Using Marginal Structural Modeling to Estimate the Cumulative Impact of an Unconditional Tax Credit on Self-Rated Health.

In previous studies, researchers estimated short-term relationships between financial credits and health outcomes using conventional regression analyses, but they did not account for time-varying confounders affected by prior treatment (CAPTs) or the credits' cumulative impacts over time. In this study, we examined the association between total number of years of receiving New Zealand's Family Tax Credit (FTC) and self-rated health (SRH) in 6,900 working-age parents using 7 waves of New Zealand longitudinal data (2002-2009). We conducted conventional linear regression analyses, both unadjusted and adjusted for time-invariant and time-varying confounders measured at baseline, and fitted marginal structural models (MSMs) that more fully adjusted for confounders, including CAPTs. Of all participants, 5.1%-6.8% received the FTC for 1-3 years and 1.8%-3.6% for 4-7 years. In unadjusted and adjusted conventional regression analyses, each additional year of receiving the FTC was associated with 0.033 (95% confidence interval (CI): -0.047, -0.019) and 0.026 (95% CI: -0.041, -0.010) units worse SRH (on a 5-unit scale). In the MSMs, the average causal treatment effect also reflected a small decrease in SRH (unstabilized weights: ß = -0.039 unit, 95% CI: -0.058, -0.020; stabilized weights: ß = -0.031 unit, 95% CI: -0.050, -0.007). Cumulatively receiving the FTC marginally reduced SRH. Conventional regression analyses and MSMs produced similar estimates, suggesting little bias from CAPTs.

Do changes in neighborhood and household levels of smoking and deprivation result in changes in individual smoking behavior? A large-scale longitudinal study of New Zealand adults.

Health behavior takes place within social contexts. In this study, we investigated whether changes in exposure to neighborhood deprivation and smoking prevalence and to household smoking were associated with change in personal smoking behavior. Three waves of biannual data collection (2004-2009) in a New Zealand longitudinal study, the Survey of Family, Income and Employment (SoFIE)-Health, were used, with 13,815 adults (persons aged ≥15 years) contributing to the analyses. Smoking status was dichotomized as current smoking versus never/ex-smoking. Fixed-effects regression analyses removed time-invariant confounding and adjusted for time-varying covariates (neighborhood smoking prevalence and deprivation, household smoking, labor force status, income, household tenure, and family status). A between-wave decile increase in neighborhood deprivation was significantly associated with increased odds of smoking (odds ratio (OR) = 1.08, 95% confidence interval (CI): 1.02, 1.14), but a between-wave increase in neighborhood smoking prevalence was not (OR = 1.04, 95% CI: 0.98, 1.10). Changing household exposures between waves to live with another smoker (compared with a nonsmoker (referent)) increased the odds of smoking (OR = 2.48, 95% CI: 1.84, 3.34), as did changing to living in a sole-adult household (OR = 1.52, 95% CI: 1.07, 2.14). Tobacco control policies and programs should address the broader household and neighborhood circumstances within which individual smoking takes place.

What will it take to get to under 5% smoking prevalence by 2025? Modelling in a country with a smokefree goal.

BACKGROUND: New Zealand has a goal of becoming a smokefree nation by the year 2025. Smoking prevalence in 2012 was 17%, but is over 40% for Maori (indigenous New Zealanders). We forecast the prevalence in 2025 under a business-as-usual (BAU) scenario, and determined what the initiation and cessation rates would have to be to achieve a <5% prevalence. METHODS: A dynamic model was developed using Census and Health Survey data from 1981 to 2012 to calculate changes in initiation by age 20 years, and net annual cessation rates, by sex, age, ethnic group and time period. Similar parameters were also calculated from a panel study for sensitivity analyses. 'Forecasts' used these parameters, and other scenarios, applied to the 2011-2012 prevalence. FINDINGS: Since 2002-2003, prevalence at age 20 years has decreased annually by 3.1% (95% uncertainty interval 0.8% to 5.7%) and 1.1% (-1.2% to 3.2%) for non-Maori males and females, and by 4.7% (2.2% to 7.1%) and 0.0% (-2.2% to 1.8%) for Maori, respectively. Annual net cessation rates from the dynamic model ranged from -3.0% to 6.1% across demographic groups, and from 3.0% to 6.0% in the panel study. Under BAU, smoking prevalence is forecast to be 11% and 9% for non-Maori males and females by 2025, and 30% and 37% for Maori, respectively. Achieving <5% by 2025 requires net cessation rates to increase to 10% for non-Maori and 20% for Maori, accompanied by halving or quartering of initiation rates. CONCLUSIONS: The smokefree goal of <5% prevalence is only feasible with large increases in cessation rates.

