (PPYEP) was a community-based research project that aimed to investigate empowerment and co-design modules to build the capacity of Pasifika youth to develop community interventions for preventing prediabetes. METHODS: This paper reports findings from a formative evaluation process of the programme using thematic analysis. It emphasises the adoption, perceptions and application of empowerment and co-design based on the youth and community providers' experiences. RESULTS: We found that the programme fostered a safe space, increased youth's knowledge about health and healthy lifestyles, developed their leadership and social change capacities, and provided a tool to develop and refine culturally centred prediabetes-prevention programmes. These themes emerged non-linearly and synergistically throughout the programme. CONCLUSIONS: Our research emphasises that empowerment and co-design are complementary in building youth capacity in community-based partnerships in health promotion. Implications for public health: Empowerment and co-design are effective tools to develop and implement culturally tailored health promotion programmes for Pasifika peoples. Future research is needed to explore the programme within different Pasifika contexts, health issues and Indigenous groups.

Social Vulnerability Indicators for Flooding in Aotearoa New Zealand.

Social vulnerability indicators are a valuable tool for understanding which population groups are more vulnerable to experiencing negative impacts from disasters, and where these groups live, to inform disaster risk management activities. While many approaches have been used to measure social vulnerability to natural hazards, there is no single method or universally agreed approach. This paper proposes a novel approach to developing social vulnerability indicators, using the example of flooding in Aotearoa New Zealand. A conceptual framework was developed to guide selection of the social vulnerability indicators, based on previous frameworks (including the MOVE framework), consideration of climate change, and a holistic view of health and wellbeing. Using this framework, ten dimensions relating to social vulnerability were identified: exposure; children; older adults; health and disability status; money to cope with crises/losses; social connectedness; knowledge, skills and awareness of natural hazards; safe, secure and healthy housing; food and water to cope with shortage; and decision making and participation. For each dimension, key indicators were identified and implemented, mostly using national Census population data. After development, the indicators were assessed by end users using a case study of Porirua City, New Zealand, then implemented for the whole of New Zealand. These indicators will provide useful data about social vulnerability to floods in New Zealand, and these methods could potentially be adapted for other jurisdictions and other natural hazards, including those relating to climate change.

Pasifika Prediabetes Youth Empowerment Programme: learnings from a youth-led community-based intervention study.

AIM: Using a co-design approach, we describe exploratory findings of a community-based intervention to mobilise Pasifika communities into action, with the intent of reducing the risk factors of prediabetes. METHOD: A group of 25 Pasifika youth aged 15-24 years from two distinctive Pasifika communities in New Zealand were trained to lead a small-scale, community-based intervention programme (among 29 participants) over the course of eight weeks. The intervention, which targeted adults aged 25-44 years who were overweight or obese, employed both an empowerment-based programme and a co-design approach to motivate community members to participate in a physical-activity-based intervention programme. RESULTS: Findings show significant reductions in total body weight and waist circumference, as well as improved physical activity. CONCLUSIONS: The strength of this intervention was evident in the innovative approach of utilising Pasifika-youth-led and co-designed approaches to motivate communities into healthier lifestyles. The approaches used in this project could be utilised in a primary healthcare setting as a community-wide strategy to reduce diabetes risk, particularly among Pasifika peoples.

Hypospadias Prevalence and Trends in International Birth Defect Surveillance Systems, 1980-2010.

