Geoffrey Berry

Meta-analysis on the association between environmental tobacco smoke (ETS) exposure and the prevalence of lower respiratory tract infection in early childhood.

The aim of this study was to obtain quantitative information from published data on the association between environmental tobacco smoke (ETS) exposure and the prevalence of serious lower respiratory tract infections (LRTI) in infancy and early childhood. We identified 21 relevant publications on the relation between ETS and the prevalence of serious LRTI by reviewing reference lists in relevant reports and by conducting manual and computer searches (Medline database; Dissertation abstracts index of Xerox University Microfilms) of published reports between 1966 and 1995. Thirteen studies were included in a quantitative overview using random effects modeling to derive pooled odds ratios.

Prevalence of asthma in adults in Busselton, Western Australia.

OBJECTIVE--To estimate whether the prevalence of asthma in adults increased over a nine year interval. DESIGN--Serial cross sectional studies of the population with a protocol that included both subjective and objective measurements. SETTING--Busselton, Western Australia. SUBJECTS--A random sample of 553 subjects aged 18-55 years in 1981, and of 1028 subjects aged 18-55 years in 1990. MAIN OUTCOME MEASURES--Respiratory symptoms measured by self administered questionnaire, bronchial responsiveness measured by bronchial challenge with histamine, and allergy measured by skin prick tests. RESULTS--Symptoms with increased prevalence were those with significant association with allergy in this population. Recent wheeze increased from 17.5% to 28.8% (p < 0.001) and diagnosed asthma increased from 9.0% to 16.3% (p < 0.001). The increase was greatest in subjects less than 30 years old. The prevalence of shortness of breath coming on at rest and of hay fever also increased significantly, but the prevalence of shortness of breath on exertion, chronic cough, bronchial hyperresponsiveness, current asthma (defined as recent wheeze plus bronchial hyperresponsiveness), and allergy did not increase. The severity of bronchial responsiveness did not change significantly in any symptom group. CONCLUSIONS--Young adults showed a significant increase in reporting of symptoms related to allergy but not in the prevalence of current asthma. The increase in symptoms may be due to increased awareness of asthma in this community, to changed treatment patterns, or to increased exposures to allergens.

Involving the general public in priority setting: experiences from Australia

The discussion over whether community preferences have a legitimate role to play in priority setting has been highly polarised. Skeptics warn of the risk of establishing a dictatorship of the uninformed, while advocates proclaim the legitimacy of the participatory process. The one group who appears not to be consulted in this debate is the citizens themselves. In this study, a convenience sample of 373 citizens attending two medical clinics in central Sydney were surveyed about whether the general public has a legitimate role to play in informing priority setting in health care. Respondents were presented with three different levels of priority setting: across health care programmes, across medical procedures, and at a global level. To assist respondents in understanding the choices and trade-offs involved, they were given information about current levels of funding and the cost-effectiveness of each alternative. Respondents were asked whether they felt the preferences of the general public should be used to inform priority setting at each level. Of particular interest was the question of whether their willingness to use public preferences depended on the level of priority setting. Respondents were also asked about who elses preferences should be used to inform priority setting at each level. The results suggest that the public overwhelmingly want their preferences to inform priority-setting decisions in health care. This was seen to be particularly important in informing decisions about how to prioritise across broad health care programmes and about the criteria to be used to allocate funds across different population groups. In contrast, the preferences of medical professionals and health service managers were rated most highly in relation to the prioritisation of different treatments and medical procedures. In most cases, however, respondents did not advocate the use of one particular groups preferences. Even when the preferences of the general public were considered most important, it was felt that any decision-making process needed to be informed by the preferences of a range of groups. The preferences of politicians were viewed as least important to processes of priority setting in health care.

Cd4% is the best predictor of development of Aids in a cohort of Hiv-infected homosexual men

To determine the relationships between individuals baseline T-cell subsets, their rates of change with time, and AIDS-free survival time, data were collected at 6-monthly intervals from 379 HIV-seropositive homosexual Sydney men, of whom 31 developed AIDS during the 3-year observation period. Both CD4% and rate of change of CD4% in an individual had significant prognostic value in determining AIDS-free survival time. Compared with subjects whose CD4% remained stable, subjects whose CD4% dropped by 7% or more in a year had a relative hazard of 35.1 (95% confidence interval = 11.7–105.6, P < 0.001) of developing AIDS. Increasing CD4% had a significant protective effect, reducing the risk of developing AIDS. CD4%, CD4 cell count and CD4:CD8 ratios showed steeper declines in subjects who were later diagnosed with AIDS than in those who remained AIDS-free. The rates of immunological change in AIDS-free seroconverters and seropositives were similar, despite indeterminate differences in durations of infections. In the multivariate Cox regression analysis, baseline CD4%, the rate of change of CD4%, and baseline lymphocyte count were associated with AIDS-free survival time. Baseline CD4% had greater prognostic value than baseline CD4 cell count. Baseline CD8%, baseline CD8 count, their rates of change and their mean square errors were not independently significant in this analysis. These findings are important for clinicians monitoring HIV infection in an individual and for entry criteria and monitoring procedures in clinical trials. They also have implications for resource-poor settings; prognosis based on CD4% can be made with a flow cytometer without a full blood count. Data were collected before zidovudine was available and thus reflect the natural history of HIV infection.

