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Biomedical subjects

M Tobias

Publications and source records attributed to M Tobias.

At least 19 recordsLinked to original sources
PubMed2004

How much downside? Quantifying the relative harm from tobacco taxation.

OBJECTIVE: To estimate the loss of life expectancy attributable to tobacco taxation (via financial hardship and flow-on health effect) in New Zealand. DESIGN: Data were used on the gradients in life expectancy and smoking by neighbourhood socioeconomic deprivation and survey data on tobacco expenditure. Three estimates were modelled of the percentage of the crude association of neighbourhood deprivation with life expectancy that might be mediated via financial hardship: 100%, 50%, and 25% (best estimate). From this information the impact of tobacco taxation on life expectancy was estimated. MAIN RESULTS: For the total population, the estimated loss of life expectancy due to tobacco tax ranged from 0.005 years to 0.027 years. For people living in the most deprived 30% of neighbourhoods, the range was 0.009 to 0.044 years (that is, 3 to 16 days of lost life expectancy). For the total population the loss of life expectancy attributable to tobacco tax ranged from 119 to 460 times less than that attributable to deprivation. The loss of life expectancy attributable to tobacco tax was 42 to 257 times less than that attributable to smoking. CONCLUSIONS: The estimated harm to life expectancy from tobacco taxation (via financial hardship) is orders of magnitude smaller than the harm from smoking. Although the analyses involve a number of simplistic assumptions, this conclusion is likely to be robust. Policy makers should be reassured that tobacco taxation is likely to be achieving far more benefit than harm in the general population and in socioeconomically deprived populations.

Aged↗
PubMed2001

Site fertility and the morphological and photosynthetic acclimation of Pinus sylvestris needles to light.

Morphological and photosynthetic acclimation of current-year needles to canopy gradients in light availability (seasonal mean integrated quantum flux density, Q(int)) was studied in the temperate conifer, Pinus sylvestris L., at two sites of contrasting nutrient availability. The nutrient-rich site supported a monospecific P. sylvestris stand on an old-field. The trees were approximately 30 years old and 19-21 m tall. Mean foliar N and P contents (+/- SD) were 1.53 +/- 0.11% and 0.196 +/- 0.017%, respectively. The nutrient-poor site was located on a raised bog supporting a sparse stand of 50- to 100-year-old trees, with a height of 1-2 m, and mean needle N and P contents of 0.86 +/- 0.12% and 0.074 +/- 0.010%, respectively. At both sites, needle thickness (T) and width (W) increased with increasing Qint, and leaf dry mass per unit leaf area (MA) was also greater at higher irradiance. The light effects on MA-the product of needle density (D) and volume to total area ratio (V/AT)-resulted primarily from large increases in V/AT with Qint rather than from modifications of D, which was relatively insensitive to light. Although needle morphology versus light relationships were qualitatively similar at both sites, needles were shorter, and the slopes of W, T, MA and V/AT versus light relationships were lower, at the nutrient-poor than at the nutrient-rich site, indicating that the plasticity of foliar morphological characteristics was affected by nutrient availability. As a result of lower plasticity, needles at the nutrient-poor site were narrower, thinner, and had lower MA at high irradiance than needles at the nutrient-rich site. The maximum carboxylase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Vcmax) and the maximum photosynthetic electron transport rate (Jmax) scaled positively with foliar N and P contents. The correlations were generally stronger with P than with N, suggesting that needle photosynthetic capacity was more heavily limited by the availability of P than of N. The Jmax/Vcmax ratio was positively related to the foliar P/N ratio, indicating that Jmax was more strongly suppressed than Vcmax under conditions of low P availability. Phosphorus and N deficiency also limited the plasticity of foliar photosynthetic characteristics. There was a moderate increase in needle photosynthetic capacity of up to 1.6-fold from the bottom to the top of the canopy at the nutrient-rich site, but net assimilation rates were essentially independent of canopy position at the nutrient-poor site. Stomatal constraints on photosynthesis were similar between the sites, indicating that photosynthetic acclimation was curtailed at the biochemical level. We conclude that the foliar capacity for morphological and physiological acclimation to high light significantly decreases with decreasing nutrient availability in P. sylvestris, and that both N and P availability are potentially important determinants of foliar carbon gain capacities.

