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R Attewell

Publications and source records attributed to R Attewell.

At least 19 recordsLinked to original sources
PubMed2005

Improving response rates to primary and supplementary questionnaires by changing response and instruction burden: cluster randomised trial.

OBJECTIVE: Supplementary questionnaires provide additional information from subgroups, but may have an attritional effect on response rates. We examined the effects of different instruction methods on response rates to a two-part questionnaire. METHODS: The ACT Kindergarten Health Survey comprises a health questionnaire for all school-entry children. A supplementary questionnaire targets children with respiratory symptoms. We cluster-randomised 109 schools in the ACT (4,494 children) to two instruction groups. Group 1 (instruction burden) had instructions to complete the supplementary questionnaire if certain questions in the primary questionnaire were answered. Group 2 (response burden) had instructions to complete both questionnaires irrespective of answers to the primary questionnaire. RESULTS: Instructing all respondents to complete both questionnaires regardless of eligibility resulted in a statistically significantly lower primary questionnaire response rate (82% vs. 87%), but a statistically significantly higher response rate to the supplementary questionnaire (99% vs. 91%). The net effect was a small overall gain (82% vs. 79%) for the response burden group. CONCLUSION: Increasing the response burden had a minor impact on response rate to the primary questionnaire, but increased the response rate for most items to the supplementary questionnaire. IMPLICATIONS: Large surveys may be broken into primary and supplementary questionnaires, if strategies to maximise response rates are used. Questionnaires may need to be modified to take into account the likely attrition on response to either questionnaire resulting from instruction and response burdens.

Child↗
PubMed2001

Asthma screening as part of a routine school health assessment in the Australian Capital Territory.

OBJECTIVE: To determine the feasibility and performance of a routine screen for childhood asthma in new entrants to primary school relative to diagnosis by a paediatrician. DESIGN: Cross-sectional study with a validation substudy. PARTICIPANTS AND SETTING: All 4539 new primary school entrants (mean age, 5.72 years; 95% CI, 5.71-5.74) in the Australian Capital Territory (ACT) in 1999; 180 of these children (73% of the 248 contacted) participated in the validation substudy. MAIN OUTCOME MEASURE: Performance of the screening test relative to a paediatrician's diagnosis of current asthma (defined as a history of wheeze suggestive of a clinical diagnosis of asthma within the past 12 months) based on history and examination. RESULTS: 3748 of the 4539 new primary school entrants (83%) returned completed asthma and respiratory questions. The screening test was positive in 38% of children. Estimated sensitivity was 92% (95% CI, 75%-99%); specificity, 76% (95% CI, 72%-80%); positive predictive value, 51% (95% CI, 41%-63%); negative predictive value, 98% (95% CI, 90%-100%); positive likelihood ratio, 3.8 (95% CI, 2.8-4.8); and negative likelihood ratio, 0.14 (95% CI, 0.02-0.33). CONCLUSIONS: It is feasible to conduct population screens for asthma that have good diagnostic test performance against a specialist paediatrician's diagnosis through school health programs. This approach could facilitate monitoring changes in asthma prevalence over time.

Asthma↗
PubMed2001

The relationship between low level nitrogen dioxide exposure and child lung function after cold air challenge.

BACKGROUND: Nitrogen dioxide (NO(2)) or home gas appliance use has been inconsistently associated with adverse respiratory outcomes in childhood. OBJECTIVES: (i) To examine the contribution of home gas appliance type and personal NO(2) exposure. (ii) To examine the relationship between NO(2) exposure and child lung function and respiratory history. (iii) To assess whether these relationships vary by house dust mite sensitization status. METHODS: A cross-sectional survey of 344 children (71% of the eligible group) with a mean age of 9.1 years from four randomly selected schools in the Australian Capital Territory from July to September 1999. Study measurements included a parental questionnaire, NO(2) exposure by passive gas samplers, skin prick testing for 10 aeroallergens and lung function at rest and after cold air challenge. RESULTS: Total NO(2) exposure was low with a mean concentration of 10.1 ppb. No associations were found between NO(2) exposure or gas appliance use and asthma, wheeze or baseline lung function. Personal NO(2) exposure was associated with a reduction in forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) after cold air challenge (adjusted difference - 0.12% (- 0.23% to - 0.01%) per 1 ppb increase). After exclusion of children who had home heating changed because of asthma, gas heater use was also significantly associated with a reduction in this measure (adjusted difference - 2.0% (- 3.7% to - 0.2%)). There was some evidence that these reductions were greater among the non-mite-sensitized children. CONCLUSIONS: The effect of low-level NO(2) exposure on these respiratory outcomes was not marked. The possible effect of low-level NO(2) exposure on non-specific bronchial reactivity requires confirmation. Future studies on NO(2) and respiratory health should include measures of house dust mite sensitization and bronchial hyper-responsiveness.

