Relationship of meteorological factors and air pollutants with medical care utilization for gastroesophageal reflux disease in urban area

Figure 1 Granger causality test of the relationship between meteorological factors and air pollutants and GERD-related medical utilization. A: Various meteorological factors and air pollutants (MFAPs) show a direct or indirect association with GERD-related medical utilization; B: Relationship between the five selected MFAPs and GERD-related medical utilization. All variables were significantly correlated except AT and WS. The five selected MFAPs were significantly correlated to GERD-related medical utilization. MFAPs: Meteorological factors and air pollutants; GERD: Gastroesophageal reflux disease; WS: Wind speed; SD: Sunshine duration; AT: Average temperature; CO: Carbon monoxide; PM_2.5: Particulate matter with a diameter ≤ 2.5 µm.