Sleep variability, 6-sulfatoxymelatonin, and diabetic retinopathy.

PURPOSE: Recent evidence suggests that diabetic retinopathy (DR) is associated with abnormal melatonin regulation, possibly related to dysfunction of the melanopsin-expressing intrinsically photosensitive retinal ganglion cells. This study explored melatonin regulation in type 2 diabetes (T2D) patients with DR and its relation to sleep and circadian functioning. METHODS: Thirty-five participants (10 non-diabetic controls, 10 T2D without DR, and 15 T2D with DR) were recruited. Overnight urine 6-sulfatoxymelatonin (aMT6s) and objective sleep and wrist activity (7-day actigraphy) were obtained. RESULTS: After adjusting for covariates, having T2D with DR was significantly associated with lower urinary aMT6s (ß = - 1.369, p = 0.004) compared with controls, while having T2D without DR was not (p = 0.418). T2D patients with DR reported poorer sleep quality (p = 0.014) and had greater variability of sleep duration (p = 0.017) than others, while no differences were found in sleep duration, efficiency, and rest-activity rhythm. After adjusting for covariates, lower nocturnal aMT6s was significantly associated with greater sleep variability. CONCLUSION: T2D patients with DR exhibited low overnight production of aMT6s which likely contributed to sleep irregularities possibly due to weak circadian signaling. Whether or not melatonin supplementation could improve health in T2D patients with DR remains to be explored.

Lack of associations between thyroid function and obstructive sleep apnea severity in adults with prediabetes and diabetes mellitus.

PURPOSE: Hypothyroidism is associated with a high frequency of obstructive sleep apnea (OSA). However, the prevalence of OSA in hypothyroid patients is not different from the general population in many reports. The importance of thyroid function screening in sleep-disordered breathing is still controversial. This study aimed to explore the association between thyroid dysfunction and OSA in the adults with prediabetes or diabetes mellitus type 2, who have very high prevalence of OSA. METHODS: OSA was assessed using an in-home monitoring device, WatchPAT200. OSA severity was measured using apnea-hypopnea index (AHI), oxygen desaturation index (ODI), minimum oxygen saturation (minO2), and time spent under oxygen saturation < 90% (T90). Patients with pre-existing thyroid dysfunction were excluded. RESULTS: Participants included 70 men and 118 women with mean age 52.8 ± 10.9 years and body mass index 28.2 ± 4.9 kg/m2. One hundred forty participants (75%) had OSA, with a median AHI of 10.1 (interquartile range 4.8, 18.3). The percentage of positive thyroid autoantibody (thyroperoxidase and thyroglobulin antibody) was similar among the subjects with and without OSA. There was no correlation between the levels of thyroid function (TSH, FT3, FT4, TSH/FT3, and TSH/FT4 ratio) and the severity indices of OSA (AHI, ODI, minO2, and T90). CONCLUSIONS: These data do not support universal screening for thyroid dysfunction in OSA patients with diabetes or prediabetes.

Instrumental Acoustic Voice Characteristics in Adults with Type 2 Diabetes.

OBJECTIVE: The objective of this study was to investigate if there are differences in acoustic parameters between diabetic patients and normal controls. METHODS: A prospective cross-sectional study was performed in 83 diabetic patients and 70 healthy controls. Voice parameters including fundamental frequency (F0), jitter, shimmer, amplitude perturbation quotient, noise-to-harmonic ratio, smoothed amplitude perturbation quotient, and relative average perturbation were analyzed using Computerized Speech Lab with the Multi-Dimensional Voice Program. RESULTS: F0 in female diabetic patients was significantly lower than controls (222.23 ± 27.89 Hz versus 241.08 ± 28.21 Hz, P< 0.01). In female diabetic subgroups with disease duration more than 10 years, poor glycemic control, or neuropathy, the F0 was still significantly lower. Multivariate analysis showed that F0 was significantly associated with diabetes after controlled for age, body mass index, presence of hypertension, and dyslipidemia. (P= 0.022). However, F0 was not able to predict the presence of diabetes as shown by logistic regression analysis (P= 0.243). CONCLUSIONS: Voice fundamental frequency is lower in females with diabetes. However, voice fundamental frequency cannot adequately predict the presence of diabetes.