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Biomedical subjects

D R English

Publications and source records attributed to D R English.

At least 19 recordsLinked to original sources
PubMed2001

Segregation analyses of 1,476 population-based Australian families affected by prostate cancer.

Segregation analyses aim to detect genetic factors that have a major effect on an individual's risk of disease and to describe them in terms of mode of inheritance, age-specific cumulative risk (penetrance), and allele frequency. We conducted single- and two-locus segregation analyses of data from 1,476 men with prostate cancer diagnosed at age <70 years and ascertained through population registries in Melbourne, Sydney, and Perth, Australia, and from their brothers, fathers, and both maternal and paternal lineal uncles. Estimation and model selection were based on asymptotic likelihood theory and were performed through use of the software MENDEL. All two-locus models gave better fits than did single-locus models, even if lineal uncles were excluded or if we censored data (age and disease status) for relatives at 1992, when prostate-specific-antigen testing started to have a major impact on the incidence of prostate cancer in Australia. Among the genetic models that we considered, the best-fitting ones included a dominantly inherited increased risk that was greater, in multiplicative terms, at younger ages, as well as a recessively inherited or X-linked increased risk that was greater, in multiplicative terms, at older ages. The recessive and X-linked effects were strongly confounded, and it was not possible to fit them together. Penetrance to age 80 years was approximately 70% (95% confidence interval [CI] 57%-85%) for the dominant effect and virtually 100% for the recessive and X-linked effects. Approximately 1/30 (95% CI 1/80-1/12) men would carry the dominant risk, and 1/140 (95% CI 1/220-1/90) would carry the recessive risk or 1/200 (95% CI 1/380-1/100) would carry the X-linked risk. Within discussed limitations, these analyses confirm the genetic heterogeneity, of prostate cancer susceptibility, that is becoming evident from linkage analyses, and they may aid future efforts in gene discovery.

Age of Onset↗
PubMed2001

Smoking and prostate cancer: findings from an Australian case-control study.

BACKGROUND: To examine the risk of smoking on histopathologically-confirmed moderate- and high-grade prostate cancer. MATERIALS AND METHODS: A population-based case-control study was conducted in Melbourne, Sydney and Perth between 1994 and 1998 in men aged below 70 years. Cases were recruited from cancer registries and controls were selected from electoral registers. 1498 cases and 1434 controls were interviewed and a detailed smoking history obtained. Data were analyzed by unconditional logistic regression, adjusting for age, study center, year of recruitment, family history and country of birth. RESULTS: The odds ratios (OR) were 1.02 (0.85-1.22) for former smoking and 0.82 (0.65-1.05) for current smoking. The respective ORs were 0.95 (0.78-1.15) and 0.76 (0.59-0.99) for moderate grade tumors, and 1.28 (0.96-1.70) and 1.00 (0.67-1.47) for high-grade tumors (P = 0.2 for test that ORs of the two grades were identical). There was no evidence of a dose-response effect for duration of smoking, amount smoked daily, pack-years of smoking and years since quitting and most ORs for these variables were close to unity. CONCLUSIONS: Smoking was not associated with the incidence of prostate cancer. The widths and upper limits of the confidence intervals for the effects of current and former smoking were consistent with weak effects at most.

Adult↗
PubMed2001

Reduced sun exposure and tanning in children after 2 years of a school-based intervention (Australia).

OBJECTIVE: This paper presents the results of the evaluation of measured suntan and parent-reported sun exposure in participating children after 2 years of the Kidskin study, a 5-year school-based sun protection intervention undertaken in Perth, Western Australia (1995-1999). METHODS: The study involves three groups: a control, a "moderate", and a "high" intervention group. Participants were 5 or 6 years of age at the beginning of the study. Control schools received the standard Health Education curriculum, while intervention schools received a multicomponent intervention including a specially designed curriculum. Children in the high intervention group also received program materials over the summer vacation and were offered sun-protective swimwear at low cost. At the end of the second summer, suntan was measured and parents completed a questionnaire about their child's sun-related behavior. RESULTS: Children in the intervention groups--especially the high group--were less tanned at the end of the summer; this effect was greater for the back than for the forearms. These children were also reported to have received less sun exposure and made greater use of sun protection measures. CONCLUSION: Intensive school-based interventions can reduce tanning and reported sun exposure in children.