Risk factors for onset and remission of atopy, wheeze, and airway hyperresponsiveness

Background: Although many children with asthma may have a remission as they grow and other children who did not have asthma may develop asthma in adult life, knowledge about the factors that influence the onset and prognosis of asthma during adolescence and young adulthood is very limited. Methods: A cohort of 8–10 year old children (n=718) living in Belmont, New South Wales, Australia were surveyed six times at 2 yearly intervals from 1982 to 1992, and then again 5 years later in 1997. From this cohort, 498 subjects had between three and seven assessments and were included in the analysis. Atopy, airway hyperresponsiveness (AHR), and wheeze in the last 12 months were measured at each survey. Late onset, remission, and persistence were defined based on characteristics at the initial survey and the changes in characteristics at the follow up surveys. Results: The proportion of subjects with late onset atopy (13.7%) and wheeze (12.4%) was greater than the proportion with remission of atopy (3.2%) and wheeze (5.6%). Having atopy at age 8–12 years (OR 2.8, 95% CI 1.5 to 5.1) and having a parental history of asthma (OR 2.0, 95% CI 1.02 to 4.13) were significant risk factors for the onset of wheeze. Having AHR at age 8–12 years was a significant risk factor for the persistence of wheeze (OR 4.3, 95% CI 1.3 to 15.0). Female sex (OR 1.9, 95% CI 1.01 to 3.60) was a significant risk factor for late onset AHR whereas male sex (OR 1.9, 95% CI 1.1 to 2.8) was a significant risk factor for late onset atopy. Conclusions: The onset of AHR is uncommon during adolescence, but the risk of acquiring atopy and recent wheeze for the first time continues during this period. Atopy, particularly present at the age of 8–10 years, predicts the subsequent onset of wheeze.

Malignant pleural and peritoneal mesotheliomas in former miners and millers of crocidolite at Wittenoom, Western Australia

Aims: To report the number of malignant pleural and peritoneal mesotheliomas that have occurred in former Wittenoom crocidolite workers to the end of 2000, and to compare this with earlier predictions. Methods: A group of 6493 men and 415 women who had worked at the former Wittenoom crocidolite mine and mill at some time between 1943 and 1966 have been followed up throughout Australia and Italy to the end of 2000. Results: The cumulative number of mesotheliomas up to 2000 was 235 in men (202 pleural, 33 peritoneal) and seven (all pleural) in women. There had been 231 deaths with mesothelioma (9% of known deaths). Conclusions: The number of deaths in men with mesothelioma between 1987 and 2000 was at the low end of the predictions made earlier based on the number of cases to 1986. If this trend continues, it is predicted that about another 110 deaths with mesothelioma will occur in men by 2020.

A Randomized Controlled Trial Of Cyclosporine Withdrawal In Renal-Transplant Recipients: 15-Year Results.

Background. In renal transplantation, the immunosuppressive efficacy of cyclosporine is counterbalanced by its nephrotoxicity. Although cyclosporine improves short-term graft survival, its long-term effects are unclear. Methods. Recipients of first cadaver renal transplants were randomized into three groups between 1983 and 1986: azathioprine and prednisolone alone (AP, n=158), long term cyclosporine alone (Cy, n=166), and short-term cyclosporine followed by azathioprine and prednisolone (CyAP, n=165). All groups received methylprednisolone induction. Results. There were no significant differences in patient survival at 15 years (48 vs. 56 vs. 51%, P=0.14), and 15-year graft survival (censored for death) in those patients in the CyAP group (47 vs. 44 vs. 59%, P=0.06) was not significantly different statistically. When deaths or graft losses before 12 months were censored, the differences in 15-year graft survival between the groups were significant (58%, 51%, 70%, P=0.01). The CyAP group also had lower mean serum creatinine at all time points beyond 3 months posttransplant out to 10 years (143 vs. 169 vs. 131 μmoles/L, P=0.04). Per protocol analysis, after censoring patients at change in therapy, increased the observed differences in 15-year graft survival between the groups (54 vs. 38 vs. 65%, P=0.01). Conclusion. Survival and function of first cadaveric kidney transplants is improved by use of short-term cyclosporine followed by azathioprine and prednisolone. Long-term cyclosporine use reduces long-term graft survival.

