Cochlear, auditory brainstem responses in Type 1 diabetes: relationship with metabolic variables and diabetic complications

AIMS

Few studies have analysed the presence of hearing abnormalities in diabetes. We assessed the presence of subclinical auditory alterations and their possible association with early vascular and neurological dysfunction in young adults with Type 1 diabetes of long duration.

METHODS

Thirty-one patients with Type 1 diabetes (mean age 33 ± 2.3 years, disease duration 25.7 ± 4.2 years) and 10 healthy controls underwent pure tone audiometry (PTA), distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) analyses. Associations with metabolic variables and chronic complications were explored.

RESULTS

Compared with healthy controls, patients with diabetes had significantly higher mean hearing thresholds, although still within the normoacusic range. DPOAE intensities at medium frequencies (2.8-4 kHz) were significantly lower in patients with diabetes. In ABR, in addition to waves I, III and V, we observed the appearance of a visible wave IV in patients with diabetes compared with controls (prevalence 61% vs. 10%, P < 0.05), and its appearance was related to a prolonged I-V interval (4.40 ± 0.62 ms vs. 4.19 ± 0.58 ms, P < 0.05). Diastolic blood pressure was higher in people with abnormal DPOAE (P < 0.05), whereas systolic blood pressure correlated with wave V and interpeak I-V interval latencies. A trend towards an association between evidence of wave IV and the presence of somatic neuropathy or abnormal cardiovascular autonomic tests was observed.

CONCLUSIONS

Young adults with long-term Type 1 diabetes have subclinical abnormalities in qualitative auditory perception, despite normal hearing thresholds, which might reflect neuropathic and/or vascular alterations.

Diagnosis of type 1 diabetes within the first five years of life influences quality of life and risk of severe hypoglycemia in adulthood

Progressive adaptation to disease is paramount to improve quality of life (QoL) and other psychological dimensions in type 1 diabetes (T1DM). This study aimed at identifying possible correlations between QoL, locus of control (LoC) and clinical variables in patients with T1DM followed up for 16 years. Fifty-nine patients (27 women) with T1DM, part of a cohort of 112 followed since 1996, accepted to participate. Patients were divided into those in whom onset of T1DM had been during the first 5 years of life (n = 16) or later. They were also stratified into worsened, stable and improved, based on whether their HbA1c had increased/decreased by 1 percentage point between baseline and last follow-up visit. QoL was measured by the Diabetes Quality of Life questionnaire (DQOL), translated into Italian and re-validated. The LoC was measured by the Peyrot- and Rubin-specific questionnaire. Patients who developed T1DM before age 5 had a better total DQOL score than those who developed it later in life, mainly due to the satisfaction dimension and a tendency to decreased fatalism in adult age. All subjects whose HbA1c had worsened from baseline had had their diagnosis after age 5 and reported more frequent episodes of hypoglycemia. Onset of diabetes after age 5 and more frequent hypoglycemia was more likely in subjects with worsened HbA1c (ORs 7.6, p < 0.10 and 20.3, p < 0.01, respectively, from a multivariate logistic model with HbA1c, dichotomized in 'worsened' vs all others, as dependent variable). Onset of T1DM during the first 5 years of life may result in better QoL and less fatalism in the long term. Presumably, these patients have no memory of disease onset, which may reduce trauma and facilitate adaptation to managing life with diabetes.