I was 55 when I stopped drinking, now 58. The stats (in Australia) say that there's a lot of problem drinking among older middle aged people, not binge drinking but sheer volume. That makes sense to me as I've seen a lot of my friends' intake gradually increase once the kids became independent. It might start with a wine in the evening, but if you're pre-disposed, it builds up until before you know it you can drink a bottle without blinking.
A lot of middle aged drinking happens in nice houses with waged people who don't make a fuss, just head off to bed, so it can be invisible.
Excessive drinking in middle age can cause all sorts of mental and physical damage and it's often kept secret from the doctor.