Damien Jolley

Reduction of Solar Keratoses by Regular Sunscreen Use

BACKGROUND The incidence of and mortality from skin cancer are increasing in many countries. In view of the added concern about ozone depletion, many organizations are promoting the regular use of sunscreens to prevent skin cancer, despite the absence of evidence that these products have this effect. Solar (actinic) keratosis is a precursor of squamous-cell carcinoma of the skin. METHODS We conducted a randomized, controlled trial of the effect on solar keratoses of daily use of a broad-spectrum sunscreen cream with a sun-protection factor of 17 in 588 people 40 years of age or older in Australia during one summer (September 1991 to March 1992). The subjects applied either a sunscreen cream or the base cream minus the active ingredients of the sunscreen to the head, neck, forearms, and hands. RESULTS The mean number of solar keratoses increased by 1.0 per subject in the base-cream group and decreased by 0.6 in the sunscreen group (difference, 1.53; 95 percent confidence interval, 0.81 to 2.25). The sunscreen group had fewer new lesions (rate ratio, 0.62; 95 percent confidence interval, 0.54 to 0.71) and more remissions (odds ratio, 1.53; 95 percent confidence interval, 1.29 to 1.80) than the base-cream group. There was a dose-response relation: the amount of sunscreen cream used was related to both the development of new lesions and the remission of existing ones. CONCLUSIONS Regular use of sunscreens prevents the development of solar keratoses and, by implication, possibly reduces the risk of skin cancer in the long-term.

Risk of Cardiovascular and All-Cause Mortality in Individuals With Diabetes Mellitus, Impaired Fasting Glucose, and Impaired Glucose Tolerance The Australian Diabetes, Obesity, and Lifestyle Study (AusDiab)

Background— Diabetes mellitus increases the risk of cardiovascular disease (CVD) and all-cause mortality. The relationship between milder elevations of blood glucose and mortality is less clear. This study investigated whether impaired fasting glucose and impaired glucose tolerance, as well as diabetes mellitus, increase the risk of all-cause and CVD mortality. Methods and Results— In 1999 to 2000, glucose tolerance status was determined in 10 428 participants of the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab). After a median follow-up of 5.2 years, 298 deaths occurred (88 CVD deaths). Compared with those with normal glucose tolerance, the adjusted all-cause mortality hazard ratios (HRs) and 95% confidence intervals (CIs) for known diabetes mellitus and newly diagnosed diabetes mellitus were 2.3 (1.6 to 3.2) and 1.3 (0.9 to 2.0), respectively. The risk of death was also increased in those with impaired fasting glucose (HR 1.6, 95% CI 1.0 to 2.4) and impaired glucose tolerance (HR 1.5, 95% CI 1.1 to 2.0). Sixty-five percent of all those who died of CVD had known diabetes mellitus, newly diagnosed diabetes mellitus, impaired fasting glucose, or impaired glucose tolerance at baseline. Known diabetes mellitus (HR 2.6, 95% CI 1.4 to 4.7) and impaired fasting glucose (HR 2.5, 95% CI 1.2 to 5.1) were independent predictors for CVD mortality after adjustment for age, sex, and other traditional CVD risk factors, but impaired glucose tolerance was not (HR 1.2, 95% CI 0.7 to 2.2). Conclusions— This study emphasizes the strong association between abnormal glucose metabolism and mortality, and it suggests that this condition contributes to a large number of CVD deaths in the general population. CVD prevention may be warranted in people with all categories of abnormal glucose metabolism.

WAIST CIRCUMFERENCE, WAIST-HIP RATIO AND BODY MASS INDEX AND THEIR CORRELATION WITH CARDIOVASCULAR DISEASE RISK FACTORS IN AUSTRALIAN ADULTS

Objectives.  To compare body mass index (BMI), waist circumference and waist–hip ratio (WHR) as indices of obesity and assess the respective associations with type 2 diabetes, hypertension and dyslipidaemia.

The Australian Diabetes, Obesity and Lifestyle Study (AusDiab)--methods and response rates.

The Australian Diabetes, Obesity and Lifestyle Study (AusDiab) addresses the urgent need for data on diabetes prevalence, risk factors and associated conditions in Australia. Here we describe the methods used and the response rates obtained. AusDiab was a population-based cross-sectional survey of national diabetes mellitus prevalence and associated risk factors in people aged > or =25 years, conducted between May 1999 and December 2000 in the six states and the Northern Territory of Australia. The study involved an initial household interview, followed by a biomedical examination that included an oral glucose tolerance test (OGTT), standard anthropometric tests, blood pressure measurements and the administration of questionnaires. Of the 20347 eligible people (aged > or =25 years and resident at the address for > or =6 months) who completed a household interview, 11247 (55.3%) attended for the biomedical examination. Of those who completed the biomedical examination 55.1% were female. Comparisons with the 1998 Australian population estimates showed that younger age responders were under-represented at the biomedical examination, while the middle-aged and older age groups were over-represented. Weighting of the AusDiab data for age and gender have corrected for this bias. AusDiab, which is the largest national diabetes prevalence study undertaken in a developed nation to have used an OGTT, provides a valuable national resource for the study of the prevalence and possible causes of diabetes, as well as identifying possible risk factors that may lead to diabetes. Furthermore, it generates the baseline data for a prospective 5-year cohort study. The data will be important for national and regional public health and lifestyle education and health promotion programs.

