Luciana da Conceição Antunes

Obesity and shift work: chronobiological aspects.

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.

Correlation of shift work and waist circumference, body mass index, chronotype and depressive symptoms

OBJECTIVE Correlate shift work with body mass index (BMI), waist circumference, chronotype and depressive symptoms. SUBJECTS AND METHODS This study comprising 14 shift workers and 13 day workers. Subjects were workers from the health area aged 25 to 60 years. Minor psychiatric disorders were accessed by Self Report Questionnaire (SRQ-20) and depressive symptoms by Beck Depression Inventory (BDI). Chronotype was accessed using Morningness-Eveningness Questionnaire (MEQ). Anthropometric measures were taken. RESULTS Shift workers presented higher BMI (P = 0.03) and waist circumference (P = 0.004) than day workers. Years on shift work were significantly correlated to waist circumference (r = 0.43; P = 0.03) and age (r = 0.47; P = 0.02). Shift work was not correlated with depressive symptoms and chronotype. CONCLUSION These results may suggest a role played by shift work on the development and/or the early clinic manifestations of metabolic disturbances, becoming a risk factor to metabolic syndrome.

The Central Sensitization Inventory validated and adapted for a Brazilian population: psychometric properties and its relationship with brain-derived neurotrophic factor

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 α=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.

Distinct aspects of pain catastrophizing according to chronic pain syndromes

Introduction: Catastrophizing is the tendency to magnify the threat value of pain and has been associated with measures of physical and psychological disability among individuals with several pain conditions. The aim of this study was to investigate whether pain catastrophizing is differentially associated with distinct pain syndromes. Methods: This is a cross-sectional study including 158 patients (40 with fibromyalgia, 25 with myofascial pain syndrome, 33 with chronic tensional type headache, 33 with endometriosis, and 27 with knee osteoarthritis) and 93 healthy subjects. The recruitment procedure occurred in concurrence with randomized controlled trials. Participants answered the following instruments: Brazilian Portuguese Pain-Catastrophizing Scale, Beck Depression Inventory II, State-Trait Anxiety Inventory, Pittsburgh Sleep Quality Index, visual analogue scale for pain, as well as a sociodemographic questionnaire. Results: For the total pain catastrophizing score, patients with endometriosis had significantly more catastrophizing thoughts than knee osteoarthritis (p < 0.05). Healthy participants had lower scores than any clinical group. More interestingly were the dimensions of pain catastrophizing, which showed significant differences in more than two groups, especially magnification scores, since these scores were able to discriminate, in a particular way, the majority of clinical samples from each other. We also observed differences between rumination, magnification and helplessness scores in all groups, suggesting that the characteristics of pain catastrophizing are distinct according to the pain disorder. Conclusions: The results suggest that dimensions of pain catastrophizing differ between pain syndromes. Therefore, it is important that researchers and clinicians focus on cognitive and emotional aspects of pain perception to have more successful interventions. Keywords: Chronic pain; catastrophizing; cross-sectional study

Fasting ghrelin but not PYY(3-36) is associated with insulin-resistance independently of body weight in Wistar rats

OBJECTIVE The objective of this study was to evaluate the association between insulin-resistance and fasting levels of ghrelin and PYY in Wistar rats. MATERIALS AND METHODS A total of 25 male Wistar rats, weighing 200-300 g, was included in this study. The animals were maintained in cages with a 12/12h light-dark cycle and fed standard chow and water ad libitum. After 12-h overnight fasting, ghrelin, PYY, insulin and glucose values were determined. Insulin resistance was assessed by means of the HOMA-IR, which was ranked and the median was used as a cut-off value to categorize insulin-resistance. HOMA-IR values equal and above 2.62 were considered insulin-resistant (IR) while values below 2.62 were considered insulin sensitive (IS). Differences between means were determined using the Student t-test. Multiple regression and Pearsons correlation test were used to evaluate the association between variables. RESULTS HOMA-IR median IQ range values for IS and IR groups were, respectively, 1.56 (0.89 - 2.16) vs. [4.06 (3.50 - 4.61); p < 0.001]. The IR group presented increased levels of fasting ghrelin, PYY and insulin respectively: [50.35 (25.99 - 74.71) pg/mL vs. 12.33 (8.77 - 15.89) pg/mL; p = 0.001]; [54.38 (37.50 - 71.26) pg/mL vs. 33.17 (22.34 - 43.99) pg/mL; p = 0.016]; [18.04 (14.48 - 21.60) uU/mL vs. 7.09 (4.83 - 9.35) uU/mL; p = 0.001]. Ghrelin, but not PYY, correlated linearly and positively with HOMA-IR: ghrelin vs. HOMA-IR (r = 0.52; p = 0.008), and PYY vs. HOMA-IR (r = 0.22; p = 0.200). This correlation was independent of body weight. CONCLUSION Fasting ghrelin and PYY serum levels are increased in lean, relatively insulin resistant Wistar rats, and this increase is independent of weight.