PLOD1 and type 2 diabetes mellitus: In the present study, we found that LH and FSH both started to increase obviously approximately from the age of 45 years among patients with T2DM, and displayed peaks of LH and FSH among patients with T2DM aged between 61 and 65, both of which were obviously earlier than that in non-T2DM controls; meanwhile, E2 started to decrease obviously approximately from the age of 40 years among patients with T2DM, while it started to decrease obviously approximately from the age of 45 years among non-T2DM controls (Figure 2).