PubMed Health⌕ Search

Biomedical subjects

Tony Blakely

Publications and source records attributed to Tony Blakely.

At least 37 records · Page 2Linked to original sources
PubMed2005

Are mortality differences and trends by education any better or worse in New Zealand? A comparison study with Norway, Denmark and Finland, 1980-1990s.

UNLABELLED: During the 1980s and early 1990s New Zealand experienced major social and economic change, decreasing all-cause mortality rates for the majority ethnic group, and high (but falling) cardiovascular disease (CVD) mortality rates. This paper explores whether inequalities in mortality by education were greater, and increased more, in New Zealand than in Nordic countries (Denmark, Finland, Norway), and determines the contribution of CVD to these differences and trends. METHODS: We used mortality rates for 30-59 year olds by education, and slope (SII) and relative (RII) indices of inequality, calculated from comparable linked census mortality data. RESULTS: Mortality inequalities in New Zealand were at the high end of the Nordic range when standardised by age only, but were mid-range when also standardised by ethnicity. Over time, relative inequalities in all-cause mortality increased similarly in all countries. In New Zealand a large increase in inequality for cardiovascular disease (CVD) mortality was the major contributor. In contrast both CVD and other causes of death were important drivers of increasing inequalities in Nordic countries. Absolute inequalities in all-cause mortality were stable over time among males across all countries, and increased modestly among females. The contribution of CVD to absolute inequality was stable or decreasing over time in all countries. CONCLUSION: Overall, inequalities in mortality in New Zealand did not widen more rapidly than in northern European countries. However, rapid social and economic change may have affected trends in CVD mortality among low educated men and women, and especially the ethnic minority groups.

Adult↗
PubMed2005

Widening ethnic mortality disparities in New Zealand 1981-99.

The aim of this paper is to determine the extent of undercounting of Mäori and Pacific deaths in New Zealand during the 1980s and 1990s, and to calculate corrected ethnic mortality and life expectancy trends. We calculated adjustment ratios for undercounting of Mäori and Pacific deaths (and over-counting of non-Mäori non-Pacific (nMnP) deaths) using the linked census-mortality data. These ratios were then used to calculate corrected mortality rates and life expectancies. Mäori deaths were underestimated by a quarter, and Pacific deaths by a third, during the 1980s and early 1990s. Undercounting was minor in the late 1990s following alignment of ethnicity collection on mortality data to approximate the census. Corrected mortality rates demonstrated 30% (males) and 26% (females) decreases among nMnP from 1980-84 to 1996-99, smaller decreases among Mäori (8% and 7%) and no clear change among Pacific people (9% decrease for males, 4% increase for females). The gap in life expectancy increased from an average of 7.7 years in 1980-84 to 10.8 years in 1996-99 for Mäori, and from 3.3 to 7.7 years for Pacific people, in comparison to nMnP people. Deaths among 45-64 and 65 plus year olds, and cardiovascular disease and cancer deaths, were the main contributors to these disparities. The economic reforms in New Zealand during the 1980s and early 1990s impacted harder upon Mäori and Pacific people in terms of unemployment and income, and are a likely explanation for the diverging mortality trends in this period. Both behavioural factors and health services probably also play a role, but in the absence of trend data by ethnicity, their contribution to diverging mortality trends is unknown. Internationally, our study demonstrates marked undercounting of Mäori and Pacific deaths. We strongly encourage researchers and custodians of vital statistics in other countries to investigate the possibility of undercounting of deaths by ethnicity.

Adolescent↗
PubMed2005

Do social and economic reforms change socioeconomic inequalities in child mortality? A case study: New Zealand 1981-1999.

BACKGROUND: Socioeconomic inequalities in child mortality are known to exist; however the trends in these inequalities have not been well examined. This study examines the trends in child mortality inequality between 1981 and 1999 against the background of the rapid and dramatic social and economic restructuring in New Zealand during this time period. METHODS: Record linkage studies of census and mortality records of all New Zealand children aged 0-14 years on census night 1981, 1986, 1991, 1996, each followed up for three years for mortality between ages 1-14 years. Socioeconomic position was measured using maternal education, household income, and highest occupational class in the household. Standardised mortality rates, rate ratios, and rates differences as well as regression based measures of inequality were calculated. RESULTS: Mortality in all socioeconomic groups fell between 1981 and 1999. Socioeconomic inequality in child mortality existed by all measures of socioeconomic position, however only trends by income suggested a change over time: the relative index of inequality increased from 1.5 in 1981-84 to 1.8 in 1996-99 (p trend 0.06), but absolute inequality remained stable (slope index of inequality 15/100 000 in 1981-84 and 14/100 000 in 1996-99. CONCLUSIONS: Dramatic changes in income in New Zealand possibly translated into increasing relative inequality in child mortality by income, but not by education or occupational class. The a priori hypothesis that socioeconomic inequalities in child mortality would have increased in New Zealand during a period of rapid structural reform and widening income inequalities was only partly supported.

