Shift work, parental cardiovascular disease and myocardial infarction in males

Effect of night shift work on the reduction of glomerular filtration rate using data from Korea Medical Institute (2016-2020)

Background

Shift work increases the risk of chronic diseases, including metabolic diseases. However, studies on the relationship between shift work and renal function are limited. The aim of this study was to investigate the association between shift work and a decreased glomerular filtration rate (GFR).

Methods

Data were evaluated for 1,324,930 workers who visited the Korean Medical Institute from January 1, 2016 to December 31, 2020 and underwent a health checkup. Daytime workers were randomly extracted at a ratio of 1:4 after matching for age and sex. In total, 18,190 workers aged over 40 years were included in the analyses; these included 3,638 shift workers and 14,552 daytime workers. Participants were categorized into the shift work group when they underwent a specific health checkup for night shift work or indicated that they were shift workers in the questionnaire. The odds ratio was calculated using a conditional logistic regression to investigate the relevance of shift work for changes in GFR.

Results

35 workers in the shift group and 54 in the daytime group exhibited an estimated GFR (eGFR) value of < 60 mL/min/1.73m2 (p < 0.01). The difference in eGFR values between two checkups differed significantly depending on the type of work (p < 0.01); the difference in the shift work group (-9.64 mL/min/1.73 m2) was larger than that in the daytime work group (-7.45 mL/min/1.73 m2). The odds ratio for eGFR reduction to < 60 mL/min/1.73 m2 in the shift group versus the daytime group was 4.07 (95% confidence interval: 2.54-6.52), which was statistically significant.

Conclusions

The results of this study suggest that eGFR decreases by a significantly larger value in shift workers than in daytime workers; thus, shift work could be a contributing factor for chronic kidney disease (CKD). Further prospective studies are necessary to validate this finding and identify measures to prevent CKD in shift workers.

Melatonin improves cardiac remodeling and brain-heart sympathetic hyperactivation aggravated by light disruption after myocardial infarction

Light in the external environment might affect cardiovascular function. The light disruption seems to be related to changes in cardiovascular physiological functions, and disturbing light may be a risk factor for cardiovascular diseases. Prior studies have found that light disruption after myocardial infarction (MI) exacerbates cardiac remodeling, and the brain-heart sympathetic nervous system may be one of the key mechanisms. However, how to improve light-disrupted cardiac remodeling remains unclear. Melatonin is an indoleamine secreted by the pineal gland and controlled by endogenous circadian oscillators within the suprachiasmatic nucleus, which is closely associated with light/dark cycle. This study aimed to explore whether melatonin could improve light-disrupted cardiac remodeling and modulate the brain-heart sympathetic nervous system. Our study revealed that light disruption reduced serum melatonin levels, aggravated cardiac sympathetic remodeling, caused overactivation of the brain-heart sympathetic nervous system, exacerbated cardiac dysfunction, and increased cardiac fibrosis after MI, while melatonin treatment improved light disruption-exacerbated cardiac remodeling and brain-heart sympathetic hyperactivation after MI. Furthermore, RNA-Seq results revealed the significant changes at the cardiac transcription level. In conclusion, melatonin may be a potential therapy for light-disrupted cardiac remodeling.

Re-evaluating the causes and consequences of non-resolving inflammation in chronic cardiovascular disease

Cardiac injuries, like heart attacks, drive the secondary pathology with advanced heart failure. In this process, non-resolving inflammation is a prime component of accelerated cardiovascular disease and subsequent fatal events associated with imbalanced diet, physical inactivity, disrupted circadian rhythms, neuro-hormonal stress, and poly- or co-medication. Laboratory rodents have established that splenic leukocyte-directed resolution mechanisms are essential for cardiac repair after injury. Here, we discuss the impact of three lifestyle-related factors that are prime causes of derailed cardiac healing, putative non-resolving inflammation-resolution mechanisms in cardiovascular diseases, and progressive heart failure after cardiac injury. The presented review resurfaces the lifestyle-related risks and future research directions required to understand the molecular and cellular mechanisms between the causes of cardiovascular disease and their related consequences of non-resolving inflammation.

Incidence of occupational injuries and diseases among seafarers: a descriptive epidemiological study based on contacts from onboard ships to the Italian Telemedical Maritime Assistance Service in Rome, Italy

OBJECTIVES

Workers at sea have high mortality, injuries and illnesses and work in a hazardous environment compared to ashore workers. The present study was designed to measure the incidence of occupational injuries and diseases among seafarers and quantify the contribution of differences in rank and job onboard on seafarers' diseases and injuries rates.

