Causes of international increases in older age life expectancy.

In high-income countries, life expectancy at age 60 years has increased in recent decades. Falling tobacco use (for men only) and cardiovascular disease mortality (for both men and women) are the main factors contributing to this rise. In high-income countries, avoidable male mortality has fallen since 1980 because of decreases in avoidable cardiovascular deaths. For men in Latin America, the Caribbean, Europe, and central Asia, and for women in all regions, avoidable mortality has changed little or increased since 1980. As yet, no evidence exists that the rate of improvement in older age mortality (60 years and older) is slowing down or that older age deaths are being compressed into a narrow age band as they approach a hypothesised upper limit to longevity.

US Spending on Personal Health Care and Public Health, 1996-2013.

Importance: US health care spending has continued to increase, and now accounts for more than 17% of the US economy. Despite the size and growth of this spending, little is known about how spending on each condition varies by age and across time. Objective: To systematically and comprehensively estimate US spending on personal health care and public health, according to condition, age and sex group, and type of care. Design and Setting: Government budgets, insurance claims, facility surveys, household surveys, and official US records from 1996 through 2013 were collected and combined. In total, 183 sources of data were used to estimate spending for 155 conditions (including cancer, which was disaggregated into 29 conditions). For each record, spending was extracted, along with the age and sex of the patient, and the type of care. Spending was adjusted to reflect the health condition treated, rather than the primary diagnosis. Exposures: Encounter with US health care system. Main Outcomes and Measures: National spending estimates stratified by condition, age and sex group, and type of care. Results: From 1996 through 2013, $30.1 trillion of personal health care spending was disaggregated by 155 conditions, age and sex group, and type of care. Among these 155 conditions, diabetes had the highest health care spending in 2013, with an estimated $101.4 billion (uncertainty interval [UI], $96.7 billion-$106.5 billion) in spending, including 57.6% (UI, 53.8%-62.1%) spent on pharmaceuticals and 23.5% (UI, 21.7%-25.7%) spent on ambulatory care. Ischemic heart disease accounted for the second-highest amount of health care spending in 2013, with estimated spending of $88.1 billion (UI, $82.7 billion-$92.9 billion), and low back and neck pain accounted for the third-highest amount, with estimated health care spending of $87.6 billion (UI, $67.5 billion-$94.1 billion). The conditions with the highest spending levels varied by age, sex, type of care, and year. Personal health care spending increased for 143 of the 155 conditions from 1996 through 2013. Spending on low back and neck pain and on diabetes increased the most over the 18 years, by an estimated $57.2 billion (UI, $47.4 billion-$64.4 billion) and $64.4 billion (UI, $57.8 billion-$70.7 billion), respectively. From 1996 through 2013, spending on emergency care and retail pharmaceuticals increased at the fastest rates (6.4% [UI, 6.4%-6.4%] and 5.6% [UI, 5.6%-5.6%] annual growth rate, respectively), which were higher than annual rates for spending on inpatient care (2.8% [UI, 2.8%-2.8%] and nursing facility care (2.5% [UI, 2.5%-2.5%]). Conclusions and Relevance: Modeled estimates of US spending on personal health care and public health showed substantial increases from 1996 through 2013; with spending on diabetes, ischemic heart disease, and low back and neck pain accounting for the highest amounts of spending by disease category. The rate of change in annual spending varied considerably among different conditions and types of care. This information may have implications for efforts to control US health care spending.

Burden of Traumatic Brain Injury in New Zealand: Incidence, Prevalence and Disability-Adjusted Life Years.

OBJECTIVE: The study aimed to estimate the incidence, prevalence and disability-adjusted life years (DALY) for traumatic brain injury (TBI) in New Zealand (NZ) in 2010. METHODS: A multi-state life table model was constructed using inputs from the Brain Injury Outcomes New Zealand in the Community study for the first-ever incidence of TBI in a lifetime and its severity distribution, from the NZ Ministry of Health's Mortality Collection for the data on TBI mortality and from Statistics of NZ for the population data. The modeled estimate of prevalence was combined with the disability weights for TBI (by stage and severity level) from the Global Burden of Disease 2010 study to obtain estimates of health loss (DALYs) for TBI. RESULTS: Approximately, 11,300 first-ever incident TBIs occurred in NZ during 2010, with 527,000 New Zealanders estimated to have ever experienced a TBI (prevalent cases). The estimated 20,300 DALYs attributable to TBI accounted for 27% of total injury-related health loss and 2.4% of DALYs from all causes. Of the total DALYs attributable to TBI, 71% resulted from fatal injuries. However, non-fatal outcomes accounted for a substantial share of the burden (29%) with mild TBI making the greater contribution of non-fatal outcomes (56%). CONCLUSIONS: The burden of TBI in NZ is substantial, and mild TBI contributes to a major part of non-fatal outcomes.

