Vulnerability to heat-related mortality in Latin America: a case-crossover study in Sao Paulo, Brazil, Santiago, Chile and Mexico City, Mexico.
BACKGROUND
Factors affecting vulnerability to heat-related mortality are not well understood. Identifying susceptible populations is of particular importance given anticipated rising temperatures from climatic change.


METHODS
We investigated heat-related mortality for three Latin American cities (Mexico City, Mexico; São Paulo, Brazil; Santiago, Chile) using a case-crossover approach for 754 291 deaths from 1998 to 2002. We considered lagged exposures, confounding by air pollution, cause of death and susceptibilities by educational attainment, age and sex.


RESULTS
Same and previous day apparent temperature were most strongly associated with mortality risk. Effect estimates remained positive though lowered after adjustment for ozone or PM(10). Susceptibility increased with age in all cities. The increase in mortality risk for those >or=65 comparing the 95th and 75th percentiles of same-day apparent temperature was 2.69% (95% CI: -2.06 to 7.88%) for Santiago, 6.51% (95% CI: 3.57-9.52%) for São Paulo and 3.22% (95% CI: 0.93-5.57%) for Mexico City. Patterns of vulnerability by education and sex differed across communities. Effect estimates were higher for women than men in Mexico City, and higher for men elsewhere, although results by sex were not appreciably different for any city. In São Paulo, those with less education were more susceptible, whereas no distinct patterns by education were observed in the other cities.


CONCLUSIONS
Elevated temperatures are associated with mortality risk in these Latin American cities, with the strongest associations in São Paulo, the hottest city. The elderly are an important population for targeted prevention measures, but vulnerability by sex and education differed by city.
Bell
Michelle L
ML
EnvironmentalHealth, Yale University, New Haven, CT06511, USA. michelle.bell@yale.edu
O'Neill
Marie S
MS
Ranjit
Nalini
N
Borja-Aburto
Victor H
VH
Cifuentes
Luis A
LA
Gouveia
Nelson C
NC
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000393:Air Pollutants / Q000633:toxicity; D001938:Brazil; D002648:Child; D002675:Child, Preschool; D002677:Chile; D002947:Cities; D018592:Cross-Over Studies; D004522:Educational Status; D005260:Female; D005583:Fourier Analysis; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008800:Mexico; D008875:Middle Aged; D009026:Mortality; D010126:Ozone / Q000633:toxicity; D052638:Particulate Matter; D012737:Sex Factors; D055815:Young Adult
D000393:Air Pollutants; D052638:Particulate Matter; D010126:Ozone