Association between night shift work and NAFLD: a prospective analysis of 281,280 UK Biobank participants

Associations of ambient air pollution and lifestyle with the risk of NAFLD: a population-based cohort study

BACKGROUND

Both ambient air pollution and lifestyle factors contribute to the incidence of non-alcoholic fatty liver disease (NAFLD), but previous studies usually focused on single-factor associations. We aimed to assess the joint associations of ambient air pollution and lifestyle with the NAFLD risk and investigate whether lifestyle modifies the association of air pollution with NAFLD risk.

METHODS

A total of 417,025 participants from the UK Biobank were included in this study. Annual average concentrations of NO2, NOx, PM2.5, PM10, and PM2.5-10 were estimated. A composite lifestyle score was determined based on physical activity, alcohol intake, smoking status, dietary patterns, sedentary time, and sleep duration. Cox proportional hazards regression models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs), as well as the population attributable fraction (PAF). Potential additive interactions of air pollution with lifestyle were also examined by the relative excess risk due to the interaction (RERI) and the attributable proportion due to the interaction (AP).

RESULTS

4752 (1.14%) incident NAFLD events were recorded. Long-term exposure to air pollutants and an unhealthy lifestyle were significantly associated with the increased risk of incident NAFLD. Lifestyle was the primary factor of incident NAFLD, with a PAF of 37.18% (95% CI: 29.67%, 44.69%). In addition, a significant additive interaction between air pollution and lifestyle for NAFLD risk was observed (RERI: 0.36, 95% CI: 0.09-0.63).

CONCLUSIONS

Long-term exposure to ambient air pollutants and poor lifestyle were jointly associated with a higher risk of NAFLD.

Shift work and non-alcoholic fatty liver disease in young, healthy workers

Non-alcoholic fatty liver disease (NAFLD) is a relatively common disease, and preventing its occurrence is important for both individual health and reducing social costs. Shift work is reported to have several negative effects on health. An association has been observed between NAFLD and both sleep time and quality; however, this association remains unclear in night shift workers. We aimed to evaluate the relationship between shift work and the incidence of NAFLD. Overall, 45,149 Korean workers without NAFLD were included at baseline. NAFLD was defined as the presence of a fatty liver observed on ultrasonography without excessive alcohol use. incidence rate ratios for incident NAFLD were estimated using negative binomial regression according to age groups (20s, 30s, 40s, and 50s). In the 20s age group, shift work showed a significant incidence rate ratio (IRR) for NAFLD in all models. After adjusting for all variables, the IRR (95% confidence interval) was 1.24 (1.08-1.43) in the 20s age group. In their 20s, a significant association between shift work and incident NAFLD was consistently observed among women and workers with poor sleep quality. In this large-scale cohort study, shift work was significantly associated with the development of NAFLD among young workers in their 20s.

Associations between systemic inflammation indicators and nonalcoholic fatty liver disease: evidence from a prospective study

Background

Although inflammation has been linked to nonalcoholic fatty liver disease (NAFLD), most studies have focused only on a single indicator, leading to inconsistent results. Therefore, a large prospective study that includes a variety of well-documented single and composite indicators of inflammation is needed. This study aimed to thoroughly investigate the potential associations between different systemic inflammatory indicators and NAFLD in the UK Biobank cohort.

Methods

After excluding ineligible participants, 378,139 individuals were included in the study. Associations between systemic inflammatory indicators and hepatic steatosis were assessed using multivariate logistic regression. The relationships between systemic inflammatory indicators and nonalcoholic fatty liver disease were analysed using Cox proportional hazards models, and nonlinear associations were investigated using restricted cubic splines.

Results

According to the cross-sectional analysis, systemic inflammatory indicators significantly correlated with hepatic steatosis. Over a median follow-up of 13.9 years, 4,145 individuals developed NAFLD. After sufficient adjustment for confounding factors, CRP levels were found to be nonlinearly positively associated with NAFLD risk (P<0.001), representing the strongest correlation among the tested relationships; lymphocyte count and the LMR showed an L-shaped correlation; monocyte count and neutrophil count showed a linear positive correlation (all P< 0.001); and the NLR, PLR, and SII showed a U-shaped correlation (all P<0.001).

Conclusions

Multiple systemic inflammatory indicators are strongly associated with the development of NAFLD, and aggressive systemic inflammation management may have a favourable impact on reducing the burden of NAFLD; further randomized controlled studies are needed.