Self-reported experience of racial discrimination and health care use in New Zealand: results from the 2006/07 New Zealand Health Survey.

OBJECTIVES: We investigated whether reported experience of racial discrimination in health care and in other domains was associated with cancer screening and negative health care experiences. METHODS: We used 2006/07 New Zealand Health Survey data (n = 12 488 adults). We used logistic regression to examine the relationship of reported experience of racial discrimination in health care (unfair treatment by a health professional) and in other domains (personal attack, unfair treatment in work and when gaining housing) to breast and cervical cancer screening and negative patient experiences adjusted for other variables. RESULTS: Racial discrimination by a health professional was associated with lower odds of breast (odds ratio [OR] = 0.37; 95% confidence interval [CI] = 0.14, 0.996) and cervical cancer (OR = 0.51; 95% CI = 0.30, 0.87) screening among Maori women. Racial discrimination by a health professional (OR = 1.57; 95% CI = 1.15, 2.14) and racial discrimination more widely (OR = 1.55; 95% CI = 1.35, 1.79) were associated with negative patient experiences for all participants. CONCLUSIONS: Experience of racial discrimination in both health care and other settings may influence health care use and experiences of care and is a potential pathway to poor health.

Application of a system dynamics model to inform investment in smoking cessation services in New Zealand.

OBJECTIVES: We estimated the long-term effects of smoking cessation interventions to inform government decision-making regarding investment in tobacco control. METHODS: We extracted data from the 2006 New Zealand Tobacco Use Survey and other sources and developed a system dynamics model with the iThink computer simulation package. The model derived estimates of population cessation rates from smoking behaviors and applied these over a 50-year period, from 2001 to 2051, under business-as-usual and enhanced cessation intervention scenarios. RESULTS: The model predicted larger effects by 2051 with the enhanced cessation than with the business-as-usual scenario, including: an 11% greater decline in adult current smoking prevalence (9 versus 10 per 100 people), 16% greater decline in per capita tobacco consumption (370 versus 440 cigarette equivalents per year), and 11% greater reduction in tobacco-attributable mortality (3000 versus 3300 deaths per year). CONCLUSIONS: The model generated reliable estimates of the effects on health and on tobacco use of interventions designed to enhance smoking cessation. These results informed a decision announced in May 2007 to increase funding for smoking cessation by NZ $42 million over 4 years.

Socioeconomic inequalities in cancer survival in New Zealand: the role of extent of disease at diagnosis.

We examined socioeconomic inequalities in cancer survival in New Zealand among 132,006 people ages 15 to 99 years who had a cancer registered (1994-2003) and were followed up to 2004. Relative survival rates (RSR) were calculated using deprivation-specific life tables. A census-based measure of socioeconomic position (New Zealand deprivation based on the 1996 census) based on residence at the time of cancer registration was used. All RSRs were age-standardized, and further standardization was used to investigate the effect of extent of disease at diagnosis on survival. Weighted linear regression was used to estimate the deprivation gap (slope index of inequality) between the most and least deprived cases. Socioeconomic inequalities in cancer survival were evident for all of the major cancer sites, with the deprivation gap being particularly high for prostate (-0.15), kidney and uterus (both -0.14), bladder (-0.12), colorectum (-0.10), and brain (+0.10). Accounting for extent of disease explained some of the inequalities in survival from breast and colorectal cancer and melanoma and all of the deprivation gaps in survival of cervical cancer; however, it did not affect RSRs for cancers of the kidney, uterus, and brain. No substantial differences between the total compared with the non-Maori population were found, indicating that the findings were not due to confounding by ethnicity. In summary, socioeconomic disparities in survival were consistent for nearly all cancer sites, persisted in ethnic-specific analyses, and were only partially explained by differential extent of disease at diagnosis. Further investigation of reasons for persisting inequalities is required.

How much does health care contribute to health gain and to health inequality? Trends in amenable mortality in New Zealand 1981-2004.