Effectiveness of needle-exchange programmes for prevention of HIV infection

BACKGROUND Needle-exchange programmes (NEPs) are potentially a key strategy for containing the spread of HIV infection among injecting drug users, but their implementation has been limited by uncertainty about their effectiveness. We used an ecological study design to compare changes over time in HIV seroprevalence in injecting drug users worldwide, for cities with and without NEPs. METHODS Published reports of HIV seroprevalence in injecting drug users were identified, and unpublished information on HIV seroprevalence for injecting drug users entering drug treatment in the USA between 1988 and 1993 was obtained from the Centers for Disease Control and Prevention. Details of the implementation of NEPs were obtained from published reports and experts. For each of the 81 cities with HIV seroprevalence data from more than 1 year and NEP implementation details, the rate of change of seroprevalence was estimated by regression analysis. The average difference in this rate for cities with and without NEPs was calculated. FINDINGS On average, seroprevalence increased by 5.9% per year in the 52 cities without NEPs, and decreased by 5.8% per year in the 29 cities with NEPs. The average annual change in seroprevalence was 11% lower in cities with NEPs (95% CI -17.6 to -3.9, p = 0.004). INTERPRETATION A plausible explanation for this difference is that NEPs led to a reduction in HIV incidence among injecting drug users. Despite the possibility of confounding, our results, together with the clear theoretical mechanisms by which NEPs could reduce HIV incidence, strongly support the view that NEPs are effective.

Leukemia Risk Associated With Low-Level Benzene Exposure

Background: Men who were part of an Australian petroleum industry cohort had previously been found to have an excess of lympho-hematopoietic cancer. Occupational benzene exposure is a possible cause of this excess. Methods: We conducted a case-control study of lympho-hematopoietic cancer nested within the existing cohort study to examine the role of benzene exposure. Cases identified between 1981 and 1999 (N = 79) were age-matched to 5 control subjects from the cohort. We estimated each subject’s benzene exposure using occupational histories, local site-specific information, and an algorithm using Australian petroleum industry monitoring data. Results: Matched analyses showed that the risk of leukemia was increased at cumulative exposures above 2 ppm-years and with intensity of exposure of highest exposed job over 0.8 ppm. Risk increased with higher exposures; for the 13 case-sets with greater than 8 ppm-years cumulative exposure, the odds ratio was 11.3 (95% confidence interval = 2.85-45.1). The risk of leukemia was not associated with start date or duration of employment. The association with type of workplace was explained by cumulative exposure. There is limited evidence that short-term high exposures carry more risk than the same amount of exposure spread over a longer period. The risks for acute nonlymphocytic leukemia and chronic lymphocytic leukemia were raised for the highest exposed workers. No association was found between non-Hodgkin lymphoma or multiple myeloma and benzene exposure, nor between tobacco or alcohol consumption and any of the cancers. Conclusions: We found an excess risk of leukemia associated with cumulative benzene exposures and benzene exposure intensities that were considerably lower than reported in previous studies. No evidence was found of a threshold cumulative exposure below which there was no risk.

Cardiovascular risk factors for people with mental illness

Objective: The objective of this study was to document the prevalence of risk factors for cardiovascular disease among people with chronic mental illness. Method: A cross-sectional survey was conducted of 234 outpatients attending a community mental health clinic in the North-western Health Care Network in Melbourne, Australia. Prevalence of smoking, alcohol consumption, body mass index, hypertension, salt intake, exercise and history of hypercholesterolemia was assessed. Results: Compared with a community sample, the mentally ill had a higher prevalence of smoking, overweight and obesity, lack of moderate exercise, harmful levels of alcohol consumption and salt intake. No differences were found on hypertension. Men, but not women, with mental illness were less likely to undertake cholesterol screening. Conclusions: Psychiatric outpatients have a high prevalence of cardiovascular risk factors which may account for the higher rate of cardiovascular mortality among the mentally ill. Further research is needed to trial and evaluate interventions to effectively modify risk factors in this vulnerable population.

