The Australian National Diabetes Services Scheme (NDSS) have tracked an increasing longevity in people with T1D (type 1 diabetes) since they beginning of their monitoring in 1997. From an average of 68.8 years in 1997, up to 70 years in men and 71.3 years in women in 2010.
However when compared to the rest of the population; current thinking is that the average person with T1D lives 12.2 years fewer.

Reference: https://pubmed.ncbi.nlm.nih.gov/26796634/ & https://www.aihw.gov.au/getmedia/c164ec7c-fc66-4991-8e53-62eba274ead4/aihw-cvd-79.pdf.aspx