The present review has the objective of summarising chronobiological aspects of shift work and obesity. There was a systematic search in PubMed databases, using the following descriptors: shift work; obesity; biological clock. Shift work is extremely frequent in several services and industries, in order to systematise the needs for flexibility of the workforce, necessary to optimise productivity and business competitiveness. In developing countries, this population represents a considerable contingent workforce. Recently, studies showed that overweight and obesity are more prevalent in shift workers than day workers. In addition, the literature shows that shift workers seem to gain weight more often than those workers submitted to a usual work day. In conclusion, there is considerable epidemiological evidence that shift work is associated with increased risk for obesity, diabetes and CVD, perhaps as a result of physiological maladaptation to chronically sleeping and eating at abnormal circadian times. The impact of shift work on metabolism supports a possible pathway to the development of obesity and its co-morbities. The present review demonstrated the adverse cardiometabolic implications of circadian misalignment, as occurs chronically with shift workers.

Key words: HOMA-IR; insulin-resistance; insulin tolerance test

Objectives: The primary aim was to assess the psychometric properties (including internal consistency, construct validity, reproducibility, and factor structure) of the Central Sensitization Inventory (CSI), adapted and validated for a Brazilian population (CSI-BP). Additionally, we evaluated the relationship between the CSI-BP and the serum brain-derived neurotrophic factor (BDNF) and determined if the symptoms elicited by the CSI-BP discriminate between subjects who do/do not respond to the conditioned pain modulation (CPM) task, as assessed by change in numeric pain scale (0–10) score. Patients and methods: A cross-sectional study was conducted in a pain clinic in a tertiary teaching hospital. A total of 222 adults with chronic musculoskeletal pain and 63 healthy control subjects completed the CSI-BP and the Brazilian Portuguese pain-catastrophizing scale (BP-PCS). A team of experts translated the CSI according to the international guidelines. Test–retest, item analysis, convergent validity, and factor analysis were performed. Later, a random subsample (n=77) was used to correlate the CSI-BP adjusted index with change in numeric pain-scale score during the CPM task and a BDNF blood sample. Results: The CSI-BP presented strong psychometric properties (test–retest reliability 0.91, Cronbach’s a=0.91). Confirmatory factor analysis yielded a four-factor structure, supporting the original English version. The CSI-BP adjusted index showed moderate positive correlation with the BP-PCS, and classified more than 80% of patients correctly vs healthy controls. Serum BDNF levels explained 27% of the variation in the CSI-BP adjusted index. Subjects with impairment in the descending modulatory system had higher CSI-BP adjusted index scores than subjects who responded normally to the CPM task: 49.35 (12.1) vs 39.5 (12.33), respectively (P<0.05). Conclusion: The CSI-BP was found to be a psychometrically strong and reliable instrument, with primary evidence of validity. Higher scores on the CSI-BP were correlated positively with serum BDNF and with greater dysfunction of the descending pain-modulatory system.

Objective: This study compared urinary 6-sulfatoxymelatonin (aMT6s) over 24 hours among fibromyalgia (FM), major depression disorder (MDD), and healthy control (HC) groups, and examined whether rhythm is correlated with depressive symptoms. To answer this question we compared the rhythm of urinary aMT6s secretion among each group in four time series: morning (06:00–12:00 hours), afternoon (12:00–18:00 hours), evening (18:00–24:00 hours), and night (24:00–06:00 hours). In the FM subjects, we assessed if the rhythm of urinary aMT6s secretion is associated with pain severity, sleep quality, number of trigger points (NTPs), and the pain pressure threshold (PPT). Patients and methods: We included 54 women, aged 18–60 years with diagnosis of FM (n=18), MDD (n=19), and HC (n =17). The 24-hour urinary aMT6s was evaluated according to four standardized periods. The assessment instruments were the Hamilton Depression Rating Scale (HDRS), Pittsburgh Sleep Quality Index, and Fibromyalgia Impact Questionnaire. Results: A generalized estimating equation revealed no difference in the daily load of aMT6s secretion among the three groups (P=0.49). However, at the daily time (06:00–18:00 hours), the load secretion of aMT6s reached 41.54% and 60.71% in the FM and MDD, respectively, as compared to 20.73% in the HC (P<0.05). A higher score in the HDRS was positively correlated with the amount of aMT6s secretion during daytime (06:00–18:00 hours). Also, multivariate linear regression revealed that in FM subjects, the aMT6s secretion during daytime (06:00–18:00 hours) was negatively correlated with the PPTlog (partial η²=0.531, P=0.001). However, it was positively correlated with depressive symptoms (partial η²=0.317, P=0.01); PQSI (partial η²=0.306, P=0.017), and NTPs (partial η²=0.23, P=0.04). Conclusion: A more significant load of aMT6s secretion during daytime hours was observed in MDD and FM subjects compared to HC. These findings help to comprehend the biological basis of these disorders and show how disruption in melatonin secretion is positively correlated with clinical symptoms.

