International Journal of Biometeorology

, Volume 50, Issue 2, pp 121–129 | Cite as

Impact of control for air pollution and respiratory epidemics on the estimated associations of temperature and daily mortality

  • Marie S. O’Neill
  • Shakoor Hajat
  • Antonella Zanobetti
  • Matiana Ramirez-Aguilar
  • Joel Schwartz
Original Article


We assessed the influence of control for air pollution and respiratory epidemics on associations between apparent temperature (AT) and daily mortality in Mexico City and Monterrey. Poisson regressions were fit to mortality among all ages, children (ages 0–14 years) and the elderly (ages ≥65 years). Predictors included mean daily AT, season, day of week and public holidays for the base model. Respiratory epidemics and air pollution (particulate matter <10 μm in aerodynamic diameter and O3) were added singly and then jointly for a fully adjusted model. Percent changes in mortality were calculated for days of relatively extreme temperatures [cold (10–11°C) for both cities and heat (35–36°C) for Monterrey], compared to days at the overall mean temperature in each city (15°C in Mexico City, 25°C in Monterrey). In Mexico City, total mortality increased 12.4% [95% confidence interval (CI) 10.5%, 14.5%] on cold days (fully adjusted). Among children, the adjusted association was similar [10.9% (95% CI: 5.4%, 16.7%)], but without control for pollution and epidemics, was nearly twice as large [19.7% (95% CI: 13.9%, 25.9)]. In Monterrey, the fully adjusted heat effect for all deaths was 18.7% (95% CI: 11.7%, 26.1%), a third lower than the unadjusted estimate; the heat effect was lower among children [5.5% (95% CI: −10.1%, 23.8%)]. Cold had a similar effect on all-age mortality as in Mexico City [11.7% (95% CI: 3.7%, 20.3%)]. Responses of the elderly differed little from all-ages responses in both cities. Associations between weather and health persisted even with control for air pollution and respiratory epidemics in two Mexican cities, but risk assessments and climate change adaptation programs are best informed by analyses that account for these potential confounders.


