Type 2 Diabetes: Also a “Clock Matter”?

Relationship of Social Jetlag and Chronotype With the Risk of Diabetes Among Predominantly Male Japanese Daytime Workers: A Prospective Study

Greater social jetlag and late chronotypes have been linked to poor glucose metabolism, but their effects on diabetes risk in Asians remain unclear. This study investigated the prospective association between social jetlag, chronotype and diabetes risk among Japanese workers. We included 1681 workers (73% were daytime workers) aged 18-78 years who attended a nutritional survey in 2015 and 2016 and were followed for diabetes incidence until May 31, 2022. Social jetlag was defined as the absolute difference in the midpoint of sleep times between weekdays and weekends. Chronotype was estimated using the mid-sleep time on weekends that was corrected with sleep debt on weekdays. Following the American Diabetes Association criteria, diabetes onset was defined as the time when the participant first met any of the following conditions: HbA1c ≥ 6.5%, fasting plasma glucose ≥ 126 mg/dL, random plasma glucose ≥ 200 mg/dL or current use of antidiabetic medication. The Cox proportional hazards model was used to estimate hazard ratios (HRs) for diabetes incidence. Among the study participants, 88.8% were male, 5.0% experienced ≥ 2 h of social jetlag, and 7.6% were classified as having a late chronotype. During the 7-year follow-up, 107 individuals (6.4%) developed diabetes. Among daytime workers, social jetlag was not associated with diabetes risk: multivariable-adjusted HRs (95% CI) for diabetes were 1.00, 0.90 (0.52-1.55) and 1.08 (0.43-2.75) in participants with < 1.0, 1.0 to 1.9, and ≥ 2.0 h of social jetlag, respectively. Late chronotype was associated with higher diabetes risk, although not statistically significant, compared to early chronotype; multivariable-adjusted HRs (95% CI) were 1.32 (0.80-2.18) for intermediate chronotype and 1.98 (0.77-5.10) for late chronotype. In conclusion, this study suggests an association between late chronotypes and increased risk of diabetes among daytime workers and also highlights a mediating role of lifestyle-related behaviours on chronotype and their impact on metabolic health.

Chronodisruption enhances inflammatory cytokine release from visceral adipose tissue in obesity

BACKGROUND

Chronodisruption, marked by circadian rhythm misalignment, is linked to inflammatory diseases like obesity. Chronotypes, reflecting individual circadian behavior, include morning, intermediate, and evening types, with evening chronotypes showing worse body composition and higher metabolic risk. This study evaluated the inflammatory profile of visceral adipose tissue (VAT) across chronotypes in individuals with obesity and examined clock gene expression.

METHODS

Twenty-five participants with obesity (11/14 F/M, BMI 41.59 ± 7.69 kg/m², age 41.13 ± 11.08 years) candidates for bariatric surgery were classified using the Morningness-Eveningness Questionnaire (MEQ): morning (36%), intermediate (28%), or evening (36%) chronotypes. VAT biopsies were analyzed for cytokines, chemokines, and growth factors via multiplex ELISA, and clock genes (PER1, CLOCK, BMAL1) were assessed using qPCR.

RESULTS

Body composition and biochemical parameters were similar across groups, but evening chronotypes had higher triglyceride levels (p = 0.012) and lower phase angle (p = 0.035). VAT inflammatory markers, including IL-1β (p = 0.04), IL-8 (p = 0.03), bFGF (p = 0.01), MCP-1 (p = 0.01), and MIP-1β (p = 0.05), were highest in evening and lowest in morning chronotypes. Evening chronotypes had significantly elevated bFGF levels compared to other groups (p = 0.04). PER1 mRNA expression was also higher in evening chronotypes (p = 0.02) and correlated with VAT-released bFGF (p = 0.03) and IL-1β (p = 0.03). MEQ scores negatively correlated with VAT bFGF (p = 0.02), MCP-1 (p = 0.02), and PER1 expressions.

CONCLUSION

Despite similar metabolic profiles, evening chronotypes exhibit heightened VAT inflammation and altered clock gene expression, potentially worsening their metabolic risk.

