Examining the impact of COVID-19 on Maori:non-Maori health inequities in Aotearoa, New Zealand: an observational study protocol.

INTRODUCTION: The COVID-19 pandemic has had both direct and indirect impacts on the health of populations worldwide. While racial/ethnic health inequities in COVID-19 infection are now well known (and ongoing), knowledge about the impact of COVID-19 pandemic management on non-COVID-19-related outcomes for Indigenous peoples is less well understood. This article presents the study protocol for the Health Research Council of New Zealand funded project 'Ma te Mohio ka Marama: Impact of COVID-19 on Maori:non-Maori inequities'. The study aims to explore changes in access to healthcare, quality of healthcare and health outcomes for Maori, the Indigenous peoples of Aotearoa New Zealand (NZ) and non-Maori during the COVID-19 outbreak period across NZ. METHODS AND ANALYSIS: This observational study is framed within a Kaupapa Maori research positioning that includes Kaupapa Maori epidemiology. National datasets will be used to report on access to healthcare, quality of healthcare and health outcomes between Maori and non-Maori during the COVID-19 pandemic in NZ. Study periods are defined as (a) prepandemic period (2015-2019), (b) first pandemic year without COVID-19 vaccines (2020) and (c) pandemic period with COVID-19 vaccines (2021 onwards). Regional and national differences between Maori and non-Maori will be explored in two phases focused on identified health priority areas for NZ including (1) mortality, cancer, long-term conditions, first 1000 days, mental health and (2) rheumatic fever. ETHICS AND DISSEMINATION: This study has ethical approval from the Auckland Health Research Ethics Committee (AHREC AH26253). An advisory group will work with the project team to disseminate the findings of this project via project-specific meetings, peer-reviewed publications and a project-specific website. The overall intention of the project is to highlight areas requiring health policy and practice interventions to address Indigenous inequities in health resulting from COVID-19 pandemic management (both historical and in the future).

Where Are We Dying? Ethnic Differences in Place of Death Among New Zealanders Dying of Cancer.

PURPOSE: Around a third of people with cancer will die outside of their preferred place of death, with substantial variation occurring between and within countries in terms of place of death. Here, we examine place of death within the New Zealand cancer context, with specific focus on differences between Indigenous Maori and other ethnic groups. METHODS: Using national-level data, we identified all those who died in New Zealand between 2007 and 2018 of cancer (N = 107,373), stratified by ethnicity and cancer type, and linked these patients to national health and mortality records. We then described the crude and age-standardized proportions of cancer deaths by location separately by ethnic group, and conducted logistic regression to compare odds of death within a given location between ethnic groups. RESULTS: After adjusting for age, sex, and deprivation, we found that Maori people with cancer are more likely to die in a private residence than Europeans (46% v 26%; odds ratio [OR] 2.45; 95% CI, 2.36 to 2.55), and also somewhat more likely to die in hospital (27% v 23%; OR 1.26; 95% CI, 1.21 to 1.32). Commensurately, Maori are less likely to die in either hospice inpatient unit (14% v 27%; OR 0.48; 95% CI, 0.45 to 0.51) or residential care (12% v 30%; OR 0.56; 95% CI, 0.52 to 0.59). Pacific patients generally follow the same pattern as Maori patients. These findings were largely repeated across cancer types, with some variation in the magnitude not overall pattern. CONCLUSION: It remains unclear whether these differences reflect differences in preferences for place of death between ethnic groups, or whether they reflect differences in access to appropriate supportive care. Further research is required to examine these differences in greater detail.

National Study of Pain Medicine Access Among Maori and Non-Maori Patients With Lung Cancer in New Zealand.

PURPOSE: Pain is among the most common and consequential symptoms of cancer, particularly in the context of lung cancer. Maori have extremely high rates of lung cancer, and there is evidence that Maori patients with lung cancer are less likely to receive curative treatment and more likely to receive palliative treatment and to wait longer for their treatment than non-Maori New Zealanders. The extent to which Maori patients with lung cancer are also less likely to have access to pain medicines as part of their supportive care remains unclear. METHODS: Using national-level Cancer Registry and linked health records, we describe access to subsidized pain medicines among patients with lung cancer diagnosed over the decade spanning 2007-2016 and compare access between Maori and non-Maori patients. Descriptive and logistic regression methods were used to compare access between ethnic groups. RESULTS: We observed that the majority of patients with lung cancer are accessing some form of pain medicine and there do not appear to be strong differences between Maori and non-Maori in terms of overall access or the type of pain medicine dispensed. However, Maori patients appeared more likely than non-Maori to first access pain medicines within 2 weeks before their death and commensurately less likely to access them more than 24 weeks before death. CONCLUSION: Given the plausibility that there are differences in first access to pain medicines (particularly opioid medicines) among Maori approaching end of life, further investigation of the factors contributing to this disparity is required.

