Search PubMed⌕ Search

Biomedical subjects

T Dwyer

Publications and source records attributed to T Dwyer.

At least 91 records · Page 5Linked to original sources
PubMed1995

The Tasmanian SIDS Case-Control Study: univariable and multivariable risk factor analysis.

A population-based retrospective case-control study has been conducted in Tasmania since October 1988. Study measurements pertained to the scene of death of last sleep, as well as a verbal questionnaire on relevant exposures. From 1 October 1988 to 1 October 1991, 62 cases of sudden infant death syndrome (SIDS) occurred. Case response rate for retrospective interviews was 94% (58/62). The initial control response rate was 84% (101/121). After stratification for maternal age and birthweight, there was no increase in risk associated with the usual side position (odds ratio [OR] 1.05 [0.27, 5.02]), compared with the supine position (OR 1.00, reference). The prone position was associated with increased risk [OR 5.70 (1.67, 25.58)], relative to the supine position. In the final multivariable model, predictors of SIDS in this study were usual prone position (P < 0.001), maternal smoking (P = 0.008), a family history of asthma (P = 0.045) and bedroom heating during last sleep (P = 0.039). Protective factors were maternal age over 25 years (P = 0.013) and more than one child health clinic attendance (P = 0.003). The results provide further support for current health education activities which aim to inform parents of modifiable risk factors for SIDS, including the prone sleeping position, thermal stress and infant exposure to tobacco smoke.

Breast Feeding↗
PubMed1995

Correlates of prone infant sleeping position by period of birth.

Intervention to avoid the prone sleeping position during infancy has occurred in various countries after evidence that it increases the risk of sudden infant death syndrome (SIDS). This study examined cohort data to determine if correlates of the prone position differed by period of birth, before intervention (1 May 1988 to 30 April 1991) compared with after intervention (1 May 1991 to 30 April 1992). The usual prone sleeping position was more closely associated with the following factors after intervention: teenage motherhood, low maternal education, paternal unemployment, unmarried motherhood, non-specialist antenatal care, not reading books to prepare for a baby, poor smoking hygiene, and bottle feeding. For example, the association of usual prone position with being unmarried shown by the odds ratio (95% confidence interval) was 0.54 (0.47 to 0.63) in the period before intervention and 1.92 (1.18 to 3.15) in the period after intervention. The alteration in correlates of the prone position reported here provide an example to support the theoretical concept that well known 'modifiable' risk factors for disease tend to be associated with each other in both populations and individuals. This phenomenon was not evident in the population before intervention, that is, before the prone sleeping position became a well known SIDS risk factor.

Adult↗
PubMed1995

Sunburn associated with increased number of nevi in darker as well as lighter skinned adolescents of northern European descent.

The associations of sun exposure, sunburn, skin color, and other constitutional characteristics with the density of nevi (2 mm or more in diameter) were assessed in a study of 410 secondary school children ages 14-15 years in Tasmania, Australia. Skin color was estimated by using a chromameter that measures across the visible light spectrum (400-700 nm). Skin color and lifetime history of sunburn were significant predictors of nevus density on the arms and legs of girls and boys and on the shoulders and backs of boys. The nevus density ratios between the highest and lowest exposure groups were 2.85 for the arms and legs of boys (P < 0.01), 2.19 for the arms and legs of girls (P < 0.01), and 1.72 (P = 0.03) for the shoulders and backs of boys. The increase in nevus density appeared to occur at lower levels of lifetime sunburn in children with light or medium skin than it did in children with darker skin. Darker-skinned children with a history of many sunburns ( > or = 11 lifetime sunburns) had a similar number of nevi compared with their lighter-skinned peers.

Adolescent↗
PubMed1994

Brain cancer incidence, mortality and case survival: observations from two Australian cancer registries.

