David Christie

A prospective study in the Australian petroleum industry. II Incidence of cancer

This paper reports incidence of cancer in employees of the Australian petroleum industry from 1981 to 1989. Two surveys by personal interview incorporated more than 15,000 employees, representing 92% of the eligible population. Subjects were included in the analysis after completing five years of service in the industry. At the time of this report the cohort did not include sufficiently large numbers of women for useful analysis; results presented are restricted to the men. On 31 December 1989, 50,254 person-years of observation had accumulated in the men with 152 incident cancers reported. The standardised incidence ratio (SIR) analysis showed overall cancer rates close to those of the national population. Whereas deficits were seen in some cancer sites, notably lung cancer (SIR 0.5, 95% confidence internal (95% CI) 0.3-0.9), incidence rates for some other cancer sites suggested increased risk. An excess of observed over expected cases was present in all subcategories of lymphohaematopoietic cancer except Hodgkins disease (no cases), and was most apparent in myeloid leukaemia (SIR 4.0, 95% CI 1.6-8.2). The other major site with a raised number of cases observed over expected was melanoma (SIR 1.4, 95% CI 0.8-2.1).

The occurrence of cancer in a cohort of New South Wales coal miners

Abstract: To describe the incidence of cancer in coal miners in New South Wales (NSW) between 1973 and 1992, an inception cohort of all male coal industry employees who entered the industry between 1 January 1973 and 31 December 1992 was constructed from the medical examination records of the Joint Coal Board. This cohort was matched with the NSW State Cancer Registry to determine the occurrence and type of cancer. In the cohort of 23 630 men, 297 developed 301 primary cancers in the 20–year period of observation. The standardised incidence ratio (SIR) for all cancers was 0.82. Stomach cancer has been reported to be common in coal miners but the SIR for stomach cancer was not higher than average in this cohort. A cluster of non–Hodgkins lymphoma has been reported in a NSW coal mine but an increased risk of this cancer was not evident in the industry as a whole. Similarly a cluster of cases of brain tumour has been reported. In this cohort, the SIR for brain tumour was 1.05 (95 per cent confidence interval (CI) 0.57 to 1.76) and a risk for brain tumour remains unconfirmed. The SIR for malignant melanoma was 1.13 (CI 0.90 to 1.39) altogether and 2.02 (CI 1.31 to 2.98) for those workers who started in an open–cut mine. Overall, there does not appear to be a general risk of cancer in the NSW coal industry. Open–cut miners have an increased risk of malignant melanoma, which may be related to their exposure to the sun at work.

Is cardiothoracic ratio in healthy middle aged men an independent predictor of coronary heart disease mortality ? Whitehall study 25 year follow up

Aetiological studies of myocardial ischaemia have tended to concentrate on factors which influence atherothrombotic processes in the coronary arteries rather than myocardial pathophysiology.1 The commonest clinical measure of heart size—cardiothoracic ratio—was included in the original Whitehall study of healthy middle aged civil servants. Cardiothoracic ratio is associated with left ventricular mass2 and left ventricular systolic function; since left ventricular mass determined by echocardiography has been shown to predict coronary heart disease in elderly people,1 we hypothesised that increased cardiothoracic ratio would independently predict mortality from coronary heart disease. Unlike previous studies3 we did not include mortality from stroke since it may be related to heart size through different pathophysiological mechanisms. View this table: Adjusted hazard ratios (95% confidence intervals) for the effect of cardiothoracic ratio on all cause and coronary heart disease mortality We studied the 1203 male British …

A prospective study in the Australian petroleum industry. I. Mortality.

This paper reports the mortality experience of employees of the Australian petroleum industry from 1981 to 1989. Two surveys by personal interview incorporated more than 15,000 employees representing 92% of the eligible population. Subjects were included in the analysis after completing five years of service in the industry. At the time of this report the cohort does not include sufficiently large numbers of women for useful analysis; results presented are restricted to men. By 31 December 1989, 76,529 person-years of observation had accumulated for male mortality with 241 deaths. The standardised mortality ratio (SMR) analysis showed a favourable mortality experience for most causes with overall cancer rates slightly lower than those of the national population. Whereas deficits were seen in some cancer sites, notably lung cancers (SMR 0.5, 95% confidence interval (95% CI) 0.3-0.8), mortality for lymphohaematopoietic cancers, notably leukaemia (SMR 1.6, 95% CI 0.6-3.4) suggested increased risk. The SMR for cancers of the pleura was 3.9 (95% CI 0.8-11). Two of the three cases seen had previous employment, however, in industries with likely exposure to asbestos.