Long term exposure to air pollution, mortality and morbidity in New Zealand: Cohort study.

OBJECTIVES: To investigate associations between long-term exposure to PM2.5, NO2, mortality and morbidity in New Zealand, a country with low levels of exposure. DESIGN: Retrospective cohort study. SETTING: The New Zealand resident population. METHOD: The main analyses included all adults aged 30 years and over with complete data on covariates: N = 2,223,507. People who died, or were admitted to hospital, (2013-2016) were linked anonymously to the 2013 census, and to estimates of ambient PM2.5, and NO2 concentration. We fitted Poisson regression models of mortality and morbidity in adults (≥30) for all natural causes of death, and by sub- group of major cause. Person-time of exposure, censored at the time of death, was included as an offset. We adjusted for confounding by age, sex, ethnicity, income, education, smoking status and ambient temperature. Further analyses stratified by ethnic group, and investigated respiratory hospital admissions in children. RESULTS: There were statistically significant positive associations between pollutants and natural causes of death: RR (per 10 µg/m3) for PM2.5 1.11 (1.07 to 1.15) and for NO2 1.10 (1.07 to 1.12). For morbidity, the strongest associations were for PM2.5 and ischaemic heart disease in adults, RR: 1.29 (1.23 to 1.35) and for NO2 and asthma in children, RR: 1.18 (1.09 to 1.28). In models restricted to specific ethnic groups, we found no consistent differences in any of the associations. CONCLUSIONS: The results for NO2 are higher than those published previously. Other studies have reported that the dose-response for PM2.5 may be higher at low concentrations, but less is known about NO2. It is possible NO2 is acting as a proxy for other traffic-related pollutants that are causally related to health impacts. This study underlines the importance of controlling pollution caused by motor vehicles.

Age disparities in lung cancer survival in New Zealand: The role of patient and clinical factors.

OBJECTIVE: Age is an important prognostic factor for lung cancer. However, no studies have investigated the age difference in lung cancer survival per se. We, therefore, described the role of patient-related and clinical factors on the age pattern in lung cancer excess mortality hazard by stage at diagnosis in New Zealand. MATERIALS AND METHODS: We extracted 22 487 new lung cancer cases aged 50-99 (median age = 71, 47.1 % females) diagnosed between 1 January 2006 and 31 July 2017 from the New Zealand population-based cancer registry and followed up to December 2019. We modelled the effect of age at diagnosis, sex, ethnicity, deprivation, comorbidity, and emergency presentation on the excess mortality hazard by stage at diagnosis, and we derived corresponding lung cancer net survival. RESULTS: The age difference in net survival was particularly marked for localised and regional lung cancers, with a sharp decline in survival from the age of 70. No identified factors influenced age disparities in patients with localised cancer. However, for other stages, females had a greater difference in survival between middle-age and older-age than males. Comorbidity and emergency presentation played a minor role. Ethnicity and deprivation did not influence age disparities in lung cancer survival. CONCLUSION: Sex and stage at diagnosis were the most important factors of age disparities in lung cancer survival in New Zealand.

The impact of timely cancer diagnosis on age disparities in colon cancer survival.

OBJECTIVE: We described the role of patient-related and clinical factors on age disparities in colon cancer survival among patients aged 50-99 using New Zealand population-based cancer registry data linked to hospitalisation data. METHOD: We included 21,270 new colon cancer cases diagnosed between 1 January 2006 and 31 July 2017, followed up to end 2019. We modelled the effect of age at diagnosis, sex, ethnicity, deprivation, comorbidity, and emergency presentation on colon cancer survival by stage at diagnosis using flexible excess hazard regression models. RESULTS: The excess mortality in older patients was minimal for localised cancers, maximal during the first six months for regional cancers, the first eighteen months for distant cancers, and over the three years for missing stages. The age pattern of the excess mortality hazard varied according to sex for distant cancers, emergency presentation for regional and distant cancers, and comorbidity for cancer with missing stages. Ethnicity and deprivation did not influence age disparities in colon cancer survival. CONCLUSION: Factors reflecting timeliness of cancer diagnosis most affected age-related disparities in colon cancer survival, probably by impacting treatment strategy. Because of the high risk of poor outcomes related to treatment in older patients, efforts made to improve earlier diagnosis in older patients are likely to help reduce age disparities in colon cancer survival in New Zealand.