Data from 2 Australian cancer registries covering a population of 1.7 million people were combined for the purposes of analysing brain cancer incidence, mortality and survival patterns for the time period 1978 through 1992. A total of 1,752 cases of primary brain cancer were registered, representing age-standardised incidence rates of 6.7 per 100,000 in men and 4.6 in women. Histological confirmation was available for 94% of cases. The incidence rate among persons aged 75 or over was higher during 1986-1992 than during 1978-1985, the rate for men increasing from 16.3 to 26.2 and that for women increasing from 9.7 to 18.0. The largest increases in this age group occurred for cases of glioblastoma multiforme. During the study period, 1,411 brain cancer deaths were notified to the 2 registries at age-standardised rates of 5.3 in men and 3.4 in women. Mortality rates among persons aged 75 years or older were higher during 1986-1992 than 1978-1985, increasing from 15.7 to 28.4 in men and from 10.1 to 15.3 in women. Only among men aged 15-49 years was a decline in mortality rates observed, from 3.3 to 2.4. Survival analyses indicated that age and histological type were the most powerful prognostic indicators. There was no improvement in 5-year survival for any of the age groups or histological types. An improvement in 36-month survival was noted for the 15-49 year age group diagnosed with gliomas other than glioblastoma multiforme.

Adolescent↗
PubMed1994

An assessment of the impact of public health activities to reduce the prevalence of the prone sleeping position during infancy: the Tasmanian Cohort Study.

BACKGROUND: An intervention to reduce the prevalence of the prone sleeping position during infancy was implemented in Tasmania particularly from 1991 onward. The purpose of this report is to assess the impact of public health activities in promoting avoidance of the prone infant sleeping position among cohort study participants. METHODS: The prospective cohort study involved the one-fifth of Tasmanian live births who are assessed perinatally as being at higher risk for Sudden Infant Death Syndrome (SIDS). From 1 January 1988 until 30 April 1992, 5,403 infants participated in the hospital (4 days postnatal age) and home interviews (5 weeks postnatal age) (88% of eligible infants). After the finding that cohort infants who usually slept prone were at significantly greater risk for SIDS, additional questions on awareness and choice of infant sleep position were asked. RESULTS: The proportion of infants usually sleeping prone declined from 29.9% in the cohort prior to publication of the cohort findings (1 May 1988-30 April 1991) to 5.4% in the post publication cohort (1 May 1991-30 April 1992), RR = 0.18 (0.15, 0.22). Teenage motherhood was associated with non-awareness (RR = 2.39 (1.41, 3.24)) of an association between prone position and SIDS. After adjusting for maternal age, nonawareness remained positively associated with maternal smoking, maternal education (< Year 12), and paternal unemployment, while mothers who read books to prepare for the baby and who were married were more likely to be aware. In the period after the cohort study publication, the most common reasons given for the usual prone position were that the baby preferred that position and slept better. CONCLUSION: Public health activities to reduce the prevalence of the prone sleeping position have had a significant impact, with a dramatic reduction in the proportion of cohort infants usually sleeping prone. The identification of characteristics of nonaware mothers and the reasons for choosing a particular sleeping position will be used to maintain and improve health education in this area.

Child, Preschool↗
PubMed1994

Higher lung cancer rates in young women than young men: Tasmania, 1983 to 1992.

In a background of changing lung cancer rates in the past decade, mean incidence and mortality rates for persons aged 25-44 in Tasmania for the decade 1983 through 1992 were examined using Tasmanian Cancer Registry data. The smoking behavior of Tasmanian adults and schoolchildren was also investigated, using data from a social survey conducted by the Australian Bureau of Statistics and from five secondary school smoking surveys. The Tasmanian age-standardized lung cancer incidence rates in 25-44 year olds for the 10-year period were 6.2 per 100,000 females and 3.3 per 100,000 males. Mean rates of incidence were higher for females than for males (P = 0.02). The corresponding mortality rates were 4.2 in females and 2.4 in males (P = 0.08). The prevalence of smoking by adult Tasmanian women is higher than that for other Australian women (P < 0.05), and their duration of smoking is longer (P < 0.01). Tasmanian schoolgirls have a higher smoking prevalence than Australian mainland schoolgirls (P = 0.01) and higher prevalence than Tasmanian schoolboys (P = 0.01). The data suggest that smoking prevalence among teenagers passed that for males only a decade before the observed excess of female incident cases among 25-44 year olds in Tasmania.

Adenocarcinoma↗
PubMed1994

Case report: cholangiocarcinoma and hypercalcemia.

