Air pollution and Doctors’ House Calls for respiratory diseases in Greater Paris area (2000-2003)
Abstract
Objectives: This study describes the short term relationships between the daily levels of PM10, PM2.5, NO2 and the number of doctors’ house calls for asthma, upper and lower respiratory diseases in Greater Paris for the years 2000-2003. Doctors’ house calls are a relevant health indicator for the study of short-term health effects of air pollution. Indeed, it is potentially more sensitive than indicators such as general hospital admissions due to the slightest severity of the diseases motivating the call.
Methods: Time-series analysis were used. The daily numbers of doctor’s house calls were adjusted for time trends, seasonal factors, day of the week, influenza, weather and pollen. Up to 15 days of lag between the exposure and the health effects was considered using distributed lag models.
Results: A total of about 1,760,000 doctors’ house calls for all causes occurred during the study period, among which 8027 for asthma, 52,928 for lower respiratory diseases (LRD) and 74,845 for upper respiratory diseases (URD). No significant risk increase was found between air pollution and doctors’ house calls for asthma. No significant association was found between NO2 and doctors’ house calls. An increase of 10 µg/m3 in the mean levels of PM10 encountered during the 3 previous days was associated with an increase of 3 % [0.8 %; 5.3 %] in the number of doctor’s house calls for URD or LRD. An increase of 5.9 % [2.9 %; 9.0 %] was observed in association with an increase of 10 µg/m3 in the levels of PM2.5. Considering up to 15 days between exposure and health outcomes, effects persist until 4 days after exposure and then decrease progressively. No morbidity displacement was observed.
Conclusion: Our study shows a significant heath effect of ambient particles (PM2.5 and PM10). When compared to the relative risks obtained for mortality or hospital admissions in the same area, the values of the relative risks obtained in this study confirm the higher sensibility of doctor’s house calls for respiratory diseases as an health indicator.
