Short-Term Effects of Ambient Air Pollution on Cardiovascular Diseases and Respiratory Disease in Northern Vietnam

Abstract

Objectives: This study investigated the short-term effects ambient air pollution with hospital admissions due to respiratory diseases and cardiovascular diseases in three provinces in Northern Vietnam.Methods: Hospital records of residences living in three provinces Ha noi, Phu Tho and Quang Ninh (Northern Vietnam) from national and provinces hospitals were extracted. We also obtained hourly means of ambient air pollutants (PM10, PM2.5, PM1, NO2, SO2, CO and O3) and meteorological factors in each province. Quasi-Poisson models were used to estimate the association between outcomes and atmospheric pollutants, controlling for other factors such as meteorology, holiday and influenza epidemics in each province. Specified outcomes in the analyses are asthma, chronic bronchitis, stroke, ischemic heart diseases.Results: Most ambient air pollutants were associated with increases in daily hospital admission due to respiratory hospitalizations and cardiovascular diseases. The strongest effects had been found in nitrogen dioxide (NO2) for hospitalization due to stroke and pneumonia in all ages. For example, increments of an interquartile range in the four-day average (lag0-3) level of NO2 (25.3µg/m3) were associated with 2.3% (95%CI: 0.7% - 4.6%) and 6.1% (95% CI 2.5% to 9.8%) increase in daily counts of admissions for pneumonia and stroke in Hanoi, respectively. CO concentrations were negatively associated with daily hospitalization for asthma but positively with all other outcomes in all provinces. The findings indicated that the effects differ between age groups and seasons.Conclusion: The internal consistency of the results in three provinces with wide differences in pollution sources suggests that the association of ambient air pollutions and hospital admissions also applies to Vietnam. Though relative risks are small, the related burden is large, thus, further reductions in air pollution in Vietnam will provide large benefits.