OBJECTIVE: To estimate the contribution of health care to health gain, and to ethnic and socio-economic health inequalities, in New Zealand over the past quarter century. METHOD: Amenable and all-cause mortality rates by ethnicity and equivalised household income tertile from 1981-84 to 2001-04 were estimated from linked census-mortality datasets (the New Zealand Census-Mortality Study). Amenable mortality (deaths under age 75 from conditions responsive to health care) was defined using a classification recently developed for use in Australia and New Zealand. The contribution of health care to the observed improvement in population health status was estimated by the ratio of the difference in amenable to the difference in all-cause mortality over the observation period. RESULTS: Trends in amenable causes of death were estimated to account for approximately one-third of the fall in mortality over the past quarter century, for the population as a whole and for all income and ethnic groups except Pacific peoples, for whom there was no reduction in amenable mortality. In 2001-04, amenable causes accounted for approximately one quarter of the mortality gap between all ethnic groups compared to the European/Other reference. DISCUSSION: Our finding provides one indicator of the social impact of health care over this period. More importantly, that Pacific peoples seem to have benefited less than other ethnic groups calls for urgent explanation. Also, our finding that amenable causes account for about one quarter of current mortality disparities, clearly indicates that improvement in access to and quality of health care for disadvantaged groups could substantively reduce health inequalities.

Psychiatric illness among a nationally representative sample of sole and partnered parents in New Zealand.

OBJECTIVE: To quantify the excess risk of specific, diagnosable mental illnesses experienced by sole parents in New Zealand, and to estimate the contribution of socioeconomic position (SEP), co-residence with other adults (as a proxy for social and practical support) and physical health status to this excess risk. METHODS: Data used in the present study were from the New Zealand Mental Health Survey, a nationally representative population-based household survey of 12,992 adults (16+ years) fielded in 2004. The sample included 1216 sole and 3681 partnered parents living with one or more dependent children, with an overall response rate of 73%. Mental illness (12 month prevalence of anxiety, mood, and substance use disorders, and suicidality) was measured with version 3.0 of the Composite International Diagnostic Interview. Illness severity was measured with the Sheehan Disability Scale and the Global Assessment of Functioning Scale. Covariates included household income from all sources, labour market attachment, co-residence with other adults and doctor-diagnosed chronic physical illness. Multiple logistic regression was then carried out on the weighted cross-sectional survey dataset. RESULTS: Adjusting for demographic variables, sole parents had significantly higher 12 month prevalences of mental illnesses than their partnered counterparts, with odds ratios (ORs) of 2.6 (95% confidence interval (CI)=2.0-3.3) for any mental illness, 2.9 (95%CI=2.1-4.0) for any serious mental illness, 2.2 (95%CI=1.7-2.8) for anxiety disorder, 2.6 (95%CI=2.0-3.4) for mood disorder, 3.6 (95%CI=2.2-6.0) for substance use disorder and 2.5 (95%CI=1.5-4.0) for suicidal ideation. Chronic physical illness accounted for only a small proportion of these excess risks. SEP and co-residence of another adult each explained approximately one-quarter of the excess risks and jointly explained approximately half (except for substance use disorders). Almost all of the effect of SEP was mediated by income, with employment status making only a very small independent contribution. CONCLUSIONS: The present results confirm the higher prevalence of mental illness experienced by sole parents, underlining the importance of improving access to primary mental health care, including alcohol and drug rehabilitation services, for sole parents. But they also caution against a solely clinical response and highlight a need to better understand and respond to the social and economic processes that lie behind the associations between mental health, socioeconomic position and sole parenthood in New Zealand.

Cross classification of the New Zealand population by ethnicity and deprivation: trends from 1996 to 2006.

OBJECTIVES: To describe trends in the distribution of New Zealand's major ethnic groups by small area deprivation and trends in the ethnic composition of each deprivation category. METHODS: Data sources were the 1996, 2001 and 2006 New Zealand Census of Population and Dwellings. Ethnicity (Maori, Pacific, Asian or European/Other) was defined using total response output. Each person was assigned a deprivation score by geocoding their usual residence (as recorded in the census) to meshblock level. For each time period (1996, 2001 and 2006) the deprivation score for each meshblock was calculated by principal components analysis from nine socio-economic variables included in the corresponding census (the New Zealand Index of Deprivation). RESULTS: Throughout the observation period, Maori and Pacific ethnic groups were over-represented at the more deprived and under-represented at the less deprived end of the deprivation spectrum. The European ethnic group displayed less-marked skewing, and in the opposite direction, while the Asian ethnic group showed close to the expected uniform distribution. Neither the deprivation distribution of any ethnic group, nor the ethnic composition of any deprivation decile, showed any statistically significant change over the 10-year observation period. CONCLUSIONS: Monitoring trends in the relative deprivation distributions of the ethnic groups helps assess progress towards social justice. Similarly, monitoring trends in the ethnic compositions of the different deprivation deciles is important in the formulation of social policy. Little change was found in either of these distributions over the relatively short observation period.

