Cross-sectional Gompertzian analysis: the development of a Gompertz mortality ratio (GMR) and its applicability

Many conventional epidemiological analyses of the distribution and aetiology of disease employ standardised mortality ratios (SMRs) as a basis upon which to evaluate comparative studies of disease in populations. However SMRs, whilst constructed to control for age and sex, are not capable of incorporating other variables such as life expectancy which has been demonstrated to be of crucial importance in understanding the changing relationships between mortality from different causes. The development of a Gompertz mortality ratio (GMR) and its application to recent mortality from amyotrophic lateral sclerosis (ALS) in the Counties of England and Wales illustrates the value of substituting GMRs for SMRs in the analysis of competitive relationships between conditions, especially those associated with enhanced life expectancy.