[Acute effect of air pollutants (carbon monoxide and ozone) on myocardial infarction mortality in Ningbo]

Abstract

Objective: To explore the effect of carbon monoxide (CO) and ozone (O(3)) in the air on the myocardial infarction mortality in Ningbo, Zhejiang province, from 2011 to 2015. Methods: The data of daily air quality surveillance and the causes of deaths in Ningbo from January 1, 2011 to December 31, 2015 were collected and the time series study using a generalized additive model was conducted to evaluate the relationship between the mortality of myocardial infarction and the air pollutants after adjustment for the long-term trend of death, weather conditions," days of the week" and other confounding factors. Results: The daily average concentrations of CO and O(3) in Ningbo during 2011-2015 were 0.90 (0.02-3.31) mg/m(3) and 82.78 (4-236) μg/m(3), respectively. A total of 5 388 myocardial infarction deaths occurred, with a daily average of 3 deaths. In single-pollutant model, an increase of 0.1 mg/m(3) in average concentration of CO could increase the risk of myocardial infarction mortality by 1.06% (95% CI: 0.29%-1.93%) in general population, and by 1.26% (95% CI:0.28%-2.24%) in aged people aged ≥65 years in lagged 6 days, but the influence was not significant in people aged <65 years. The influence had no significant difference in males, but it increased the risk of myocardial infarction mortality by 1.77% in females (95% CI: 0.44%-3.13%). In multi-pollutant model, CO did remain robust after adjusting for other co-pollutants. Whereas the effect of O(3) had no significant influence. Conclusion: These findings suggested that the increased risk of daily myocardial infarction mortality was associated with the increase of CO concentration, but no such association was found for O(3) in Ningbo.

Keywords: Air pollutants; Generalized additive model; Myocardial infarction; Time-series study.