Changing social inequalities in smoking, obesity and cause-specific mortality: Cross-national comparisons using compass typology.

BACKGROUND: In many countries smoking rates have declined and obesity rates have increased, and social inequalities in each have varied over time. At the same time, mortality has declined in most high-income countries, but gaps by educational qualification persist-at least partially due to differential smoking and obesity distributions. This study uses a compass typology to simultaneously examine the magnitude and trends in educational inequalities across multiple countries in: a) smoking and obesity; b) smoking-related mortality and c) cause-specific mortality. METHODS: Smoking prevalence, obesity prevalence and cause-specific mortality rates (35-79 year olds by sex) in nine European countries and New Zealand were sourced from between 1980 and 2010. We calculated relative and absolute inequalities in prevalence and mortality (relative and slope indices of inequality, respectively RII, SII) by highest educational qualification. Countries were then plotted on a compass typology which simultaneously examines trends in the population average rates or odds on the x-axis, RII on the Y-axis, and contour lines depicting SII. FINDINGS: Smoking and obesity. Smoking prevalence in men decreased over time but relative inequalities increased. For women there were fewer declines in smoking prevalence and relative inequalities tended to increase. Obesity prevalence in men and women increased over time with a mixed picture of increasing absolute and sometimes relative inequalities. Absolute inequalities in obesity increased for men and women in Czech Republic, France, New Zealand, Norway, for women in Austria and Lithuania, and for men in Finland. Cause-specific mortality. Average rates of smoking-related mortality were generally stable or increasing for women, accompanied by increasing relative inequalities. For men, average rates were stable or decreasing, but relative inequalities increased over time. Cardiovascular disease, cancer, and external injury rates generally decreased over time, and relative inequalities increased. In Eastern European countries mortality started declining later compared to other countries, however it remained at higher levels; and absolute inequalities in mortality increased whereas they were more stable elsewhere. CONCLUSIONS: Tobacco control remains vital for addressing social inequalities in health by education, and focus on the least educated is required to address increasing relative inequalities. Increasing obesity in all countries and increasing absolute obesity inequalities in several countries is concerning for future potential health impacts. Obesity prevention may be increasingly important for addressing health inequalities in some settings. The compass typology was useful to compare trends in inequalities because it simultaneously tracks changes in rates/odds, and absolute and relative inequality measures.

An estimate of limited duration cancer prevalence in New Zealand using 'big' data.

AIMS: Increases in cancer survival may increase cancer prevalence and demand for healthcare. We aimed to estimate cancer prevalence in the New Zealand population. METHODS: We used national linked health, social and census datasets from the Stats NZ Integrated Data Infrastructure to identify the number of New Zealand residents who had at least one cancer diagnosis in New Zealand. We included all primary cancers recorded on the New Zealand Cancer Registry from January 1995 to June 2013, and used the 2013 census for demographic and socioeconomic data. RESULTS: On 30 June 2013, 140,600 of 4,438,900 (3.2%) New Zealand residents had been diagnosed with cancer in the last 18.5 years. In ≥15 year olds, the age-standardised prevalence of cancer diagnosed 0 to ≤1 year, and >1 to ≤5 years, prior to 30 June 2013 was 0.4% and 1.1% in men and 0.3% and 0.9% in women, respectively. Over the 18.5-year period prevalence was greatest in the oldest ages, European/Other, highest qualified, highest income, least deprived, ex-smokers, and Canterbury, Bay of Plenty and Nelson/Marlborough District Health Boards (age-standardised). CONCLUSIONS: Groups with the highest survival and the greatest access to healthcare had the highest cancer prevalences.

Is mode of transport to work associated with mortality in the working-age population? Repeated census-cohort studies in New Zealand, 1996, 2001 and 2006.

