The haematology of indigenous Australians.

Prior to European settlement indigenous Australians were hunter-gatherers who lived in geographically isolated small clan groups, also separated by elaborate totemic rules. Today they still reside in isolated communities throughout Australia but many have moved to the cities. They share a high incidence of a range of health problems including cardiovascular disease, renal disease and infectious diseases largely attributed to a change to a more sedentary lifestyle. This paper reviews the haematology of indigenous Australians, including blood count, frequency and causes of anaemia, inherited risk factors for thrombophilia, blood groups and the incidence and types of haematological malignancies. There are some significant genetic differences between indigenous and non-indigenous Australians particularly in the frequency of blood groups, factor V Leiden and prothrombin mutations and presence of -alpha3.7 kb thalassaemia. These findings may have practical therapeutic implications (e.g. HPA phenotype for transfusion therapy and pregnancy risk) and in predicting disease risk. Other differences are acquired, related to lifestyle and living conditions (e.g. eosinophilia secondary to parasitic infections; iron and folate deficiencies), and are largely preventable.

Excess cancer mortality in Western Australian psychiatric patients due to higher case fatality rates.

OBJECTIVE: To investigate the association between mental illness and cancer incidence, mortality and case fatality. METHOD: A population-based record linkage study was undertaken based on 172,932 patients of mental health services in Western Australia. Records of mental health service contacts were linked with cancer registrations and death records. RESULTS: While there was little difference in overall cancer incidence rates between psychiatric patients and the general community (RR in males 1.05, 95%, CI 1.02-1.09, RR in females 1.02, 0.98-1.05), cancer mortality was 39%, higher in males (95%) CI: 32-46%) and 24% higher in females (17-32%). CONCLUSION: People with mental illness in Western Australia do not show an increased incidence rate of cancer, but do have higher cancer mortality. This was attributed to a higher cancer case fatality rate among people with mental illness.

A population-based study of the incidence, mortality and outcomes in patients following surgery for colorectal cancer in Western Australia.

BACKGROUND: The literature contains many reports on the management of colorectal cancer from single institutions or groups of specialist surgeons. But there are few data on community-wide patterns of treatment or the outcomes of colorectal surgery. The aim of the present study was to use a population-based linked database to assess the trends in colorectal cancer incidence and mortality in Western Australia (WA) in the period 1982-95, and to evaluate the outcomes following surgical care. METHODS: A population-based linked database was used to relate the cancer registry, hospitalization and mortality records of all patients with a diagnosis of colorectal cancer in WA during 1982-95. Data on surgical treatment and postoperative morbidity and mortality in this group of patients were available only in 1988-95. Patient records were selected using the international classification for diagnosis and procedure codes pertaining to colorectal cancer and surgery. Incidence and mortality trends in colon and rectal cancers were estimated by Poisson regression regression of age-standardized rates, and relative survival analysis was used to compare patient survival with the general population. RESULTS: During the 14-year period, 9673 patients presented with a diagnosis of colorectal cancer. The sex distribution of patients with colon cancer was evenly divided, but rectal cancer was more common in men (ratio 1:4). The mean age at diagnosis was 67.8 years (SD: 12.7). During the study period there was a significant increase in the standardized incidence rate of rectal cancer in men, and in the mortality rates from colon cancer in women. The overall crude 5-year survival was 57%. Large bowel resections were performed on 71% of patients with an in-hospital postoperative mortality of 4.2%. CONCLUSION: Colorectal cancer is a continuing major cause of morbidity and mortality in WA. The present study demonstrated increases in the incidence rate of rectal cancer in men and in the mortality rate from colon cancer in women in the period 1982-95.

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.

Treatment of Helicobacter pylori infection to reduce gastric cancer incidence: uncertain benefits of a community based programme in Australia.

