title: Motor neuron disease mortality and lifetime petrol lead exposure: Evidence from national age-specific and state-level age-standardized death rates in Australia.
abstract: BACKGROUND
  The age standardized death rate from motor neuron disease (MND) for persons 40-84 years of age in the Australian States of New South Wales, Victoria, and Queensland increased dramatically from 1958 to 2013. Nationally, age-specific MND death rates also increased over this time period, but the rate of the rise varied considerably by age-group. The historic use of lead (Pb) additives in Australian petrol is a candidate explanation for these trends in MND mortality (International Classification of Disease (ICD)-10 G12.2).
  
  
  METHODS
  Leveraging temporal and spatial variation in petrol lead exposure risk resulting from the slow rise and rapid phase-out of lead as a constituent in gasoline in Australia, we analyze relationships between (1) national age-specific MND death rates in Australia and age-specific lifetime petrol lead exposure, (2) annual between-age dispersions in age-specific MND death rates and age-specific lifetime petrol lead exposure; and (3) state-level age-standardized MND death rates as a function of age-weighted lifetime petrol lead exposure.
  
  
  RESULTS
  Other things held equal, we find that a one percent increase in lifetime petrol lead exposure increases the MND death rate by about one-third of one percent in both national age-specific and state-level age-standardized models of MND mortality. Lending support to the supposition that lead exposure is a driver of MND mortality risk, we find that the annual between-age group standard deviation in age-specific MND death rates is strongly correlated with the between-age standard deviation in age-specific lifetime petrol lead exposure.
  
  
  CONCLUSIONS
  Legacy petrol lead emissions are associated with age-specific MND death rates as well as state-level age-standardized MND death rates in Australia. Results indicate that we are approaching peak lead exposure-attributable MND mortality.
authors.affiliation: Department of Economics, Colorado State University, Fort Collins, CO 80523-1784, USA. Electronic address: sammy.zahran@colostate.edu.
authors.forename: Sammy
authors.initials: S
authors.lastname: Zahran
authors.affiliation: Centre for Environmental Sustainability and Remediation (EnSuRe), School of Science, RMIT University, PO Box 71, Bundoora, Victoria 3083, Australia. Electronic address: mark.laidlaw@rmit.edu.au.
authors.forename: Mark A S
authors.initials: MA
authors.lastname: Laidlaw
authors.affiliation: Department of Neurology, Faculty of Medicine and Health Sciences, Suite 204, 2 Technology Place Macquarie University, 2109, Australia. Electronic address: dominic.rowe@mq.edu.au.
authors.forename: Dominic B
authors.initials: DB
authors.lastname: Rowe
authors.affiliation: Centre for Environmental Sustainability and Remediation (EnSuRe), School of Science, RMIT University, PO Box 71, Bundoora, Victoria 3083, Australia. Electronic address: andy.ball@rmit.edu.au.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Ball
authors.affiliation: Department of Pharmacology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA. Electronic address: hmielke@tulane.edu.
authors.forename: Howard W
authors.initials: HW
authors.lastname: Mielke
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia / Q000453:epidemiology; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis; D005742:Gasoline; D006801:Humans; D007854:Lead / Q000633:toxicity*; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000139:chemically induced / Q000401:mortality*
chemical_list: D005742:Gasoline; D007854:Lead
keywords: Amyotrophic lateral sclerosis; Lead exposure; Leaded gasoline; Mortality; Motor neuron disease