Influence of air pollution on congenital heart disease in Xi′an city: 2009 – 2016

  Objective  To explore the association of ambient air pollution with congenital heart disease (CHD) and to provide evidences for improving CHD prevention strategies.

  Methods  We collected the data on all reported CHD incidences diagnosed from pregnancy to 7th day after birth among all fetuses and newborns in Xi’an city of Shaanxi province from October 1, 2009 to September 30, 2016. Ambient air pollution monitoring data and meteorological data during the period were also retrieved. Monthly CHD incidence rate and average concentrations of air pollutants (sulfur dioxide SO₂, nitrogen dioxide NO₂, particulate matter < 10 micron in aerodynamic diameter PM₁₀, and particulate matter < 2.5 micron in aerodynamic diameter PM_2.5) were adopted in time series analysis to describe long-term variations in CHD incidence and air pollution. Spearman rank correlation was used to analyze the association of air pollutant concentration with CHD and in different lag months (lag 0 for the month of delivery and lag 12 for 12-month before delivery). Generalized Poisson addition model was used to assess effects of air pollutants on CHD incidence.

  Results  Totally 2 098 CHD incidents were reported, accounting for 18.7% of the total birth defects reported in Xi′an city during the period. The annual CHD incidence rate increased from 73.3 /10 000 in 2010 to 150.5/10 000 in 2015. The multiple pollutants model analysis revealed that an increased SO₂ of 10 μg/m³ during early pregnancy was correlated with a 48.5% increased risk of CHD in the newborns after adjusting for NO₂, PM₁₀, and PM_2.5 (relative risk = 1.485, 95% confidence interval: 1.441 – 1.530); the analysis results also demonstrated that increased NO₂ and PM₁₀ were probably related to CHD incidence after adjusting for other air pollutants; but the analysis showed no significant impact of PM_2.5 on CHD incidence.

  Conclusion  The incidence rate of congenital heart disease is increasing generally in Xi′an city and the increase may be related to ambient air pollution. Exposure to SO₂ during the first trimester of pregnancy may increase the risk of congenital heart disease.