Could mainstream anti-smoking programs increase inequalities in tobacco use? New Zealand data from 1981-96.

OBJECTIVE: To examine changes in the socio-economic and ethnic distribution of smoking in the New Zealand population from 1981 to 1996, and to consider the implication of these data for policies aimed at reducing tobacco consumption. METHODS: Cross-sectional data were taken from 4.7 million respondents to the 1981 and 1996 New Zealand Censuses and 4,619 participants in a 1989 national survey, aged 15 to 79 years. Smoking prevalence rates were calculated by socio-economic position and ethnicity. RESULTS: Smoking prevalence fell in the period 1981-96 in every population group. However, socio-economic and ethnic differences in smoking increased in relative terms. Smoking prevalence ratios comparing the least advantaged with the most advantaged groups increased in men from 1.20 to 1.53 by income, 1.54 to 1.85 by education, and 1.49 to 1.67 by ethnicity. In women, prevalence ratios increased from 1.17 to 1.51 by income, 1.55 to 2.02 by education, and 1.85 to 2.20 by ethnicity. The greatest increase in socio-economic differences may have occurred during the 1980s, the period of greatest overall decline in total population smoking. CONCLUSIONS: Socio-economic and ethnic disparities in New Zealanders' smoking patterns increased during the 1980s and '90s, a period of significant decline in overall smoking prevalence. IMPLICATIONS: Public health programs aimed at reducing tobacco use should pay particular attention to disadvantaged, Indigenous and ethnic minority groups in order to avoid widening relative inequalities in smoking and smoking-related health outcomes.

Hepatitis B carriage explains the excess rate of hepatocellular carcinoma for Maori, Pacific Island and Asian people compared to Europeans in New Zealand.

BACKGROUND: The aim of this research was to determine the hepatitis B surface antigen (HBsAg) carrier prevalence among cases of hepatocellular carcinoma (HCC), and the population attributable risk of HBsAg carriage for HCC, by ethnicity in New Zealand. METHODS: The hospital notes of HCC cases registered with the New Zealand Cancer Registry, for the years 1987-1994 inclusive, were viewed to determine the HBsAg status. Results The HBsAg status was determined for 193 cases of HCC. The HBsAg carrier prevalence for non-Europeans with HCC was markedly higher than that for Europeans, being 76.7% for Maori, 80.0% for Pacific Island people, and 88.5% for Asians, compared to 6.0% for Europeans. In addition to the effect of ethnicity, HCC cases aged <60 years were more likely to be HBsAg carriers than those aged > or = 60 years. The estimated population attributable risk of HBsAg for HCC, within each ethnic group, was only marginally less than the HBsAg prevalence due to the high relative risk of HBsAg carriage for HCC. The standardized incidence rate ratios of HCC for Maori, Pacific Island people and Asians compared to Europeans were 9.6, 20.4, and 22.3, respectively. Hepatocellular carcinoma attributable to HBsAg carriage explained 79%, 83%, and 92% of the excess standardized rate of HCC, compared to Europeans, for Maori, Pacific Island people, and Asians, respectively. Conclusions The HBsAg carrier prevalence in non-European cases of HCC in New Zealand is between 75% and 90%. HBsAg carriage explains the majority of the excess rate of HCC in non-Europeans compared to Europeans in New Zealand.

Ecological effects in multi-level studies.

Multi-level research that attempts to describe ecological effects in themselves (for example, the effect on individual health from living in deprived communities), while also including individual level effects (for example, the effect of personal socioeconomic disadvantage), is now prominent in research on the socioeconomic determinants of health and disease. Such research often involves the application of advanced statistical multi-level methods. It is hypothesised that such research is at risk of reaching beyond an epidemiological understanding of what constitutes an ecological effect, and what sources of error may be influencing any observed ecological effect. This paper aims to present such an epidemiological understanding. Three basic types of ecological effect are described: a direct cross level effect (for example, living in a deprived community directly affects individual personal health), cross level effect modification (for example, living in a deprived community modifies the effect of individual socioeconomic status on individual health), and an indirect cross level effect (for example, living in a deprived community increases the risk of smoking, which in turn affects individual health). Sources of error and weaknesses in study design that may affect estimates of ecological effects include: a lack of variation in the ecological exposure (and health outcome) in the available data; not allowing for intraclass correlation; selection bias; confounding at both the ecological and individual level; misclassification of variables; misclassification of units of analysis and assignment of individuals to those units; model mis-specification; and multicollinearity. Identification of ecological effects requires the minimisation of these sources of error, and a study design that captures sufficient variation in the ecological exposure of interest.

Unemployment and suicide. Evidence for a causal association?

OBJECTIVES: To determine the independent associations of labour force status and socioeconomic position with death by suicide. DESIGN: Cohort study assembled by anonymous and probabilistic record linkage of census and mortality records. PARTICIPANTS: 2.04 million respondents to the New Zealand 1991 census aged 18-64 years. MAIN OUTCOME MEASURE: Suicide in the three years after census night. RESULTS: The age adjusted odds ratios (95% confidence intervals) of death by suicide among 25 to 64 year olds who were unemployed compared with employed were 2.46 (1.10 to 5.49) for women and 2.63 (1.87 to 3.70) for men. Similarly increased odds ratios were observed for the non-active labour force compared with the employed. Strong age only adjusted associations of suicide death with the socioeconomic factors of education (men only), car access, and household income were observed. Compared with those who were married on census night, the non-married had odds ratios of suicide of 1.81 (1.22 to 2.69) for women and 2.08 (1.66 to 2.61) for men. In a multivariable model the association of socioeconomic factors with suicide reduced to the null. However, marital status and labour force status remained strong predictors of suicide death. Unemployment was also strongly associated with suicide death among 18-24 year old men. Sensitivity analyses suggested that confounding by mental illness might explain about half, but not all, of the association between unemployment and suicide. CONCLUSIONS: Being unemployed was associated with a twofold to threefold increased relative risk of death by suicide, compared with being employed. About half of this association might be attributable to confounding by mental illness.

