Sleep and Association With Cardiovascular Risk Among Midwestern US Firefighters

Extrinsic and intrinsic modulators of inflammation-resolution signaling in heart failure

Chronic and uncleared inflammation is the root cause of various cardiovascular diseases. Fundamentally, acute inflammation is supportive when overlapping with safe clearance of inflammation termed resolution; however, if the lifestyle-directed extrinsic factors such as diet, sleep, exercise, or physical activity are misaligned, that results in unresolved inflammation. Although genetics play a critical role in cardiovascular health, four extrinsic risk factors-unhealthy processed diet, sleep disruption or fragmentation, sedentary lifestyle, thereby, subsequent stress-have been identified as heterogeneous and polygenic triggers of heart failure (HF), which can result in several complications with indications of chronic inflammation. Extrinsic risk factors directly impact endogenous intrinsic factors, such as using fatty acids by immune-responsive enzymes [lipoxygenases (LOXs)/cyclooxygenases (COXs)/cytochromes-P450 (CYP450)] to form resolution mediators that activate specific resolution receptors. Thus, the balance of extrinsic factors such as diet, sleep, and physical activity feed-forward the coordination of intrinsic factors such as fatty acids-enzymes-bioactive lipid receptors that modulates the immune defense, metabolic health, inflammation-resolution signaling, and cardiac health. Future research on lifestyle- and aging-associated molecular patterns is warranted in the context of intrinsic and extrinsic factors, immune fitness, inflammation-resolution signaling, and cardiac health.

Effect of a Nutrition Intervention on Mediterranean Diet Adherence Among Firefighters: A Cluster Randomized Clinical Trial

Importance

US firefighters are a working population at risk of chronic diseases, including obesity, cardiovascular disease, and cancer. This risk may be mitigated by a healthy diet.

Objective

To evaluate the effect of a Mediterranean nutrition intervention using a behavioral/environmental approach (firefighter/fire station/home) at the individual participant level.

Design, Setting, and Participants

This 12-month cluster randomized clinical trial included US career firefighters from fire stations and homes within 2 Indiana fire departments. Participants were randomized by fire station to either Mediterranean diet or control (usual care). The study was conducted from October 2016 to December 2019, and data were analyzed in November 2022.

Intervention

For the first 12 months of the study, firefighters located at fire stations randomized to the intervention group were provided with access to supermarket discounts and free samples of Mediterranean diet foods, online nutrition education platforms, email announcements and reminders, family and peer education and support, and chef demonstrations. Firefighters in fire stations allocated to the control group received no intervention and were instructed to follow their usual diet.

Main Outcomes and Measures

Change in dietary habits at 12 months as measured by a modified Mediterranean diet score (range, 0 to 51 points) at baseline and 6-month and 12-month follow-up. Cardiometabolic parameters were secondary outcomes.

Results

Of 485 included firefighters, 458 (94.4%) were male, and the mean (SD) age was 47 (7.5) years. A total of 241 firefighters (27 fire stations) were randomized to the Mediterranean nutrition intervention, and 244 (25 fire stations) were randomized to usual diet. Outcomes were analyzed using generalized linear mixed models for modified Mediterranean diet score at 6 months (n = 336) and 12 months (n = 260), adjusting for baseline age, sex, race and ethnicity, fire department, physical activity, and waist circumference. In the intervention group compared with the control group, the modified Mediterranean diet score significantly increased by 2.01 points (95% CI, 0.62-3.40; P = .005) at 6 months and by 2.67 points (95% CI, 1.14-4.20; P = .001) at 12 months. Among secondary outcomes, changes in cardiometabolic risk factors were not statistically significant at 1 year. Results from analyses with multilevel multiple imputation for missingness were similar.

Conclusions and Relevance

In this Mediterranean nutrition intervention of multicomponent behavioral/environmental changes, career firefighters had increased adherence to a Mediterranean diet.

Trial Registration

ClinicalTrials.gov Identifier: NCT02941757.

Association between nocturnal sleep duration and the risk of hyperuricemia among Chinese government employees: A cross-sectional study

Objectives

Evidence has shown that nocturnal sleep duration is associated with the risk of hyperuricemia, yet the findings are inconsistent. Thus, we aimed at exploring the association between nocturnal sleep duration and the risk of hyperuricemia in Chinese government employees.

Methods

A total of 10,321 government employees aged 20-60 years were collected from the Cohort Study on Chronic Diseases among Government Employees in Hunan Province, China. Sleep duration was self-reported. And serum uric acid levels >420 μmol/L in men and >360 μmol/L in women were considered hyperuricemia. The association between nocturnal sleep duration and hyperuricemia risk was examined utilizing multivariate logistic regression models. To further examine the connection between nocturnal sleep duration and serum uric acid levels, multiple linear regression analyses were utilized.

Results

The prevalence of hyperuricemia was 17.2%. The results of logistic regression demonstrated that, in contrast to participants whose sleep duration was 7-8 h, those who slept for <7 h had an elevated risk of hyperuricemia (OR = 1.343, 95%CI: 1.126, 1.601). Further stratified analysis revealed that this association was still observed in those without obesity (OR = 1.365; 95%CI: 1.127, 1.655), hypertension (OR = 1.290, 95%CI: 1.054, 1.578), or diabetes mellitus (OR = 1.361, 95%CI: 1.136, 1.631). Multiple linear regression showed that shorter sleep duration (< 7 h) was positively correlated with serum uric acid levels. In comparison to individuals who slept for 7-8 h, those with sleep duration of fewer than 7 h had serum uric acid levels that were 7.231 μmol/L (95% CI: 2.875, 11.588) higher.

Conclusion

Short nocturnal sleep duration (< 7 h) was associated with a higher risk of hyperuricemia, especially in participants without obesity, hypertension, or diabetes mellitus. Besides, short nocturnal sleep duration was related to greater uric acid levels.

Lifestyle and environmental factors may induce airway and systemic inflammation in firefighters

Health status depends on multiple genetic and non-genetic factors. Nonheritable factors (such as lifestyle and environmental factors) have stronger impact on immune responses than genetic factors. Firefighters work is associated with exposure to air pollution and heat stress, as well as: extreme physical effort, mental stress, or a changed circadian rhythm, among others. All these factors can contribute to both, short-term and long-term impairment of the physical and mental health of firefighters. Increased levels of some inflammatory markers, such as pro-inflammatory cytokines or C-reactive protein (CRP) have been observed in firefighters, which can lead to local, acute inflammation that promotes a systemic inflammatory response. It is worth emphasizing that inflammation is one of the main hallmarks of cancer and also plays a key role in the development of cardiovascular and respiratory diseases. This article presents possible causes of the development of an inflammatory reaction in firefighters, with particular emphasis on airway inflammation caused by smoke exposure.