Did it fall or was it pushed? The contribution of trends in established risk factors to the decline in premature coronary heart disease mortality in New Zealand.

OBJECTIVE: To estimate the contribution of trends in three risk factors--systolic blood pressure (SBP), total blood cholesterol (TBC) and cigarette smoking--to the decline in premature coronary heart disease (CHD) mortality in New Zealand from 1980-2004. METHOD: Risk factor prevalence data by 10-year age group (35-64 years) and sex was sourced from six national or Auckland regional health surveys and three population censuses (the latter only for smoking). The data were smoothed using two-point moving averages, then further smoothed by fitting quadratic regression equations (SBP and TBC) or splines (smoking). Risk factor/CHD mortality hazard ratios estimated by expert working groups for the World Health Organization Global Burden of Disease Study 2001 were used to translate average annual changes in risk factor prevalences to the corresponding percentage changes in premature CHD mortality. The expected trends in CHD mortality were then compared with the observed trend to estimate the contribution of each risk factor to the decline. FINDINGS: Approximately 80% (73% for males, 87% for females) of the decline in premature CHD mortality from 1980 to 2004 is estimated to have resulted from the joint trends in population SBP and TBC distributions and smoking prevalence. Overall, approximately 42%, 36% and 22% of the joint risk factor effect was contributed by trends in SBP, TBC and smoking respectively. CONCLUSION: Our estimate for the joint risk factor contribution to the CHD mortality decline of 80% exceeds those of two earlier New Zealand studies, but agrees closely with a similar Australian study. This provides an indicator of the scope that still remains for further reduction in CHD mortality through primary and secondary prevention.

Can the incidence and prevalence of coronary heart disease be determined from routinely collected national data? Population-based estimates for New Zealand in 2001--03.

OBJECTIVE: To produce internally consistent estimates of coronary heart disease (CHD) incidence, prevalence, survival and mortality as a decision aid for service planning and resource allocation. METHODS: Incidence was defined as first occurrence of a major coronary event, i.e. the sum of first CHD hospital admissions and out-of-hospital CHD deaths without a hospital admission for CHD in the preceding five years. Mortality was defined as the sum of deaths coded to CHD and deaths coded to related causes but with prior hospitalisation for CHD (in the preceding five years). Data were sourced from the New Zealand Health Information Service and record linkage was carried out using a unique national identifier, the National Health Index (NHI). Given estimates for incidence and mortality, multi-state lifetables were built and estimates for prevalence, survival, lifetable risk, and median age at onset extracted. RESULTS: Estimated prevalence of CHD increased exponentially from around 2% for males and 0.5% for females at age 40-44 to peak at around 18% and 12% respectively at age 85-89. Median age at onset of CHD was 67.5 years for males and 77.5 years for females. Median survival duration was 9.5 years for males and 6.2 years for females. The lifetable risk of CHD was estimated at 35% for males and 28% for females. CONCLUSIONS: This study provides a complete and internally consistent picture of the descriptive epidemiology of CHD for the whole New Zealand population in 2001--03. This information will be useful for planning and funding of coronary prevention, treatment and rehabilitation services.

Burden of Alzheimer's disease: population-based estimates and projections for New Zealand, 2006-2031.