Relationship between lung asbestos fiber type and concentration and relative risk of mesothelioma. A case‐control study

Lung tissue from 221 definite and probable cases of malignant mesothelioma reported to the Australian Mesothelioma Surveillance Program from January 1980 through December 1985 and from an age–sex frequency matched control series of 359 postmortem cases were examined by light microscopic (LM) and analytical transmission electron microscopic (TEM) analysis and energy dispersive x‐ray analysis (EDAX). Concentrations of total fibers (coated and uncoated) (LM), crocidolite, amosite, chrysotile, and unidentified amphibole (TEM) (fibers/g dry lung tissue) were measured. Fiber concentrations < 10 μm in length and < 10 μm in length were separately quantified. By comparing cases (221) and controls (359 LM, 103 TEM), odds ratios for increasing fiber concentrations compared with < 15 000 fibers/g (LM) and < 200 000 fibers/g (TEM) (the respective detection limits) were calculated. Univariate analyses showed statistically significant dose–response relationships between odds ratio and fiber concentration for all fiber concentration measures. The relationship between log(odds ratio) and log(fiber concentration) was linear. Multiple logistic regression analysis showed that a model containing crocidolite < 10 μm, amosite < 10 μm, and chrysotile < 10 μm as explanatory variables best described the data. The odds ratios for a ×10 increase in fiber concentration (fibers/μg) were as follows: crocidolite ≧ 10 μm, 29.4 (95% confidence interval [CI], 3.6 to 241); chrysotile ≧ 10 μm, 15.7 (95% CI, 6.1 to 40); amosite < 10 μm, 2.3 (95% CI, 1.0 to 5.3). An additive risk model gave similar results. In a subgroup of cases and controls with only chrysotile in the lungs, a significant trend in odds ratio with increasing fiber content was found.

Models for mesothelioma incidence following exposure to fibers in terms of timing and duration of exposure and the biopersistence of the fibers.

The health effects of inhaled fibers are related to the intensity and duration of exposure and occur many years after the exposure. In particular, the incidence of mesothelioma after exposure to asbestos is proportional to the intensity of exposure (fibers per milliliter of air) and the duration of exposure, and to the time that has elapsed since the exposure. The incidence increases with time since exposure to a power of between 3 and 4. The disease process resulting from exposure to fibers in the air is presumably related to the dose of fibers in the lungs, which depends on the exposure level and duration, and also on the size characteristics of the fibers influencing their inhalation and retention in the lungs. Models incorporating these characteristics have been found to be satisfactory in explaining the incidence of mesothelioma over time after exposure to asbestos. Most of the epidemiological modeling has been for occupational exposure to one of the amphibole asbestos types (crocidolite or amosite), for which heavy exposure produces a high incidence of mesothelioma. Occupational exposure to chrysotile asbestos has resulted in a much lower incidence of mesothelioma. Crocidolite asbestos is much more biopersistent than chrysotile asbestos in the sense that after retention in the lungs it is eliminated only slowly (half-time of several years). If fibers are eliminated then the dose in the lungs declines following exposure, and this may influence the disease process. This concept is more important for synthetic mineral fibers, such as glass wool, which are used as a substitute for asbestos. These fibers are much less biopersistent than asbestos, with half-times of weeks or even days. Biopersistence is related to the dissolution of fibers. This is a physical-chemical process that may be expected to proceed at about the same rate in rats and humans. The predicted effect of biopersistence of fibers has been explored using the basic mesothelioma incidence model generalized to include a term representing exponential elimination over time. The influence of solubility of fibers on the mesothelioma rate is 17 times higher in humans than in rats. This is because rats are aging and developing cancer at a much quicker rate than humans, and hence the influence of dissolution is less. Thus, the predicted mesothelioma incidence in humans is highly dependent on the rate of elimination across the range covering asbestos and the more durable synthetic fibers, but in rats a similar dependence occurs at a 17 times higher rate of elimination corresponding to the less durable synthetic fibers. The possible carcinogenic effects of fibers are often determined from animal experiments, but these results suggest that the extrapolation from rats to humans is highly dependent on the biopersistence of fibers, in the situation where the elimination is through dissolution of fibers at a rate independent of species and the speed of the cancer process is species dependent. This implies that relatively soluble fibers that do not produce disease in rat experiments are even less likely to produce disease in humans.

Sexual health and use of condoms among local and international sex workers in Sydney.

OBJECTIVES: To compare indicators of sexual health and predictors of condom use for commercial sex among local and international female sex workers first attending an STD clinic. SETTING: A public STD clinic in Sydney, Australia. SUBJECTS: All sex workers first attending between June 1991 and May 1993. METHODS: Cross-sectional analysis of demographic, behavioural and morbidity data from proforma medical records. RESULTS: 91 local sex workers and 123 international sex workers (predominantly from Thailand, Malaysia and China) first presented during the study period. There were significantly higher prevalences of chlamydia (0 v. 15%, p = 0.0002), gonorrhoea (0 v. 14%, p = 0.0006), syphilis (0 v. 10%, p = 0.006) and clinical genital herpes (0 v. 5%, p = 0.04) among international sex workers. The only case of HIV infection was in an international sex worker. Inconsistent condom use for commercial sex was significantly more common among international sex workers (RR = 4.5; 95% CI 3.1-6.5). On multivariate analysis, inconsistent condom use in international sex workers was associated with a recent history of prostitution outside Australia (p = 0.04), while inconsistent condom usage among local sex workers was associated with increasing age (p = 0.003). CONCLUSIONS: These data illustrate the efficacy of condoms and the success of targeted education programmes in local sex workers in Sydney. By contrast, international sex workers continued to be at high risk of STDs. The international sex industry in Sydney requires enhanced culture-specific interventions. Immigration laws as they affect sex workers should also be reviewed.