The Role of the Chronotype in Developing an Excessive Body Weight and Its Complications-A Narrative Review

The chronotype, the personal predisposition towards morning or evening activities, significantly influences health conditions, sleep, and eating regulations. Individuals with evening chronotypes are often at a higher risk for weight gain due to misalignment between their natural tendencies of functioning and social schedules, resulting in insufficient sleep, disruptions in eating habits, and decreased physical activity levels. Often, impaired glucose tolerance and changes in melatonin, adiponectin, and leptin secretion, along with alterations in the clock gene functions in subjects with evening preferences, may be predisposed to obesity. These disturbances contribute to metabolic dysregulation, which may lead to the subsequent onset of obesity complications, such as hypertension, type 2 diabetes, sleep apnea, and liver diseases. Targeting critical components of the circadian system and synchronizing people's chronotypes with lifestyle conditions could deliver potential strategies for preventing and treating metabolic disorders. Thus, it is recommended to take a personalized chronobiological approach to maintain a normal body weight and metabolic health. Nevertheless, future studies are needed to identify the clear mechanisms between the chronotype and human health. This article provides a narrative review and discussion of recent data to summarize studies on the circadian rhythm in the context of obesity. The manuscript represents a comprehensive overview conducted between August and November 2024 using the National Library of Medicine browser (Medline, Pub-Med, Web of Science).

Circadian dysfunction and cardio-metabolic disorders in humans

The topic of human circadian rhythms is not only attracting the attention of clinical researchers from various fields but also sparking a growing public interest. The circadian system comprises the central clock, located in the suprachiasmatic nucleus of the hypothalamus, and the peripheral clocks in various tissues that are interconnected; together they coordinate many daily activities, including sleep and wakefulness, physical activity, food intake, glucose sensitivity and cardiovascular functions. Disruption of circadian regulation seems to be associated with metabolic disorders (particularly impaired glucose tolerance) and cardiovascular disease. Previous clinical trials revealed that disturbance of the circadian system, specifically due to shift work, is associated with an increased risk of type 2 diabetes mellitus. This review is intended to provide clinicians who wish to implement knowledge of circadian disruption in diagnosis and strategies to avoid cardio-metabolic disease with a general overview of this topic.

Multi-omics Investigations in Endocrine Systems and Their Clinical Implications

Innovative techniques such as the "omics" can be a powerful tool for the understanding of intracellular pathways involved in homeostasis maintenance and identification of new potential therapeutic targets against endocrine-metabolic disorders. Over the last decades, proteomics has been extensively applied in the study of a wide variety of human diseases, including those involving the endocrine system. Among the most endocrine-related disorders investigated by proteomics in humans are diabetes mellitus and thyroid, pituitary, and reproductive system disorders. In diabetes, proteins implicated in insulin signaling, glucose metabolism, and β-cell activity have been investigated. In thyroid diseases, protein expression alterations were described in thyroid malignancies and autoimmune thyroid illnesses. Additionally, proteomics has been used to investigate the variations in protein expression in adrenal cancers and conditions, including Cushing's syndrome and Addison's disease. Pituitary tumors and disorders including acromegaly and hypopituitarism have been studied using proteomics to examine changes in protein expression. Reproductive problems such as polycystic ovarian syndrome and endometriosis are two examples of conditions where alterations in protein expression have been studied using proteomics. Proteomics has, in general, shed light on the molecular underpinnings of many endocrine-related illnesses and revealed promising biomarkers for both their detection and treatment. The capacity of proteomics to thoroughly and objectively examine complex protein mixtures is one of its main benefits. Mass spectrometry (MS) is a widely used method that identifies and measures proteins based on their mass-to-charge ratio and their fragmentation pattern. MS can perform the separation of proteins according to their physicochemical characteristics, such as hydrophobicity, charge, and size, in combination with liquid chromatography. Other proteomics techniques include protein arrays, which enable the simultaneous identification of several proteins in a single assay, and two-dimensional gel electrophoresis (2D-DIGE), which divides proteins depending on their isoelectric point and molecular weight. This chapter aims to summarize the most relevant proteomics data from targeted tissues, as well as the daily rhythmic variation of relevant biomarkers in both physiological and pathophysiological conditions within the involved endocrine system, especially because the actual modern lifestyle constantly imposes a chronic unentrained condition, which virtually affects all the circadian clock systems within human's body, being also correlated with innumerous endocrine-metabolic diseases.

Circadian Clock and Nutrition

Rhythmicity is a fundamental characteristic of every living organism [...].