Smoking uptake is associated with increased psychological distress: results of a national longitudinal study.

BACKGROUND: There is evidence that smoking is associated with poorer mental health. However, the underlying mechanisms for this remain unclear. We used longitudinal data to assess whether smoking uptake, or failed quit attempts, are associated with increased psychological distress. METHODS: Data were used from Waves 3 (2004/05), 5 (2006/07) and 7 (2008/09) of the longitudinal New Zealand Survey of Family, Income and Employment. Fixed-effects linear regression analyses were performed to model the impact of changes in smoking status and quit status (exposure variables) on changes in psychological distress (Kessler 10 (K10)). RESULTS: After adjusting for time-varying demographic and socioeconomic covariates, smoking uptake was associated with an increase in psychological distress (K10: 0.22, 95% CI 0.01 to 0.43). The associations around quitting and distress were in the expected directions, but were not statistically significant. That is, smokers who successfully quit between waves had no meaningful change in psychological distress (K10: -0.05, 95% CI -0.34 to 0.23), whereas those who tried but failed to quit, experienced an increase in psychological distress (K10: 0.18, 95% CI -0.05 to 0.40). CONCLUSIONS: The findings provide some support for a modest association between smoking uptake and a subsequent increase in psychological distress, but more research is needed before such information is considered for inclusion in public health messages.

Do changes in income, deprivation, labour force status and family status influence smoking behaviour over the short run? Panel study of 15,000 adults.

BACKGROUND: Improving social circumstances (e.g., an increase in income, finding a job or moving into a good neighbourhood) may reduce tobacco use, but robust evidence on the effects of such improvements is scarce. Accordingly we investigated the link between changing social circumstances and changing tobacco smoking using repeated measures data. METHODS: 15 000 adults with at least two observations over three waves (each 2 years apart) of a panel study had data on smoking status, family, labour force, income and deprivation (both neighbourhood and individual). Fixed effects regression modelling was used. FINDINGS: The odds of smoking increased 1.42-fold (95% CI 1.16 to 1.74) for a one log-unit increase in personal income among 15-24-year-olds, but there was no association of increased smoking with an increase in income among 25+ year olds. Moving out of a family nucleus, increasing neighbourhood deprivation (e.g., 1.83-fold (95% CI 1.18 to 2.83) increased odds of smoking for moving from least to most deprived quintile of neighbourhoods), increasing personal deprivation and moving into employment were all associated with increased odds of smoking. The number of cigarettes smoked a day changed little with changing social circumstances. INTERPRETATION: Worsening social circumstances over the short run are generally associated with higher smoking risk. However, there were counter examples: for instance, decreasing personal income among young people was associated with decreased odds of smoking, a finding consistent with income elasticity of demand (the less one's income, the less one can consume). This paper suggests that improving social circumstances is not always pro-health over the short run; a more nuanced approach to the social determinants of health is required.

Do changes in social and economic factors lead to changes in drinking behavior in young adults? Findings from three waves of a population based panel study.

BACKGROUND: Social and economic measures in early childhood or adolescence appear to be associated with drinking behavior in young adulthood. Yet, there has been little investigation to what extent drinking behavior of young adults changes within young adulthood when they experience changes in social and economic measures in this significant period of their life. METHODS: The impact of changes in living arrangement, education/employment, income, and deprivation on changes in average weekly alcohol units of consumption and frequency of hazardous drinking sessions per month in young adults was investigated. In total, 1,260 respondents of the New Zealand longitudinal Survey of Family, Income and Employment (SoFIE) aged 18-24 years at baseline were included. RESULTS: Young adults who moved from a family household into a single household experienced an increase of 2.32 (95% CI 1.02 to 3.63) standard drinks per week, whereas those young adults who became parents experienced a reduction in both average weekly units of alcohol (ß = -3.84, 95% CI -5.44 to -2.23) and in the frequency of hazardous drinking sessions per month (ß = -1.17, 95% CI -1.76 to -0.57). A one unit increase in individual deprivation in young adulthood was associated with a 0.48 (95% CI 0.10 to 0.86) unit increase in average alcohol consumption and a modest increase in the frequency of hazardous drinking sessions (ß = 0.25, 95% CI 0.11 to 0.39). CONCLUSIONS: This analysis suggests that changes in living arrangement and individual deprivation are associated with changes in young adult's drinking behaviors. Alcohol harm-minimization interventions therefore need to take into account the social and economic context of young people's lives to be effective.

