GAD1 and diabetes mellitus: In a multivariable linear regression analysis including age, sex, race, ethnicity, BMI percentile, C-peptide, presence of DKA, GAD antibody positivity, IA-2 antibody positivity, unknown diabetes type at diagnosis was associated with older age (p = 0.047), negative IA-2 autoantibody (p = 0.005), lower C-peptide (p = 0.004), and absence of DKA (p = 0.024) after adjustment for confounding factors (Table 2).