Avoidant restrictive food intake disorder (ARFID) is an eating disorder characterized by persistent insufficient nutritional and/or energy intake. ARFID, before referred to as “selective eating disorder”, was introduced recently in the DSM-5 as a replacement for and expansion of the previous diagnosis. Individuals with ARFID may limit food variety and intake due to avoidance based on the sensory characteristics of the food or related to any adverse consequences of eating without the intention of losing weight and concerns of body image. The limited understanding of avoidant and restrictive eating poses challenges to effective treatment and management, impacting directly on the growth and development of children and adolescents. The ARFID neurobiological concept has not yet been clearly defined to clinical practice for nutritionists, thereby hindering screening and impeding the development of treatment recommendations. This narrative review provide useful practical information to consult the pathophysiology, the neurobiology, the clinical features, the assessment and the treatment for healthcare professionals seeking to enhance their clinical knowledge and management of this disorder.

Background: Major depressive disorder (MDD) and fibromyalgia (FM) present overlapped symptoms. Although the connection between these two disorders has not been elucidated yet, the disruption of neuroplastic processes that mediate the equilibrium in the inhibitory systems stands out as a possible mechanism. Thus, the purpose of this cross-sectional exploratory study was: (i) to compare the motor cortex inhibition indexed by transcranial magnetic stimulation (TMS) measures [short intracortical inhibition (SICI) and intracortical facilitation (ICF)], as well as the function of descending pain modulatory systems (DPMS) among FM, MDD, and healthy subjects (HS); (ii) to compare SICI, ICF, and the role of DPMS evaluated by the change on Numerical Pain Scale (NPS) during the conditioned pain modulation test (CPM-test) between FM and MDD considering the BDNF-adjusted index; (iii) to assess the relationship between the role of DPMS and the BDNF-adjusted index, despite clinical diagnosis. Patients and Methods: A cohort of 63 women, aged 18 to 75 years [FM (n = 18), MDD (n = 19), and HC (n = 29)]. Results: The MANCOVA analysis revealed that the mean of SICI was 53.40% larger in FM compared to MDD [1.03 (0.50) vs. 0.55 (0.43)] and 66.99% larger compared to HC [1.03 (0.50) vs. 0.34 (0.19)], respectively. The inhibitory potency of the DPMS assessed by the change on the NPS during CPM-test was 112.29 % lower in the FM compared to MDD [0.22 (1.37) vs. −0.87 (1.49)]. The mean of BDNF from FM compared to MDD was 35.70% higher [49.82 (16.31) vs. 14.12 (8.86)]. In FM, the Spearman’s coefficient between the change in the NPS during CPM-test with the SICI was Rho = −0.49, [confidence interval (CI) 95%; −0.78 to −0.03]. The BDNF-adjusted index was positively correlated with the disinhibition of the DPMS. Conclusion: These findings support the hypothesis that in FM a deteriorated function of cortical inhibition, indexed by a higher SICI parameter, a lower function of the DPMS, together with a higher level of BDNF indicate that FM has different pathological substrates from depression. They suggest that an up-regulation phenomenon of intracortical inhibitory networks associated with a disruption of the DPMS function occurs in FM.