Infant mortality and air pollution: modifying effect by social class.
Studies link air pollution with increased mortality; however, information on infants is scarce and inconclusive.


OBJECTIVE
We studied short-term PM10 exposure, relating to increased respiratory-related infant mortality, and estimated for poor living conditions.


METHODS
A case-crossover approach modeled the relationship between infant mortality (1 month-1 year of age), and ambient PM10 levels on days before death in Ciudad Juarez, Mexico (1997-2001). Socioeconomic level (SES) of the deceased was defined by residence location.


RESULTS
Overall air pollutants did not affect infant mortality (odds ratio [OR] = 1.02, 95% confidence interval [CI] = 0.94-1.11 for PM10, lag1) but low SES increased risk. Each 20 microg/m3 in PM10 (24-hour average, lag1, cumulative over 2 previous days) increased respiratory-related mortality (OR = 1.61, 95% CI = 0.97-2.66; OR = 2.56; 95% CI = 1.06-6.17, respectively). Ozone levels did not affect infant mortality for any SES.


CONCLUSIONS
Worse living conditions among lower SES concurred with increased mortality.
Romieu
Isabelle
I
Instituto Nacional de Salud Pública, Av Universidad 655, Col. Santa. Ma., Ahuacatitlan, Cuernavaca Morelos 65708, Mexico. iromieu@correo.insp.mx
Ramírez-Aguilar
Matiana
M
Moreno-Macias
Hortensia
H
Barraza-Villarreal
Albino
A
Miller
Paul
P
Hernández-Cadena
Leticia
L
Carbajal-Arroyo
Luz Aurora
LA
Hernandez-Avila
Mauricio
M
D000393:Air Pollutants / Q000032:analysis; D000397:Air Pollution / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D008800:Mexico / Q000453:epidemiology; D012111:Residence Characteristics; D012140:Respiratory Tract Diseases / Q000401:mortality; D012923:Social Class; D012959:Socioeconomic Factors
D000393:Air Pollutants