OBJECTIVE: To estimate the burden of Alzheimer's disease (AD, including 'mixed' dementia) in New Zealand in 2006, and project this burden out to 2031. METHOD: An incidence to prevalence methodology was utilized, the foundation of which is a discrete time Markov model allowing for multiple stages of disease (early vs late). Population estimates and projections, and all-cause mortality rates, were obtained from Statistics New Zealand. In the absence of usable New Zealand data, data on disease incidence and progression were obtained from systematic reviews of the international (mainly European, Australian and North American) literature. Projection scenarios included a demographic scenario in which change resulted only from increases in population size and ageing; a prevention scenario in which incidence rates were reduced by 25% from 2011; a treatment scenario in which disease progression rates were likewise reduced by 25% from 2011; and a combined scenario capturing both interventions. RESULTS: The model estimated that approximately 28000 people are currently living with AD (whether formally diagnosed or not), approximately 55% in the early and 45% in the late stage of the disease; approximately 6600 people newly develop AD each year; and approximately 2300 people die from (as opposed to with) this condition. The model projected that the prevalence of AD will increase approximately 2.5-fold (to approx. 70,000 people) by 2031, if demographic drivers are unopposed. Plausible improvements in prevention and treatment, however, acting together, could reduce this growth by up to 50%, so that the prevalence of AD only doubles. CONCLUSION: Even this more optimistic projection has profound implications for the funding and provision of dementia care services, as well as for patients, their families, informal carers and the psychogeriatric workforce. New service configurations and models of care will be necessary. Access, quality and coordination standards for home care, day care, respite care, residential care and specialist services (including memory clinics) will need to respond accordingly.

Can administrative health utilisation data provide an accurate diabetes prevalence estimate for a geographical region?

AIM: To validate the New Zealand Ministry of Health (MoH) Virtual Diabetes Register (VDR) using longitudinal laboratory results and to develop an improved algorithm for estimating diabetes prevalence at a population level. METHODS: The assigned diabetes status of individuals based on the 2014 version of the MoH VDR is compared to the diabetes status based on the laboratory results stored in the Auckland regional laboratory result repository (TestSafe) using the New Zealand diabetes diagnostic criteria. The existing VDR algorithm is refined by reviewing the sensitivity and positive predictive value of the each of the VDR algorithm rules individually and as a combination. RESULTS: The diabetes prevalence estimate based on the original 2014 MoH VDR was 17% higher (n = 108,505) than the corresponding TestSafe prevalence estimate (n = 92,707). Compared to the diabetes prevalence based on TestSafe, the original VDR has a sensitivity of 89%, specificity of 96%, positive predictive value of 76% and negative predictive value of 98%. The modified VDR algorithm has improved the positive predictive value by 6.1% and the specificity by 1.4% with modest reductions in sensitivity of 2.2% and negative predictive value of 0.3%. At an aggregated level the overall diabetes prevalence estimated by the modified VDR is 5.7% higher than the corresponding estimate based on TestSafe. CONCLUSION: The Ministry of Health Virtual Diabetes Register algorithm has been refined to provide a more accurate diabetes prevalence estimate at a population level. The comparison highlights the potential value of a national population long term condition register constructed from both laboratory results and administrative data.

Effects of self-reported racial discrimination and deprivation on Maori health and inequalities in New Zealand: cross-sectional study.

BACKGROUND: Inequalities in health between different ethnic groups in New Zealand are most pronounced between Maori and Europeans. Our aim was to assess the effect of self-reported racial discrimination and deprivation on health inequalities in these two ethnic groups. METHODS: We used data from the 2002/03 New Zealand Health Survey to assess prevalence of experiences of self-reported racial discrimination in Maori (n=4108) and Europeans (n=6269) by analysing the responses to five questions about: verbal attacks, physical attacks, and unfair treatment by a health professional, at work, or when buying or renting housing. We did logistic regression analyses to assess the effect of adjustment for experience of racial discrimination and deprivation on ethnic inequalities for various health outcomes. FINDINGS: Maori were more likely to report experiences of self-reported racial discrimination in all instances assessed, and were almost ten times more likely to experience discrimination in three or more settings than were Europeans (4.5% [95% CI 3.2-5.8] vs 0.5% [0.3-0.7]). After adjustment for discrimination and deprivation, odds ratios (95% CI) comparing Maori and European ethnic groups were reduced from 1.67 (1.35-2.08) to 1.18 (0.92-1.50) for poor or fair self-rated health, 1.70 (1.42-2.02) to 1.21 (1.00-1.47) for low physical functioning, 1.30 (1.11-1.54) to 1.02 (0.85-1.22) for low mental health, and 1.46 (1.12-1.91) to 1.11 (0.82-1.51) for cardiovascular disease. INTERPRETATION: Racism, both interpersonal and institutional, contributes to Maori health losses and leads to inequalities in health between Maori and Europeans in New Zealand. Interventions and policies to improve Maori health and address these inequalities should take into account the health effects of racism.

Tobacco consumption in New Zealand: why did it fall?

