Night work is related to higher global and central adiposity in Brazil: National Health Survey, 2013

Shift Work and Metabolic Syndrome Updates: A Systematic Review

Shift work can cause circadian cycles disturbances and misaligns the endogenous rhythms. The physiological variables are driven by the circadian system and, its misalignment, can impair the metabolic functions. Thus, the main objective of this study was to evaluate the metabolic alterations as a result of shift work and night work reported in articles published in the last 5 years, using the eligibility criteria both gender and indexed articles in English language. In order to execute this work, we perform a systematic review according to PRISMA guidelines and searched about Chronobiology Disorders and Night Work, both related to metabolism, in Medline, Lilacs, ScienceDirect and Cochrane. Cross-sectional, cohort and experimental studies with low risk of bias were included. We found a total of 132 articles, and, after the selection process, 16 articles remained to be analyzed. It was observed that shift work can cause circadian misalignment and, consequently, some metabolic parameters alterations such as an impaired glycemic control and insulin functioning, cortisol phase release, cholesterol fractions imbalance, changes in morphological indexes and melatonin secretion. There are some limitations, such as heterogenicity in used databases and the 5 years restriction period, because the effects of sleep disturbance may have been reported earlier. In conclusion, we suggest that shift work interferes with the sleep-wake cycle and eating patterns, which cause crucial physiological alterations that, together, can lead to metabolic syndrome.

Relationship Between Rotating Night Shift Work and Anthropometric Markers of Overall and Central Adiposity

Purpose

This study aimed to investigate possible association between rotating night shift (RNS) work and anthropometric markers of overall and central adiposity among male workers.

Methods

Medical records of workers who underwent medical examination at the Occupational Medicine Unit affiliated with Alexandria Faculty of Medicine were reviewed in December 2021 to extract data about RNS, overall adiposity [body mass index (BMI) from 25 to 29.9 kg/m² indicated overweight, while BMI ≥30 kg/m² indicated obesity], central adiposity (waist circumference ≥94 cm). Univariate and multivariate logistic regression were done to model adiposity as a function of potential demographic, lifestyle, and occupational factors.

Results

Data of 647 male workers, including daytime workers (26.9%) and RNS workers (73.1%) who spent 1-5 years, 6-9 years, or ≥10 years working RNS, were analyzed. No association was found between RNS work and overall adiposity (BMI ≥30 kg/m²). In multivariate regression, age, residence, and smoking status were predictors of an increased BMI. Compared with young workers (<30 years old), the odds of an increased BMI (BMI ≥25 kg/m²) were 2.6 and 3.01 times higher among workers who were 30-<40, and 40-<50 years old, respectively [95% CI=(1.35, 5.05) and (1.19, 7.56), respectively]. Workers who lived in urban areas were less likely to have had an increased BMI (OR=0.34, 95% CI=0.16, 0.74). The odds of an increased BMI were 2.14 times higher in workers who never smoked compared with current smokers (95% CI=1.12, 4.11). No association was found between RNS and central adiposity. In multivariate regression, age was the sole predictor of central adiposity.

Conclusion

The study supports the idea that RNS work might not be associated with overall or central adiposity and highlights a possible association between central adiposity and age and association between BMI and age, residence, and smoking behavior. Longitudinal, larger studies are required to explore the relationship between RNS and adiposity.

Metabolic syndrome and cardiovascular diseases: Going beyond traditional risk factors

Metabolic syndrome (MS) is a chronic non-infective syndrome characterised clinically by a set of vascular risk factors that include insulin resistance, hypertension, abdominal obesity, impaired glucose metabolism, and dyslipidaemia. These risk factors are due to a pro-inflammatory state, oxidative stress, haemodynamic dysfunction, and ischaemia, which overlap in 'dysmetabolic' patients. This review aimed to evaluate the relationship between the traditional components of MS with cardiovascular disease (CVD), inflammation, and oxidative stress. MEDLINE-PubMed, EMBASE, and Cochrane databases were searched. Chronic low-grade inflammatory states and metaflammation are often accompanied by metabolic changes directly related to CVD incidence, such as diabetes mellitus, hypertension, and obesity. Moreover, the metaflammation is characterised by an increase in the serum concentration of pro-inflammatory cytokines, mainly interleukin-1 β (IL-1β), IL-6, and tumour necrosis factor-α (TNF-α), originating from the chronically inflamed adipose tissue and associated with oxidative stress. The increase of reactive oxygen species overloads the antioxidant systems causing post-translational alterations of proteins, lipids, and DNA leading to oxidative stress. Hyperglycaemia contributes to the increase in oxidative stress and the production of advanced glycosylation end products (AGEs) which are related to cellular and molecular dysfunction. Oxidative stress and inflammation are associated with cellular senescence and CVD. CVD should not be seen only as being triggered by classical MS risk factors. Atherosclerosis is a multifactorial pathological process with several triggering and aetiopathogenic mechanisms. Its medium and long-term repercussions, however, invariably constitute a significant cause of morbidity and mortality. Implementing preventive and therapeutic measures against oxy-reductive imbalances and metaflammation states has unquestionable potential for favourable clinical outcomes in cardiovascular medicine.