I only tell people about health issues if it is relevant to the situation. Back pain that means I can't stand for long, or gut problems that mean I may need the loo more frequently, or whatever. The same applies to my blood glucose. It is need to know.
Of course I witter about it endlessly on this forum (captive audience who can skip my posts if they are too boring), and it is a major part of my life since it dictates every mouthful I eat and drink. But I never bother telling a waiter or aquaintance. In fact I am MUCH more vocal about the gluten free thing, since that is harder to monitor and if I get it wrong I have 2 weeks of 'consequences'.
One pet hate I have is when people around me are unable to shut up about their own health. The food allergies. The symptoms of their menopause, headache, itchy mozzie bites, blood pressure, the hangnail, and yes, their chronic health conditions too... I'm not interested in their self obsessions. I have enough of my own. And I am not going to tell them about mine because the day is too short and I actually fancy a non-self-obsessed bit of communication please.
My family is small, and they all know - but it took 4 years for me to tell all 3 of them. In fact I think I only told them when my father got his T2 membership.
None of my 11 in laws know. Can't be bothered to explain. They read the Daily Mail, so no point.
My boss knows I am T2 and do 'a wacky food allergy/low carb thing'. She is T2 and eats Weight Watchers Ready Meals, so we don't have much in common.
My husband is a star, a hero and utterly supportive. I don't deserve him, and he knows everything.