BACKGROUND: Increasing active transport is proposed as a means to address both health and environmental issues. However, the associations between specific modes, such as cycling, walking and public transport, and health outcomes remain unclear. We examined the association between mode of travel to work and mortality. METHODS: Cohort studies of the entire New Zealand working population were created using 1996, 2001 and 2006 censuses linked to mortality data. Mode of travel to work was that reported on census day, and causes of death examined were ischaemic heart disease and injury. Main analyses were Poisson regression models adjusted for socio-demographics. Sensitivity analyses included: additional adjustment for smoking in the 1996 and 2006 cohorts, and bias analysis about non-differential misclassification of cycling vs car use. RESULTS: Walking (5%) and cycling (3%) to work were uncommon. Compared with people reporting using motor vehicles to travel to work, those cycling had a reduced all-cause mortality (ACM) in the socio-demographic adjusted models RR 0.87 (0.77-0.98). Those walking (0.97, 0.90-1.04) and taking public transport (0.96, 0.88-1.05) had no substantive difference in ACM. No mode of transport was associated with detectable statistically significant reductions in cause-specific mortality. Sensitivity analyses found weaker associations when adjusting for smoking and stronger associations correcting for likely non-differential misclassification of cycling. CONCLUSIONS: This large cohort study supports an association between cycling to work and reduced ACM, but found no association for walking or public-transport use and imprecise cause-specific mortality patterns.

Health system costs for individual and comorbid noncommunicable diseases: An analysis of publicly funded health events from New Zealand.

BACKGROUND: There is little systematic assessment of how total health expenditure is distributed across diseases and comorbidities. The objective of this study was to use statistical methods to disaggregate all publicly funded health expenditure by disease and comorbidities in order to answer three research questions: (1) What is health expenditure by disease phase for noncommunicable diseases (NCDs) in New Zealand? (2) Is the cost of having two NCDs more or less than that expected given the independent costs of each NCD? (3) How is total health spending disaggregated by NCDs across age and by sex? METHODS AND FINDINGS: We used linked data for all adult New Zealanders for publicly funded events, including hospitalisation, outpatient, pharmaceutical, laboratory testing, and primary care from 1 July 2007 to 30 June 2014. These data include 18.9 million person-years and $26.4 billion in spending (US$ 2016). We used case definition algorithms to identify if a person had any of six NCDs (cancer, cardiovascular disease [CVD], diabetes, musculoskeletal, neurological, and a chronic lung/liver/kidney [LLK] disease). Indicator variables were used to identify the presence of any of the 15 possible comorbidity pairings of these six NCDs. Regression was used to estimate excess annual health expenditure per person. Cause deletion methods were used to estimate total population expenditure by disease. A majority (59%) of health expenditure was attributable to NCDs. Expenditure due to diseases was generally highest in the year of diagnosis and year of death. A person having two diseases simultaneously generally had greater health expenditure than the expected sum of having the diseases separately, for all 15 comorbidity pairs except the CVD-cancer pair. For example, a 60-64-year-old female with none of the six NCDs had $633 per annum expenditure. If she had both CVD and chronic LLK, additional expenditure for CVD separately was $6,443/$839/$9,225 for the first year of diagnosis/prevalent years/last year of life if dying of CVD; additional expenditure for chronic LLK separately was $6,443/$1,291/$9,051; and the additional comorbidity expenditure of having both CVD and LLK was $2,456 (95% confidence interval [CI] $2,238-$2,674). The pattern was similar for males (e.g., additional comorbidity expenditure for a 60-64-year-old male with CVD and chronic LLK was $2,498 [95% CI $2,264-$2,632]). In addition to this, the excess comorbidity costs for a person with two diseases was greater at younger ages, e.g., excess expenditure for 45-49-year-old males with CVD and chronic LLK was 10 times higher than for 75-79-year-old males and six times higher for females. At the population level, 23.8% of total health expenditure was attributable to higher costs of having one of the 15 comorbidity pairs over and above the six NCDs separately; of the remaining expenditure, CVD accounted for 18.7%, followed by musculoskeletal (16.2%), neurological (14.4%), cancer (14.1%), chronic LLK disease (7.4%), and diabetes (5.5%). Major limitations included incomplete linkage to all costed events (although these were largely non-NCD events) and missing private expenditure. CONCLUSIONS: The costs of having two NCDs simultaneously is typically superadditive, and more so for younger adults. Neurological and musculoskeletal diseases contributed the largest health system costs, in accord with burden of disease studies finding that they contribute large morbidity. Just as burden of disease methodology has advanced the understanding of disease burden, there is a need to create disease-based costing studies that facilitate the disaggregation of health budgets at a national level.