Child↗
PubMed2001

Prevalence of urinary symptoms in urban Australian men aged 40-69.

BACKGROUND: This study was devised to determine the prevalence of urinary symptoms among men living in the Australian cities of Melbourne, Sydney or Perth, and to identify factors associated with the presence of moderate-to-severe urinary symptoms. METHODS: The study comprised a population-based sample of 1,216 men, aged 40-69 years, whose names were obtained through electoral rolls and who participated as controls in a case-control study of risk factors for prostate cancer. As part of a structured face-to-face interview, the men completed the International Prostate Symptom Score (IPSS). Men with moderate (IPSS = 8-19) or severe (IPSS > or = 20) urinary symptoms were compared with those with mild or no symptoms (IPSS < 8) using unconditional logistic regression. RESULTS: The age-specific prevalence of moderate-to-severe urinary symptoms (IPSS > or = 8) in men aged 40-49, 50-59, 60-69 years was 16%, 23% and 28%, respectively. Compared with men with no or mild urinary symptoms (IPSS < 8), men with moderate-to-severe symptoms were more likely to report not currently living as married [odds ratio (OR) = 1.5; 95% confidence interval (CI) 1.1-2.0] and being circumcised (OR = 1.5; 95% Cl 1.2-2.0). The increased likelihood associated with drinking an average of > 60 g day(-1) of alcohol in the 2 years before interview was of marginal statistical significance (OR = 1.6; 1.0-2.6). There were no significant differences between men with IPSS > or = 8 and those with IPSS < 8 with respect to body mass index, education level, having had a vasectomy, or cigarette smoking. CONCLUSION: Among Australian men, being circumcised, or not currently living as married, were associated with increased prevalence of urinary symptoms.

Adult↗
PubMed2001

A psychometric experiment in causal inference to estimate evidential weights used by epidemiologists.

A psychometric experiment in causal inference was performed on 159 Australian and New Zealand epidemiologists. Subjects each decided whether to attribute causality to 12 summaries of evidence concerning a disease and a chemical exposure. The 1,748 unique summaries embodied predetermined distributions of 19 characteristics generated by computerized evidence simulation. Effects of characteristics of evidence on causal attribution were estimated from logistic regression, and interactions were identified from a regression tree analysis. Factors with the strongest influence on the odds of causal attribution were statistical significance (odds ratio = 4.5 if 0.001 < or = P < 0.05 and 7.2 if P < 0.001, vs P > or = 0.05); refutation of alternative explanations (odds ratio = 8.1 for no known confounder vs none adjusted); strength of association (odds ratio = 2.0 if 1.5 < relative risk < or = 2.0 and 3.6 if relative risk > 2.0, vs relative risk < or = 1.5); and adjunct information concerning biological, factual, and theoretical coherence. The refutation of confounding reduced the cutpoint in the regression tree for decision-making based on strength of association. The effect of the number of supportive studies reached saturation after it exceeded 12 studies. There was evidence of flawed logic in the responses concerning specificity of effects of exposure and a tendency to discount evidence if the P-value was a "near miss" (0.050 < P < 0.065). Evidential weights based on regression coefficients for causal criteria can be applied to actual scientific evidence.

Adult↗
PubMed2000

Multiple sclerosis in Australia: prognostic factors.

In order to determine the influence of age of onset, sex, onset symptoms, clinical course and interval from onset to first relapse on the subsequent outcome of multiple sclerosis (MS), data from 2934 cases of MS documented in a large population based study undertaken in Australia have been analysed. Disability on prevalence day (30 June 1981) was defined on the Kurtzke disability scale as mild (DSS 0-3), moderate (DSS 4-6) and severe (DSS 7-9). Prognostic factors associated with mild vs moderate/severe, and moderate vs severe disability on prevalence day were identified by logistic regression analysis. A worse prognosis was significantly associated with older age of onset, progressive disease course, onset symptoms that were multiple, pyramidal or cerebellar, and a short interval between onset and first relapse.

