Controlled population‐based comparative study of USA and international adult [55‐74] neurological deaths 1989‐2014
The rises in neurological mortality have been questioned as an artefact, for example, due to improved diagnosis of ALS14 and the effect of changing demographics giving rise to the “Gompertzian hypothesis.” This states that the neurological increases are a consequence of people living longer and therefore developing age‐related diseases that they had not lived long enough to develop previously.15 However, the diagnostic issue has limited impact as it is mortality rates that are measured not separate diagnostic categories, and at this point, there is little evidence of diagnostic uncertainty as the primary cause of death is categorized as being due to a neurological condition.1 Moreover, the Gompertzian position appears to have ignored the marked changes between the sexes and in different countries.1 Crucially, the Gompertzian hypothesis does not account for the substantial rise in early onset dementia reported in many Western countries.12
To reduce a primarily Gompertzian explanation, this population‐based study focuses upon people aged 55‐74 years, below life expectancies in the developed world and utilizes the latest WHO data, updated December 2016 to take the analysis up to 2014.23 Consequently, studying the adults aged 55‐74 over a relatively short time means any Gompertzian influence will be minimal. However, to place the results on adults aged 55‐74 in a wider context, the over‐75s rates and matching population increases are also examined to explore any possible strengths of the Gompertzian influence.
Two control mortalities are juxtaposed against neurological death rates, Cancer Mortality and Circulatory Disease Deaths (CDD) because they are considered age related. It should be noted, however, that this analysis is not designed to postulate about possible aetiologies, but only to determine whether there continues to be substantial increases in neurological deaths over the past two decades and whether there are any significant differences in the US rates and the other nations.