@article { author = {Khoshbin, E. and Davies, R.B.}, title = {-}, journal = {Iranian International Journal of Science(Not Publish)}, volume = {6}, number = {0}, pages = {-}, year = {2005}, publisher = {}, issn = {}, eissn = {}, doi = {}, abstract = {Background: 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. Methods: 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 Conclusions: 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).}, keywords = {frailty models,MND,true and spurious temporal dependence}, title_fa = {-}, abstract_fa = {}, keywords_fa = {}, url = {https://iijs.ut.ac.ir/article_30824.html}, eprint = {https://iijs.ut.ac.ir/article_30824_0461fdb786b60701184a63818d4bc085.pdf} }