Chlorophyll↗
PubMed2001

Avoidable mortality in New Zealand, 1981-97.

OBJECTIVE: To describe avoidable mortality in New Zealand, including trends and variations between groups by age, gender, ethnicity and degree of deprivation. METHOD: New Zealand Health Information Service mortality unit records, 1981 to 1997, were classified as 'avoidable' or 'unavoidable' based on a reassessment of ICD9 codes and an upper age limit of 75 years. 'Avoidable' causes of death were further subcategorised according to the level of intervention involved (primary, secondary or tertiary). Deaths were assigned a deprivation score using a Census-based small area deprivation index, the NZDep96. Mortality rates were age standardised by the direct method, with Segi's world population as the reference. RESULTS: Avoidable mortality declined 38% from 1981 to 1997; unavoidable mortality declined only 9%. In 1996-97 almost 70% of deaths in the 0-74 age range were still considered to be potentially avoidable. Almost 80% of avoidable deaths occur in the 45-74 age group. These deaths are dominated by the emergence of chronic diseases such as ischaemic heart disease, diabetes and smoking-related cancers. In younger age groups, injury (including suicide) dominates avoidable mortality. Males experience a greater burden of avoidable mortality than females--a relative excess of 54% (approximately 2,000) in 1996-97. The gender difference is largely attributable to diseases and injuries amenable to primary prevention, with the largest single contribution coming from ischaemic heart disease. The ethnic gap in avoidable mortality remains wide: rates for Mäori and Pacific people were 2-2 1/2 times higher than European rates in 1996-97. Similar gradients are seen with deprivation. CONCLUSION AND IMPLICATIONS: Avoidable mortality analysis provides a useful tool for evidence-based health needs assessment and health policy development.

Acute Disease↗
PubMed2001

Potentially avoidable hospitalisations in New Zealand, 1989-98.

OBJECTIVE: To describe potentially avoidable hospitalisation in New Zealand, including recent trends and variations between groups differentiated by age, gender, ethnicity and degree of deprivation. METHOD: Hospital discharges among people aged 0-74 years for the years 1989-98 were classified as 'potentially avoidable' or 'unavoidable' based on the ICD9-CMA code of the principal diagnosis. Potentially avoidable hospitalisations (PAH) were further subcategorised according to the intervention involved--primary prevention, ambulatory care or injury prevention. RESULTS: By 1998, one in three of these hospitalisations was theoretically avoidable--two-thirds of these through more effective primary health care services. Although in practice only a proportion of these could realistically have been avoided, these estimates reveal considerable scope for further reduction in the incidence of serious disease and injury. Maori and Pacific people had age-standardised PAH rates approximately 60% higher than European and other New Zealanders. Similar discrepancies exist by socio-economic deprivation. Had all New Zealanders enjoyed the PAH rates of the most advantaged 40% of the population, 28% fewer potentially avoidable hospitalisations would have occurred in 1998, some 26,000 hospital admissions. CONCLUSION: This analysis has revealed significant scope for the health sector to contribute to population health gain and, in particular, to improvement in equity of outcomes across ethnic and socio-economic groups. Potentially avoidable hospitalisations provide a useful tool for evidence-based population health needs analysis and health policy development.

Adolescent↗
PubMed1999

Immunity to hepatitis B in two birth cohorts given plasma-derived or yeast-derived vaccine.

AIM: To determine the antibody response to either yeast-derived or low-dose, plasma-derived hepatitis B vaccine, in two cohorts of infants monitored by an immunisation coordinator and immunised by general practitioners. METHODS: Infants born to two cohorts of non-carrier mothers in Northland were followed up, the first receiving a low-dose, plasma-derived vaccine, the second a yeast-derived vaccine. An immunisation coordinator enrolled the mothers into the programme during pregnancy, promoted full immunisation against hepatitis B and later obtained blood samples from their babies. In each cohort, four subsamples of babies, randomly assigned, were bled for estimation of antibody levels to hepatitis B at ages 18, 30, 42 and 54 months (1 1/2, 2 1/2, 3 1/2, 4 1/2 years). No infant was bled more than once. RESULTS: In both cohorts, antibody levels declined significantly with age. By age 4 1/2 years, 5.1% of children (95% confidence interval (CI): 3.5-7.1) immunised with yeast-derived vaccine were estimated to have antibody levels to hepatitis B below the acceptable level for protection of 10 IU/L. The proportion for those immunised with plasma-derived vaccine was 14.3% (95% CI: 7.4-24.1). CONCLUSIONS: Children receiving yeast-derived vaccine do not require a second booster dose at school entry, although this might be considered at age 11. There are grounds to suggest that those who received low-dose, plasma-derived vaccine (prior to 1990) should be offered a booster before age 11.