Hypercalcemia is a relatively common problem seen in the presence of malignancy, and is the most common life-threatening metabolic disorder in patients with cancer. In the hospitalized patient, malignancy is the most common cause of hypercalcemia. It is estimated that hypercalcemia occurs in 10% to 20% of patients with cancer. Usually, it is a sign of advanced disease. Approximately 85% of patients with cancer and hypercalcemia will have disease metastatic to bone. The remaining 15%, however, will have some other etiology for their hypercalcemia, typically squamous carcinomas of the head and neck, esophagus, and lung. This type of hypercalcemia has been termed humoral hypercalcemia of malignancy and has been associated with the secretion of various cytokines, including parathyroid hormone-related protein. In this case report, the authors document the production of parathyroid hormone-related protein by an adenocarcinoma-cholangiocarcinoma. This is documented both by measurement of the protein in the patient's serum and staining of the protein within the tumor by a monoclonal antibody. A general discussion of hypercalcemia and malignancy also is provided.

Bile Duct Neoplasms↗
PubMed1994

The relation between climatic temperature and sudden infant death syndrome differs among communities: results from an ecologic analysis.

We examined the negative relation between temperature and the sudden infant death syndrome (SIDS) in 22 communities in seven countries. We estimated the percentage increase in SIDS rate for a 1 degree C drop in climatic temperature. The relation differed substantially among communities. In New Zealand and Australia (10 communities), the association was consistently strong; in Europe (seven communities), it varied from strong to weak; and in the USA (five communities), it was moderate or weak. We postulate that low climatic temperature indirectly increases the incidence of SIDS, particularly in countries where outdoor climatic temperature modifies the indoor temperature and clothing habits.

Australia↗
PubMed1994

The Australian Schools Health and Fitness Survey. Physical fitness related to blood pressure but not lipoproteins.

BACKGROUND: Recent research indicates that levels of conventional coronary heart disease risk factors in children are related to the premature development of atheroma. It is therefore important to determine how risk factors might be modified on a population scale in children. METHODS AND RESULTS: In 1985, the Australian Schools Health and Fitness Survey was conducted on a representative sample of Australian schoolchildren aged 7 to 15 years. In children aged 9, 12, and 15, data on plasma cholesterol, triglycerides, and high-density lipoprotein cholesterol were obtained along with measurements of blood pressure, fitness, and body fatness. From an original sample of 2400 in these three age categories 1919 underwent the full set of measurements. Univariate analysis of these data revealed a strong association between body fatness and plasma lipids. There was no significant association between fitness (measured as physical work capacity at a heart rate of 170 beats per minute per kilogram of lean body mass) and plasma lipids, but a significant negative association was found for fitness and systolic blood pressure (r = -.12, P < .001). Multiple regression analysis revealed that the association of fitness with systolic blood pressure was only partly accounted for by the confounding effect of lower body fatness in fitter children. CONCLUSIONS: These data collected on a representative sample of children under standardized conditions confirm a previous finding of a link between fitness and blood pressure in schoolchildren and also support a growing consensus that fitness is only weakly linked to plasma lipids and lipoproteins in children and adolescents.

Adolescent↗
PubMed1993

Factors potentiating the risk of sudden infant death syndrome associated with the prone position.

BACKGROUND: In several studies the sudden infant death syndrome (SIDS) has been significantly associated with sleeping in the prone position. It is not known how the prone position increases the risk of SIDS. METHODS: We analyzed data from a case-control study (58 infants with SIDS and 120 control infants) and a prospective cohort study (22 infants with SIDS and 213 control infants) in Tasmania. Interactions were examined in matched analyses with a multiplicative model of interaction. RESULTS: In the case-control study, SIDS was significantly associated with sleeping in the prone position, as compared with other positions (unadjusted odds ratio, 4.5; 95 percent confidence interval, 2.1 to 9.6). The strength of this association was increased among infants who slept on natural-fiber mattresses (P = 0.05), infants who were swaddled (P = 0.09), infants who slept in heated rooms (P = 0.006), and infants who had had a recent illness (P = 0.02). These variables had no significant effect on infants who did not sleep in the prone position. A history of recent illness was significantly associated with SIDS among infants who slept prone (odds ratio, 5.7; 95 percent confidence interval, 1.8 to 19) but not among infants who slept in other positions (odds ratio, 0.83). In the cohort study, the risk of SIDS was greater among infants who slept prone on natural-fiber mattresses (odds ratio, 6.6; 95 percent confidence interval, 1.3 to 33) than among infants who slept prone on other types of mattresses (odds ratio, 1.8). CONCLUSIONS: When infants sleep prone, the elevated risk of SIDS is increased by each of four factors: the use of natural-fiber mattresses, swaddling, recent illness, and the use of heating in bedrooms.