Gender differences in the mental health of single parents: New Zealand evidence from a household panel survey.

BACKGROUND: In many countries single parents report poorer mental health than partnered parents. This study investigates whether there are gender differences in the mental health of single parents in New Zealand (and whether any gender difference varies with that among partnered parents), and examines key social and demographic mediators that may account for this difference. METHODS: We used data on 905 single parents and 4,860 partnered parents from a New Zealand household panel survey that included the Kessler-10 measure of psychological distress. Linear regression analyses were used to investigate both interactions of gender and parental status, and confounding or mediation by other covariates. RESULTS: High/very high levels of psychological distress were reported by 15.7 % of single mothers and 9.1 % of single fathers, and 6.1 % of partnered mothers and 4.1 % of partnered fathers. In an Ordinary Least Squares regression of continuous K10 scores on gender, parental status and the interaction of both (plus adjustment for ethnicity, number of children and age), female single parents had a 1.46 higher K10 score than male single parents (95 % CI 0.48-2.44; 1.46). This difference was 0.98 (95 % CI -0.04 to 1.99) points greater than the gender difference among partnered parents. After controlling for further confounding or mediating covariates (educational level, labour force status and socioeconomic deprivation) both the gender difference among single parents (0.38, -0.56 to 1.31) and the interaction of gender and parental status (0.28 greater gender difference among single parents, -0.69 to 1.65) greatly reduced in magnitude and became non-significant, mainly due to adjustment for individual socioeconomic deprivation. CONCLUSION: The poorer mental health of single parents remains an important epidemiological phenomenon. Although research has produced mixed findings of the nature of gender differences in the mental health of single parents, our research adds to the increasing evidence that it is single mothers who have worse mental health. Our findings on the potential explanations of the gender difference in sole parent mental health suggest that socioeconomic deprivation is a key contributor.

Cannabis, ischemic stroke, and transient ischemic attack: a case-control study.

BACKGROUND AND PURPOSE: There is a temporal relationship between cannabis use and stroke in case series and population-based studies. METHODS: Consecutive stroke patients, aged 18 to 55 years, who had urine screens for cannabis were compared with a cohort of control patients admitted to hospital without cardiovascular or neurological diagnoses. RESULTS: One hundred sixty of 218 (73%) ischemic stroke/transient ischemic attack patients had urine drug screens (100 men; mean [SD] age, 44.8 [8.7] years). Twenty-five (15.6%) patients had positive cannabis drug screens. These patients were more likely to be men (84% versus 59%; χ2: P=0.016) and tobacco smokers (88% versus 28%; χ2: P<0.001). Control urine samples were obtained from 160 patients matched for age, sex, and ethnicity. Thirteen (8.1%) control participants tested positive for cannabis. In a logistic regression analysis adjusted for age, sex, and ethnicity, cannabis use was associated with increased risk of ischemic stroke/transient ischemic attack (odds ratio, 2.30; 95% confidence interval, 1.08-5.08). However after adjusting for tobacco use, an association independent of tobacco could not be confirmed (odds ratio, 1.59; 95% confidence interval, 0.71-3.70). CONCLUSIONS: This study provides evidence of an association between a cannabis lifestyle that includes tobacco and ischemic stroke. Further research is required to clarify whether there is an association between cannabis and stroke independent of tobacco. CLINICAL TRIAL REGISTRATION URL: http://www.anzctr.org.au. Unique identifier: ACTRN12610000198022.

In-work tax credits for families and their impact on health status in adults.

