Andrew Sporle

Compression, expansion or dynamic equilibrium? The evolution of health expectancy in New Zealand

Study objective: To evaluate the New Zealand evidence for three theories of population health change: compression of morbidity, expansion of morbidity, and dynamic equilibrium. Design: Using the Sullivan method, repeated cross sectional survey information on functional limitation prevalence was combined with population mortality data and census information on the utilisation of institutional care to produce health expectancy indices for 1981 and 1996. Setting: The adult population of New Zealand in 1981 and 1996. Participants: 6891 respondents to the 1981 social indicators survey; 8262 respondents to the 1996 household disability survey. Main results: As a proportion of overall life expectancy at age 15 the expectation of non-institutionalised mobility limitations increased from 3.5% to 6% for men, and from 4.5% to 8% for women; the expectation of agility limitation increased from 3% to 7.5% for men and from 4.5% to 8.5% for women, and the expectation of self care limitations increased from 2.0% to 4.5% for men and from 3.0% to 6.0% for women. These changes were primarily attributable to increases in the expectation of moderate functional limitation. Conclusion: The dynamic equilibrium scenario provides the best fit to current New Zealand evidence on changes in population health. Although an aging population is likely to lead to an increase in demand for disability support services, the fiscal impact of this increase may be partially offset by a shift from major to moderate limitations, with a consequential reduction in the average levels of support required.

Adolescents' perceptions of a health survey using multimedia computer-assisted self-administered interview

Objective: To ascertain young peoples perceptions of an adolescent health survey when administered by multimedia computer assisted self‐administered Interview (M‐CASI) through analysis of (1) questionnaire item responses and (2) focus group interviews.

Quality of hospital care for Māori patients in New Zealand: retrospective cross-sectional assessment

BACKGROUND New Zealand has a substantial indigenous minority--the Māori--that has considerably worse health status than the majority population. We aimed to assess possible disparities in quality of hospital care for Māori with data on preventable adverse events as an indicator of suboptimum treatment. METHODS We undertook a nationally representative cross-sectional survey of admissions to general public hospitals with more than 100 beds providing acute care. A sample of 6579 patients admitted in 1998 to 13 hospitals was selected by stratified systematic list sample. We did a two-stage retrospective assessment of records by structured implicit review. Outcome measures were occurrence, effect, and preventability of adverse events. FINDINGS Māori accounted for just greater than 15% of admissions and were on average younger, were more likely to be from from deprived areas, had a different case mix, and were in hospital for a shorter stay compared with patients of non-Māori/non-Pacific origin. Overall, after age standardisation, 14% of admissions for Māori were associated with an adverse event, compared with 11% for non-Māori/non-Pacific patients (p=0.01 for difference between groups). For preventable, in-hospital events, this disparity persisted after controlling for age, other sociodemographic factors, and case mix (adjusted odds ratio 1.47; p=0.05). Analysis of potential causal factors showed no markedly or consistently different pattern between the groups. INTERPRETATION Despite a predominantly publicly funded hospital system, our findings suggest that hospital care received by Māori is marginally poorer than that received by New Zealand citizens of non-Māori/non-Pacific origin. Although no cause specific to Māori was evident, various policy and system issues can be addressed.

Persistent social class mortality differences in New Zealand men aged 15-64: an analysis of mortality during 1995-97.

Objective : Social class mortality differences in New Zealand men aged 15–64 years have previously been examined for the periods 1975–77 and 1985–87 using the Elley‐Irving social class scale. The objective was to repeat these analyses for 1995–97 in order to examine time trends, and to assess current social class patterns of mortality.

The New Zealand Socio-economic Index of Occupational Status: methodological revision and imputation for missing data

Objectives: To revise and update the New Zealand Socio‐economic Index (NZSEI) in the light of methodological issues in its construction, and to develop an imputation method for use where occupational information is not available.

Risk of stomach cancer in Aotearoa/New Zealand: A Māori population based case-control study.

Māori, the indigenous people of New Zealand, experience disproportionate rates of stomach cancer, compared to non-Māori. The overall aim of the study was to better understand the reasons for the considerable excess of stomach cancer in Māori and to identify priorities for prevention. Māori stomach cancer cases from the New Zealand Cancer Registry between 1 February 2009 and 31 October 2013 and Māori controls, randomly selected from the New Zealand electoral roll were matched by 5-year age bands to cases. Logistic regression was used to estimate odd ratios (OR) and 95% confidence intervals (CI) between exposures and stomach cancer risk. Post-stratification weighting of controls was used to account for differential non-response by deprivation category. The study comprised 165 cases and 480 controls. Nearly half (47.9%) of cases were of the diffuse subtype. There were differences in the distribution of risk factors between cases and controls. Of interest were the strong relationships seen with increased stomach risk and having >2 people sharing a bedroom in childhood (OR 3.30, 95%CI 1.95–5.59), testing for H pylori (OR 12.17, 95%CI 6.15–24.08), being an ex-smoker (OR 2.26, 95%CI 1.44–3.54) and exposure to environmental tobacco smoke in adulthood (OR 3.29, 95%CI 1.94–5.59). Some results were attenuated following post-stratification weighting. This is the first national study of stomach cancer in any indigenous population and the first Māori-only population-based study of stomach cancer undertaken in New Zealand. We emphasize caution in interpreting the findings given the possibility of selection bias. Population-level strategies to reduce the incidence of stomach cancer in Māori include expanding measures to screen and treat those infected with H pylori and a continued policy focus on reducing tobacco consumption and uptake.