DESIGN

Descriptive epidemiological study.

SETTING AND PARTICIPANTS

This study's data were based on contacts (n=423) for medical requests from Compagnie Maritime d'Affrètement/Compagnie Générale Maritime (CMA-CGM) container ships to the Italian Telemedical Maritime Assistance Service in Rome from 2016 to 2019, supplemented by data on the estimated total at-risk seafarer population on container ships (n=13 475) over the study period.

OUTCOME MEASURES

Distribution of injuries by anatomic location and types of diseases across seafarers' ranks and worksites. We determined the incidence rate and incidence rate ratio (IRR) with a 95% CI.

RESULTS

The total disease rate was 25 per 1000 seafarer-years, and the overall injury rate was 6.31 per 1000 seafarer-years over the 4 years study period. Non-officers were more likely than officers to have reported gastrointestinal (IRR 2.12, 95% CI 1.13 to 4.26), dermatological (IRR 3.66, 95% CI 1.27 to 14.42) and musculoskeletal (IRR 2.25, 95% CI 1.11 to 5.05) disorders onboard container ships. Deck workers were more likely than engine workers to be injured in the wrist and hand (IRR 3.25, 95% CI 1.19 to 10.23).

CONCLUSIONS

Rates of reported injury and disease were significantly higher among non- officers than officers; thus, this study suggests the need for rank-specific preventative measures. Future studies should consider risk factors for injury and disease among seafarers in order to propose further preventive measures.

The Impact of the Circadian Genes CLOCK and ARNTL on Myocardial Infarction

The circadian rhythm regulates various physiological mechanisms, and its disruption can promote many disorders. Disturbance of endogenous circadian rhythms enhances the chance of myocardial infarction (MI), showing that circadian clock genes could have a crucial function in the onset of the disease. This case-control study was performed on 1057 participants. It was hypothesized that the polymorphisms of one nucleotide (SNP) in three circadian clock genes (CLOCK, ARNTL, and PER2) could be associated with MI. Statistically significant differences, estimated by the Chi-square test, were found in the distribution of alleles and genotypes between MI and no-MI groups of the CLOCK (rs6811520 and rs13124436) and ARNTL (rs3789327 and rs12363415) genes. According to the results of the present study, the polymorphisms in the CLOCK and ARNTL genes could be related to MI.

Association between shift work and obesity in a large sample of Iranian steel industry workers

Obesity is associated with several chronic diseases, and previous research suggests that shift work could be associated with the risk of overweight and obesity, but the results remain inconclusive. Furthermore, only a few studies report related findings for industrial workforce with high job-related stress. The aim of this cross-sectional study was to see if such association exists in a large sample of 3063 industrial workers in a developing country. The sample was selected among 16,000 steel company workers through multistage cluster sampling. We took anthropometric measurements, including body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR). Information about potential confounders was collected with a self-administered questionnaire. The association between shift work and both general and abdominal obesity was established with multinomial and binary logistic regression analysis. The study sample consisted of 1683 (54.9 %) rotational shift workers and 1380 (45.1 %) day workers. Shift work was significantly associated with higher risk of overweight after adjusting for the impacts of potential confounders (OR=1.2; 95 % CI:1.04-1.4) but not with abdominal obesity. This study established that shift work was an independent risk factor for overweight in industrial shift workers. Modification of working schedules is recommended, particularly for prolonged, continuous shift work.

Interaction between Shift Work and Established Coronary Risk Factors

Background:

Shift work is associated with increased risk of cardiovascular disease, but the causes have not yet been fully established. It has been proposed that the coronary risk factors are more hazardous for shift workers, resulting in a potential interaction effect with shift work.

Objective:

To analyse interaction effects of work schedule and established risk factors for coronary artery disease on the risk of myocardial infarction.

Methods:

This analysis was conducted in SHEEP/VHEEP, a case-control study conducted in two counties in Sweden, comprising all first-time cases of myocardial infarction among men and women 45–70 years of age with controls stratified by sex, age, and hospital catchment area, totalling to 4648 participants. Synergy index (SI) was used as the main outcome analysis method for interaction analysis.

Results:

There was an interaction effect between shift work and physical inactivity on the risk of myocardial infarction with SI of 2.05 (95% CI 1.07 to 3.92) for male shift workers. For female shift workers, interaction effects were found with high waist-hip ratio (SI 4.0, 95% CI 1.12 to 14.28) and elevated triglycerides (SI 5.69, 95% CI 1.67 to 19.38).

Conclusion:

Shift work and some established coronary risk factors have significant interactions.