BACKGROUND: Hypospadias is a common male birth defect that has shown widespread variation in reported prevalence estimates. Many countries have reported increasing trends over recent decades. OBJECTIVE: To analyze the prevalence and trends of hypospadias for 27 international programs over a 31-yr period. DESIGN, SETTING, AND PARTICIPANTS: The study population included live births, stillbirths, and elective terminations of pregnancy diagnosed with hypospadias during 1980-2010 from 27 surveillance programs around the world. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We used joinpoint regression to analyze changes over time in international total prevalence of hypospadias across programs, prevalence for each specific program, and prevalence across different degrees of severity of hypospadias. RESULTS AND LIMITATIONS: The international total prevalence of hypospadias for all years was 20.9 (95% confidence interval: 19.2-22.6) per 10000 births. The prevalence for each program ranged from 2.1 to 39.1 per 10000 births. The international total prevalence increased 1.6 times during the study period, by 0.25 cases per 10000 births per year (p<0.05). When analyzed separately, there were increasing trends for first-, second-, and third-degree hypospadias during the early 1990s to mid-2000s. The majority of programs (61.9%) had a significantly increasing trend during many of the years evaluated. Limitations include known differences in data collection methods across programs. CONCLUSIONS: Although there have been changes in clinical practice and registry ascertainment over time in some countries, the consistency in the observed increasing trends across many programs and by degrees of severity suggests that the total prevalence of hypospadias may be increasing in many countries. This observation is contrary to some previous reports that suggested that the total prevalence of hypospadias was no longer increasing in recent decades. PATIENT SUMMARY: We report on the prevalence and trends of hypospadias among 27 birth defect surveillance systems, which indicate that the prevalence of hypospadias continues to increase internationally.

Investigating differences in dietary patterns among a small cross-sectional study of young and old Pacific peoples in NZ using exploratory factor analysis: a feasibility study.

OBJECTIVES: Obesity among Pasifika people living in New Zealand is a serious health problem with prevalence rates more than twice those of the general population (67% vs 33%, respectively). Due to the high risk of developing obesity for this population, we investigated diet quality of Pacific youth and their parents and grandparents. Therefore, we examined the dietary diversity of 30 youth and their parents and grandparents (n=34) to identify whether there are generational differences in dietary patterns and investigate the relationship between acculturation and dietary patterns. METHODS: The study design of the overarching study was cross-sectional. Face-to-face interviews were conducted with Pasifika youth, parents and grandparents to investigate dietary diversity, that included both nutritious and discretionary food items and food groups over a 7 day period. Study setting was located in 2 large urban cities, New Zealand. Exploratory factor analyses were used to calculate food scores (means) from individual food items based on proportions consumed over the week, and weights were applied to calculate a standardised food score. The relationship between the level of acculturation and deprivation with dietary patterns was also assessed. RESULTS: Three distinctive dietary patterns across all participants were identified from our analyses. Healthy diet, processed diet and mixed diet. Mean food scores indicated statistically significant differences between the dietary patterns for older and younger generations. Older generations showed greater diversity in food items consumed, as well as eating primarily a 'healthy diet'. The younger generation was more likely to consume a 'processed diet'. There was significant association between acculturation and deprivation with the distinctive dietary patterns. CONCLUSION: Our investigation highlighted generational differences in consuming a limited range of food items. Identified dietary components may, in part, be explained by specific acculturation modes (assimilation and marginalised) and high socioeconomic deprivation among this particular study population.

The Importance of Using Public Health Impact Criteria to Develop Environmental Health Indicators: The Example of the Indoor Environment in New Zealand.

Developing environmental health indicators is challenging and applying a conceptual framework and indicator selection criteria may not be sufficient to prioritise potential indicators to monitor. This study developed a new approach for prioritising potential environmental health indicators, using the example of the indoor environment for New Zealand. A three-stage process of scoping, selection, and design was implemented. A set of potential indicators (including 4 exposure indicators and 20 health indicators) were initially identified and evaluated against indicator selection criteria. The health indicators were then further prioritised according to their public health impact and assessed by the five following sub-criteria: number of people affected (based on environmental burden of disease statistics); severity of health impact; whether vulnerable populations were affected and/or large inequalities were apparent; whether the indicator related to multiple environmental exposures; and policy relevance. Eight core indicators were ultimately selected, as follows: living in crowded households, second-hand smoke exposure, maternal smoking at two weeks post-natal, asthma prevalence, asthma hospitalisations, lower respiratory tract infection hospitalisations, meningococcal disease notifications, and sudden unexpected death in infancy (SUDI). Additionally, indicators on living in damp and mouldy housing and children's injuries in the home, were identified as potential indicators, along with attributable burden indicators. Using public health impact criteria and an environmental burden of disease approach was valuable in prioritising and selecting the most important health impacts to monitor, using robust evidence and objective criteria.

