Mortality in the New South Wales coal industry, 1973-1992.

OBJECTIVE: To study the mortality of coalminers in New South Wales (NSW) between 1973 and 1992. DESIGN AND PARTICIPANTS: 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 records of Joint Coal Board medical examinations. This cohort was matched with the NSW Death Register to determine the number and causes of deaths in cohort members. RESULTS: The cohort consisted of 23,630 men; 491 died during the study period. The standardised mortality ratio (SMR) for all causes of death was 0.76; that is, after age correction, coalminers have a 24% lower mortality than the general NSW population. Deaths from cancer were lower than expected, and there was a 27% lower mortality from respiratory disease. However, a substantial excess of non-motor-vehicle accidents (SMR, 1.60) was found. Most of these deaths can be attributed to occupation, and some to specific incidents. These excess death rates are confined to underground miners; open cut miners have a substantially lower rate than the general population. CONCLUSIONS: A "healthy worker" effect may explain the lower overall mortality. Although "black lung" is no longer a problem, accidents are still common in underground coalmining. The major expansion of open cut mining in recent years has improved the situation.

Suicide and related deaths in Victorian doctors.

A cohort of University of Melbourne medical graduates (1950-1959 graduates inclusive) was followed up until December 31, 1986. Vital status at the end of the study period was ascertained and, for those who had died, cause of death was determined. The cohort consisted of 1453 members (1279 men and 174 women). One hundred and twenty-six of the group had died (115 men and 11 women) and 68 (4.7%; 57 men and 11 women) were lost to follow-up. The major causes of death were cardiovascular disease and malignant neoplasms. The standardised mortality ratios (SMRs) for all-cause mortality were low (59 for the male doctors and 84 for the female doctors) indicating that male doctors experience a "force of mortality" 59% that of the general population and female doctors 84%. For the male doctors, the SMR for suicide was 113 (95% confidence interval [CI], 54-207) (10 of 115 deaths in male doctors) about double the SMR for mortality from all causes. For the female doctors, the SMR for suicide was 501 (95% CI, 103-1500) (3 of 11 deaths in female doctors). For deaths resulting from all accidents the SMR was low for the males (29) and higher for the females (126). The SMR for mental disorders for the male doctors was marginally raised (132). This study reveals some indication of a problem in doctors in regard to deaths by suicide, other violent deaths and mental disorders. A larger study involving a control group of equivalent social class is required to confirm the findings of this study.

Arbovirus infection in a Murray Valley community.

Serum antibodies to Ross River virus and Murray Valley encephalitis virus were measured during 1974-1975 in residents of Echuca, an urban Murray Valley community. A representative group of volunteers was obtained by random selection of households. The prevalence of antibodies to both viruses increased progressively with age. Prevalence was equal in both sexes for both viruses in all age groups, indicating that the risk of infection was mainly determined by geography rather than by personal activities. Antibody levels remained unchanged in the following year when there was no disease activity in the area. The stability of antibody levels permitted retrospective estimates of mean rates of infection. These were approximately 0.4% per annum for both viruses when age was used as the index for years of exposure. With allowance for other factors, the best estimate for both virus infections is probably closer to 1%. The morbidity rate for Ross River virus infection appeared to be low. It is concluded that infection with Ross River virus and with Murray Valley encephalitis-related viruses is endemic in the Murray Valley.

Heart disease prevention project: a randomised controlled trial in industry.

Twenty-four factories or other occupational groups, employing 18 210 men aged 40 to 59, were formed into matched pairs. One of each pair was allocated randomly to receive a five to six year programme of medical examinations and intervention to reduce the levels of the main coronary risk factors. Men at factories in the intervention group were given advice on dietary reduction of plasma cholesterol concentrations, stopping or reducing cigarette smoking, regular exercies for the sedentary and reduced energy intake for the overweight, and hypertension was treated. The programme was delivered mainly through existing occupational medical services, helped by a small central staff. Personal consultations were largely confined to men with a high risk of developing coronary heart disease. Changes in risk factors were assessed by regular standardised examinations of random samples of men. The spread of information by general propaganda proved easy, but a change in habits seemed to require personal contact. Small but significant reductions occurred, mainly in the high-risk group, but these were not sustained when pressure was relaxed.

Blood pressure measurement in the United Kingdom Heart Disease Prevention Project.

A blood pressure measurement was part of a cardiovascular screening examination of 8397 middle-aged men taking part in the intervention section of the United Kingdom Heart Disease Prevention Project. Standardised training techniques reduced observer bias to acceptable limits in four out of a total of five observers. The time of day and room temperature both made significant differences to the blood pressure measurement. High room temperatures in particular apparently had a marked effect in reducing the level of blood pressure. There were consistent and large positive associations with increasing age and overweight. The survey revealed a poor degree of blood pressure control in the community at the time of screening--only 7% of the "hypertensive" population had their diastolic pressure controlled to below 100 mm Hg.

The epizootiology of bovine ephemeral fever in Australia and Papua-New Guinea.

The epizootiology of ephemeral fever in Australia from its first recognition until 1968 was reviewed. Since 1968, ephemeral fever often in a silent form has been shown to be enzootic in northern Australia, by the use of sentinel cattle. The major epizootics which occured in 1970-1971, 1972-1974 and 1974-1975 are described. These epizootics were characterised by an apparently rapid movement of disease in a general north-south direction in summer months. Ephemeral fever antibody was detected in 11% of 1009 domesticated and feral water buffaloes.