Evaluation of Cognitive Deficits in Adults with Type 1 Diabetes Stratified by the Age of Diabetes Onset: A Cross-Sectional Study

Introduction Type 1 diabetes (T1DM) is associated with cognitive deficits, and age at diagnosis is thought to play a substantial role. However, there are limited data for the cognitive performance in young adults, in relation to the age of diabetes onset. The lack of information is particularly striking in the context of developing regions. Methods This cross-sectional study was performed from August 2018 to July 2020. We included adult participants with T1DM, stratified by the age of diabetes onset (till 6 years of age, between 7 to 12 years of age, and 13 to < 18 years of age) and compared them with the control group (no diabetes or pre-diabetes). We filled a structured case record proforma for all participants and recorded relevant socio-demographic and medical details. Detailed neuropsychological assessment with 13 psychological tests representing four cognitive domains was carried-(1) attention, working memory and executive functions; (2) learning and memory; (3) visuoperceptual functions; and (4) information processing speed. Results We evaluated 100 individuals, 73 (men 48.0%) with T1DM and 27 (men 51.9%) without T1DM. After adjustment for age, gender and education, the mean differences in composite Z scores (for the four cognitive domains) between participants with T1DM and without T1DM were 0.08 for attention, working memory and executive functions (p = 0.614); 0.07 for learning and memory (p = 0.694); 0.05 for visuoperceptual (p = 0.784); and 0.22 for information processing speed (p = 0.305). No significant differences were found for the three subgroups of individuals with T1DM, when compared with the control group. Effect size (Cohen's d) for the individual tests (n = 13) ranged from - 0.36 to + 0.39, and none of the comparisons were statistically significant. Amongst the participants with T1DM, higher education had a significant positive association with three of the four cognitive domains evaluated. Conclusions To conclude, our findings suggest minimal differences in the cognitive functioning of patients with T1DM with different age of onset of diabetes compared to healthy controls, when evaluated in early adulthood. This is possibly the first study from South Asia with an in-depth and comprehensive assessment of cognitive functions in patients with T1DM, using a detailed neuropsychological battery.