Evaluating a community-based public health intervention using a complex systems approach.

Background: This article outlines the methods being used to evaluate a community-based public health intervention. This evaluation approach recognizes that not only is the intervention, Healthy Families NZ, complex, but the social systems within which it is being implemented are complex. Methods: To address challenges related to complexity, we discuss three developing areas within evaluation theory and apply them to an evaluation case example. The example, Healthy Families NZ, aims to strengthen the prevention system in Aotearoa/New Zealand to prevent chronic disease in 10 different geographic areas. Central to the evaluation design is the comparative case method which recognizes that emergent outcomes are the result of 'configurations of causes'. 'Thick', mixed-data, case studies are developed, with each case considered a view of a complex system. Qualitative Comparative Analysis is the analytical approach used to systematically compare the cases over time. Conclusions: This article describes an approach to evaluating a community-based public health intervention that considers the social systems in which the initiative is being implemented to be complex. The evaluation case example provides a unique opportunity to operationalize and test these methods, while extending their more frequent use within other fields to the field of public health.

Male Sexual Function in New Zealand: A Population-Based Cross-Sectional Survey of the Prevalence of Erectile Dysfunction in Men Aged 40-70 Years.

BACKGROUND: Sexual function declines with age and erectile dysfunction (ED) is a common condition worldwide; however, prevalence rates vary markedly between populations and reliable data specific to New Zealand (NZ) are lacking. AIM: To assess the prevalence of ED in NZ men using a population-based cross-sectional survey. METHODS: Postal questionnaires were sent, according to a modified Dillman method, to a randomly selected age-stratified population-based sample of 2,000 men 40 to 70 years old obtained from the electoral roll. Self-reported erectile function was assessed using the five-item International Index of Erectile Function (IIEF-5) and the single-question self-assessment tool. OUTCOMES: The prevalence of ED is presented as crude, age-adjusted to the distribution of the NZ population, and standardized to the World Health Organization World Standard Population (WSP). Associations between sexual function and age were analyzed using χ2 test. RESULTS: The response rate was 30% (599) and 28% (562) were complete for analysis. The crude prevalence of ED was 42% (22% mild, 10% mild to moderate, 6% moderate, and 4% severe), the age-adjusted prevalence was 38%, and the WSP-adjusted prevalence was 37%. Among men reporting ED, 16% were medically diagnosed and 22% were treated. ED affected 24% of men in their 40s, 38% in their 50s, and 60% in their 60s (P < .001). Age was associated with a significant increase in diagnosed ED (P = .001), treated ED (P = .006), dissatisfaction with current sexual function (P < .001), associated anxiety or depression (P = .023), and a decrease in sexual activity (P < .001). CLINICAL TRANSLATION: Approximately one in three NZ men 40 to 70 years old might have ED. Although comparable to overseas populations, this prevalence is high. STRENGTHS AND LIMITATIONS: This study provides the most reliable, comprehensive, and current information on ED and its risk factors in NZ men. Strengths include the large sample, the use of random selection from a population-based sampling frame, established effective survey methods, and the validated IIEF-5. Limitations include the inability of cross-sectional data to determine causation, non-sampling errors associated with the population-based sampling frame, the low response rate, the inability to assess non-respondents, the possibility of men with ED who were sexually inactive not responding or not completing the IIEF-5, and the inherent inability to rule out recall bias. CONCLUSION: ED is a marker of subclinical cardiovascular disease. The high prevalence and low levels of diagnosis and treatment indicate a lost opportunity for timely intervention to delay or prevent the progression toward clinical disease. Quilter M, Hodges L, von Hurst P, et al. Male Sexual Function in New Zealand: A Population-Based Cross-Sectional Survey of the Prevalence of Erectile Dysfunction in Men Aged 40-70 Years. J Sex Med 2017;14:928-936.