BACKGROUND: By improving two social determinants of health (poverty and unemployment) in low- and middle-income families on or at risk of welfare, in-work tax credit for families (IWTC) interventions could impact health status and outcomes in adults. OBJECTIVES: To assess the effects of IWTCs on health outcomes in working-age adults (18 to 64 years). SEARCH METHODS: We searched 16 electronic academic databases, including the Cochrane Public Health Group Specialised Register, Cochrane Database of Systematic Reviews (The Cochrane Library 2012, Issue 7), MEDLINE and EMBASE, as well as six grey literature databases between July and September 2012 for records published between January 1980 and July 2012. We also searched key organisational websites, handsearched reference lists of included records and relevant journals, and contacted academic experts. SELECTION CRITERIA: We included randomised and quasi-randomised controlled trials and cohort, controlled before-and-after (CBA) and interrupted time series (ITS) studies of IWTCs in working-age adults. Included primary outcomes were: self rated general health; mental health/psychological distress; mental illness; overweight/obesity; alcohol use and tobacco use. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed the risk of bias in included studies. We contacted study authors to obtain missing information. MAIN RESULTS: Five studies (one CBA and four ITS) comprising a total of 5,677,383 participants (all women) fulfilled the inclusion criteria and were synthesised narratively. The in-work tax credit intervention assessed in all included studies is the permanent Earned Income Tax Credit in the United States, established in 1975. This intervention distributed nearly USD 62 billion to over 27 million individuals in 2011, and its administration costs were less than one per cent of its total costs. All included studies carried a high risk of bias (especially from confounding and insufficient control for underlying time trends). Due to the small number of (observational) studies and their high risk of bias, we judged this body of evidence to have very low overall quality.One study found that IWTC had no detectable effect on self rated general health and mental health/psychological distress five years after its implementation (i.e. a considerable change in the generosity of the permanent IWTC) and on overweight/obesity eight years after implementation. One study found no effect of IWTC on tobacco use five years after implementation, one a moderate reduction in tobacco use one year after implementation (odds ratio 0.95, 95% confidence interval (CI) 0.94 to 0.96), and one differential effects, with no effect in African-Americans and a large reduction in European-Americans two years after implementation (risk difference -11.1%, 95% CI -20.9% to -1.3%). No evidence was available for the effect of IWTC on mental illness and alcohol use. No adverse effects of IWTC were identified.One study also found no detectable effect of IWTC on the number of bad physical health days and of risky biomarkers for inflammation, cardiovascular disease and metabolic conditions eight years after implementation. One study found that IWTC had a large, positive effect on income from wages or salaries one year after implementation. Two studies found no effect on employment two and five years after implementation, whereas two found a moderate increase five and eight years after implementation and one a large increase in employment due to IWTC one year after implementation.No differences in outcomes between groups with different educational status were found for self rated health and mental health/psychological distress. In one study European-American women with lower levels of education were more likely to reduce tobacco use, while tobacco use did not change among African-American women with lower levels of education. However, no differences in tobacco use by educational status were observed in a second study. Two studies found that the intervention may have reduced inequity with respect to employment, where women with less education were more likely to move into employment (although one did not establish whether this difference was statistically significant), while two studies found no such difference and no studies found differences by ethnic group on employment rates. AUTHORS' CONCLUSIONS: In summary, the small and methodologically limited existing body of evidence with a high risk of bias provides no evidence for an effect of in-work tax credit for families interventions on health status (except for mixed evidence for tobacco smoking) in adults.

Tackling 'wicked' health promotion problems: a New Zealand case study.

This paper reports on a complex environmental approach to addressing 'wicked' health promotion problems devised to inform policy for enhancing food security and physical activity among Maori, Pacific and low-income people in New Zealand. This multi-phase research utilized literature reviews, focus groups, stakeholder workshops and key informant interviews. Participants included members of affected communities, policy-makers and academics. Results suggest that food security and physical activity 'emerge' from complex systems. Key areas for intervention include availability of money within households; the cost of food; improvements in urban design and culturally specific physical activity programmes. Seventeen prioritized intervention areas were explored in-depth and recommendations for action identified. These include healthy food subsidies, increasing the statutory minimum wage rate and enhancing open space and connectivity in communities. This approach has moved away from seeking individual solutions to complex social problems. In doing so, it has enabled the mapping of the relevant systems and the identification of a range of interventions while taking account of the views of affected communities and the concerns of policy-makers. The complex environmental approach used in this research provides a method to identify how to intervene in complex systems that may be relevant to other 'wicked' health promotion problems.

