Age- and gender-specific dynamics and next-generation reference intervals for pepsinogen in northern China

Figure 2 Effects of age and sex on pepsinogen I, pepsinogen II, and pepsinogen I/II ratio levels. A: Pepsinogen (PG) I levels increase significantly with age, with males exhibiting higher levels than females; B: Similarly, PG II levels show an evident increase with age, with males having higher levels; C: PG I/II ratio remains relatively stable across different demographic groups. Although a slight downward trend with age was observed, no statistically significant differences were found. PG: Pepsinogen; PGR: Pepsinogen I/II ratio.