OBJECTIVE: To estimate the relative contributions of trends in smoking prevalence and trends in smoking intensity (average number of cigarettes smoked per day) to the observed decline in per capita tobacco consumption in New Zealand from 1984 to 2004. METHOD: Tobacco consumption and smoking prevalence time series data were sourced from Statistics New Zealand and the ACNielsen Omnibus Survey respectively and checked for accuracy against other sources. The contribution of changes in smoking prevalence to the observed decline in tobacco consumption was estimated by counterfactual modelling. The corresponding contribution of trends in smoking intensity was then calculated by difference. RESULTS: Changes in smoking prevalence accounted for 48% of the decline in per capita tobacco consumption from 1984-89 and for 39% thereafter. Correspondingly, changes in smoking intensity accounted for 52% of the consumption decline during the first five years of the study period and 61% thereafter (i.e. from 1990 to 2004). DISCUSSION: Understanding the relative contributions of trends in smoking prevalence and smoking intensity to the observed decline in per capita tobacco consumption is important, because the relationship between smoking intensity and health effects is non-linear. Our results indicate that the dramatic fall in tobacco consumption in New Zealand over the past 30 years will not be accompanied by an equivalent reduction in tobacco-attributable morbidity and mortality. Furthermore, our findings raise doubts as to how much longer tobacco consumption will continue to decline, given that smoking intensity is already low. The key message for the tobacco control program is to re-focus on helping smokers to quit and stay quit.

How much does health care contribute to health inequality in New Zealand?

OBJECTIVE: To quantify the contribution of health care to ethnic and socio-economic inequalities in health in New Zealand in 2000-02, using the concept of 'amenable' mortality (deaths at ages 0-74 years from causes responsive to health care). DATA SOURCES AND METHODS: Mortality data for 2000-02 were provided by the New Zealand Health Information Service and 2001 Census population data were provided by Statistics New Zealand. The classification of ICD-10 codes as amenable or non-amenable used in the Australian and New Zealand Atlas of Avoidable Mortality (2006) was adopted. Ethnicity was categorised as Maori, Pacific or European/Other. Socio-economic position was measured using a Census-based small area deprivation index, the NZDep2001. Mortality rates were standardised for age by the direct method for the ethnic group comparisons, and for both age and ethnicity for the deprivation group comparisons. The contribution of health care to health inequality was then quantified as the ratio of the difference in standardised amenable mortality rates to the difference in standardised total mortality rates (in the age group 0-74 years) between relevant groups. RESULTS: Amenable causes of death were estimated to account for 27%, 34%, 33% and 44% of the total mortality disparity (0-74 years) for Maori males, Maori females, Pacific males and Pacific females respectively, relative to their European/ Other counterparts (adjusting for age). The corresponding proportions for the 'deprived' population relative to the 'non-deprived' population were 26% (males) and 30% (females), adjusting for age and ethnicity. CONCLUSIONS: Amenable causes of death made a substantial contribution to differences in mortality in the 0-74 year age range between ethnic and socio-economic groups in New Zealand in 2000-02, ranging from 26-44% depending on the group.

Co-occurrence and clustering of tobacco use and obesity in New Zealand: cross-sectional analysis.

OBJECTIVE: To describe the co-occurrence and clustering/aversion of tobacco use and obesity in New Zealand. METHOD: Data were sourced from the 2002/03 New Zealand Health Survey, a nationally representative household survey that included measured body mass index (BMI) and self-reported smoking status. The association of cigarette smoking, obesity, and the combination of these risk factors with socio-demographic variables was analysed by multiple logistic regression. Clustering/aversion (defined as observed prevalence of [smoking + obesity] > or < expected prevalence, where expected prevalence = prevalence of [smoking] x prevalence of [obesity]) was also estimated. RESULTS: The joint prevalence of smoking plus obesity in the adult population (15+ years) was 4.5%. However, this was 10% for Maori and 8.5% for deprivation quintile 5. Adjusting for relevant covariates, Maori were twice as likely to have both risk factors as non-Maori. A smooth deprivation gradient was found, with deprivation quintile 1 (least deprived) only one-fifth as likely to have both risk factors as quintile 5 (most deprived). There was no evidence of clustering, and aversion (negative clustering) was demonstrated only for middle-aged adults and for Maori. DISCUSSION: Since smoking cessation is associated with weight gain, substantial aversion might have been expected across all subgroups, yet this was not found. The most likely explanations are that the extent of weight gain associated with smoking cessation has been overestimated or is often not sustained. Even so, health promotion and clinical interventions need to take the dually exposed population into account, addressing not only the unhealthy behaviours themselves but also the social context in which dual exposure occurs.