Air pollution and risk of respiratory and cardiovascular hospitalizations in the most populous city in Vietnam

<p id="sp0030">Air pollution has become an alarming issue in Vietnam recently; however, there was only one study so far on the effects of ambient air pollution on population health. Our study aimed to investigate the short-term effects of air pollutants including PM₁₀, NO₂, SO₂, and O₃ on respiratory and cardiovascular hospitalizations in Ho Chi Minh City (HCMC), the largest city in Vietnam. Data on hospitalization from the two largest hospitals in HCMC and daily records of PM₁₀, NO₂, SO₂, O₃ and meteorological data were collected from February 2004 to December 2007. A time-series regression analysis with distributed lag model was applied for data analysis. Changes in levels of NO₂ and PM₁₀ were strongly associated with hospital admissions for both respiratory and cardiovascular diseases (CVD); whereas levels of SO₂ were only moderately associated with respiratory and CVD hospital admissions and O₃ concentration was not associated with any of them. For a 10 μg/m³ increase of each air pollutant, the risk of respiratory admissions increased from 0.7% to 8% while the risk of CVD admissions increased from 0.5% to 4%. Females were found to be more sensitive than males to exposure to air pollutants in regard to respiratory diseases. In regard to CVD, females (RR, 1.04, 95% CI, 1.01 - 1.07) had a slightly higher risk of admissions than males (RR, 1.03, 95% CI, 1 - 1.06) to exposure to NO₂. In contrast, males (RR, 1.007, 95%CI, 1 - 1.01) had a higher risk of admission than females (RR, 1.004, 95%CI, 1.001 - 1.007) to exposure to PM₁₀. People in the age group of 5 - 65 year-olds had a slightly higher risk of admissions caused by air pollutants than the elderly (65 + years old) except for a significant effect of PM₁₀ on the risk of cardiovascular admissions was found for the elderly only.