The protective effect of vitamin D supplementation as adjunctive therapy to antidepressants on brain structural and functional connectivity of patients with major depressive disorder: a randomized controlled trial.

BACKGROUND: Growing evidence points to the pivotal role of vitamin D in the pathophysiology and treatment of major depressive disorder (MDD). However, there is a paucity of longitudinal research investigating the effects of vitamin D supplementation on the brain of MDD patients. METHODS: We conducted a double-blind randomized controlled trial in 46 MDD patients, who were randomly allocated into either VD (antidepressant medication + vitamin D supplementation) or NVD (antidepressant medication + placebos) groups. Data from diffusion tensor imaging, resting-state functional MRI, serum vitamin D concentration, and clinical symptoms were obtained at baseline and after an average of 7 months of intervention. RESULTS: Both VD and NVD groups showed significant improvement in depression and anxiety symptoms but with no significant differences between the two groups. However, a greater increase in serum vitamin D concentration was found to be associated with greater improvement in depression and anxiety symptoms in VD group. More importantly, neuroimaging data demonstrated disrupted white matter integrity of right inferior fronto-occipital fasciculus along with decreased functional connectivity between right frontoparietal and medial visual networks after intervention in NVD group, but no changes in VD group. CONCLUSIONS: These findings suggest that vitamin D supplementation as adjunctive therapy to antidepressants may not only contribute to improvement in clinical symptoms but also help preserve brain structural and functional connectivity in MDD patients.

Association between exposure to outdoor artificial light at night during pregnancy and glucose homeostasis: A prospective cohort study.

BACKGROUND: Outdoor artificial light at night (ALAN) has been linked to an elevated risk of diabetes, but the available literature on the relationships between ALAN and glucose homeostasis in pregnancy is limited. METHODS: A prospective cohort study of 6730 pregnant women was conducted in Hefei, China. Outdoor ALAN exposure was estimated using satellite data with individual addresses at a spatial resolution of approximately 1 km, and the average ALAN intensity was calculated. Gestational diabetes mellitus (GDM) was diagnosed based on a standard 75-g oral glucose tolerance test. Multivariable linear regression and logistic regression were used to estimate the relationships between ALAN and glucose homeostasis. RESULTS: Outdoor ALAN was associated with elevated glucose homeostasis markers in the first trimester, but not GDM risk. An increase in the interquartile range of outdoor ALAN values was related to a 0.02 (95% confidence interval [CI]: 0.00, 0.03) mmol/L higher fasting plasma glucose, a 0.42 (95% CI: 0.30, 0.54) µU/mL increase in insulin and a 0.09 (95% CI: 0.07, 0.12) increase in homeostatic model assessment of insulin resistance (HOMA-IR) during the first trimester. Subgroup analyses showed that the associations between outdoor ALAN exposure and fasting plasma glucose, insulin, and HOMA-IR were more pronounced among pregnant women who conceived in summer and autumn. CONCLUSIONS: The results provided evidence that brighter outdoor ALAN in the first trimester was related to elevated glucose intolerance in pregnancy, especially in pregnant women conceived in summer and autumn, and effective strategies are needed to prevent and manage light pollution.

Circadian rhythms of melatonin and its relationship with anhedonia in patients with mood disorders: a cross-sectional study.

BACKGROUND: Mood disorders are strongly associated with melatonin disturbances. However, it is unclear whether there is a difference in melatonin concentrations and melatonin circadian rhythm profiles between depression and bipolar disorder. In addition, the relationship between anhedonia, a common symptom of affective disorders, and its melatonin circadian rhythm remains under-investigated. METHODS: Thirty-four patients with depression disorder, 20 patients diagnosed with bipolar disorder and 21 healthy controls participated in this study. The Revised Physical Anhedonia Scale (RPAS) was performed to assess anhedonia. Saliva samples were collected from all subjects at fixed time points (a total of 14 points) in two consecutive days for measuring the melatonin concentrations to fit circadian rhythms of subjects. Melatonin circadian rhythms were compared between the three groups using ANOVA. Partial correlation analysis and linear regression analysis were used to explore the correlation between melatonin rhythm variables and anhedonia. RESULTS: We found that the peak phase of melatonin in the depression group was significantly advanced compared to the control group (P < 0.001) and the bipolar disorder group (P = 0.004). The peak phase of melatonin and RPAS showed a negative correlation (P = 0.003) in depression patients, which was also demonstrated in the multiple linear regression model (B=-2.47, P = 0.006). CONCLUSIONS: These results suggest that circadian rhythms of melatonin are differentiated in depression and bipolar disorder and correlate with anhedonia in depression. Future research needs to explore the neurobiological mechanisms linking anhedonia and melatonin circadian rhythms in depressed patients.