Bedding and Linens↗
PubMed1993

Non-melanoma skin cancer: ten years of cancer-registry-based surveillance.

The Tasmanian Cancer Registry carried out population-based surveillance of non-melanoma skin cancer (NMSC) from 1978 to 1987. A total of 8,651 NMSC were recorded in 7,160 individuals, representing an age-standardized rate of 161/100,000 per year. Ninety-four percent of cases were based on histological diagnosis. Incidence of basal-cell carcinoma (BCC) was higher than the incidence of squamous-cell carcinoma (SCC). The incidence of NMSC was twice as high in men as in women. Incidence increased substantially with age, more markedly for SCC than BCC. For most body sites, BCC was more frequent, but on highly exposed sites such as the backs of hands, lower limbs in women and ears in men, the incidence of SCC was higher. There was an overall increase of 7% per year in the age-standardized incidence rate of NMSC. The increase was more marked for BCC than for SCC, and was consistent across age groups and both sexes. A first NMSC during the study period was associated with a 12-fold increase among men and a 15-fold increase among women in the risk of development of a new NMSC within 5 years, when compared with the NMSC incidence recorded for the population as a whole.

Adult↗
PubMed1993

A comparison of prospective and retrospective responses on sudden infant death syndrome by case and control mothers.

Based on information from two studies of sudden infant death syndrome (SIDS) from 1988-1991 in Tasmania, Australia, prospective and retrospective maternal responses to an identical set of questions were compared for 27 cases and 25 controls. There was good agreement on demographic factors, maternal obstetric history, parental smoking, and infant feeding practices. Reported changes in sleep habits were slightly greater for cases, and further work is needed to determine if this reflects recall bias or real changes during early infant life. Case mother reports regarding family history of disease and infant bedding were more discrepant, suggesting recall bias and supporting prospective collection of this information.

Bias↗
PubMed1993

p53 expression in incidental prostatic cancer.

Incidental prostate cancer is an indolent disease typically characterized by a benign clinical course. This is not clearly established, however, as recent reports suggest that up to 27% of cases progress with long-term follow-up. The indolent history of this disease led initially to the hypothesis that mutations of the p53 gene would be an infrequent event in this patient population. Archival specimens from 24 patients with Stage A1 carcinomas were evaluated for abnormal p53 expression. In 23 patients the disease was diagnosed after transurethral resection for bladder outlet obstructive symptoms, and in one patient after a radical prostatectomy. Using a monoclonal antibody (PAb 240) and an immunohistochemical technique, a total of 36 microfoci of tumor were evaluated. Thirteen (36%) microfoci were positive with an intense nuclear staining pattern (2+), and eight (22%) microfoci had an intermediate staining pattern. Four areas of prostatic intraepithelial neoplasia also stained positively with a 2+ staining pattern. These results suggest that abnormal p53 expression is a feature of a significant number of incidental prostatic carcinomas and that this occurrence is an early event in the development of the malignant phenotype.

Aged↗
PubMed1992

Interstate differences in incidence and mortality from melanoma. A re-examination of the latitudinal gradient.

