title: Brief Report: Investigating Uncertainty in the Minimum Mortality Temperature: Methods and Application to 52 Spanish Cities.
abstract: The minimum mortality temperature from J- or U-shaped curves varies across cities with different climates. This variation conveys information on adaptation, but ability to characterize is limited by the absence of a method to describe uncertainty in estimated minimum mortality temperatures.
  
  
  
  We propose an approximate parametric bootstrap estimator of confidence interval (CI) and standard error (SE) for the minimum mortality temperature from a temperature-mortality shape estimated by splines.
  
  
  
  The coverage of the estimated CIs was close to nominal value (95%) in the datasets simulated, although SEs were slightly high. Applying the method to 52 Spanish provincial capital cities showed larger minimum mortality temperatures in hotter cities, rising almost exactly at the same rate as annual mean temperature.
  
  
  
  The method proposed for computing CIs and SEs for minimums from spline curves allows comparing minimum mortality temperatures in different cities and investigating their associations with climate properly, allowing for estimation uncertainty.
authors.affiliation: From the aInstitute of Environmental Assessment and Water Research, Spanish Council for Scientific Research, Barcelona, Spain; and bLondon School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Tobías
authors.forename: Ben
authors.initials: B
authors.lastname: Armstrong
authors.forename: Antonio
authors.initials: A
authors.lastname: Gasparrini
mesh_terms: D002947:Cities; D016001:Confidence Intervals; D006801:Humans; D015233:Models, Statistical; D009026:Mortality; D013030:Spain; D013696:Temperature; D035501:Uncertainty