Factors Affecting Age of Onset and Rate of Progression of MND

As Motor Neuron Disease (MND) involves a progressive deterioration in nerve function, it is possible that risk factors for the disease will also accelerate the progression of the disease. This paper uses the two stages of age at onset and age at death to measure progression. Conventional parametric survival models are used to identify significant covariate from a large number of variables which have been suggested as risk factors for “MND / Frailty” models are used to characterize more fully the two stage progression process. Results and The results suggest the polluted work environments are associated with early onset of MND. Although there is a negative dependence between duration from onset to death and age at onset, this is not necessarily inconsistent with the expected progressive deterioration; there is a tantalizing suggestion from the frailty modeling that this may be the net result of a positive association due to variation in the rate of progression over the population and a negative association due to the direct effect of age (for example, because the elderly are more at risk from infections).