Air↗
PubMed1998

The relationship between childhood sexual abuse and alcohol abuse in women--a case-control study.

AIMS: The aim of this paper was to examine the association between reporting childhood sexual abuse (CSA) and alcohol abuse in a community sample of women using multivariate analysis which took into account a range of potential confounding variables (such as a family history of alcoholism) and effect modifiers (such as having an alcoholic partner). DESIGN: A two-stage retrospective case-control study was used to investigate the relationship between reporting CSA and alcohol abuse in women. PARTICIPANTS: Seven hundred and ten women randomly selected from the Australian federal electoral rolls. MEASUREMENTS: The Alcohol Use Disorders Identification Test (AUDIT) was used to measure alcohol abuse. A series of questions based on those developed by Wyatt (1985) were used to ascertain the prevalence of CSA. FINDINGS: The final model showed that the relationship between a history of CSA and alcohol abuse reflected a complex interaction between CSA and a range of other factors in a woman's background. CSA was not by itself a significant predictor of alcohol abuse (OR = 0.61; 95% CI = 0.31-1.20). However, a history of CSA became significant in combination with co-factors which included: having a mother who was perceived as cold and uncaring; having an alcoholic partner; and believing that alcohol is a sexual disinhibitor. CONCLUSION: This study indicates that CSA alone is not a causative factor in the development of alcohol abuse among women and highlights the importance of examining the family background of women with alcohol problems.

Adolescent↗
PubMed1998

Mixed feelings: satisfaction and disillusionment among Australian GPs.

BACKGROUND AND AIMS: Medical practitioners' satisfaction with their work impacts on quality of care for their patients and on their own sense of fulfillment. Reforms introduced in the early 1990s into Australian general practice have led to concerns over the morale of GPs. This study examines satisfaction and dissatisfaction of GPs with regard to the reform strategy. METHOD: GPs throughout Australia were approached via a popular GP magazine to express their views in a questionnaire comprising closed-end and open-ended questions enquiring about satisfaction with their current role and sources of satisfaction (and dissatisfaction) of working in general practice. Factor analysis was used to identify different sources of satisfaction (and dissatisfaction), which were intercorrelated and which together represented underlying factors. Logistic regression modelling was used to determine which sources were most strongly associated with being satisfied (or not satisfied), and to explore GP characteristics associated with satisfaction. RESULTS: A total of 2186 questionnaires were returned, representing the opinions of 14-18% of Australian GPs. Two-thirds (68%) of respondents reported being satisfied, most frequently with the variety of work and establishing relationships with patients and their families. Six satisfaction factors were identified on factor analysis, the most important characterizing social and interpersonal roles. Leading sources of dissatisfaction related to perceived interference by the government. Six dissatisfaction factors were identified on factor analysis, the most important characterizing governmental issues. However, on logistic regression other sources of dissatisfaction (reflecting disillusionment) were most strongly associated with not being satisfied. CONCLUSIONS: The main sources of satisfaction are those which typify the long-term caring role of the community GP. While the reform strategy aimed to address problems with the organization and financing of general practice, the resulting intervention is the focus of dissatisfaction. Among dissatisfied GPs these attitudes may arise primarily from a sense of disillusionment.

Adult↗
PubMed1998

Postoperative prognosis in craniopharyngioma with respect to cardiovascular mortality, survival, and tumor recurrence.

