INS and type 2 diabetes mellitus: Eighty-five per cent (104/123) of all participants meeting criteria for type 1 diabetes (C-peptide <200 pmol/l and insulin therapy within 3 years) in the cohort diagnosed >30 were treated with insulin within 1 year of diagnosis (78% [104/133] for those defined by low C-peptide only) vs 18% (55/306) of those meeting criteria for type 2 diabetes (Fig. 1).