Fig. 2

Incidence rate and adjusted hazard ratio of COPD. Incidence rates are presented as a bar graph. Adjusted hazard ratios were presented with 95% confidence intervals as a line graph. Body mass index 21.0–21.9 kg/m2 was the reference value for the hazard ratio. The value of the X-axis represents the body mass index value as a 1 kg/m2 interval (e.g., 20 represents 20–20.9 kg/m2). (A) total, (B) male, (C) female. IR: incidence rate, aHR: adjusted hazard ratio, BMI: body mass index.