Specific causes of death, survival, and recurrence rates were assessed in a cohort of 60 patients who had undergone surgery for craniopharyngioma between 1951 and 1988. Compared to the general population, the standardized mortality ratio (SMR) was increased [5.55; 95% confidence interval (CI), 3.68-8.22], and it was higher among females (SMR, 11.4) than males (SMR, 4.79). The risk of cardio- and cerebrovascular mortality (SMR, 3.21; 95% CI, 1.29-6.61) was also enhanced. The cumulative survival rates 10 and 15 yr after the initial operation were 68% (95% CI 54-78) and 59% (95% CI 30-63), respectively. A multivariate survival analysis adjusting for age showed a protective effect of radiotherapy (hazard ratio, 0.3; 95% CI, 0.1-0.8) and an increased risk of death after recurrence (hazard ratio, 4.4; 95% CI, 1.4-14), but no obvious effect of radicality at surgery. However, when patients who had died within 6 months after surgery were excluded, no significant protective effect of radiotherapy remained. The cumulative frequency of recurrence after 10 yr was 33% (95% CI, 22-48%), and that after 15 yr was 40% (95% CI, 28-56%). The incidence of recurrence did not differ significantly with respect to age, radicality at surgery, or postoperative radiotherapy. The determinants for long term outcome in patients with craniopharyngioma are interrelated in a complex way, which calls for strict selection criteria in follow-up studies and the use of multivariate statistical models.

Cardiovascular Diseases↗
PubMed1994

Retention patterns of asbestos fibres in lung tissue among asbestos cement workers.

Retention patterns in lung tissue (determined by transmission electron microscopy and energy dispersive spectrometry) of chrysotile, tremolite, and crocidolite fibres were analysed in 69 dead asbestos cement workers and 96 referents. There was an accumulation of tremolite with time of employment. Among workers who died within three years of the end of exposure, the 13 with high tremolite concentrations had a significantly longer duration of exposure than seven in a low to intermediate category (medians 32 v 20 years; p = 0.018, one sided). Crocidolite showed similar patterns of accumulation. In workers who died more than three years after the end of exposure, there were no correlations between concentrations of amphibole fibres and time between the end of exposure and death. Chrysotile concentrations among workers who died shortly after the end of exposure were higher than among the referents (median difference in concentrations 13 million fibres (f)/g dry weight; p = 0.033, one sided). No quantitative differences in exposure (duration or intensity) could be shown between workers with high and low to intermediate concentrations. Interestingly, all seven workers who had had a high intensity at the end of exposure (> 2.5 f/ml), had low to intermediate chrysotile concentrations at death, whereas those with low exposure were evenly distributed (31 subjects in both concentration categories); hence, there was a dependence between last intensity of exposure and chrysotile concentration (p = 0.014). Among 14 workers with a high average intensity of exposure, both those (n = 5) with high tissue concentrations of chrysotile and those (n = 10) with high tissue concentrations of tremolite fibres had more pronounced fibrosis than those with low to intermediate concentrations (median fibrosis grades for chrysotile: 2 v 1, p = 0.021; for tremolite: 2 v 0.5, p = 0.012). Additionally, workers who died shortly after the end of exposure with high concentrations of chrysotile and crocidolite had smoked more than those with low intermediate concentrations (medians for chrysotile 35 v 15 pack-years, p = 0.030; for crocidolite 37 v 15 pack-years, p = 0.012). The present data indicate that chrysotile has a relatively rapid turnover in human lungs, whereas the amphiboles, tremolite and crocidolite, have a slower turnover. Further, chrysotile retention may be dependent on dose rate. Chrysotile and crocidolite deposition and retention may be increased by tobacco smoking; chrysotile and tremolite by fibrosis.

Aged↗
PubMed1993

Indoor radon-daughter concentration and gamma radiation in urban and rural homes on geologically varying ground.

The radon (Rn)-daughter level (track film, 3 months) was lower in 129 urban than in 197 rural houses (geometric means, (GM) 18 versus 40 Bq/m3; P < 0.001; range 3-416). In rural dwellings higher levels were found in those built over deposits of alum shale occurrences (P = 0.04; 12 on porous glaciofluvial cover 94 Bq/m3; 127 others 43 Bq/m3; significant interaction, P = 0.01), than in 158 others (37 Bq/m3). There was no systematic effect of the type of water supply, neither of indoor smoking. One hundred twenty three homes with a complete cellar were lower than 200 with no or part cellar (18 versus 40 Bq/m3; P < 0.001). There was only a weak association between log-transformed gamma radiation (GM 10, range 33-50 microR/h) and Rn-daughter levels (r = 0.18; 95% confidence interval 0.07-0.28). Our results show the importance for indoor Rn-daughter levels of the bedrock and cover beneath the house, and the need for Rn-daughter measurements in epidemiological studies.