Proposed new industry code on unhealthy food marketing to children and young people: will it make a difference?

Reducing the exposure of children and young people to the marketing of unhealthy foods is a core strategy for reducing the high overweight and obesity prevalence in this population. The Advertising Standards Authority (ASA) has recently reviewed its self-regulatory codes and proposed a revised single code on advertising to children. This article evaluates the proposed code against eight criteria for an effective code, which were included in a submission to the ASA review process from over 70 New Zealand health professors. The evaluation found that the proposed code largely represents no change or uncertain change from the existing codes, and cannot be expected to provide substantial protection for children and young people from the marketing of unhealthy foods. Government regulations will be needed to achieve this important outcome.

The incidence of Orofacial Cleft in live births in New Zealand.

AIM: To determine the incidence of orofacial cleft at birth in New Zealand over 10 years from January 2000. METHODS: Comparison of data collected from cleft units and data held on the national minimum dataset. RESULTS: The overall incidence of OFC in New Zealand over a 10 year period was found to be 1.79 per 1,000 live births, higher than the norm for Western society. The major reason for this increased rate was an increased rate for the Maori 2.37 per 1,000 live births, specifically related to a Cleft Palate alone rate over twice that of the European (1.54 vs 0.73 per 1,000 live births). The rate for Pacific was half way between (1.04 per 1,000 live births). The rate of Cleft Lip alone was significantly lower in both Maori and Pacific populations. Different sex ratios were also seen in relation to Cleft Lip and Cleft Lip and Palate for Maori and Pacific compared to those normally reported. CONCLUSIONS: Maori have an increased incidence of Orofacial Cleft due to one of the highest rates of Cleft Palate alone in the world. Further aetiological studies involving genetic and environmental factors are required to elicit the reasons for this increased incidence.

Understanding Pasifika youth and the obesogenic environment, Auckland and Wellington, New Zealand.

AIM: In New Zealand, the burden of obesity is greatest among Pacific people, especially in children and adolescents. We investigated the factors of the obesogenic environment that were indigenous to Pasifika youths' social-cultural context, their food purchasing behaviours, and associated anthropometric measures. METHODS: An exploratory study of 30 Pasifika youth aged 16-24 years in Wellington and Auckland, New Zealand. RESULTS: A large proportion of the participants were obese (mean body mass index: 31.0kg/m2; waistto-hip ratio: 0.84; waist-to-height ratio: 0.6), suggesting that the future health and wellbeing trajectory of the studied Pasifika youth is poor. Purchasing behaviours of food and snacks over a 7-day period provided meaningful insights that could be a useful future research tool to examine the role of their physical environment on food access and availability. CONCLUSIONS: From this exploratory study, we highlight the following: (i) the future health trajectory of Pasifika youth is poor. Developing the youths' healthy lifestyle knowledge may lend itself to developing culturally relevant intervention programmes; (ii) identifying the enablers and barriers within the Pasifika ontext of an obesogenic environment can provide very useful information; (iii) use of spatial analysis using purchased food receipts adds to the current knowledge base of obesity-related research, although this was an exploratory investigation. We need to address these highlights if we are to reverse the trend of obesity for this population.

HBsAg loss in a New Zealand community study with 28-year follow-up: rates, predictors and long-term outcomes.