Socioeconomic and Tobacco Mediation of Ethnic Inequalities in Mortality over Time: Repeated Census-mortality Cohort Studies, 1981 to 2011.

BACKGROUND: Racial/ethnic inequalities in mortality may be reducible by addressing socioeconomic factors and smoking. To our knowledge, this is the first study to estimate trends over multiple decades in (1) mediation of racial/ethnic inequalities in mortality (between Maori and Europeans in New Zealand) by socioeconomic factors, (2) additional mediation through smoking, and (3) inequalities had there never been smoking. METHODS: We estimated natural (1 and 2 above) and controlled mediation effects (3 above) in census-mortality cohorts for 1981-1984 (1.1 million people), 1996-1999 (1.5 million), and 2006-2011 (1.5 million) for 25- to 74-year-olds in New Zealand, using a weighting of regression predicted outcomes. RESULTS: Socioeconomic factors explained 46% of male inequalities in all three cohorts and made an increasing contribution over time among females from 30.4% (95% confidence interval = 18.1%, 42.7%) in 1981-1984 to 41.9% (36.0%, 48.0%). Including smoking with socioeconomic factors only modestly altered the percentage mediated for males, but more substantially increased it for females, for example, 7.7% (5.5%, 10.0%) in 2006-2011. A counterfactual scenario of having eradicated tobacco in the past (but unchanged socioeconomic distribution) lowered mortality for all sex-by-ethnic groups and resulted in a 12.2% (2.9%, 20.8%) and 21.2% (11.6%, 31.0%) reduction in the absolute mortality gap between Maori and Europeans in 2006-2011, for males and females, respectively. CONCLUSIONS: Our study predicts that, in this high-income country, reducing socioeconomic disparities between ethnic groups would greatly reduce ethnic inequalities in mortality over the long run. Eradicating tobacco would notably reduce ethnic inequalities in absolute but not relative mortality.

Changing smoking-mortality association over time and across social groups: National census-mortality cohort studies from 1981 to 2011.

The difference in mortality between current and never-smokers varies over time, affecting future projections of health gains from tobacco control. We examine this heterogeneity by sex, ethnicity and cause of death on absolute and relative scales using New Zealand census data. These data included smoking status, and were linked to subsequent mortality records in 1981-84, 1996-99 and 2006-11 for 25-74 year olds (16.1 million person-years of follow-up). Age-standardised mortality rates and rate differences (SRDs) were calculated comparing current to never-smokers, and Poisson regression was used to adjust for multiple socioeconomic factors and household smoking. We found that mortality declined over time in never-smokers; however, mortality trends in current-smokers varied by sex, ethnicity and cause of death. SRDs were stable over time in European/Other men, moderately widened in European/Other women and markedly increased in Maori men and women (Indigenous population). Poisson smoking-mortality rate ratios (RRs) increased from 1981-84 to 1996-99 with a moderate increase from 1996-99 to 2006-11 (RRs 1.48, 1.77, 1.79 in men and 1.51, 1.80, 1.90 in women). Socioeconomic confounding increased over time. In summary, this marked heterogeneity in smoking-mortality RRs over time has implications for estimating the future health and inequality impacts of tobacco control interventions.

Changing ethnic inequalities in mortality in New Zealand over 30 years: linked cohort studies with 68.9 million person-years of follow-up.

