Kristie Carter

Trends in Stroke Incidence in Auckland, New Zealand, During 1981 to 2003

Background and Purpose— Long-term trends in stroke incidence in different populations have not been well characterized, largely as a result of the complexities associated with population-based stroke surveillance. Methods— We assessed temporal trends in stroke incidence using standard diagnostic criteria and community-wide surveillance procedures in the population (≈1 million) of Auckland, New Zealand, over 12-month calendar periods in 1981–1982, 1991–1992, and 2002–2003. Age-adjusted first-ever (incident) and total (attack) rates, and temporal trends, were reported with 95% confidence intervals (CIs). Rates were analyzed by sex and major age groups. Results— From 1981 to 1982, stroke rates were stable in 1991–1992 and then declined in 2002–2003, to produce overall modest declines in standardized incidence (11%; 95% CI, 1 to 19%) and attack rates (9%; 95% CI, 0 to 16%) between the first and last study periods. Some favorable downward trends in vascular risk factors such as cigarette smoking were counterbalanced by increasing age and body mass index, and frequency of diabetes, in patients with stroke. Conclusions— There has been a modest decline in stroke incidence in Auckland over the last 2 decades, mainly during 1991 to 2003, in association with divergent trends in major risk factors.

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.

The association of food security with psychological distress in New Zealand and any gender differences

Food security (access to safe, nutritious, affordable food) is intrinsically linked to feelings of stress or distress and it is strongly associated with socioeconomic factors. However, the impact of food insecurity on mental health, independent of confounding socioeconomic factors, is not clear. We investigated the association of food insecurity with psychological distress in New Zealand, controlling for socioeconomic factors. Secondarily, we examined the association in males and females. We used data from the Survey of Families, Income and Employment (SoFIE) (N = 18,955). Respondents were classified as food insecure if, in the last 12 months, they: used special food grants/banks, had to buy cheaper food to pay for other things, or went without fresh fruit and vegetables often. Psychological distress was measured using the Kessler-10 scale dichotomised at low (10-15) and moderate to high (16+). Logistic regression analyses were used to investigate the association of food insecurity with psychological distress using a staged modelling approach. Interaction models included an interaction between food security and gender, as well as interactions between gender and all other covariates (significant at p-value < 0.1). Models were repeated, stratified by gender. A strong relationship between food insecurity and psychological distress was found (crude odds ratio OR 3.4). Whilst substantially reduced, the association remained after adjusting for confounding demographic and socioeconomic variables (adjusted OR 1.8). In stratified models, food insecure females had slightly higher odds for psychological distress (fully adjusted OR 2.0) than males (fully adjusted OR 1.5). As such, an independent association of food insecurity with psychological distress was found in both males and females--slightly more so in females. However, we cannot rule out residual confounding as an explanation for the independent association and any apparent gender interaction.

Very Long-Term Outcome After Stroke in Auckland, New Zealand

Background and Purpose— Limited information exists on the long-term outcome from stroke. We aimed to determine survival and health status at 21-year follow-up of patients who participated in a population-based stroke incidence study undertaken in Auckland, New Zealand. Methods— During 12 months beginning March 1, 1981, half of all residents of Auckland with acute first-ever or recurrent stroke (n=680) were assessed and followed up prospectively during the next 2 decades. In 2002, their vital status and health-related quality of life (HRQoL) using the 36-item short-form questionnaire (SF-36) were determined by telephone interviews. Kaplan–Meier survival probabilities for the stroke cohort were compared with life table estimates for the New Zealand population. The SF-36 profile of 21-year stroke survivors was compared with a standardized New Zealand population. Results— Overall, 626 of the original cohort had died and 4 were lost to follow-up, leaving 50 (7%) individuals (57% male; mean age 70 years) available in 2002, of whom 12% were residents of an institutional care facility and 19% required help with everyday activities. The stroke cohort had nearly twice the mortality rate of the New Zealand population, but the SF-36 profile of very long-term stroke survivors was broadly similar to the general population. Conclusions— Because stroke is generally a disease of older people and has a high case fatality, it is not surprising that <1 in 10 people survive 2 decades after onset. However, of those who do, their HRQoL profile suggests that they meld relatively successfully within the general population, despite ongoing disability and a higher mortality risk.

