Abstract / Summary
Background/Objectives: Sleep health contributes to glucose homeostasis and metabolic regulation. We explored associations between subjective sleep characteristics, glycemic control, and diabetes-related clinical factors in adults with type 1 diabetes mellitus (T1DM). Methods: This exploratory cross-sectional, pilot investigation included 30 adults with T1DM at the Emergency Clinical County Hospital of Târgu Mureș between April 2025 and March 2026. We analyzed subjective sleep parameters, 90- and 14-day continuous glucose monitoring (CGM) data, clinical and laboratory parameters, diabetes distress and depression symptom scores. Results: Mean age was 39.0 ± 12.87 years, and 56.7% were male. Mean HbA1c was 7.28 ± 1.24%, 90-day time in range (TIR) was 61.47 ± 17.90%, and the coefficient of variation (CV) was 35.91 ± 6.71%. Mean nocturnal sleep duration was 7.15 ± 0.89 h, which was negatively correlated with mean afternoon nap duration on both weekdays (Pearson’s r = −0.492, 95% CI −0.739 to −0.124, n = 30, p = 0.009) and weekends (Pearson’s r = −0.481, 95% CI −0.736 to −0.119, n = 30, p = 0.012). Moreover, weekend sleep duration (p = 0.032, r = −0.401) was negatively correlated only with TIR assessed over 90 days. Social jetlag, self-reported sleep quality, the number of self-reported nocturnal awakenings, altered sleep duration on weekdays, and daytime napping were not significantly correlated with HbA1c or CGM-derived metrics (all p > 0.05). Mean subjective sleep quality score was 3.22 ± 0.87 on a five-point Likert scale. Restful sleep was reported only on half of the monitored nights; 20% had high risk for obstructive sleep apnea (OSA). Physical activity was positively correlated with TIR assessed over both 90 days (Pearson’s r = 0.446, 95% CI 0.144 to 0.606, n = 30, p = 0.025) and 14 days (Pearson’s r = 0.464, 95% CI 0.345 to 0.704, n = 30 p = 0.037). Conclusions: Among the assessed sleep characteristics, only weekend sleep duration was significantly associated with historical 90-day TIR, whereas physical activity was positively associated with TIR over both monitoring periods. Given the exploratory nature and small sample size of this study, larger longitudinal studies are needed to clarify the relationships between sleep health and glycemic control in adults with type 1 diabetes.