BACKGROUND: Internationally, ethnic inequalities in mortality within countries are increasingly recognized as a public health concern. But few countries have data to monitor such inequalities. We aimed to provide a detailed description of ethnic inequalities (Maori [indigenous], Pacific, and European/Other) in mortality for a country with high quality ethnicity data, using both standard and novel visualization methods. METHODS: Cohort studies of the entire New Zealand population were conducted, using probabilistically-linked Census and mortality data from 1981 to 2011 (68.9 million person years). Absolute (standardized rate difference) and relative (standardized rate ratio) inequalities were calculated, in 1-74-year-olds, for Maori and Pacific peoples in comparison to European/Other. RESULTS: All-cause mortality rates were highest for Maori, followed by Pacific peoples then European/Other, and declined in all three ethnic groups over time. Pacific peoples experienced the slowest annual percentage fall in mortality rates, then Maori, with European/Other having the highest percentage falls - resulting in widening relative inequalities. Absolute inequalities, however, for both Maori and Pacific males compared to European/Other have been falling since 1996. But for females, only Maori absolute inequalities (compared with European/Other) have been falling. Regarding cause of death, cancer is becoming a more important contributor than cardiovascular disease (CVD) to absolute inequalities, especially for Maori females. CONCLUSIONS: We found declines in all-cause mortality rates, over time, for each ethnic group of interest. Ethnic mortality inequalities are generally stable or even falling in absolute terms, but have increased on a relative scale. The drivers of these inequalities in mortality are transitioning over time, away from CVD to cancer and diabetes; such transitions are likely in other countries, and warrant further research. To address these inequalities, policymakers need to enhance prevention activities and health care delivery, but also support wider improvements in educational achievement and socioeconomic position for highest need populations.

A Typology for Charting Socioeconomic Mortality Gradients: "Go Southwest".

BACKGROUND: Holistic depiction of time-trends in average mortality rates, and absolute and relative inequalities, is challenging. METHODS: We outline a typology for situations with falling average mortality rates (m↓; e.g., cardiovascular disease), rates stable over time (m-; e.g., some cancers), and increasing average mortality rates (m↑; e.g., suicide in some contexts). If we consider inequality trends on both the absolute (a) and relative (r) scales, there are 13 possible combination of m, a, and r trends over time. They can be mapped to graphs with relative inequality (log relative index of inequality [RII]; r) on the y axis, log average mortality rate on the x axis (m), and absolute inequality (slope index of inequality; SII; a) as contour lines. We illustrate this by plotting adult mortality trends: (1) by household income from 1981 to 2011 for New Zealand, and (2) by education for European countries. RESULTS: Types range from the "best" m↓a↓r↓ (average, absolute, and relative inequalities all decreasing; southwest movement in graphs) to the "worst" m↑a↑r↑ (northeast). Mortality typologies in New Zealand (all-cause, cardiovascular disease, nonlung cancer, and unintentional injury) were all m↓r↑ (northwest), but variable with respect to absolute inequality. Most European typologies were m↓r↑ types (northwest; e.g., Finland), but with notable exceptions of m-a↑r↑ (north; e.g., Hungary) and "best" or southwest m↓a↓r↓ for Spain (Barcelona) females. CONCLUSIONS: Our typology and corresponding graphs provide a convenient way to summarize and understand past trends in inequalities in mortality, and hold potential for projecting future trends and target setting.

Changing socioeconomic inequalities in cancer incidence and mortality: Cohort study with 54 million person-years follow-up 1981-2011.

Cancer is increasingly responsible for the mortality gap between high and low socioeconomic position groups in high-income countries. This study investigates which cancers are contributing more to socioeconomic gaps in mortality and how this changes over time.New Zealand census data from 1981, 1986, 1991, 1996, 2001 and 2006, were linked to three to five years of subsequent mortality and cancer registrations, resulting in 54 and 42 million years of follow-up cancer incidence and mortality, respectively. Age- and ethnicity-standardised cancer mortality rates and the slope index of inequality (SII) by income were calculated.The contribution of cancer to absolute inequalities (SII) in mortality increased from 16 to 27% for men and from 12 to 31% for women from 1981-84 to 2006-11, peaking in 1991-94 for men and in 1996-99 for women and then levelling off, parallel to peaks in lung cancer inequalities. Lung cancer was the largest driver of cancer inequality trends (49% of the cancer mortality gap in 1981-84 to 33% in 2006-11 for men and 32 to 33% for women) followed by colorectal cancer in men (2 to 11%) and breast cancer in women (declining from 44 to 13%). Women in the lowest income quintile experienced no decline in cancer mortality.The contribution of cancer to income inequalities in all-cause mortality has expanded in this high-income country. Action to address socioeconomic inequalities should prioritise equitable tobacco control, obesity control and improved access to cancer screening, early diagnosis and high quality treatment for those with the lowest incomes.

Ethnic inequalities in cancer incidence and mortality: census-linked cohort studies with 87 million years of person-time follow-up.

