> There was a significantly increased risk of all-cause mortality among female drinkers who drank 25 or more grams [of ethanol] per day and among male drinkers who drank 45 or more grams per day.

25 g is about 32 mL; 45 g => 57 mL. At 80 proof (40% ABV), that's 80 mL (2.7 US fl oz) or 143 mL (4.8 US fl oz) of liquor. A shot glass is ~1.5 US fl oz. (Or 640-1140mL => 22-39 fl oz of 5% beer, for women and men respectively.) So this is something like 2-3 "standard drink units."