Bias in relative survival methods when using incorrect life-tables: lung and bladder cancer by smoking status and ethnicity in New Zealand.

Relative survival and excess mortality approaches are commonly used to estimate and compare net survival from cancer. These approaches are based on the assumption that the underlying (non-cancer) mortality rate of cancer patients is the same as that of the general population. This assumption is likely to be violated particularly in the context of smoking-related cancers. The magnitude of this bias has not been estimated. The objective of this article is to estimate the bias in relative survival ratios (RSRs) and excess mortality rate ratios (EMRRs) from using total population compared to correct subpopulation specific life-tables. Analyses were conducted on 1996-2001 linked census-cancer data (including smoking status) for people with lung and bladder cancer, using sex-specific (standard practice), sex- and ethnic-specific, sex- and smoking-specific and sex-, ethnic- and smoking-specific life-tables. Five-year RSRs using sex-specific life-tables, compared to fully stratified life-tables, were underestimated by 10-25% for current smoking and Maori populations. For example, the current smoker male bladder cancer RSR was 0.700 for sex-specific life-tables, compared to 0.838 for fully stratified life-tables. Similarly, EMRRs comparing current to never smokers and Maori to non-Maori were overestimated using sex-specific life-tables only: modestly only for lung cancer, but markedly for bladder cancer. For example, the EMRR comparing current to never smokers with bladder cancer in a fully adjusted regression model was 1.475 when using sex-specific life-tables only, but reduced to 1.098 when using fully stratified life-tables. Substantial bias can occur when estimating relative cancer survival across subpopulations if non-matching life-tables are used.

Ethnicity and functional outcome after stroke.

BACKGROUND AND PURPOSE: There is limited information on the influence of ethnicity on functional outcome after stroke. We examined functional outcomes among European New Zealanders, Maori, Pacific, and Asian people 6 months after stroke in a population-based context. METHODS: This was a prospective incidence and 6-month outcomes study of all new stroke patients (excluding subarachnoid hemorrhage) that occurred over 1 year in a defined geographical area in Auckland, New Zealand, during 2002 to 2003. Ethnicity was self-defined. Outcome measures included the Frenchay Activities Index, 36-item Short Form questionnaire, independence, death, composite of death and dependence, and living situation. RESULTS: Functional measures were available in 1127 patients 6 months after stroke. Frenchay Activities Index scores were associated with ethnicity on both univariable and multivariable analysis, with Asian and Pacific people having worse scores. Physical Component Summary score of the 36-item Short Form was associated with ethnicity on univariable (scores for Pacific, Maori, and Asian people were higher than those for Europeans) but not multivariable analysis. Asian people were less likely to be dead compared to Europeans, and Pacific people were more likely to be dependent on others for help than Europeans. Pacific people were more likely to be dead or dependent than Europeans. Asian and Pacific people were more likely to be living at home than Europeans. CONCLUSIONS: Ethnicity was associated independently with functional outcomes. The association was attenuated when adjusted for stroke severity and other covariates. The direction of the relationship was not consistent between measures for individual ethnic groups.

Socioeconomic disparities in stroke rates and outcome: pooled analysis of stroke incidence studies in Australia and New Zealand.