BACKGROUND AND AIMS: HBsAg seroclearance is the most desired endpoint in chronic hepatitis B (CHB) but occurs uncommonly. Recent studies have shown baseline HBsAg levels to be predictive of HBsAg loss up to 10 years. We report the 28-year rates of HBsAg loss and outcomes in the Kawerau study cohort from New Zealand, and assess the predictive value of baseline HBsAg levels to predict long-term HBsAg loss. METHODS: The 1984 Kawerau community study identified 572 CHB patients, followed up for 28 years (41 % HBeAg-positive, median age 17 years, range 1-71 years). In 2012, surviving individuals attended a local clinic for an interview, blood tests and transient elastography. RESULTS: 384/218 (74 %) surviving individuals attended the clinic in 2012. Spontaneous HBsAg loss occurred in 145 (33 %) after 12,702 person-years of follow-up (1.14 per 100 person-years). Liver stiffness measurements were significantly lower if HBsAg loss occurred <50 years (mean 6.1 kPa) versus >50 years (mean 11.6 kPa), p = 0.0002. No HCC occurred following HBsAg loss (median follow-up 72 months). Predictors of HBsAg loss were older age and lower baseline HBsAg level (HR for HBsAg loss at 28 years 2.7 (95 % CI 1.7-4.2), 6.7 (95 % CI 3.9-11.4) and 9.4 (95 % CI 5.2-16.9), respectively, for HBsAg 1000-9999, 100-999 and <100 IU/mL compared to HBsAg >10,000 IU/mL at baseline, (p < 0.0001). Baseline HBsAg was a superior predictor of HBsAg loss compared to HBV DNA at all time-points: AUROC at 15 years: 0.87 (95 % CI 0.82-0.93) versus 0.73 (95 % CI 0.66-0.80) (p < 0.0001) and AUROC at 28 years: 0.74 (95 % CI 0.69-0.79) versus 0.67 (95 % CI 0.62-0.72) (p = 0.0007). The optimal cut-off HBsAg level to predict HBsAg seroclearance at 28 years is HBsAg <10,000 IU/mL (sensitivity 72 %, specificity 64 %, NPV 88 %). CONCLUSIONS: Rates of HBsAg loss in our community cohort were high, and occurred earlier than previously reported. Earlier HBsAg loss was associated with less severe liver fibrosis. Baseline HBsAg level was a good predictor of long-term HBsAg loss up to 28 years and superior to HBV DNA.

Serum concentrations of chlorinated dibenzo-p-dioxins, furans and PCBs, among former phenoxy herbicide production workers and firefighters in New Zealand.

PURPOSE: To quantify serum concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dioxin-like compounds in former phenoxy herbicide production plant workers and firefighters, 20 years after 2,4,5-T production ceased. METHODS: Of 1025 workers employed any time during 1969-1984, 430 were randomly selected and invited to take part in a morbidity survey and provide a blood sample; 244 (57%) participated. Firefighters stationed in close proximity of the plant and/or engaged in call-outs to the plant between 1962 and 1987 also participated (39 of 70 invited). Reported here are the serum concentrations of TCDD and other chlorinated dibenzo-dioxins, dibenzofurans, and polychlorinated biphenyls (PCBs). Determinants of the serum concentrations were assessed using linear regression. RESULTS: The 60 men who had worked in the phenoxy/TCP production area had a mean TCDD serum concentration of 19.1 pg/g lipid, three times the mean concentration of the 141 men and 43 women employed in other parts of the plant (6.3 and 6.0 pg/g respectively), and more than 10 times the mean for the firefighters (1.6 pg/g). Duration of employment in phenoxy herbicide synthesis, maintenance work, and work as a boilerman, chemist, and packer were associated with increased serum concentrations of TCDD and 1,2,3,4,7-pentachlorodibenzo-p-dioxin (PeCDD). Employment as a boilerman was also associated with elevated serum concentrations of PCBs. CONCLUSIONS: Occupations in the plant associated with phenoxy herbicide synthesis had elevated levels of TCDD and PeCDD. Most other people working within the plant, and the local firefighters, had serum concentrations of dioxin-like compounds comparable to those of the general population.

Rapid Assessment of Environmental Health Impacts for Policy Support: The Example of Road Transport in New Zealand.