The 1996 pertussis epidemic in New Zealand: vaccine effectiveness.

AIM: To assess if reduced vaccine effectiveness may have accounted for increased hospitalisations in the 1996 pertussis epidemic. METHODS: Vaccine effectiveness was estimated by comparing vaccine coverage of the population (derived from a literature review) with that of cases (from notification data available from 1 June 1996) -- the screening method. Only three doses of pertussis vaccine were in the immunisation schedule until 1996, so vaccine effectiveness was calculated for three or more doses. RESULTS: Most likely estimates of vaccine effectiveness for Europeans were 88% (95% confidence interval 71 to 95%) for 5- to 14-month-olds, 80% for 15-month to 4-year-olds (66 to 88%) but lower for children aged 5 years and older with confidence limits including zero. Vaccine effectiveness estimates for Maori were less for each age group but based on few observations. CONCLUSIONS: The increase in hospitalisations for young children in the 1996 epidemic cannot be directly attributed to a reduced vaccine effectiveness, as vaccine effectiveness estimates for preschool Europeans are in line with international evidence. Additionally, the vaccine effectiveness estimates in this study are likely to be underestimates due to bias. The lower estimates for vaccine effectiveness among Maori are likely to reflect increased pressure of these biases, although a biological basis for the difference or clustering of factors that cause failure are also possible. The vaccine effectiveness estimates decrease with age, a likely combination of waning vaccine immunity and the cross-sectional nature of the screening method itself for determining vaccine effectiveness.

Orientation in time: implications for psychopathology and psychotherapy.

Considerations derived from the fields of physics, philosophy, anthropology, and psychology suggest that our popular conception of time as a unidirectional and uniform flow may not be an adequate description of the human experience of time. Indeed, other dimensions of temporality may constitute important aspects of human phenomenology with respect to both adaptive and maladaptive or psychopathological mental states. Exploration of the temporal aspect of experience and temporal reorientation may be helpful psychotherapeutic maneuvers that are greatly facilitated by hypnosis.

Mild head injury is not always mild; implications for damage litigation.

The traditional view that mild head injury involves an essentially reversible physiological process is examined and is found to be largely invalid. It is concluded that long-term impairment following mild head injury is fairly common and that the degree of impairment can be assessed clinically. Such an assessment involves a combination of objective electrophysiological and psychometric investigations as well as professional interpretation. With the use of this approach the possibility of malingering can be ruled out in most cases and significant impairment, when it exists, can be demonstrated beyond reasonable doubt.

The effect of eradicating poverty on childhood unintentional injury mortality in New Zealand: a cohort study with counterfactual modelling.

BACKGROUND: The aim of this study was to examine the effect of household income on unintentional injury mortality in children and to model the potential impact of eradicating income poverty as an injury prevention strategy. METHODS: A national retrospective cohort study linking census to mortality records carried out in New Zealand during a 3-year period following the 1991 census and including children aged 0-14 years on census night. The main outcome measures are odds ratios (ORs) for unintentional injury death by equivalised household income category and proportional reductions (population-attributable risk) in unintentional injury mortality from modelled scenarios of nil poverty. RESULTS: One-third of children lived in households earning less than 60% of the national median household income. Age-adjusted odds of death from unintentional injury were higher for children from any income category compared with the highest, and were most elevated for children from households earning less than 40% of the national median income (OR 2.81, 95% CI 1.73 to 4.55). Adjusting for ethnicity, household education, family status and labour force status halved the effect size (OR 1.83, 1.02 to 3.28). Thirty per cent of injury mortality was attributable to low or middle household income using the highest income category as reference. Altering the income distribution to eradicate poverty, defined by a threshold of 50% or 60% of the national median income, reduced injury mortality in this model by a magnitude of 3.3% to 6.6%. CONCLUSIONS: Household income is related to a child's risk of death from unintentional injury independent of measured confounders. Most deaths attributable to low income occur among households that are not defined as "in poverty". The elimination of poverty may reduce childhood unintentional injury mortality by 3.3% to 6.6%.

Socioeconomic inequality in voting participation and self-rated health.

OBJECTIVES: This study tested the hypothesis that disparities in political participation across socioeconomic status affect health. Specifically, the association of voting inequality at the state level with individual self-rated health was examined. METHODS: A multilevel study of 279,066 respondents to the Current Population Survey (CPS) was conducted. State-level inequality in voting turnout by socioeconomic status (family income and educational attainment) was derived from November CPS data for 1990, 1992, 1994, and 1996. RESULTS: Individuals living in the states with the highest voting inequality had an odds ratio of fair/poor self-rated health of 1.43 (95% confidence interval [CI] = 1.22, 1.68) compared with individuals living in the states with the lowest voting inequality. This odds ratio decreased to 1.34 (95% CI = 1.14, 1.56) when state income inequality was added and to 1.27 (95% CI = 1.10, 1.45) when state median income was included. The deleterious effect of low individual household income on self-rated health was most pronounced among states with the greatest voting and income inequality. CONCLUSIONS: Socioeconomic inequality in political participation (as measured by voter turnout) is associated with poor self-rated health, independently of both income inequality and state median household income.