OBJECTIVE: To assess the influence of area-level socioeconomic status (SES) on incidence and case-fatality rates for stroke. DESIGN, SETTING AND PARTICIPANTS: Analysis of pooled data for 3077 patients with incident stroke from three population-based studies in Perth, Melbourne, and Auckland between 1995 and 2003. MAIN OUTCOME MEASURES: Incidence and 12-month case-fatality rates for stroke. RESULTS: Annual age-standardised stroke incidence rates ranged from 77 per 100,000 person-years (95% CI, 72-83) in the least deprived areas to 131 per 100,000 person-years (95% CI, 120-141) in the most deprived areas (rate ratio, 1.70; 95% CI, 1.47-1.95; P < 0.001). The population attributable risk of stroke was 19% (95% CI, 12%-27%) for those living in the most deprived areas compared with the least deprived areas. Compared with people in the least deprived areas, those in the most deprived areas tended to be younger (mean age, 68 v 77 years; P < 0.001), had more comorbidities such as hypertension (58% v 51%; P < 0.001) and diabetes (22% v 12%; P < 0.001), and were more likely to smoke (23% v 8%; P < 0.001). After adjustment for age, area-level SES was not associated with 12-month case-fatality rate. CONCLUSIONS: Our analysis provides evidence that people living in areas that are relatively more deprived in socioeconomic terms experience higher rates of stroke. This may be explained by a higher prevalence of risk factors among these populations, such as hypertension, diabetes and cigarette smoking. Effective preventive measures in the more deprived areas of the community could substantially reduce rates of stroke.

Effects of childhood socioeconomic position on subjective health and health behaviours in adulthood: how much is mediated by adult socioeconomic position?

BACKGROUND: Adult socioeconomic position (SEP) is one of the most frequently hypothesised indirect pathways between childhood SEP and adult health. However, few studies that explore the indirect associations between childhood SEP and adult health systematically investigate the mediating role of multiple individual measures of adult SEP for different health outcomes. We examine the potential mediating role of individual measures of adult SEP in the associations of childhood SEP with self-rated health, self-reported mental health, current smoking status and binge drinking in adulthood. METHODS: Data came from 10,010 adults aged 25-64 years at Wave 3 of the Survey of Family, Income and Employment in New Zealand. The associations between childhood SEP (assessed using retrospective information on parental occupation) and self-rated health, self-reported psychological distress, current smoking status and binge drinking were determined using logistic regression. Models were adjusted individually for the mediating effects of education, household income, labour market activity and area deprivation. RESULTS: Respondents from a lower childhood SEP had a greater odds of being a current smoker (OR 1.70 95% CI 1.42-2.03), reporting poorer health (OR 1.82 95% CI 1.39-2.38) or higher psychological distress (OR 1.60 95% CI 1.20-2.14) compared to those from a higher childhood SEP. Two-thirds to three quarters of the association of childhood SEP with current smoking (78%), and psychological distress (66%) and over half the association with poor self-rated health (55%) was explained by educational attainment. Other adult socioeconomic measures had much smaller mediating effects. CONCLUSIONS: This study suggests that the association between childhood SEP and self-rated health, psychological distress and current smoking in adulthood is largely explained through an indirect socioeconomic pathway involving education. However, household income, area deprivation and labour market activity are still likely to be important as they are intermediaries in turn, in the socioeconomic pathway between education and health.

The association between failed quit attempts and increased levels of psychological distress in smokers in a large New Zealand cohort.

BACKGROUND: Although the association between smoking status and poorer mental health has been well documented, the association between quit status and psychological distress is less clear. The aim of the present study is to investigate the association of smoking status and quit status with psychological distress. METHODS: Data for this study is from a single year of the Survey of Families, Income and Employment (SoFIE) conducted in New Zealand (2004/05) (n = 18,525 respondents). Smoking status and quit status were treated as exposure variables, and psychological distress (Kessler-10) was treated as the outcome variable. Logistic regression analyses were performed to determine the association of smoking with psychological distress in the whole adult population and quit status with psychological distress in the ex- and current-smoking population. RESULTS: Current smokers had higher rates of high and very high psychological distress compared to never smokers (adjusted odds ratio (aOR) = 1.45; 95% CI: 1.24-1.69). Unsuccessful quitters had much higher levels of high to very high levels of psychological distress (16%) than any other group. Moreover, compared to long-term ex-smokers, unsuccessful quitters had a much higher odds of high to very high levels of psychological distress (aOR = 1.73; 95% CI: 1.36-2.21). CONCLUSION: These findings suggest that the significant association between smoking and psychological distress might be partly explained by increased levels of psychological distress among current smokers who made a quit attempt in the last year. This issue needs further study as it has implications for optimising the design of quitting support.

How does self-reported history of stroke compare to hospitalization data in a population-based survey in New Zealand?

