WOOD-BURNING STOVES AND LOWER RESPIRATORY ILLNESSES IN NAVAJO CHILDREN

Background. Acute lower respiratory illnesses (ALRI) have been associa ted with exposure to domestic smoke. To examine further this associati on, a case-control study was conducted among Navajo children seen at t he Public Health Service Indian Hospital at Fort Defiance, AZ. Methods . Cases, children hospitalized with an ALRI (n = 45), were ascertained from the inpatient logs during October, 1992, through March, 1993. Co ntrols, children who had a health record at the same hospital and had never been hospitalized for ALRI, were matched 1:1 to cases on date of birth and gender. Home interviews of parents of subjects during March and April, 1993, elicited information on heating and cooking fuels an d other household characteristics. Indoor air samples were collected f or determination of time-weighted average concentrations of respirable particles (i.e. <10 mu m in diameter). Results. Age of cases at the t ime of admission ranged from 1 to 24 months (median, 7 months); 60% of the cases were male. Matched pair analysis revealed an increased risk of ALRI for children living in households that cooked with any wood ( odds ratio (OR), 5.0; 95% confidence interval (CI), 0.6 to 42.8), had indoor air concentrations of respirable particles greater than or equa l to 65 mu g/m(3) (i.e. 90th percentile) (OB 7.0, 95% CI 0.9 to 56.9), and where the primary caretaker was other than the mother (OR 9, 95% CI 1.1 to 71.4). Individual adjustment for potential confounders resul ted in minor change (i.e. <20%) in these results. Indoor air concentra tion of respirable particles was positively correlated with cooking an d heating with wood (P < 0.02) but not with other sources of combustio n emissions. Conclusions. Cooking with wood-burning stoves was associa ted with higher indoor air concentrations of respirable particles and with an increased risk of ALRI in Navajo children.