Figure 1
From: Short and long term exposure to air pollution increases the risk of ischemic heart disease
A schematic illustration of the participant selection process used in the present study. Of 1,125,691 participants, 2155 ischemic heart disease participants were matched with 8620 control participants for age, group, sex, income group, and region of residence. Then, ischemic heart disease patients and control participants were matched according to the meteorological data and air pollution data before the index date.
