Hair graying may be caused by melanocyte stem cells (MSC) depletion by genotoxic stress in the hair bulge. Hair graying may also be sometimes caused by dysfunction of the melanocytes by oxidative stress in the hair bulb. In addition, hair graying may be attributable to MSC depletion by active hair growth. Graying is associated with age-related defects in MSC maintenance. Irreversible DNA damage caused by genotoxic stressors such as ionizing radiation interrupts MSC comeback in mice.

Hair graying is associated with various autoimmune disorders including vitiligo and several rare premature aging syndromes including the Hutchinson Gilford and Werner syndrome. Hair graying may also reflect nutritional deficiencies (especially of vitamins) and the use of drugs such as chloroquine.

We do not know exactly the cause of hair graying in humans.

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6029974/

We have the same thing. We’re all just old though.

I doubt that's caused by coffee. Hair graying is mostly genetics. Coffee does stain your teeth though.

Due to coffee or statistically?