OBJECTIVE: To investigate the patterns of cutaneous malignant melanoma (CMM) mortality in Australia. DESIGN: A descriptive analysis of melanoma incidence and mortality in Australia supplemented by a case series analysis of melanoma survival. Melanoma mortality rates were based on tabulations supplied by the Australian Bureau of Statistics for the years 1969-1989. Melanoma incidence rates were based on State cancer registry records for the years 1977-1990. The case series survival analysis was based on detailed individual records from the population-based cancer registries in Tasmania and South Australia. MAIN OUTCOME MEASURES: The level of and rise in melanoma mortality rates during 1969-1989 in Australia; the five-year survival rates for Tasmanian and South Australian cases; and male:female incidence ratios related to latitude. RESULTS: We found annual increases in melanoma mortality rates of 2.5% in men (P < 0.0001) and 1.1% in women (P < 0.0001) for all Australia. The five-year survival rates (with 95% confidence intervals [CI]) were: 67% (59%-75%) for Tasmanian men; 79% (76%-83%) for South Australian men; 80% (74%-86%) for Tasmanian women and 88% (86%-91%) for South Australian women. A change in the male:female incidence ratio with latitude was also found--women have significantly higher incidence rates at higher latitudes, but similar rates to men at lower latitudes. CONCLUSIONS: The age standardised mortality from CMM for the period 1969 to 1989 shows little variation by State for women, despite a considerable range in latitude. CMM mortality in men is increasing at a faster rate than that in women. Between 1982 and 1987 the male:female incidence ratio in high latitudes in the Southern Hemisphere showed an excess of cases in women, a finding which we believe has not been reported before.

Aged↗
PubMed1992

Climatic temperature and variation in the incidence of sudden infant death syndrome between the Australian states.

OBJECTIVE: To describe the relationship between climatic temperature and the incidence of sudden infant death syndrome (SIDS) for the Australian States and examine the extent to which differences in climatic temperature might explain the regional variation of SIDS in Australia. DESIGN: Case series study. A generalised linear model was used to model the association between monthly average temperature and the incidence of SIDS. SETTING: The report is population based. Data are available from all Australian States. SUBJECTS: Cases of SIDS from birth to less than 12 months of age occurring in Queensland (1981-1987), New South Wales (1981-1987), Victoria (1984-1987), Tasmania (1975-1989), South Australia (1980-1989), and Western Australia (1980-1988). RESULTS: Every one degree Celsius decrease in average monthly temperature within the range 9 degrees C to 25 degrees C is associated with a 10.6% (95% confidence interval, 9.6%-11.7%) increase in the incidence of SIDS. Climatic temperature accounts for 84% of the interstate variation in the rate of SIDS. After controlling for the effect of temperature, a significant overall difference in SIDS incidence remains (P less than 0.0001) for the Australian States. CONCLUSION: Climatic temperature accounts for most but not all of the regional variation of SIDS incidence in the Australian States. The remaining variation may reflect differences in the maternal and infant characteristics of the State populations.

Australia↗
PubMed1992

Sudden infant death syndrome: factors contributing to the difference in incidence between Victoria and Tasmania.

OBJECTIVE: To examine how much of the difference in incidence of sudden infant death syndrome (SIDS) between Tasmania and Victoria could be accounted for by the effect of differing climatic temperature and the effect of the differing prevalence of maternal and infant characteristics in the two State populations. DESIGN: A two population ecological comparison. Two previously published predictive models were applied to quantify the contribution of several factors to the higher incidence of SIDS in Tasmania compared with Victoria. SETTING: A population based study involving the two Australian States of Tasmania and Victoria. PATIENTS: The characteristics of the 1985 to 1987 live birth cohorts of Tasmania and Victoria were examined. Cases were defined as all infants dying in 1985 to 1987 whose cause of death was stated as SIDS. RESULTS: The rate of SIDS for Tasmania and Victoria 1985 to 1987 was 3.76 per 1000 live births and 2.18 per 1000 live births respectively. Adjustment of the Tasmanian rate for the effect of the interstate difference in climatic temperature resulted in a lower Tasmanian rate of 2.92 per 1000 live births. Adjustment for the effect of interstate differences in maternal age, birthweight, infant sex, month of birth and intention to breast-feed at hospital discharge decreased the Tasmanian rate to 2.47 per 1000 live births. CONCLUSION: Approximately 82% of the interstate difference in SIDS incidence between Tasmania and Victoria from 1985 to 1987 can be accounted for by differences in climatic temperature, maternal age, birth-weight, infant sex, month of birth and feeding intention at hospital discharge.

Adult↗