Abnormal amplitude of low-frequency fluctuations associated with sleep efficiency in major depressive disorder.

BACKGROUND: Sleep disturbance is one of the most frequent somatic symptoms in major depressive disorder (MDD), but the neural mechanisms behind it are not well understood. Sleep efficiency (SE) is a good indicator of early awakening and difficulty falling asleep in MDD patients. Our study aimed to investigate the relationship between sleep efficiency and brain function in MDD patients. METHODS: We recruited 131 MDD patients from the Fourth People's Hospital in Hefei, and 71 well-matched healthy controls who were enrolled from the community. All subjects underwent resting-state functional MRI. Brain function was measured using the fractional amplitude of low-frequency fluctuation (fALFF), sleep efficiency was objectively measured by polysomnography (PSG), and clinical scales were used to evaluate depressive symptoms and sleep status. Multivariate regression analysis was performed to assess the relationship between the amplitude of the low frequency fluctuation fraction and sleep efficiency. RESULT: Three brain regions with relevance to sleep efficiency in MDD patients were found: inferior occipital gyrus (Number of voxels = 25, peak MNI coordinate x/y/z = -42/-81/-6, Peak intensity = 4.3148), middle occipital gyrus (Number of voxels = 55, peak MNI coordinate x/y/z = -30/-78/18, Peak intensity = 5.111), and postcentral gyrus (Number of voxels = 26, peak MNI coordinate x/y/z = -27/-33/60, Peak intensity = 4.1263). But there was no significant relationship between fALFF and SE in the healthy controls. CONCLUSION: The reduced sleep efficiency in MDD may be related to their lower neural activity in the inferior occipital gyrus, middle occipital gyrus, and postcentral gyrus. The findings may provide a potential neuroimaging basis for the clinical intervention in patients with major depressive disorder with sleep disturbances.

Association between ambient particulate matters and anhedonia among patients with depression.

Recent studies have linked ambient air pollution to depression. Anhedonia is a core symptom of depression which severely impacts on prognosis. The present study aims to investigate the association of PM2.5 and PM10 exposure with anhedonia in depressed patients. A total of 538 patients with depression who were hospitalized at the Fourth People's Hospital of Hefei between June 2017 and December 2021 were included. We estimated ambient particulate matters exposure, including PM2.5 and PM10, using a satellite-based spatiotemporal model at a resolution of 1 km2. The revised Physical Anhedonia Scale (RPAS) and the revised Social Anhedonia Scale (RSAS) were evaluated. The association of ambient particulate matters and anhedonia was examined using multiple linear regression models, adjusted for potential confounders. We observed that exposure to PM2.5 were significantly associated with increased RSAS score and RPAS score, with the major effect in the 12-month exposure window (ß = 1.238; 95%CI, 0.353, 2.123) and 18-month exposure window (ß = 1.888; 95%CI, 0.699, 3.078), respectively. Meanwhile, PM10 levels were also significantly associated with increased RSAS score and RPAS score, with the major effect in the 18-month exposure window (ß = 1.220; 95%CI, 0.439, 2) and 3-month exposure window (ß = 1.602; 95%CI, 0.062, 3.143), respectively. Subgroup analysis showed that both PM2.5 and PM10 were significantly associated with anhedonia in females, patients < 40 years old, low family income group, and those who had a higher educational level. Our study suggests that long-term PM2.5 and PM10 exposure are associated with more severe anhedonia in patients with depression. These associations were different in subgroup by age, gender, family income, and educational level.