BACKGROUND: Cancer makes up a large and increasing proportion of excess mortality for indigenous, marginalised and socioeconomically deprived populations, and much of this inequality is preventable. This study aimed to determine which cancers give rise to changing ethnic inequalities over time. METHODS: New Zealand census data from 1981, 1986, 1991, 1996, 2001, and 2006, were all probabilistically linked to three to five subsequent years of mortality (68 million person-years) and cancer registrations (87 million person years) and weighted for linkage bias. Age-standardised rate differences (SRDs) for Maori (indigenous) and Pacific peoples, each compared to European/Other, were decomposed by cancer type. RESULTS: The absolute size and percentage of the cancer contribution to excess mortality increased from 1981-86 to 2006-11 in Maori males (SRD 72.5 to 102.0 per 100,000) and females (SRD 72.2 to 109.4), and Pacific females (SRD -9.8 to 42.2) each compared to European/Other. Specifically, excess mortality (SRDs) increased for breast cancer in Maori females (linear trend p < 0.01) and prostate (p < 0.01) and colorectal cancers (p < 0.01) in Maori males. The incidence gap (SRDs) increased for breast (Maori and Pacific females p < 0.01), endometrial (Pacific females p < 0.01) and liver cancers (Maori males p = 0.04), and for cervical cancer it decreased (Maori females p = 0.03). The colorectal cancer incidence gap which formerly favoured Maori, decreased for Maori males and females (p < 0.01). The greatest contributors to absolute inequalities (SRDs) in mortality in 2006-11 were lung cancer (Maori males 50 %, Maori females 44 %, Pacific males 81 %), breast cancer (Maori females 18 %, Pacific females 23 %) and stomach cancers (Maori males 9 %, Pacific males 16 %, Pacific females 20 %). The top contributors to the ethnic gap in cancer incidence were lung, breast, stomach, endometrial and liver cancer. CONCLUSIONS: A transition is occurring in what diseases contribute to inequalities. The increasing excess incidence and mortality rates in several obesity- and health care access-related cancers provide a sentinel warning of the emerging drivers of ethnic inequalities. Action to further address inequalities in cancer burden needs to be multi-pronged with attention to enhanced control of tobacco, obesity, and carcinogenic infectious agents, and focus on addressing access to effective screening and quality health care.

Ethnic counts on mortality, New Zealand Cancer Registry and census data: 2006-2011.

AIM: To investigate the effects on lung function of IV magnesium in acute exacerbations of COPD (AECOPD), when given in conjunction with standard bronchodilator therapy. METHODS: This was a pilot study to a randomised, double-blinded, placebo-controlled trial. 30 patients presenting to ED with AECOPD were included. In addition to standard bronchodilator therapy, 17 patients were given saline, and 13 received 2 g of magnesium sulphate intravenously. Spirometry was carried out at presentation (TA), after initial standard bronchodilator therapy (TB) and immediately (T0), at 60 minutes (T60) and 120 minutes (T120) after trial drug infusion. Primary outcomes were percentage change in FEV1 and FVC at T0, T60 and T120. Secondary outcomes were admission rates, length of stay and requirement for NIV or mechanical ventilation. Trial registration (ANZCTR), ACTRN12613000837729. RESULTS: Greater improvements were seen in FEV1 at T0, T60 and T120 compared to TB in magnesium group (at T120, mean percentage change in FEV1 was 27.07% with magnesium versus 11.39% in the placebo group, 95%CI 3.7 to 27.7, p=0.01). Similar significantly greater improvements were noted with FVC in the magnesium group, compared to TB. CONCLUSIONS: IV magnesium sulphate used as an adjunct therapy to standard bronchodilators in AECOPD presenting to ED may improve lung function in the short term.

Patterns of cancer care costs in a country with detailed individual data.