Air Pollution, Indoor↗
PubMed1993

Mortality and tumour morbidity among Swedish market gardeners and orchardists.

In order to investigate possible effects of exposure to pesticides, mainly fungicides and insecticides, we studied a cohort of 2370 subjects, who, during the period 1965-1982, had been members of a horticulturists' trade association (market gardeners and orchardists). Compared to a regional reference population, total mortality (542 deaths; standardized mortality morbidity ratio, SMR = 0.8; 95% confidence limits, CLs = 0.7, 0.9) and mortality due to malignant tumours (133 deaths, SMR = 0.9; CLs = 0.7, 1.0), and cardiovascular and respiratory deaths were somewhat decreased. Suggestive excesses in mortality were seen for mental disorders and tumours of the stomach, skin and nervous system. The tumours of the nervous system were in particular excess in the young and middle-aged horticulturists (below age 60; six cases, SMR = 2.9; CLs = 1.1, 6.2). During the period 1965-1986, the total tumour morbidity was slightly decreased (255 cases; SMR = 0.9; CLs = 0.8, 1.0), as were gastrointestinal and respiratory tract tumours. The incidence of melanomas was increased (15 cases, SMR = 2.1; CLs = 1.2, 3.5), and tumours of the female genital organs, myelomas, and brain tumours (12 cases, SMR = 1.5; CLs = 0.8, 2.7) were slightly numerically elevated. Brain tumours in the young and middle-aged horticulturists (11 cases, SMR = 3.2; CLs = 1.6, 5.7), including meningiomas (four observed, SMR = 6.8; CLs = 1.9, 17.4), were increased, especially in the period 1975-1979. The mortality and tumour morbidity patterns in gardeners and orchardists, analysed separately, were similar to the patterns in all the horticulturists.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Prognostic potential of flow cytometric S-phase and ploidy prospectively determined in primary breast carcinomas.

In a prospective study of a consecutive breast cancer series accumulated in the period 1978-82, the S-phase fraction (SPF) and ploidy status were determined by flow cytometry performed on cell nuclei derived from samples of 580 primary tumors. Sixty percent of the tumors were non-diploid. After correction for debris the median SPF values were 7.3% overall, 12% for non-diploid tumors, and 2.9% for diploid tumors (2.6% when nodal subsets N2 and N3 and cases with metastases at presentation were excluded). The SPF values correlated both to tumor size (p = 0.008) and to the number of positive axillary lymph nodes (p = 0.03). At clinical follow-up in 1986, 467 unilateral breast cancer patients who had undergone radical treatment for cure could be evaluated with respect to the prognostic value of both the SPF value and ploidy status. The median duration of follow-up was then 59 months (range 2-90), and the median time-to-recurrence 24 months (range 2-69, n = 137). At follow-up in 1991, 201/467 of the patients had died, the median duration of follow-up being 50 months (range 2-126) for the decreased, and 119 (range 6-148) for the survivors. In multivariate analysis (Cox's proportional hazards models), the strongest independent predictors of distant recurrence-free survival (DRFS) were the number of positive axillary lymph nodes (p less than 0.0001), the debris-corrected SPF value alone (p = 0.003, versus p = 0.05 for uncorrected value), and ploidy status combined with the corrected SPF value (p = 0.0002). When age was taken into account, both the corrected SPF value and the ploidy-SPF combination were predictors of crude survival (p = 0.006 and p = 0.002, respectively). In univariate life-table analysis, the 5-year DRFS rate was 93% in node-negative (N0) cases with an SPF less than 7.3%, as compared to 80% in those with an SPF greater than or equal to 7.3% (p = 0.005). Among node-positive cases, the prognostic value of the SPF was confined to those with 1-3 positive nodes, the 5-year DRFS rate being 68% in cases with an SPF less than 7.3%, as compared to 40% in cases with an SPF greater than or equal to 7.3% (p = 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

Prognostic significance of flow cytometric DNA analysis and estrogen receptor content in breast carcinomas--a 10 year survival study.