Adolescent↗
PubMed2000

The age-range of risk of developing multiple sclerosis: evidence from a migrant population in Australia.

The prevalence of multiple sclerosis in the Australian-born population in five different regions of Australia has a strong correlation with latitude, the disease becoming increasingly prevalent with increasing south latitude. In this study, the prevalence in the migrant population from the UK and Ireland (UKI) in the different regions also showed a significant correlation with latitude, but this relationship was strongly influenced by the high prevalence in Hobart. Except for Hobart, the prevalence in migrants was considerably less than that in their countries of origin. The prevalence of multiple sclerosis among those migrating before the age of 15 years from the high-risk UKI to lower-risk Australia was not significantly different to that among those migrating at or after that age, and this finding was confirmed in a case-control study which demonstrated little association between age at migration and risk of developing multiple sclerosis. These findings suggest that the risk from environmental factors in multiple sclerosis may operate over a period of many years and not only in childhood and early adult life.

Adult↗
PubMed2000

Improved sun protection behaviour in children after two years of the Kidskin intervention.

OBJECTIVE: To evaluate a school-based intervention in terms of reducing children's sun exposure and improving their use of sun protection measures. METHODS: 'Kidskin' is a five-year, school-based intervention study in Perth, Western Australia, of a cohort of children who were five or six years old in 1995. The study involves three groups: control, 'moderate' and 'high' intervention. Children in the control schools received the standard health curriculum; those in the intervention schools received a multicomponent intervention, including a specially designed curriculum. Children in the high intervention group also received program materials over the summer holidays and were offered sun-protective swimwear at a low cost. After two years, parents completed a questionnaire about their child's sun-related behavior. RESULTS: Children in the intervention groups--especially the 'high' group--were reported to have had less sun exposure. This involved covering the back more often, spending more time in the shade when outdoors and wearing a style of swimsuit that covered the trunk. There was also evidence that children in the intervention groups spent less time outdoors in the middle of the day. There was little difference between groups in the wearing of hats or sunscreen. CONCLUSIONS: Our school-based intervention improved children's sun protection, but had little effect on specific behaviours that have already been vigorously promoted. IMPLICATIONS: School-based prevention campaigns would benefit from focusing on sun protection using clothing and shade, and reducing sun exposure in the middle of the day. There may be little potential to improve hat and sunscreen use.

Child↗
PubMed1999

Prostate cancer testing: behaviour, motivation and attitudes among Western Australian men.

OBJECTIVE: To estimate the proportion of Western Australian men aged 40-80 years who had been tested for prostate cancer, their experiences of screening and perception of its benefit. DESIGN AND SETTING: Cross-sectional survey (random telephone survey) of Western Australian men conducted in February 1998. PARTICIPANTS: 400 men aged 40-80 years from 670 eligible households (60% response rate from contactable households with eligible men). MAIN OUTCOME MEASURES: Proportion of respondents tested for prostate cancer (by prostate-specific antigen [PSA] test or digital rectal examination); reasons for having been tested; information provided by the doctor before testing; reasons given for and beliefs about the benefits of testing. RESULTS: Of 391 asymptomatic men, 220 (56%) recalled having been tested for prostate cancer and 167 (43%) had had a PSA test. Of those tested, 86% had their first test in the previous five years. The two most common reasons for testing were media publicity and general practitioner recommendation. Thirty-eight per cent of men tested during the previous five years reported that the doctor did not discuss the "pros and cons" of the test; 39% reported a discussion of less than five minutes' duration; 17% were given printed information before undergoing the test for the first time. Half were "very convinced" of the benefits of testing for prostate cancer. CONCLUSIONS: Men are being tested for prostate cancer with minimal pretest counselling or written information.

Adult↗
PubMed1999

Evaluation of an intervention to reduce sun exposure in children: design and baseline results.

