Sex- and season-dependent differences in C-peptide levels at diagnosis of immune-mediated type 1 diabetes

Abstract

Aims/hypothesis: The incidence of type 1 diabetes varies according to age, sex and season of diagnosis. We investigated whether these and other clinical, biological and anthropometric parameters were correlated with residual beta cell function in newly diagnosed patients, since it is possible that the nature of external and/or genetic disease accelerators may be (partly) reflected in the inaugural disease presentation. Materials and methods: The correlates of random Cpeptide levels sampled shortly after diagnosis (median [interquartile range]: 3 [0-14] days) were studied by multivariate analysis in 1,883 islet-antibody-positive diabetic patients aged <40 years who were diagnosed between 1989 and 2000. Results: Higher C-peptide levels (above percentile 50 of patients) were associated with older age at diagnosis, female sex, diagnosis in the high-incidence season (October to March), less-decreased BMI (expressed as a standard deviation score), lower insulin requirements after stabilisation, lower prevalence of ketonuria and a less-increased glycaemia at diagnosis (all p<0.001). C-peptide levels were not correlated with calendar year at diagnosis, duration of symptoms prior to diagnosis, HLA-DQ2/DQ8 genotype or islet antibody status.Conclusions/interpretation: Sex-and seasondependent differences in residual functional beta cell mass and/or insulin resistance have been identified at diagnosis of type 1 diabetes. They may reflect differences in disease-precipitating external or lifestyle factors and should be further investigated longitudinally in prediabetes to further identify putative aetiological factors, which may provide targets for prevention.

HLA-DQ genotypes - but not immune markers - differ by ethnicity in patients with childhood onset type 1 diabetes residing in Belgium

“…The same study showed that overweight or obese children with newly diagnosed T1D had a greater preservation of β‐cell function compared to lean children. Our work confirmed this correlation between random C‐peptide level and BMI SDS, as well as with age at diagnosis, suggesting that younger patients have lower C‐peptide levels at diagnosis and a more rapid decline in β‐cell function, reflecting the aggressiveness of T1D disease process in younger age . In 1998, Dorchy et al showed that the subgroup of diabetic children younger than 8 yr of age had lower C‐peptide level at diagnosis than the subgroup aged 8–14 yr .…”

Distribution of C-Peptide and Its Determinants in North American Children at Risk for Type 1 Diabetes

“…This may suggest that boys with autoimmunity are less likely to progress to overt disease than comparable girls and that the pathogenesis of T1D among boys may be slower compared with girls. Overall β-cell function may need to be further reduced in boys than in girls to progress to T1D (32,33). In addition, girls may have less insulin sensitivity owing to higher BMIZ than boys at the same age.…”

The effect of birth order and parental age on the risk of type 1 and 2 diabetes among young adults

“…Compared with childhood-onset type 1 diabetes, late-onset type 1 diabetic patients seem to have higher C-peptide values at diagnosis [38], disease progression is slower [39], and there are differences in epidemiological patterns [11]. It has been suggested that the environmental factors that trigger type 1 diabetes might be different in adult-onset disease [39].…”