Hi Andrei:
I just wanted to point out one quick thing I noticed here: if you're leaking to the degree that you need protection (absorbent products / adult diapers), it is important that you speak to a medical professional so that they can rule out any serious causes of incontinence. I don't want to assume that you haven't already spoken to a doctor, but in case anyone else is reading this (or in case you haven't seen a doctor), I just want to point out that people often assume that leakage is "normal" as they age, when in fact it is never "normal" - it always is a symptom of something working incorrectly in the body.
To address your question, you might find this SharePost helpful about nocturia: http://www.healthcentral.com/incontinence/c/45/12997/nocturia/