Change in income and change in self-rated health: Systematic review of studies using repeated measures to control for confounding bias

It is generally assumed that income is strongly and positively associated with health. However, much of the evidence supporting this assumption comes from cross-sectional data or analyses that have not fully accounted for biases from confounding and health selection (the reverse pathway from health to income). This paper reports results of a systematic review of panel and longitudinal studies investigating whether changes in income led to changes in self-rated health (SRH) in adults. A variety of electronic databases were searched, up until January 2010, and thirteen studies were included, using data from five different panel or longitudinal studies. The majority of studies found a small, positive and statistically significant association of income with SRH, which was much reduced after controlling for unmeasured confounders and/or health selection. Residual bias, particularly from measurement error, probably reduced this association to the null. Most studies investigated short-term associations between income and SRH or the effect of temporary (usually one year) income changes or shocks, so did not rule out possibly stronger associations between health and longer-term average income or income lagged over longer time periods. Nevertheless, the true causal short-term relationship between income and health, estimated by longitudinal studies of income change and SRH that control for confounding, may be much smaller than that suggested by previous, mostly cross-sectional, research.

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.

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%; &khgr;2: P=0.016) and tobacco smokers (88% versus 28%; &khgr;2: 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

What are the determinants of food insecurity in New Zealand and does this differ for males and females

Aims: Food insecurity is a lack of assured access to sufficient nutritious food. We aimed to investigate the demographic and socio‐economic determinants of food insecurity in New Zealand and whether these determinants vary between males and females.

Cohort Profile: Survey of Families, Income and Employment (SoFIE) and Health Extension (SoFIE-health)

Panel studies in Western countries have transformed and greatly improved understanding of many social, economic and health trends, such as the British Panel Household Survey and the Whitehall study in the UK, and the Household, Income and Labour Dynamics in Australia (HILDA) survey. In New Zealand (NZ) there are a number of birth cohort and population-specific longitudinal studies: the Dunedin multidisciplinary health and development study, the Christchurch health and development study, the Pacific Islands Family Study and the Health Work and Retirement longitudinal study. However, there was a need for a longitudinal study that covered all age ranges which could provide an understanding of the dynamics of the NZ economy and its interrelationship between the social and economic well-being of individuals, families and households and the factors affecting this well-being. Statistics New Zealand was granted funding from the Foundation for Research, Science and Technology (Government organization) in 1997 to conduct a feasibility study for a longitudinal survey of income, employment and family dynamics. Following the feasibility study, the Survey of Families, Income and Employment (SoFIE) study was developed and first went into the field in October 2002. SoFIE is a single fixed panel longitudinal survey with duration of 8 years. Information is collected once a year from the same individuals on income levels, sources and changes; and on the major influences on income such as employment and education experiences, household and family status and changes, demographic factors and health status. Every 2 years (Waves 2, 4, 6 and 8) information on assets and liabilities is collected to monitor net worth and savings. A successful bid was made to the Health Research Council of NZ by health researchers to have a battery of health questions in Waves 3, 5 and 7—giving rise to the SoFIE-Health sub-study.

Improved Survival after Stroke: Is Admission to Hospital the Major Explanation? Trend Analyses of the Auckland Regional Community Stroke Studies

Background: There is uncertainty regarding the impact of changes in stroke care and natural history of stroke in the community. We examined factors responsible for trends in survival after stroke in a series of population-based studies. Methods: We used statistical models to assess temporal trends in 28-day and 1-year case fatality after first-ever stroke cases registered in 3 stroke incidence studies undertaken in Auckland, New Zealand, over uniform 12-month calendar periods in 1981–1982 (n = 1,030), 1991–1992 (1,305) and 2001–2002 (1,423). Cox proportional hazards regression was used to evaluate the significance of pre-defined ‘patient’, ‘disease’ and ‘service/care’ factors on these trends. Results: Overall, there was a 40% decline in 28-day case fatality after stroke over the study periods, from 32% (95% confidence interval, 29–35%) in 1981–1982 to 23% (21–25%) in 1991–1992 and then 19% (17–21%) in 2002–2003. Similar relative declines were seen in 1-year case fatality. In regression models, the trends were still significant after adjusting for patient and disease factors. However, further adjustment for care factors (higher hospital admission and neuroimaging) explained most of the improvement in survival. Conclusions: These data show significant downwards trends in case fatality after stroke in Auckland over 20 years, which can largely be attributed to improved stroke care associated with increases in hospital admission and brain imaging during the acute phase of the illness.