Temperature Mortality Weather Air pollution Mexico 


  1. Basu R, Samet J (2003) The relationship between elevated ambient temperature and mortality: a review of the epidemiologic evidence. Epidemiol Rev 24:190–202CrossRefGoogle Scholar
  2. Borja-Aburto VH, Loomis DP, Bangdiwala SI, Shy CM, Rascon-Pacheco RA (1997) Ozone, suspended particulates, and daily mortality in Mexico City. Am J Epidemiol 145:258–268PubMedGoogle Scholar
  3. Braga AL, Zanobetti A, Schwartz J (2000) Do respiratory epidemics confound the association between air pollution and daily deaths? Eur Respir J 16:723–728CrossRefPubMedGoogle Scholar
  4. Braga AL, Zanobetti A, Schwartz J (2001) The time course of weather related deaths. Epidemiology 12:662–667PubMedGoogle Scholar
  5. Braga ALF, Zanobetti A, Schwartz J (2002) The effect of weather on respiratory and cardiovascular deaths in 12 U.S. cities. Environ Health Perspect 110:859–863Google Scholar
  6. Brumback BA, Ryan LM, Schwartz J, Neas LM, Stark PC, Burge HA (2000) Transitional regression models with application to environmental time series. J Am Stat Assoc 95:16–28Google Scholar
  7. Curriero FC, Heiner KS, Samet JM, Zeger SL, Strug L, Patz JA (2002) Temperature and mortality in 11cities of the eastern United States. Am J Epidemiol 155:80–87CrossRefPubMedGoogle Scholar
  8. Dominici F, McDermott A, Zeger SL, Samet JM (2002) On the use of generalized additive models in time-series studies of air pollution and health. Am J Epidemiol 156:193–203CrossRefPubMedGoogle Scholar
  9. Easterling DR, Meehl GA, Parmesan C, Changnon SA, Karl TR, Mearns LO (2000) Climate extremes: observations, modeling, and impacts. Science 289:2068–2074CrossRefPubMedGoogle Scholar
  10. Gouveia N, Hajat S, Armstrong B (2003) Socio-economic differentials in the temperature-mortality relationship in Sao Paulo, Brazil. Int J Epidemiol 32Google Scholar
  11. Hajat S, Kovats RS, Atkinson RW, Haines A (2002) Impact of hot temperatures on death in London: a time series approach. J Epidemiol Community Health 56:367–372CrossRefPubMedGoogle Scholar
  12. Hastie TJ, Tibshirani RJ (1990) Generalized additive models. Chapman and Hall, LondonGoogle Scholar
  13. Health Effects Institute (2003) Special report: revised analyses of time-series studies of air pollution and health. Health Effects Institute, Boston, MA Scholar
  14. Hoeppe P (1999) The physiological equivalent temperature—a universal index for the biometeorological assessment of the thermal environment. Int J Biometeorol 43:71–75CrossRefPubMedGoogle Scholar
  15. Houghton JT, Ding Y, Griggs DJ, Noguer M, van der Linden PJ, Xiaosu D (eds) (2001) Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). Cambridge University Press, UKGoogle Scholar
  16. INEGI (2004) Vol. original source: Thomas BrinkhoffGoogle Scholar
  17. Kalkstein LS, Valimont KM (1986) An evaluation of summer discomfort in the United States using a relative climatological index. Bull Am Meteorol Soc 67:842–848CrossRefGoogle Scholar
  18. Karl TR, Knight RW, Plummer N (1995) Trends in high-frequency climate variability in the twentieth century. Nature 377:217–220CrossRefGoogle Scholar
  19. Katsouyanni K, Zmirou D, Spix C, Sunyer J, Schouten JP, Ponka A, Anderson HR, Le Moullec Y, Wojtyniak B, Vigotti MA, Bacharova L, Schwartz J (1997) Short-term effects of air pollution on health: a European approach using epidemiologic time series data. The APHEA Project. Air Pollution Health Effects—A European Approach. Public Health Rev 25:7–18; discussion 19–28PubMedGoogle Scholar
  20. Keatinge WR, Donaldson GC, Cordioli E, Martinelli M, Kunst AE, Mackenbach JP, Nayha S, Vuori I (2000) Heat related mortality in warm and cold regions of Europe: observational study. Br Med J 321:670–3Google Scholar
  21. Klinenberg E (2002) Heat wave: A social autopsy of disaster in Chicago. University of Chicago Press, Chicago, Ill.Google Scholar
  22. McCullagh P, Nelder JA (1989) Generalized linear models, 2nd edn. Chapman and Hall, LondonGoogle Scholar
  23. O’Neill MS, Zanobetti A, Schwartz J (2003) Modifiers of the temperature and mortality association in seven U.S. cities. Am J Epidemiol 157:1074–1082CrossRefPubMedGoogle Scholar
  24. O’Neill MS, Loomis D, Borja-Aburto VH (2004) Ozone, area social conditions, and mortality in Mexico City. Environ Res 94(3):234–242CrossRefPubMedGoogle Scholar
  25. Patashnick H, Rupprecht EG (1991) Continuous PM-10 measurements using the tapered element oscillating microbalance. J Air Waste Manage 41:1079–1083Google Scholar
  26. Romieu I, Ramirez-Aguilar M, Moreno-Macias H, Barraza-Villarreal A, Miller P, Hernandez-Cadena L, Carbajal-Arroyo LA, Hernandez-Avila M (2004). Infant mortality and air pollution: modifying effect by social class. Journal of Occupational & Environmental Medicine 46(12):1210–1216Google Scholar
  27. Semenza JC, Rubin CH, Falter KH, Selanikio JD, Flanders WD, Howe HL, Wilhelm JL (1996) Heat-related deaths during the July 1995 heat wave in Chicago. New Engl J Med 335:84–90CrossRefPubMedGoogle Scholar
  28. Semenza JC, McCullough JE, Flanders WD, McGeehin MA, Lumpkin JR (1999) Excess hospital admissions during the July 1995 heat wave in Chicago. Am J Prev Med 16:269–77CrossRefPubMedGoogle Scholar
  29. Steadman RG (1979) The assessment of sultriness. Part II. Effects of wind, extra radiation and barometric pressure on apparent temperature. J Appl Meteorol 18:874–885CrossRefGoogle Scholar
  30. Thurston GD, Ito K (2001) Epidemiological studies of acute ozone exposures and mortality. J Exp Anal Environ Epidemiol 11:286–294CrossRefGoogle Scholar
  31. Website Met-One (accessed April 7, 2004)
  32. Whitman S, Good G, Donoghue ER, Benbow N, Shou W, Mou S (1997) Mortality in Chicago attributed to the July 1995 heat wave. Am J Public Health 87:1515–1518PubMedGoogle Scholar
  33. Wilkinson P, McMichael T, Kovats S, Pattenden S, Hajat S, Armstrong B (2002) International study of temperature and heatwaves on urban mortality in low and middle income countries (ISOTHURM). Epidemiology 13:S81Google Scholar
  34. Wypij D (1996) Spline and smoothing approaches to fitting flexible models for the analysis of pulmonary function data. Am J Resp Crit Care 154:S223–S228Google Scholar

Copyright information

© ISB 2005

Authors and Affiliations

  • Marie S. O’Neill
    • 1
  • Shakoor Hajat
    • 2
  • Antonella Zanobetti
    • 3
  • Matiana Ramirez-Aguilar
    • 4
  • Joel Schwartz
    • 3
  1. 1.Department of EpidemiologyUniversity of MichiganAnn ArborUSA
  2. 2.London School of Hygiene and Tropical MedicinePublic and Environmental Health Research UnitLondonUK
  3. 3.Harvard School of Public HealthExposure, Epidemiology, and Risk ProgramBostonUSA
  4. 4.Instituto Nacional de Salud PúblicaAvenida Universidad 655CuernavacaMéxico

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