Aging↗
PubMed1999

Independent life expectancy in New Zealand, 1996-97.

The objective of this article is to describe independent life expectancy (ILE) in New Zealand in 1996-97, including variations in this indicator between age, gender and ethnic groups. ILE is defined as the number of years a person can expect to live without any self-reported functional limitation requiring the assistance of another person or a complex assistive device. ILE is a positive measure of health. Its complement, expectation of life with dependency (LED), is also a useful indicator. Together, ILE and LED add up to total life expectancy (LE). The contribution to ILE from disability and mortality at each age is analysed in this article. The elasticity of ILE to changes in mortality and to changes in disability is also investigated. Finally, the burden of injury is estimated by calculating the potential gain in ILE that would result were injury-related disability and mortality to be eliminated.

Activities of Daily Living↗
PubMed1999

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.

Adolescent↗
PubMed1998

A measles epidemic controlled by immunisation.

AIM: In 1997, an immunisation campaign, using measles-mumps-rubella vaccine, was planned for children aged 2-10 years to prevent a measles epidemic predicted by mathematical modelling. The epidemic started before the campaign and is described here. METHOD: Measles hospitalisation, notification and laboratory data were combined. RESULTS: The epidemic started in April 1997 and was largely over by January 1998. No deaths were identified and only one hospitalisation was coded as measles encephalitis, compared to seven deaths and ten cases of measles encephalitis in the 1991 epidemic. For the 12 months from 1 March 1997 there were 2,169 (60 per 100,000) measles cases identified, 314 (9 per 100,000) of whom were hospitalised. Two-thirds of hospitalised cases were notified. The age-standardised measles incidence rates were 33, 34, and 174 per 100,000 for Europeans, Maori and Pacific people, respectively. The respective age-standardised hospitalisation rates were 4, 9 and 32 per 100,000. Measles incidence was highest for under one-year-olds (904 per 100,000) and low for 11-16 year-olds (27 per 100,000)--the cohort previously offered a second vaccine dose. Most cases were aged 10 years and under, and this group were the main drivers of virus transmission. CONCLUSIONS: The immunisation campaign prevented 90-95% of predicted cases. The campaign was appropriately targeted at children aged 10 years and under.

Adult↗
PubMed1998

Chickenpox immunisation in New Zealand.

PREVENTION: The appropriate use of varicella vaccine, effective in the prevention of chickenpox, has been considered by a Ministry of Health Working Party in 1996 and 1997, including discussion at a workshop held in Wellington, 26-27 June 1996. The introduction of varicella vaccine into the routine childhood immunisation schedule was not supported at this stage. The use of the only varicella vaccine for which the Minister of Health has given consent for distribution in New Zealand, Varilrix (SmithKline Beecham Limited), in healthy children aged nine months to 13 years inclusive, was supported. Consent has not been given for the use of Varilrix in immunocompromised people or in adults. This report discusses other groups that could be candidates for vaccination, such as children with deteriorating renal function and susceptible health care workers who regularly come into contact with especially vulnerable patients. In these cases, the vaccine would need to be administered on a named patient basis. The use of Varilrix in immunocompromised people was not supported. SURVEILLANCE: Enhanced surveillance of chickenpox and zoster are required in New Zealand. Adverse reactions to Varilrix should be carefully monitored. OUTBREAK CONTROL: There are insufficient data at present to support the use of Varilrix in outbreak control. The frequency, cost and current management of nosocomial outbreaks should be ascertained. This information may also assist in the decision whether to incorporate a varicella vaccine into the routine childhood immunisation schedule in the future.

Adolescent↗
PubMed1998

Hepatitis B virus carrier prevalence in New Zealand: population estimates using the 1987 police and customs personnel survey.

