Longitudinal analysis of respiratory outcomes among bauxite exposed workers in Western Australia.

INTRODUCTION: Occupational exposure to bauxite is common in the aluminium industry but little is known about the associated health effects. This study investigates respiratory health in relation to respirable bauxite dust exposure longitudinally over a 13 year period. METHODS: An inception cohort study recruited 91 male bauxite miners and 363 male alumina refinery workers. Annual measurements of respiratory symptoms and lung function were made. Cumulative exposure to bauxite was derived from job histories and air monitoring data. Mixed-effects modeling was used. RESULTS: No associations were found between cumulative bauxite exposure and respiratory symptoms or lung function. However, when analysis was restricted to the first three rounds, FEV1 was significantly lower in all exposure groups than in those unexposed but with no significant trend. CONCLUSION: Increasing exposure to bauxite dust in the aluminum industry was not associated with respiratory symptoms or consistent decrements in lung function.

Is potroom asthma due more to sulphur dioxide than fluoride? An inception cohort study in the Australian aluminium industry.

OBJECTIVES: Although an asthma-like syndrome has been recognised in aluminium smelter workers for over 70 years, the causal agent has been difficult to identify. METHODS: An inception cohort study was conducted at two Australian aluminium smelters where 446 employees participated over a period of 9 years. Cumulative exposures between interviews were estimated from job histories using a task exposure matrix based on measurements in the smelters. Participants completed an MRC respiratory questionnaire, spirometry and methacholine challenge test. Data were analysed with generalised estimating equations to allow for repeated measurements of each participant. RESULTS: Wheeze and chest tightness, the two symptoms most closely related to asthma, showed associations with occupational exposures. SO(2) exposure was significantly associated with these symptoms, bronchial hyper-responsiveness (BHR) to methacholine (a feature of asthma), airflow limitation (reduced forced expiratory volume in 1 second/forced vital capacity ratio) and longitudinal decline in lung function. Fluoride exposure was associated with the same outcomes, but less strongly. Inhalable dust and the benzene soluble fraction (BSF) were associated with symptoms of asthma and BHR. Although many of the exposures were highly correlated, further modelling suggested that of the known respiratory irritants, SO(2) was more likely than fluoride to be primarily responsible for the symptoms observed. Fluoride, inhalable dust and SO(2) were the most important airborne contaminants associated with effects on lung function. CONCLUSIONS: The observed effects were detected at contaminant levels within occupational exposure standards, so further reductions are required, particularly in SO(2) exposures.

Dietary patterns identified using factor analysis and prostate cancer risk: a case control study in Western Australia.

PURPOSE: Dietary patterns offer an alternative method for analyzing dietary intakes that take into account the whole diet. We investigated empirical dietary patterns and prostate cancer risk in Western Australia (WA) using a population-based case-control study. METHODS: Incident prostate cancer cases were identified via the WA Cancer Registry. Controls were sourced from the WA electoral roll, frequency matched on age. A food frequency questionnaire (FFQ) estimated usual dietary intake from 10 years earlier. Factor analysis identified dietary patterns in FFQ data. Effects of independent dietary patterns on prostate cancer risk were examined using unconditional logistic regression, adjusting for potential confounders. RESULTS: A total of 546 cases and 447 controls provided data. Three distinct dietary patterns were identified, which we labeled vegetable, Western, and health-conscious. An increased risk for prostate cancer was observed with the Western pattern, which consisted of high intakes of red and processed meats, fried fish, hamburgers, chips, high-fat milk, and white bread. Men in the highest quartile for Western pattern score had an odds ratio of 1.82 (95% confidence interval 1.15-2.87, trend p = 0.02). Results were similar for aggressive cases and attenuated for non-aggressive cancers. CONCLUSIONS: A western style diet may lead to increased risks for prostate cancer, especially aggressive prostate cancer.

History of tobacco and health.

Tobacco comes from plants that are native to the Americas around Peru and Ecuador,where it has been found since prehistoric times. It was brought back to Europe by early explorers where it was adopted by society and re-exported to the rest of the world as European colonization took place. Smoking tobacco in pipes of one sort or other gave way to handmade and then manufactured cigarettes, especially during the First World War. Smoking rates increased dramatically during the 20th century in developed countries until recently and rates are still increasing in underdeveloped countries. An epidemic of smoking-related diseases has followed the prevalence of smoking. Scientific knowledge of the harmful effects of active tobacco smoking has accumulated during the past 60 years since early descriptions of the increasing prevalence of lung cancer. The first epidemiological studies showing an association between smoking and lung cancer were published in 1950. In 1990 the US Surgeon General concluded that smoking was the most extensively documented cause of disease ever investigated but governments worldwide have been ambivalent and slow in taking action to reduce smoking. Tobacco smoking is now agreed to be a major cause of a vast number of diseases and other adverse effects. Since the 1980s passive smoking including exposure in utero has also been implicated as a significant cause of numerous diseases. In response, the tobacco industry has managed to forestall and prevent efforts to control this major health problem.