Adolescent↗
PubMed2005

Ethnic inequalities in cancer survival in New Zealand: linkage study.

We explored the contribution of stage at diagnosis to ethnic disparities in cancer survival in New Zealand. We linked 115811 adult patients with invasive cancer registered on the cancer registry (1994 to 2002) to mortality data. Age-standardized, 5-year relative survival rates were lowest for Maori, intermediate for Pacific people (otherwise known as Pacific Islanders), and highest for non-Maori/non-Pacific people for many cancers. Stage at diagnosis accounted for only part of these differences. Possible factors responsible for ethnic inequalities might include access to specialized cancer services and the quality of care received.

Adolescent↗
PubMed2004

Decades of disparity: widening ethnic mortality gaps from 1980 to 1999.

BACKGROUND: Maori and Pacific deaths were severely undercounted in the mid-1980s and first half of 1990s, resulting in numerator-denominator bias when calculating mortality rates by ethnicity. We used the New Zealand Census-Mortality Study to adjust for this bias and calculate corrected ethnic-specific mortality rates from 1980 to 1999. METHODS: Age-specific adjusters were calculated for the period 1980-99. They were applied to mortality data to obtain a corrected number of deaths. Mortality rates (by age and gender) were calculated by dividing the total number of adjusted deaths by the respective census counts. RESULTS: Contrary to unadjusted rates, corrected Maori and Pacific mortality rates were clearly higher than non- Maori non-Pacific rates during the 1980s and early 1990s. From 1980-84 (1361 per 100,000 for males and 965 per 100,000 for females) to 1996-99 (1258 and 894), there was only a modest decrease in Maori 1 to 74 year old mortality rates. Pacific mortality rates changed little from 1980-84 (1264 and 672) to 1996-99 (1144 and 696 per 100,000 for males and females respectively). Non-Maori non-Pacific mortality rates, however, decreased by about 30% from 1980-84 (919 and 553) to 1996-99 (641 and 407 per 100,000 for males and females, respectively). Cancer (lung, prostate, breast, colorectal) mortality rates tended to increase over time among Maori compared to steadily decreasing among non-Maori non-Pacific. Of note, Pacific colorectal cancer mortality rates have increased by about ten-fold during the 1980s and 1990s. All ethnic groups experienced falls in cardiovascular disease mortality rates, but the decreases were much greater among non-Maori non-Pacific. CONCLUSION: The gaps between Maori and non-Maori non-Pacific mortality widened over the 1980s and 1990s mainly due to steadily declining non-Maori non-Pacific mortality rates and stagnant Maori mortality rates. Likewise, the gaps between Pacific and non-Maori non-Pacific mortality also widened during that period.

Adolescent↗
PubMed2004

Income and mortality: the shape of the association and confounding New Zealand Census-Mortality Study, 1981-1999.

OBJECTIVE: To determine the shape of the income-mortality association, before and after adjusting for confounding by other socioeconomic variables. METHODS: Poisson regression analyses were conducted on 11.7 million years of follow-up of 25-59 year old New Zealand census respondents spanning four separate cohort studies (1981-1984, 1986-1989, 1991-1994, and 1996-1999). RESULTS: Mortality among low-income people was approximately two times that among high-income people. Adjustment for potential socioeconomic confounders (marital status, education, car access, and neighbourhood socioeconomic deprivation) halved the strength of the income-mortality association, but did not appreciably change the shape of the association. Further adjustment for labour force status largely removed the income-mortality association. The association of non-transformed income with mortality was non-linear, with a flattening out of the slope at higher incomes. Both the logarithm and rank of income appeared to have a better linear fit with the mortality rate, although the association of mortality with the logarithm of income flattened out notably at low incomes. CONCLUSIONS: Much, but not all, of the crude association of income with mortality could be due to confounding. Adjusting income-mortality associations for labour force status (also a proxy for health status) is problematic: on the one hand, it over-adjusts the association as poor health will be on the pathway from income to mortality; on the other hand, it appropriately adjusts for both confounding by labour force status and reverse causation whereby income changes as a result of poor health. Both logarithmic and rank transformations of income have a reasonable linear fit with income.