AIM: To estimate the population hepatitis B surface antigen (HBsAg) carrier prevalence for adults in New Zealand. METHOD: Data for 1987 from the New Zealand Police Department and New Zealand Customs Department hepatitis B sero-marker survey were further analysed. The sample size was 5510 staff who had completed a questionnaire, had blood sera taken and were not already immunised against hepatitis B. RESULTS: Maori adults had a HBsAg carrier prevalence of 5.43% (95% confidence interval 3.07-8.81), Pacific adults 4.44% (1.65-9.42), and European adults 0.42% (0.26-0.65). Other ethnic minorities and people with two or more self-assigned ethnic identities had a carrier prevalence of 3.85% (1.06-9.56). There were non-significant differences in this study for carrier prevalence by sex, age and region. CONCLUSIONS: Policy formation on screening programmes for hepatitis B carriers should assume a HBsAg carrier prevalence of about 5% for Maori, Pacific people and ethnic minorities, and about 0.5% for New Zealanders of European extraction.

Adult↗
PubMed1998

Potential for prevention of premature death and disease in New Zealand.

AIM: To assess the potential for preventing major causes of premature death, disease and injury in New Zealand. METHODS: Population attributable risks for major modifiable risk factors for important causes of death and disease in New Zealand were calculated using available national and international data on the relative risk of disease and the prevalence of risk factors in the relevant New Zealand population. Attainable changes in risk factor prevalences were used to model population attributable risks over the next five years. These estimates were then used to estimate potential reductions in absolute numbers of deaths from major diseases. RESULTS: High population attributable risks were found for several disease/risk factor combinations: smoking and lung cancer (81% in Maori), smoking and coronary heart disease (44% in Maori), smoking and sudden infant death syndrome (49% in Maori); raised serum cholesterol and coronary heart disease (58%); physical inactivity and coronary heart disease (35%), physical inactivity and diabetes (30%), physical inactivity and colorectal cancer (33%), physical inactivity and fractured neck of femur (65%); obesity and hypertension (66%), obesity and diabetes (46%); lack of fruits and vegetables and stomach cancer (46%), and colorectal cancer (34%). The estimated, readily attainable reduction in absolute numbers of annual deaths due to decrease in risk factor prevalence was greatest for smoking (457 deaths), followed by hypertension (326), physical inactivity (303) and raised serum cholesterol (142). CONCLUSION: There is significant scope for reducing mortality from major non-communicable diseases although for some diseases such as the cancers, there will be a time lag of many years before the full benefits are realised. Together, reducing the prevalence of smoking, hypertension, physical inactivity and raised serum cholesterol would result in 1228 fewer deaths per year.

Exercise↗
PubMed1998

The burden of infectious disease in New Zealand.

New Zealand mortality records for the years 1980 to 1993 were analysed to estimate the aggregate burden of infectious disease using a recoding of ICD-9 codes to identify deaths with infectious aetiology. The recoding scheme was modified from one developed by US CDC, which used expert panels to assign ICD codes to categories dependent on the proportion of the code attributable to infection. ICD-9 Chapter One ('Infectious and parasitic diseases') accounted for only 0.7% of total deaths. Following recoding, this proportion increased tenfold, with 6.9% of deaths attributable to infectious disease. This proportion was stable or declined only slowly between 1980 and 1993. While rates varied by age, gender and ethnicity, the results indicate that infectious disease still accounts for a substantial proportion of the burden of disease in New Zealand.

Adolescent↗
PubMed1994

Monosomy 8q: prenatal diagnosis and autopsy findings.

The autopsy findings of a fetus with deletion of the long arm of chromosome 8 are described. Many of the features are similar to those of the tricho-rhino-phalangeal syndromes, types I and II, which are associated with deletions on chromosome 8q24. Other findings in this case, such as total absence of the corpus callosum and intestinal malrotation, have not been described in these syndromes. Genes involved in the development of the latter malformations may reside in adjacent regions on the long arm of chromosome 8. An elevated serum level of beta human chorionic gonadotropin (beta hCG) was found during pregnancy. This aberration should be included with other chromosomal disorders which may be detected by this test.

Abortion, Induced↗