The prospective prognostic significance of flow cytometry derived DNA-ploidy status, the level of the S-phase fraction (SPF), estrogen receptor (ER) content, and combinations of these factors, was evaluated with respect to overall survival (OS) in a series of 516 breast cancer patients who were without signs of residual or distant disease after primary completed treatment. The median duration of survival follow-up time was ten years (range, 95-148 months) for surviving patients. Of the single factors, ER was the only significant predictor among node-negative patients; the ten-year OS rate was 71% in cases with ER-rich tumors vs. 62% for ER-poor tumors (p = 0.03). Where tumors were both non-diploid and ER-poor, the ten-year OS rate was 58%, as compared to 75% for the remaining node-negative patients (p = 0.003), who constituted a low-risk group whose survival was comparable with that in the age-matched normal population. Among patients with 1-3 positive nodes, the ten-year OS rate was 65% in patients whose tumors had an SPF < 7.3% vs. 50% if the SPF was > or = 7.3% (p = 0.01), and 58% in cases with ER-rich tumors vs. 45% where the tumors were ER-poor (p = 0.02). In a multivariate analysis, apart from age and menopausal status the combination of ploidy status and ER content was the significant (p = 0.002) predictor of OS in node-negative patients. Thus, combining ploidy and ER status, both of which are variables easily determined, enabled the selection of a subgroup of patients at high risk of relapse and reduced survival whose prognosis should be improved by effective adjuvant systemic treatment, whereas the remaining low risk N0 patients can not be expected to derive any survival benefit from adjuvant therapy since their predicted survival is already on a par with that of the general population.

Adult↗
PubMed1992

Growth of xenografted squamous cell carcinoma of the head and neck--possible correlation with patient survival.

Tumor biopsies from 100 cases of squamous cell carcinoma of the head and neck (HNSCC) were xenografted to athymic nude mice. To ascertain whether xenograft take might be a factor of clinical significance, it was compared with patient survival, the patients being divided into two groups (take and non-take) according to the results of transplantation. The tumor take rate was 29%. Median survival time with respect to cancer death was 18 months in the take group, as compared with over 74 months in the non-take group (p = 0.06). No significant differences were observed between the two groups with respect to age, tumor size, nodal status, clinical stage or histological differentiation. The findings suggest that take of HNSCC xenografts in nude mice may reflect the malignant potential of the original tumor. Moreover, the possibility cannot be excluded of a selection bias favoring the use of such malignant xenografts in therapeutic studies in nude mice.

Animals↗
PubMed1992

Flow cytometry DNA analysis and prediction of loco-regional recurrences after mastectomy in breast cancer.

The study concerns whether DNA flow cytometry and estrogen receptor analysis might help predict which breast cancer patients, particularly node-positive ones, were at the greatest risk of developing loco-regional recurrence (LRR). Such patients would best benefit from postoperative radiotherapy following modified radical mastectomy and axillary lymph node dissection. After this type of surgery, 506 patients were followed up for a median time of nearly 5 years. Among the 235 patients given postoperative radiotherapy, the loco-regional control rate was 100% in N0 cases (n = 93), 94% in cases with 1-3 positive nodes (n = 90), 93% in cases with 4-9 positive nodes (n = 43), and 67% in cases with 10 or more positive nodes (n = 9). Among the 271 non-irradiated patients, the corresponding figures for loco-regional control were 91% in N0 cases (n = 141), 71% in cases with 1-3 positive nodes (n = 84), 65% in cases with 4-9 positive nodes (n = 31), and 67% in cases with 10 or more positive nodes (n = 15). Ploidy status, level of S-phase fraction, estrogen receptor content, and primary tumor size did not, in the present material, yield significant additional information with regard to the risk of LRR in the different nodal subgroups, a finding confirmed in multivariate analysis where the only significant predictor of LRR was the number of positive nodes (p = 0.01). Adjuvant tamoxifen treatment could not replace postoperative radiotherapy for achieving loco-regional tumor control, the overall rate of which was 81% among patients treated with tamoxifen only (n = 117), as compared with 98% among those also treated with radiotherapy (n = 54) (p = 0.003).

Breast Neoplasms↗
PubMed1991

An epidemiological study of cancer risk among workers exposed to ethylene oxide using hemoglobin adducts to validate environmental exposure assessments.

