Social class as indicated by area of residence: a mortality study within an Australian industrial population

The influence of social class on morbidity and mortality is well known and, in many epidemiological settings, its role as a potential confounding variable must be addressed. In occupational studies, particularly those based within a single industry, it is difficult to measure social class by scales based on occupational prestige. In a population study within the Australian petroleum industry, the all-cause mortality of males has been examined by social class, as indicated by area of residence, specifically, postcode. Rates of mortality were higher in the lower social classes, and the gradient was similar to that observed previously. The mortality rate of the lowest social class group relative to the highest was 1.73, and the test for trend was significant (p = 0.003). Whilst adjustment for smoking reduced the gradient somewhat, a social class effect remained.