BACKGROUND AND PURPOSE: There is mixed evidence concerning the validity of self-reported history of stroke in population-based studies. We aimed to examine the validity of self-reported stroke using hospitalization with a primary diagnosis of stroke as the reference group. METHODS: Self-reported history of stroke was taken from the Survey of Families, Income, and Employment (N=18 950; 2004-2005) and defined as a respondent answering yes to the question, "Have you ever been told by a doctor that you have had a stroke?". Survey of Families, Income, and Employment respondents consented to link their data to the New Zealand Health Information Service records of publically funded hospitalizations between 1990 and 2006. We calculated positive predictive value, sensitivity, and specificity of self-reported stroke against hospitalization for stroke. RESULTS: Approximately 2% of the adult Survey of Families, Income, and Employment population reported they had been told by a doctor that they had a stroke. Only 1% had evidence of hospitalization for stroke since 1990. The sensitivity of self-reported stroke was 73% and specificity was 98%. However, the positive predictive value, people who reported having a stroke with confirmation of hospitalization for stroke, was low at 29%. CONCLUSIONS: The use of self-reported stroke will most likely overestimate the prevalence of stroke. A combination of methods is required to determine prevalence in population-based studies.

Trends in incidence and outcome of stroke in Perth, Western Australia during 1989 to 2001: the Perth Community Stroke Study.

BACKGROUND AND PURPOSE: We studied temporal trends in major stroke outcomes in Perth, Western Australia (WA), comparing 3 12-month periods, roughly 5 years apart, between 1989 and 2001. METHODS: The Perth Community Stroke Study (PCSS) used uniform definitions and procedures in a representative segment (approximately 143,000 people in the year 2000) of Perth, WA. Crude and age-standardized incidence and 28-day case fatality for stroke in the different study periods were compared using Poisson regression. We also undertook temporal comparisons of severity, risk factors, and management of stroke to define the basis for any changes in rates. Data are reported with 95% confidence intervals (CI). RESULTS: There were 251, 213, and 183 first-ever strokes identified in the first, second, and third study periods, respectively, reflecting significant declines in stroke rates overall, for major age groups, and for both ischemic stroke and intracerebral hemorrhage. The decline in rates was greater in men than women. Compared with the 1989 to 1990 period, sex- and age-adjusted rates declined by 25% (95% CI 10% to 37%) in 1995 to 1996, and by 43% (95% CI 31% to 53%) in 2000 to 2001, corresponding to a 5.5% average annual decrease overall. There were correspondingly significant reductions in the frequencies of key risk factors among cases. However, early case fatality remained stable, both overall and for major pathological subtypes of stroke. CONCLUSIONS: These data confirm significant declines in the incidence of stroke on the western side of Australia, coincident with some improvement in the vascular risk profile of cases in the population. Decreasing risk rather than improving survival appears to be the main driver of falling mortality from stroke in this population.

Stroke surveillance: population-based estimates and projections for New Zealand.

OBJECTIVE: To estimate the incidence, prevalence and mortality of stroke in New Zealand (NZ) in 2001, projected to 2011. METHODS: Multistate lifetable models were constructed using smoothed rates of first-ever stroke incidence and relative risks of mortality estimated from the most recent Auckland Regional Community Stroke (ARCOS) Study. Estimates of the burden of stroke in NZ were calculated by applying rates output by the model to the 2001 population. Stroke incidence, prevalence and mortality were then projected to 2011, assuming similar trends in stroke incidence and case fatality to those estimated between the 1991/92 and 2002/03 studies. RESULTS: A total of 5,200 first-ever strokes were estimated to have occurred in NZ in 2001. Rates of stroke rose exponentially with increasing age and were 20% higher among males than females at most ages. Nevertheless, the lifetable risk of stroke was lower for males (16%) than females (18%). On average, males survived a year longer than females after a first-ever stroke (9.0 vs. 8.2 years). The incidence rates of first-ever stroke declined by approximately 1% per year between 1991 and 2003. The lifetable risk of stroke remained stable for females but increased for males (from 14% to 16%) over this period. Stroke prevalence also increased by approximately 1% per year, whereas stroke-related mortality fell by 4% per year. If these trends continue, approximately 6,000 first-ever strokes (2% annual increase), 45,000 stroke survivors (2% annual increase) and 2,000 stroke-related deaths (1% annual decline) are expected in 2011. CONCLUSION: Stroke mortality is falling faster than stroke incidence. This, together with population growth and ageing, will lead to a rising burden of stroke-related disability over the next decade.

