Particulate Matter and Malaria: A Case-Control Study

Abstract

ISEE-0821 Background and Objective: It has been hypothesized that smoke from the burning of biomass fuels could offer some protection against malaria, particularly in regions where the use of these fuels with traditional stoves is prevalent. Smoke may discourage mosquitoes from entering or resting in houses. The aim of this study was to investigate the effects of smoke in the sleeping rooms on the risk of clinical malaria in children in Nouna, Burkina Faso, a region with very high rates of biomass use. Methods: This case-control study examined differences in sleeping room PM10 concentrations and exposures in households of children ≤9 years old. Seventy-seven confirmed cases of malaria were matched to 141 community controls. Data collection involved interviews, visual inspections, measurements of area PM10 concentrations and mosquito captures within sleeping rooms. Results: Mean area sleeping room concentrations were 329 μg/m3 for cases and 245 μg/m3 for controls. Mean exposures were 2760 μg/m3 hrs and 2680 μg/m3 hrs for cases and controls, respectively. Univariate analyses indicated a significant difference between cases and controls, particularly with exposures of PM10 ≥1000 μg/m3 hrs (OR = 0.40, 95%CI: 0.20–0.81). Additional multivariate analyses adjusting for several sleeping area characteristics such as reported bed net use, door area and holes or spaces in the sleeping area did not result in any significant changes to this relationship. Analyses with sleeping area behaviours such as the number of persons in the same room as the case or control, waking time and bed time also did not show an effect. Surprisingly, counts of Anopheles gambiae were not found to be significantly correlated with either PM10 concentrations or exposure. Conclusions: These results could suggest that PM10 may offer some protection against clinical malaria and that the relationship is not modified by sleeping room behaviours or characteristics. The lack of association with mosquito counts may need further investigation.