Censuses↗
PubMed2004

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. METHODS: Data were drawn from the following New Zealand national surveys: 1996 Population Census; 1996/97 and 1997/98 Household Economic Surveys; 1996/97 Household Health Survey. Three sets of statistical analyses were applied: alternating least squares to generate socio-economic scores; cluster and discriminant function analyses to identify cut-points; and regression and logistic regression to develop and test imputation methods. RESULTS: Socio-economic scores for the full-time workforce in 1996 showed a different distribution, but much the same occupational ordering, as in 1991. The introduction of part-time workers and income adjustment multipliers for self-employed workers significantly affected scores for management and agricultural titles. The application of cluster and discriminant function analyses generated six groupings that were relatively distinct occupationally. An imputation method based on an averaging of scores within age/qualification categories was found to achieve acceptable results. CONCLUSIONS: Methodological improvements in the construction of the NZSEI have enhanced its empirical robustness, while a simple imputation technique has widened the potential application of the scale.

Data Collection↗
PubMed2004

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.

Adolescent↗
PubMed2003

Unlocking the numerator-denominator bias III: adjustment ratios by ethnicity for 1981-1999 mortality data. The New Zealand Census-Mortality Study.

AIM: Maori and Pacific deaths are under-counted in mortality data relative to census data. This 'numerator-denominator' bias means that routinely calculated mortality rates by ethnicity are incorrect. We used New Zealand Census-Mortality Study data to quantify the bias from 1981 to 1999. METHODS: The 1981, 1986, 1991 and 1996 Censuses were each anonymously and probabilistically linked to three years of subsequent mortality data, allowing a comparison of ethnicity recording. RESULTS: Compared with death registrations, 16% more 0-74 year old decedents during 1981-1984 had self-identified as '1/2 or more Maori' on the 1981 Census, and 32% more during both 1986-1989 and 1991-1994 had self-identified as 'sole Maori' on the 1986 and 1991 Censuses. From September 1995, mortality data have allowed multiple ethnicity to be recorded. During 1996-1999, 7% more decedents identified Maori as one of their ethnic groups on the 1996 Census compared with mortality data. For Pacific decedents, 55%, 76% and 68% more self-identified as 'sole Pacific' on census data compared with data recorded on death registrations for 1981-1984, 1986-1989 and 1991-1994 respectively, but there was no difference for 1996-1999. The bias for Maori (but not for Pacific) was greater among the young and those living in central and southern regions of New Zealand. CONCLUSIONS: The 1995 change to ethnicity recording on mortality data has improved the robustness of ethnicity data collection. These adjustment factors for 1981-1999 allow for more accurate calculations of ethnic-specific mortality rates over the last 20 years.

Adolescent↗
PubMed2003

Child mortality, socioeconomic position, and one-parent families: independent associations and variation by age and cause of death.

BACKGROUND: Although the association between child mortality and socioeconomic status is well established, it is unclear whether child mortality differences by socioeconomic position are present at all ages. The association of one-parent families with mortality, and whether any such association is due to associated low socioeconomic position, is also not clear. METHODS: In all, 480 of 693 (69%) 0-14 year old deaths during 1991-1994 were linked to 1991 census records. Analyses were weighted to adjust for potential linkage bias. RESULTS: There was approximately twofold higher mortality among the lowest compared with the highest socioeconomic categories of education, income, car access, and neighbourhood deprivation. Occupational class differences were weaker. These socioeconomic differences in mortality were strongest among infants (particularly sudden infant death syndrome [SIDS] mortality), but similar across other age groups (1-4, 5-9, and 10-14 years). The socioeconomic differences were of a similar magnitude for unintentional injury, cancer, congenital, and other deaths. Multivariable analyses demonstrated persistent independent associations of education, income, car access, and neighbourhood deprivation with mortality. Rate ratios (adjusted for age and ethnicity) for one-parent families compared with two-parent or other families were 1.2 (95% CI: 1.0, 1.5) and 1.8 (95% CI: 1.2, 2.5) for all-cause and unintentional injury mortality, respectively. Further adjustment for socioeconomic factors reduced these associations to 0.8 (95% CI: 0.6, 1.2) and 1.2 (95% CI: 0.7, 2.2), respectively. CONCLUSIONS: There does not appear to be notable variation in relative risk terms of socioeconomic differences in child mortality by age or cause of death. Any association of one-parent families with child mortality is due to associated low socioeconomic position.

Adolescent↗