Trends in ethnic disparities in stroke incidence in Auckland, New Zealand, during 1981 to 2003.

BACKGROUND AND PURPOSE: Although geographical variations in stroke rates are well documented, limited data exist on temporal trends in ethnic-specific stroke incidence. METHODS: We assessed trends in ethnic-specific stroke rates using standard diagnostic criteria and community-wide surveillance procedures in Auckland, New Zealand (NZ) in 1981 to 1982, 1991 to 1992, and 2002 to 2003. Indirect and direct methods were used to adjust first-ever (incident) and total (attack) rates for changes in the structure of the population and reported with 95% CIs. Ethnicity was self-defined and categorized as "NZ/European," "Maori," "Pacific peoples," and "Asian and other." RESULTS: Stroke attack (19%; 95% CI, 11% to 26%) and incidence rates (19%; 95% CI, 12% to 24%) declined significantly in NZ/Europeans from 1981 to 1982 to 2002 to 2003. These rates remained high or increased in other ethnic groups, particularly for Pacific peoples in whom stroke attack rates increased by 66% (95% CI; 11% to 225%) over the periods. Some favorable downward trends in vascular risk factors, such as cigarette smoking, were counterbalanced by increasing age, body mass index, and diabetes in certain ethnic groups. CONCLUSIONS: Divergent trends in ethnic-specific stroke incidence and attack rates, and of associated risk factors, have occurred in Auckland over recent decades. The findings provide mixed views as to the future burden of stroke in populations undergoing similar lifestyle and structural changes.

Ethnic disparities in incidence of stroke subtypes: Auckland Regional Community Stroke Study, 2002-2003.

BACKGROUND: Limited population-based data exist on differences in the incidence of major pathological stroke types and ischaemic stroke subtypes across ethnic groups. We aimed to provide such data within the large multi-ethnic population of Auckland, New Zealand. METHODS: All first-ever cases of stroke (n=1423) in a population-based register in 940 000 residents (aged 15 years) in Auckland, New Zealand, for a 12-month period in 2002-2003, were classified into ischaemic stroke, primary intracerebral haemorrhage (PICH), subarachnoid haemorrhage, and undetermined stroke, according to standard definitions and results of neuroimaging/necropsy (in over 90% of cases). Ischaemic stroke was further classified into five subtypes. Ethnicity was self-identified and grouped as New Zealand (NZ)/European, Maori/Pacific, and Asian/other. Incidence rates were standardised to the WHO world population by the direct method, and differences in rates between ethnic groups expressed as rate ratios (RRs), with NZ/European as the reference group. FINDINGS: In NZ/European people, ischaemic stroke comprised 73%, PICH 11%, and subarachnoid haemorrhage 6%, but PICH was higher in Maori/Pacific people (17%) and in Asian/other people (22%). Compared with NZ/European people, age-adjusted RRs for PICH were 2.7 (95% CI 1.8-4.0) and 2.3 (95% CI 1.4-3.7) among Maori/Pacific and Asian/other people, respectively. The corresponding RR for ischaemic stroke was greater for Maori/Pacific people (1.7 [95% CI 1.4-2.0]), particularly embolic stroke, and for Asian/other people (1.3 [95% CI 1.0-1.7]). The onset of stroke in Maori/Pacific and Asian/other people began at significantly younger ages (62 years and 64 years, respectively) than in NZ/Europeans (75 years; p<0.0001). There were ethnic differences in the risk factor profiles (such as age, sex, hypertension, cardiac disease, diabetes, hypercholesterolaemia, smoking status, overweight) for the stroke types and subtypes. INTERPRETATION: Compared to NZ/Europeans, Maori/Pacific and Asian/other people are at higher risk of ischaemic stroke and PICH, whereas similar rates of subarachnoid haemorrhage were evident across ethnic groups. The ethnic disparities in the rates of stroke types could be due to substantial differences found in risk factor profiles between ethnic groups. This information should be considered when planning prevention and stroke-care services in multi-ethnic communities.