Cancer morbidity was investigated in a cohort of 2,170 ethylene oxide (EO)-exposed workers from 2 plants producing disposable medical equipment. The subjects had been employed for at least 1 year during the periods 1970-1985 and 1964-1985, respectively. The exposure to EO was assessed for each of six job categories in the plants with respect to each calendar year, on which basis values for individual cumulative exposure to EO (ppm-years) were calculated. The levels of hydroxyethyl adducts to N-terminal valine (HOEtVal) in hemoglobin fitted well with the values estimated for airborne exposure to EO. No increased cancer incidence was found [standardized morbidity ratio (SMR), 0.78; 95% CI, 0.49-1.21)]. No leukemia was observed, but one case of non-Hodgkin's lymphoma, one case of myeloma, and one case of polycythemia vera were diagnosed as compared with two expected hematopoietic and lymphatic tumors (SMR, 1.54; 95% CI, 0.32-4.5). No stomach cancer was detected as compared with the 0.5 case expected. There were no significant exposure-response associations between estimates of exposure to EO and cancer morbidity.

Adult↗
PubMed1991

Cancer morbidity in nitrate fertilizer workers.

A cohort of 2,131 male nitrate fertilizer workers was evaluated for cancer morbidity from 1963 to 1986. No significant increase in total cancer, stomach cancer (5 actual vs 6.7 expected cases), or lung cancer (13 vs 13 expected) was found. On the other hand, 26 actual cases of prostate cancer were observed vs 16 expected cases (standardized morbidity ratio, SMR = 161; 95%, confidence interval, CI = 107-239). This risk increase however, was, not enhanced by applying at least a 10-year latency period. In a cohort of 1,148 male fertilizer workers who had never been exposed to nitrate, there was an increased incidence of lung cancer (SMR = 151,95% CI = 103-220) but not of stomach cancer or prostate cancer. There was no association between airborne nitrate exposure dose and total cancer, stomach cancer, lung cancer or prostate cancer, respectively.

Adult↗
PubMed1991

Kinetics of lead in bone and blood after end of occupational exposure.

In 14 retired lead workers, followed for over 18 years after end of exposure, repeated analyses of lead levels in finger bone by an in vivo X-ray fluorescence method revealed a decrease of lead concentration. The data were analysed using an exponential retention model. For the whole group the biological half-time was 16 (asymptotic 95% confidence interval, CI 12,23) years. The median of the estimated bone lead levels at the end of exposure was 85 micrograms.g-1 above the "background" (3 micrograms.g-1). A simultaneous follow-up of blood lead levels displayed a decrease, which could be described by a tri-exponential retention model with group half-times of 34 (CI 29,41) days, 1.2 (CI 0.9,1.8) years, and 13 (CI 10,18) years, respectively. The median of the estimated blood lead levels at the end of exposure for the three components were 0.49, 0.61, and 1.1 mumol.l-1 above the "background" (0.38-0.56 mumol.l-1), respectively. The well-documented decrease of lead exposure in the general population over the years, urged the use of a decreasing "background" of blood lead during the time of the study. The slowest of the three components represented the skeleton (probably mainly cortical bone), as did mainly probably also the intermediate one (trabecular bone). The data show the rather slow turnover of lead in the skeleton, the usefulnes of in vivo skeletal lead measurements as a long-term exposure index, and the importance of bone as a source of "endogenous" lead exposure.

Adult↗
PubMed1990

Squamous cell carcinoma of the head and neck heterotransplanted to nude mice. Take rate in relation to patient survival.

Biopsy specimens from 62 human single primary squamous cell carcinomas (SCC) of the head and neck were xenografted into nude mice. To evaluate the prognostic significance of successful heterotransplantation, the 62 cases were retrospectively examined for survival, adjusting for possible confounders by multivariate analysis. The recorded take rate in the first passage was 24%. Median survival in the take group was 25 months versus 74 months in the nontake group, which is not statistically significant in this material. However, the numerical difference in survival between the take groups is in accordance with the concept that human tumors accepted as xenografts on nude mice may constitute a selected group of malignancies. This has to be considered when using heterotransplanted human tumors for in vivo investigations of SCC of the head and neck.

Aged↗