Identification of Major Ischemic Change Diffusion-Weighted Imaging Versus Computed Tomography

BACKGROUND AND PURPOSE Thrombolytic therapy is not recommended in patients with CT changes of recent major infarction, which has been defined as reduced attenuation or cerebral edema involving >33% of the middle cerebral artery territory (European Cooperative Acute Stroke Study [ECASS] criteria). Diffusion-weighted imaging (DWI) is more sensitive than CT in detecting acute ischemia, and the combination of DWI, MR perfusion imaging, and MR angiography provides additional information from a single examination. We sought to determine whether DWI could identify the presence and extent of major ischemia as well as CT in hyperacute stroke patients. METHODS Seventeen suspected hemispheric stroke patients were studied with both CT and DWI within 6 hours of symptom onset. None received thrombolytic therapy. The scans were examined separately by 2 neuroradiologists in a blinded fashion for ischemic change and cerebral edema, graded as normal, <33%, or >33% of the MCA territory. Final diagnosis of stroke was determined with the use of standard clinical criteria and T2-weighted imaging at day 90. RESULTS Sixteen of 17 patients had a final diagnosis of stroke. Acute ischemic changes were seen in all 16 on DWI (100% sensitivity) and in 12 of 16 on CT (75% sensitivity). DWI identified all 6 patients with major ischemia on CT, with excellent agreement between the 2 imaging techniques (kappa=0.88). One patient eligible for thrombolysis on the ECASS CT criteria had major ischemia on DWI. CONCLUSIONS DWI is more sensitive than CT in the identification of acute ischemia and can visualize major ischemia more easily than CT.

2001 Volvo Award winner in clinical studies : effects of a media campaign on back pain beliefs and its potential influence on management of low back pain in general practice

Study Design. Quasi-experimental, nonrandomized, nonequivalent, parallel group-controlled study involving before and after telephone surveys of the general population and postal surveys of general practitioners was conducted, with an adjacent state used as a control group. Objectives. To evaluate the effectiveness of a population-based intervention designed to alter beliefs about back pain, influence medical management, and reduce disability and workers’ compensation–related costs. Summary of Background Data. A multimedia campaign begun during 1997 in Victoria, Australia, positively advised patients with back pain to stay active and exercise, not to rest for prolonged periods, and to remain at work. Methods. The campaign’s impact on population beliefs about back pain and fear-avoidance beliefs was measured in telephone surveys, and the effect of the campaign on the potential management of low back pain by general practitioners was assessed by eliciting their likely approach to two hypothetical scenarios in mailed surveys. Demographically identical population groups in Victoria and the control state, New South Wales, were surveyed at three times: before, during, and after intervention in Victoria. Results. The studies were completed by 4730 individuals in the general population and 2556 general practitioners. There were large statistically significant improvements in back pain beliefs over time in Victoria (mean scores on the Back Beliefs Questionnaire, 26.5, 28.4, and 29.7), but not in New South Wales (26.3, 26.2, and 26.3, respectively). Among those who reported back pain during the previous year, fear-avoidance beliefs about physical activity improved significantly in Victoria (mean scores on the Fear-Avoidance Beliefs Questionnaire for physical activity, 14, 12.5, and 11.6), but not in New South Wales (13.3, 13.6, and 12.7, respectively). General practitioners in Victoria reported significant improvements over time in beliefs about back pain management, as compared with their interstate colleagues. There were statistically significant interactions between state and time for 7 of 10 responses on management of acute low back pain, and for 6 of 10 responses on management of subacute low back pain. Conclusion. A population-based strategy of providing positive messages about back pain improves the beliefs of the general population and general practitioners about back pain and appears to influence medical management.

Glucose indices, health behaviors, and incidence of diabetes in Australia: The Australian diabetes, obesity and lifestyle study

OBJECTIVE—This national, population-based study reports diabetes incidence based on oral glucose tolerance tests (OGTTs) and identifies risk factors for diabetes in Australians. RESEARCH DESIGN AND METHODS—The Australian Diabetes, Obesity and Lifestyle Study followed-up 5,842 participants over 5 years. Normal glycemia, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes were defined using World Health Organization criteria. RESULTS—Age-standardized annual incidence of diabetes for men and women was 0.8% (95% CI 0.6–0.9) and 0.7% (0.5–0.8), respectively. The annual incidence was 0.2% (0.2–0.3), 2.6% (1.8–3.4), and 3.5% (2.9–4.2) among those with normal glycemia, IFG, and IGT, respectively, at baseline. Among those with IFG, the incidence was significantly higher in women (4.0 vs. 2.0%), while among those with IGT, it was significantly higher in men (4.4 vs. 2.9%). Using multivariate logistic regression, hypertension (odds ratio 1.64 [95% CI 1.17–2.28]), hypertriglyceridemia (1.46 [1.05–2.02]), log fasting plasma glucose (odds ratio per 1 SD 5.25 [95% CI 3.98–6.92]), waist circumference (1.26 [1.08–1.48]), smoking (1.70 [96% CI 1.11–2.63]), physical inactivity (1.56 [1.12–2.16]), family history of diabetes (1.82 [1.30–2.52]), and low education level (1.85 [1.04–3.31]) were associated with incident diabetes. In age- and sex-adjusted models, A1C was a predictor of diabetes in the whole population, in those with normal glycemia, and in those with IGT or IFG. CONCLUSIONS—Diabetes incidence is 10–20 times greater in those with IGT or IFG than those with normal glycemia. Measures of glycemia, A1C, metabolic syndrome components, education level, smoking, and physical inactivity are risk factors for diabetes.