Nonalcoholic Fatty Liver Disease in Shift Workers and Its Effect on Peripheral Nerve Conduction: A Cross-Sectional Study

Introduction Nonalcoholic fatty liver disease (NAFLD) presents as a multisystem disorder, heightening the risk of developing type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVDs). Occupation emerges as a significant factor influencing the occurrence of NAFLD. Research indicates that individuals engaged in shift work face an elevated risk of NAFLD, alongside obesity and T2DM, attributed to disruptions in their circadian rhythm, which precipitate hepatic steatosis and inflammation. Remarkably, peripheral neuropathy has been observed in conjunction with advanced liver disorders and NAFLD in the general population. However, the correlation between NAFLD and peripheral neuropathy remains unestablished in shift workers. Objective To identify NAFLD in seemingly healthy rotating shift workers and assess any potential impact of NAFLD on nerve function in this demographic. Methods This cross-sectional study involved 73 apparently healthy nonalcoholic security guards (aged 35 to 60 years) working in rotating shifts. The study included a comprehensive assessment, beginning with a medical history, an evaluation of physical activity, and anthropometric measurements. Confirmation of NAFLD was achieved through abdominal ultrasonography (USG), followed by the analysis of biochemical parameters. Motor and sensory nerve conduction studies (NCS) were conducted on participants with normal vitamin B12 levels using the Aleron electromyograph (EMG) machine (Recorders and Medicare Systems Private Ltd, Budanpur, India). The evaluation encompassed the Median and Common Peroneal motor nerves, as well as Median and Sural sensory nerves. Recorded parameters for motor nerves included distal motor latency (DML), compound muscle action potential (CMAP) amplitude, conduction velocity (CV), and F-wave minimum latency (F-wave), while sensory nerve parameters comprised sensory onset latency (SOL), sensory nerve action potential (SNAP) amplitude, and CV. Results Among 73 healthy security guards working in rotating shifts, 76.1% were diagnosed with NAFLD through abdominal ultrasound. Following participant withdrawals and exclusions due to vitamin B12 deficiency, a comparison of NCS parameters between NAFLD (n=24) and Non-NAFLD (n=12) groups revealed no significant disparities in motor or sensory parameters, except for a slightly diminished CMAP amplitude in the peroneal nerve of NAFLD subjects (8.21±2.83mV vs ±10.22±2.30 mV, p< 0.040). However, these differences fell within normal ranges, indicating no notable impact on peripheral nerve conduction in the presence of NAFLD. Conclusion The results indicate a high prevalence of NAFLD among individuals working rotating shifts. Moreover, the investigation suggests that despite the presence of NAFLD, there is no discernible influence on motor and sensory peripheral nerve conduction, particularly in common peroneal, median, and sural nerves.

Effects of Oat β-Glucan and Inulin on Alleviation of Nonalcoholic Steatohepatitis Aggravated by Circadian Disruption in C57BL/6J Mice

This was the first study that examined the effects of oat β-glucan and inulin on diet-induced nonalcoholic steatohepatitis (NASH) in circadian-disrupted (CD)-male C57BL/6J mice. CD intensified NASH, significantly increasing alanine aminotransferase and upregulating hepatic tumor necrosis factor α (TNFα) and transforming growth factor β 1 (TGFβ1). However, these observations were significantly alleviated by oat β-glucan and inulin treatments. Compared to CD NASH mice, oat β-glucan significantly decreased the liver index, aspartate aminotransferase (AST), and insulin. In prebiotic-treated and CD NASH mice, significant negative correlations were found between enrichment of Muribaculaceae bacterium Isolate-036 (Harlan), Muribaculaceae bacterium Isolate-001 (NCI), and Bacteroides ovatus after oat β-glucan supplementation with TNFα and TGFβ1 levels; and enrichment of Muribaculaceae bacterium Isolate-110 (HZI) after inulin supplementation with AST level. In conclusion, oat β-glucan and inulin exhibited similar antiliver injury, anti-inflammatory, and antifibrotic activities but had no effect on cecal short-chain fatty acids and gut microbiota diversity in CD NASH mice.

Inter-individual variations in circadian misalignment-induced NAFLD pathophysiology in mice

Pathological consequences of circadian misalignment, such as shift work, show considerable individual differences, but the lack of mechanistic understanding hinders precision prevention to prevent and mitigate disease symptoms. Here, we employed an integrative approach involving physiological, transcriptional, and histological phenotypes to examine inter-individual differences in pre-symptomatic pathological progression, preceding irreversible disease onset, in wild-type mice exposed to chronic jet-lag (CJL). We observed that CJL markedly increased the prevalence of hepatic steatosis with pronounced inter-individual differences. Stratification of individual mice based on CJL-induced hepatic transcriptomic signature, validated by histopathological analysis, pinpoints dysregulation of lipid metabolism. Moreover, the period and power of intrinsic behavioral rhythms were found to significantly correlate with CJL-induced gene signatures. Together, our results suggest circadian rhythm robustness of the animals contributes to inter-individual variations in pathogenesis of circadian misalignment-induced diseases and raise the possibility that these physiological indicators may be available for predictive hallmarks of circadian rhythm disorders.