OBJECTIVE: To determine health system expenditure on cancers by time since diagnosis using data for an entire country. METHODS: New Zealand cancer registry data was linked to hospitalization, pharmaceutical, outpatient, general practice, laboratory, and other datasets, with costs ascribed to each event occurring in 2006-2011. "Excess" cancer costs were estimated by subtracting "expected costs" for citizens without cancer from the "total cost" for cancer patients ($2011 inflation-adjusted). Gamma regressions were used to estimate costs per person-month. RESULTS: For first adult cancer diagnosed that the excess cost per person was between US$3400 and US$4300 in the first month postdiagnosis (varied by sex and age), fell to US$50-US$150 per month at 2 or more years postdiagnosis (excluding those within a year of death), but increased again if dying from their cancer (US$3800-US$8300 in the last month of life). Such patterns varied by cancer, for example, in the first month postdiagnosis for 65 year olds it varied 20-fold from US$800 for prostate to US$15,900 for brain cancer. Per diagnosed case, total excess costs varied from US$5000 (melanoma) to US$66,000 (bone and connective tissue) [Corrected]. Excess cancer costs made up 6.5% of total Vote:Health expenditure in 2010-2011, with colorectal (14.7%), breast (14.4%) being the top 2 contributors, and prostate, non-Hodgkin lymphoma, leukemia, and lung each contributing about 6%. CONCLUSIONS: Costs vary substantially by time since diagnosis and cancer type. The results and regression equations reported in this paper can be used in modeling requiring cancer costs by time since diagnosis and proximity to death.

Thyroid cancer in Pacific women in New Zealand.

AIM: To describe trends in incidence rates of thyroid cancer in New Zealand between 1981-2004 with a particular focus on Pacific women. METHOD: Linked census-cancer registration data was used to calculate age standardised cancer incidence rates for thyroid cancer. Both trends over time amongst Pacific women, and differences in rates between Pacific and European/Other women in New Zealand, were assessed. RESULTS: Rates of thyroid cancer in New Zealand were higher for women than men. The highest rates of thyroid cancer in were observed amongst Pacific women with a pooled age-standardised incidence rate of 18.5/100,000 (95%CI 14.6-22.4/100,000) compared to 5.2/100,000 (95% 4.8-5.5/100,000) for European/Other; SRR 3.58 (95%CI 2.87-4.47). Sparse data mean it is difficult to clearly identify a trend over time for Pacific women but European women experienced a 73% increase from 4.0/100,000 (95%CI 3.3-4.6/100,000) in 1981=1986 to 6.9/100,000 (95%CI 5.9-7.8/100,000) in 2001-2004 (Ptrend=0.05). CONCLUSIONS: Pacific women in New Zealand have the highest rates of thyroid cancer among resident ethnic groups. Risk was highest for Pacific women over 45 years of age. More research needs to be done looking at which specific ethnicities are driving rates of thyroid cancer in New Zealand and whether the risk is influenced by birthplace and age at migration to New Zealand.

The association of active smoking with multiple cancers: national census-cancer registry cohorts with quantitative bias analysis.

PURPOSES: (1) Determine the association of multiple cancers with smoking, focusing on cancers with an uncertain association; and (2) illustrate quantitative bias analysis as applied to registry data, to adjust for misclassification of smoking and residual confounding by alcohol and obesity. METHODS: New Zealand 1981 and 1996 censuses, including smoking questions, were linked to cancer registry data giving 14.8 million person-years of follow-up. Rate ratios (RR) for current versus never smokers, adjusting for age, sex, ethnicity and socioeconomic factors were calculated and then subjected to quantitative bias analysis. RESULTS: RR estimates for lung, larynx (including ear and nasosinus), and bladder cancers adjusted for measured confounders and exposure misclassification were 9.28 (95 % uncertainty interval 8.31-10.4), 6.14 (4.55-8.30), and 2.22 (1.94-2.55), respectively. Moderate associations were found for cervical (1.82; 1.51-2.20), kidney (1.29; 1.07-1.56), liver cancer (1.75; 1.37-2.24; European only), esophageal (2.14; 1.73-2.65), oropharyngeal (2.30; 1.94-2.72), pancreatic (1.68; 1.44-1.96), and stomach cancers (1.42; 1.22-1.66). Protective associations were found for endometrial (0.67; 0.56-0.79) and melanoma (0.72; 0.65-0.81), and borderline association for thyroid (0.76; 0.58-1.00), colon (0.89; 0.81-0.98), and CML (0.66; 0.44-0.99). Remaining cancers had near null associations. Adjustment for residual confounding suggested little impact, except the RRs for endometrial, kidney, and esophageal cancers were slightly increased, and the oropharyngeal and liver (European/other) RRs were decreased. CONCLUSIONS: Our large study confirms the strong association of smoking with many cancers and strengthens the evidence for protective associations with thyroid cancer and melanoma. With large data sets, considering and adjusting for residual systematic error is as important as quantifying random error.