The Kidskin Study is a 5-year intervention study (1995-1999) involving 1,776 5- and 6-year-old children attending 33 primary schools in Perth, Western Australia. The aim of the study is to design, implement, and evaluate an intervention to reduce sun exposure in young children. There are three study groups: a control group, a "moderate intervention" group, and a "high intervention" group. The control schools receive the standard Western Australian health education curriculum, while the moderate and high intervention schools receive a specially designed curricular intervention. In addition, children in the high intervention group receive program materials over the summer holidays, when exposure is likely to be highest, and are offered sun-protective swimwear at low cost. The main outcome measure is the number of nevi on the back. Other outcomes include nevi on the chest (boys only), face, and arms, levels of suntanning, degree of freckling, and sun-related behaviors. At baseline, the three groups were similar with respect to nevi and freckling after adjustment for observer and month of observation. Sun exposure was slightly higher in the high intervention group. The groups were also similar with respect to most potential confounders, although they differed with respect to Southern European ethnicity and parental education.

Back↗
PubMed1999

Glucose utilization and glycogen turnover are accelerated in hypertrophied rat hearts during severe low-flow ischemia.

We undertook this study to determine if the metabolism of exogenous glucose and glycogen in hypertrophied hearts differed from that in normal hearts during severe ischemia. Thus, rates of glycolysis (3H2O production) and oxidation (14CO2 production) from exogenous glucose and glycogen were measured in isolated working control (n = 13) and hypertrophied (n = 12) hearts from sham-operated and aortic-banded rats during 40 min of severe low-flow ischemia. Hearts, in which glycogen was prelabelled with [5-3H]- or [14C]-glucose, were paced and perfused with Krebs-Henseleit solution containing 1.2 mM palmitate, 5.5 mM [5-3H]- or [14C]-glucose (different from the isotope used to label glycogen), 0.5 mM lactate and 100 microU/ml insulin during ischemia. Rates of glycolysis from exogenous glucose (3301 +/- 122 v 2467 +/- 167 nmol/min/g dry wt, mean +/- S.E.M., P < 0.05) and glucose from glycogen (808 +/- 27 v 725 +/- 21 nmol/min/g dry wt, P < 0.05) were accelerated in hypertrophied hearts compared to control hearts. However, rates of oxidation of exogenous glucose and glucose from glycogen were not significantly different between the two groups. As observed in normoxic non-ischemic hearts, glucose from glycogen was preferentially oxidized compared to exogenous glucose. Additionally, rates of glycogen synthesis (167 +/- 7 v 140 +/- 9 nmol/min/g dry wt, P < 0.05) were increased in hypertrophied hearts compared to control hearts during severe low-flow ischemia indicating that glycogen turnover (i.e. simultaneous synthesis and degradation) was accelerated in the hypertrophied heart. Thus, we demonstrate that glucose utilization and glycogen turnover are accelerated in the hypertrophied heart during severe low-flow ischemia as compared to the normal heart.

Animals↗
PubMed1999

Direct measurement of sun protection in primary schools.

BACKGROUND: "Kidskin" is an intervention study involving children at 33 primary schools in Perth, Western Australia. This study includes measurement of changes in implementation of schools' sun protection policies. This paper reports on measurement of observable aspects of sun protection. METHODS: Hat use was assessed from videos of children in the playground. Shade use was measured using UVR-sensitive polysulfone badges worn by a random sample of children. Shade provision was measured from aerial photographs of the schools. Principals were surveyed about school policies and practices. RESULTS: Eighty-seven percent of children wore a hat during lunch time at school, although only 14% wore the most protective styles of hats. The mean proportion of ambient UVR exposure received by Year 1 children was 15.5%; children spent less time in the sun on sunnier days. On average, 14.5% of the playground was shaded; this was not associated with children's sun exposure. Correlations between these results and the principals' estimates were poor. CONCLUSIONS: Children should be encouraged to wear more protective styles of hats and to avoid sun exposure, even on less sunny days during spring and summer. Principals' estimates of shade provision and children's sun protection behavior at school are of little value.

