As this thread is presumably aimed at T1s (from the title), who are automatically considered at higher risk of CVD events, I googled to see what I could find about statins and T1s.
Looks like there may be an associated increase of 2mmol/mol in hba1c.
Statins are independently associated with increased HbA1c in type 1 diabetes--The Thousand & 1 Study - PubMed (nih.gov)
There are some papers saying it may impair your beta cell response, but that's not really relevant to someone whose beta cells are defunct...
Not great, but the real question for me is what it does to our risk of heart disease, already significant because of the T1. As a T1 for 52 years I'm on bp tablets and both my parents had CVD events, so I'm definitely in the zone for this.
I've been on statins for ten years and can't say I've noticed any positive or negative effects from them, other than a reduction in my cholesterol levels when I take them.
I have also been taking blood pressure tablets for 30 years, to reduce my levels when they went high in my late twenties. Given that high blood pressure has a detrimental effect both on kidneys and eyes I can't say for sure that this is why I still haven't needed any eye treatment and my kidneys are still working OK, but I must admit I'm happy with the result.
As a T1 I'm a big fan of medication where appropriate (hello insulin). My GPs just obey the party line on statins, but my endocrinologists are keen on me taking them, as a T1. I raise the subject every so often, but my levels do go up significantly if I stop taking them, so I continue (albeit on a low dose).
I think you have to do your own research and look at your own personal risk factors. And remember that people tend to be vocal if they have a bad reaction to a medication, less so if it doesn't seem to have any effect
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The trouble with taking a drug as a preventative is that if you don't get the thing it's preventing then you never know whether it's because or in spite of the drug.