Helicobacter pylori is a cause of gastric adenocarcinoma, but the role of H. pylori eradication in reducing cancer risk is unknown. We sought to estimate the benefits of a screening and treatment programme for H. pylori infection, aimed at reducing the incidence of gastric cancer in Australia. The impact of this programme on cancer incidence was evaluated in sensitivity analyses utilizing Western Australian Cancer Registry data and published data on the epidemiology of H. pylori and gastric cancer. The impact of variation in parameters used in the sensitivity analyses was substantial, ranging from a 38% reduction in lifetime risk of gastric cancer in a best-case to 3% in a worst-case scenario. In an intermediate-case scenario there is a 23% reduction in lifetime risk, but in real terms this reflects a fall in cumulative incidence from 0.7 to 0.5% for males or 0.3 to 0.2% for females. The projected cumulative lifetime incidence of gastric cancer in H. pylori-infected males is 2.2% and 0.9% for females; this contrasts with 0.4 and 0.2%, respectively, for those never infected. According to an intermediate-case scenario, to prevent one gastric cancer, screening with or without subsequent treatment would be required in 617 men or 1639 women. Furthermore, this programme may be less effective in reducing cancer incidence than would be achieved naturally over the next 15 years, providing the current annual decline in gastric cancer incidence continues. In conclusion, the benefits of a community based programme of H. pylori eradication in terms of cancer risk reduction remain unclear, related largely to uncertainties in the parameters used to calculate these benefits. In Australia, any benefits obtained are likely to be, at best, modest.

Prostate cancer in Western Australia: trends in incidence and mortality from 1985 to 1996.

OBJECTIVE: To measure trends in recorded incidence and mortality rates of prostate cancer in Western Australia from 1985 to 1996 and to relate these to prostate-specific antigen (PSA) testing for prostate cancer. DESIGN: Descriptive study based on data from the Western Australian Cancer Registry, the Australian Bureau of Statistics and the Health Insurance Commission. DATA: All newly diagnosed cases of prostate cancer and all deaths from prostate cancer in Western Australia from 1985 to 1996. MAIN OUTCOME MEASURES: Recorded incidences and mortality rates for prostate cancer. RESULTS: After increasing steadily from 42 per 100,000 person-years in 1985 to 61 in 1992, the recorded incidence more than doubled to 134 per 100,000 person-years in 1994, then fell sharply to 87 in 1996. Among men aged 50 years or more, those aged 50-54 years had the largest annual increases: 14% (95% confidence interval [CI], 10%-19%) from 1985 to 1992 and 108% (95% CI, 84%-134%) from 1992 to 1994. They also had the smallest annual decline between 1994 and 1996 (8%; 95% CI, 1% increase to 16% decrease). The mortality rate showed no sudden increases or decreases. In men aged 60 years or older, the mortality rate increased annually by 2.9% (95% CI, 2%-4%) from 1985 to 1996. The number of Medicare reimbursements for PSA tests increased until May 1995, then fell. There was a significant correlation between the monthly number of PSA tests and new cases of prostate cancer (P < 0.01). CONCLUSIONS: Following a period of steady increase, the recorded incidence of prostate cancer increased dramatically in 1992 because of screening by PSA testing. From 1994, these incidence figures declined almost as sharply, partly because of reductions in testing. The mortality rate has not shown any systematic deviation from its long-term trend.

Sunglasses and clothing--an unhealthy correlation?

Increasing awareness of health effects of solar ultraviolet radiation has focused attention on protection measures, including sunglasses. Sunglasses, or fashion glasses with tinted lenses, may be associated with some risks, and quality is not evident from casual inspection. This study investigates one possible 'hazard' of sunglasses--that they may induce behavioural changes which reduce the wearer's tendency to use adequate sun protection for the rest of the body. Findings consistent with such a proposition were shown in a photographic survey of 373 people in the summer of 1991 in Perth, Western Australia. This revealed maladaptive associations between the wearing of sunglasses and a high degree of leg or arm exposure as recorded by length of sleeves or trouser legs. This was significant for the arms and the legs in males (P less than 0.05), but approached significance only for the arms in females (P less than 0.10). There was no significant association between degrees of arm and leg exposure in either sex. The health implications of these maladaptive behaviours, and some advantages and disadvantages of the survey technique, are discussed. The results suggest that promotion of sun-protective behaviour should encourage the use of both sunglasses and protective clothing, as subjects' behaviours with respect to these do not appear to be correlated in a rational manner. If public awareness of links between skin cancer and eye disease could be increased, promotion of sunglasses might lead to a reduction in the incidence of skin cancers in general, not just those in the periorbital area.