Analysis of Variance↗
PubMed1999

Sun exposure and pterygium of the eye: a dose-response curve.

PURPOSE: To present a quantitative analysis of pterygium and ocular sun exposure, a dose-response curve, and a discussion of the health-promotion implications of the findings. METHODS: A hospital-based, case-control study was conducted in Perth, Western Australia. Case subjects had surgical removal of a pterygium; control subjects had an ear, nose, or throat procedure. A lifetime history of residence, sun exposure patterns, and use of hats, spectacles, and sunglasses was obtained at interview. Measures of potential sun exposure included latitude, daily sunshine hours, and daily global solar radiant energy. The most complex estimate of actual sun exposure was the daily ocular solar radiation dose, calculated from climatic data, time spent outdoors not under shade, and the use of hats and spectacles. RESULTS: There were strong positive associations between pterygium and measures of potential and actual sun exposure. Associations were as strong for whole-life measures as for those in any specific age range. Pterygium odds ratios increased with exposure level; the odds ratio was 4.0 (95% confidence interval, 1.6 to 10.9) for the highest quarter of the daily sun exposure. The strongest associations were seen for the estimated daily ocular solar radiation dose, with an odds ratio of 6.8 (95% confidence interval, 2.6 to 19.7) for the highest quarter of exposure. CONCLUSIONS: Pterygium is strongly related to ocular sun exposure, with little evidence that exposure during any particular period of life is more important than in other periods; the implication for prevention of pterygium is that ocular protection is beneficial at all ages.

Adult↗
PubMed1999

The quantification of mortality resulting from the regular use of illicit opiates.

UNLABELLED: AIMS/DESIGN: Estimates of mortality associated with illicit opiate use provide useful information to those directing and monitoring local, national and international policies and programmes. Most studies investigating the association have, however, been small with imprecise estimates of increased mortality. The current study combines data from a number of international studies in a meta-analysis to estimate more precisely mortality associated with illicit opiate use. Because HIV infection among injecting drug users differs dramatically between countries and localities, we excluded studies where AIDS was a major contributor to mortality. Studies were included only where AIDS-specific mortality accounted for less than 2% of total mortality. FINDINGS: Our results show a mortality rate for people regularly using illicit opiates, which is more than 13 times greater than that observed for the general community. It is estimated that 9.4% of total mortality in Australians aged 15-39 years of age can be attributed to regular use of illicit opiates. Application of this aetiological fraction to Australian mortality data for 1992 indicate that approximately 401 male and 161 female deaths occurred as a result of opiate use. This represents some 15,429 and 6261 person-years of life lost (to age 70) for males and females, respectively. CONCLUSIONS: The mortality rate for illicit opiate users is approximately 13 times greater than for the general population. The large number of years of life lost is reflective of the relatively young population (15-39 years of age) in which opiate-related mortality occurs. Relative risk estimates can also be applied to data on the prevalence of illicit opiate use in other countries to produce locally based aetiological fractions and estimates of person-years of life lost.

Adolescent↗
PubMed1999

The use of observational methods for monitoring sun-protection activities in schools.

Evaluation of health promotion interventions aimed at behavioural or environmental change involves assessing change that occurs as a result of the program. Direct observational methods can be used for this purpose and this paper describes three such methods that we pilot tested for use in a 5-year intervention study aimed at reducing sun exposure in primary school children. (1) Monitoring 'No hat, no play' policies. This method involved video taping children in selected school play areas during lunch time and analysing the content of the videos to assess the proportion of children wearing various types of hats. (2) Assessing shade provision in the playground. This method involved taking aerial photographs of each school and using them to estimate the proportion of shade in play areas available to children at lunchtime. (3) Shade use. This involved children wearing polysulphone film badges to measure the amount of UV-B exposure they received during one lunch period, relative to the total possible dose registered on index badges. Each method was implemented successfully, and we demonstrated that the video and aerial photography methods produced highly reproducible results and that all three methods were feasible. These three methods will be used in our intervention study to assess longitudinal change in schools' sun-protection policy and practice.

Child↗