An integrated environmental health impact assessment of road transport in New Zealand was carried out, using a rapid assessment. The disease and injury burden was assessed from traffic-related accidents, air pollution, noise and physical (in)activity, and impacts attributed back to modal source. In total, road transport was found to be responsible for 650 deaths in 2012 (2.1% of annual mortality): 308 from traffic accidents, 283 as a result of air pollution, and 59 from noise. Together with morbidity, these represent a total burden of disease of 26,610 disability-adjusted life years (DALYs). An estimated 40 deaths and 1874 DALYs were avoided through active transport. Cars are responsible for about 52% of attributable deaths, but heavy goods vehicles (6% of vehicle kilometres travelled, vkt) accounted for 21% of deaths. Motorcycles (1 per cent of vkt) are implicated in nearly 8% of deaths. Overall, impacts of traffic-related air pollution and noise are low compared to other developed countries, but road accident rates are high. Results highlight the need for policies targeted at road accidents, and especially at heavy goods vehicles and motorcycles, along with more general action to reduce the reliance on private road transport. The study also provides a framework for national indicator development.

A cost effectiveness analysis of community water fluoridation in New Zealand.

AIM: The aim of the study was to use recent data to determine whether Community Water Fluoridation (CWF) remains a cost effective public health intervention in New Zealand, given a reduction in dental caries in all communities over time. METHOD: Local authorities that fluoridated their water supplies were asked to complete a questionnaire regarding fixed and variable costs incurred from CWF. Cost savings were calculated using data from the 2009 New Zealand Oral Health Survey. The cost effectiveness of CWF in conjunction with treatment per dmft/DMFT averted was compared to an alternative of treatment alone. Calculations were made for communities with populations of less than 5,000, 5,000 to 10,000, 10,001 to 50,000 and greater than 50,000. RESULTS: CWF was cost effective in all communities at base case. CWF remained cost effective for communities over 5,000 under all scenarios when sensitivity analysis was conducted. For communities under 5,000 the there was a positive net cost for CWF under certain scenarios. CONCLUSION: In this study, CWF was a cost effective public health intervention in New Zealand. For smaller communities cost effectiveness would be more dependent upon the population risk profile of the community.

Serological and clinical outcomes of horizontally transmitted chronic hepatitis B infection in New Zealand Maori: results from a 28-year follow-up study.

BACKGROUND: Chronic hepatitis B infection is endemic in New Zealand and has high prevalence in New Zealand Maori. Previous longitudinal studies in populations with predominantly vertically acquired chronic hepatitis B have shown low spontaneous hepatitis B surface-antigen (HBsAg) seroclearance rates: 0.5-1.4% annually (mean age of clearance 48 years). We report the 28-year follow-up data on clinical and serological outcomes in indigenous New Zealand Maori with early horizontally acquired HBV. METHODS: In 1984, community seroprevalence study identified 572 HBsAg-positive individuals, followed for 28 years. Liver-related mortality and hepatocellular carcinoma (HCC) incidence were compared between these 572 HBV carriers and 1140 HBsAg-negative matched case-controls. Surviving HBsAg-positive individuals have been followed up in 2012 with clinical assessment, blood tests and liver transient elastography. Rates of hepatitis B e-antigen (HBeAg) and HBsAg seroconversion were determined. RESULTS: After total 13 187.4 person-years follow-up, 15 HBsAg-positive patients have developed HCC compared with none of the HBsAg-negative controls (p<0.001). 12 HBsAg-positive patients died from liver-related causes compared with none in the controls (p<0.001). Spontaneous HBeAg-seroconversion occurred in 91% of HBeAg-positive patients. Spontaneous HBsAg loss occurred in 33% overall (annual clearance rate 1.34%), with higher rates at older ages (1.05% in patients<20 years at entry vs 4.3% per annum >40 years at entry, p<0.0001). Median ages of HBeAg loss and HBsAg loss were 23 years (range 6-66 years) and 40 years (range 4-80 years), respectively. CONCLUSIONS: Horizontally transmitted HBV in Maori is similarly associated with increased risk of liver-related mortality and HCC compared with Chinese, although absolute incidence rates are lower. The rates of HBeAg and HBsAg loss are high, and occur at an earlier age than previously reported.