Short-term joint effects of ambient air pollutants on emergency department visits for respiratory and circulatory diseases in Colombia, 2011-2014.

BACKGROUND: We evaluated the short-term effect of mixtures of ambient air pollutants on respiratory and circulatory morbidity in four Colombian cities. METHODS: Daily Emergency Department (ED) visit records for respiratory and circulatory selected diagnosis and daily concentrations for six criteria air pollutant were obtained in four of the five major cities in Colombia: Bucaramanga, Bogota, Cali, and Medellin during 2011-2014. Using conditional Poisson time series analysis with fixed effects, we assessed the effect of air pollutants on health outcomes using single-pollutant, two-pollutant and specific mixtures-of-pollutant models controlling for meteorology and time trends. The percentages of change in the rate of ED visits and their 95% confidence interval were estimated for the joint effect of pollutants. RESULTS: In single-pollutant models increases in gases concentrations were associated with increases in ED visits for respiratory and circulatory diseases. The two-pollutant models for respiratory diseases showed that the effect of NO2 alone (% change 2.86 95% CI 1.87-3.85) is higher than the joint effect of any of its combinations except for its combination with SO2 (% change 3.05 95%CI 1.04-5.05). The two-pollutant models for circulatory diseases showed synergistic effects between NO2 and PM2.5 (% change 2.13 95%CI 0.001-4.26). Specific mixtures models showed that the mixture of "traffic-related pollutants" has the higher joint effect on circulatory morbidity and respiratory morbidity. CONCLUSIONS: The results show the dominant effect of NO2 in air pollution mixtures on respiratory and circulatory morbidity, and the synergistic effect of NO2 and SO2 in air pollution mixtures on respiratory morbidity.

Short-Term Effects of Air Pollution on Respiratory and Circulatory Morbidity in Colombia 2011⁻2014: A Multi-City, Time-Series Analysis.

Few studies have been conducted on the effect of air pollution on morbidity in Latin America. This study analyzed the effects of air pollution on respiratory and circulatory morbidity in four major cities in Colombia. An ecological time-series analysis was conducted with pollution data from air quality monitoring networks and information on emergency department visits between 2011 and 2014. Daily 24-h averages were calculated for NO2, PM10, PM2.5, and SO2 as well as 8-h averages for CO and O3. Separate time-series were constructed by disease group and pollutant. Conditional negative binomial regression models were used with average population effects. Effects were calculated for the same day and were adjusted for weather conditions, age groups, and their interactions. The results showed that effects of some of the pollutants differed among the cities. For NO2, PM10, and PM2.5, the multi-city models showed greater and statistically significant percentage increases in emergency department visits for respiratory diseases, particularly for the 5 to 9-year-old age group. These same pollutants also significantly affected the rate of emergency department visits for circulatory diseases, especially for the group of persons over 60 years of age.