Association between passive smoking and the risk of rheumatoid arthritis: a systematic review and meta-analysis

Contributions of Dietary Patterns and Factors to Regulation of Rheumatoid Disease

Rheumatoid arthritis (RA) is a systemic autoimmune disease that commonly causes pain in joints and the progressive destruction of cartilage and bone, which significantly reduces the quality of life and increases the social burden. However, there is still no cure for RA, so it is highly important to explore additional adjuvant treatment methods. Studies have indicated that malnutrition, changes in intestinal microbiota, and changes in immune status caused by dietary imbalance are directly related to the onset of RA, indicating that dietary intervention may offer a simple, economical, and practical avenue to relieve RA. Therefore, in this review, we discuss the pathogenesis of RA and summarize the influence of different dietary patterns on RA. In particular, we pointed out that high-fat, high-sugar, and high-salt diets contribute to RA progression, whereas the Mediterranean diet (MD) is beneficial for preventing RA. Furthermore, the ingredients of food, such as dietary fiber, probiotics, and vitamins, help reduce the level of inflammation and relieve joint pain, which may play critical roles in the treatment of RA. Therefore, dietary intervention provides a potential effective approach for adjuvant therapy of RA.

Anti-arthritic and anti-inflammatory activity of linalool against formaldehyde and complete Freund's adjuvant induced arthritis in rats

Arthritis, characterized by persistent joint inflammation, poses a significant challenge due to its detrimental effects on cartilage function and subchondral bone health. This study investigates the potential pharmacological effects of linalool, a monoterpene alcohol commonly found in essential oils, as a promising treatment for arthritis. In vitro assays, including red blood cell membrane stability and protein denaturation tests, were conducted to preliminarily assess the anti-arthritic potential of linalool. Preclinical evaluations were performed on rats with arthritis induced by formaldehyde and complete Freund's adjuvant, focusing on the therapeutic effects of orally administered linalool over a 28-day period. Linalool treatment resulted in significant improvements in body weight, reduced paw inflammation, and decreased arthritis symptoms. Hematological and biochemical analyses revealed that linalool reduced lipid peroxidation and elevated antioxidant levels in arthritic rats. Reverse transcription-polymerase chain reaction analysis demonstrated a notable downregulation of pro-inflammatory markers such as IL-1β, IRAK, NF-κB, TNF-α, and IL-17, alongside an upregulation of the anti-inflammatory cytokine IL-10, in linalool-treated rats compared to controls. These results suggest that linalool is promising as an alternative therapeutic intervention for inflammatory joint diseases.

Association of exposure to second-hand smoke during childhood with blood DNA methylation

INTRODUCTION

By recent estimates, 40% of children worldwide are exposed to second-hand smoke (SHS), which has been associated with adverse health outcomes. While numerous studies have linked maternal smoking during pregnancy (MSDP) to widespread differences in child blood DNA methylation (DNAm), research specifically examining postnatal SHS exposure remains sparse. To address this gap, we conducted epigenome-wide meta-analyses to identify associations of postnatal SHS and child blood DNAm.

METHODS

Six cohorts from the Pregnancy And Childhood Epigenetics (PACE) Consortium (total N = 2,695), with SHS data and child blood DNAm (aged 7-9 years) measured with the Illumina 450K array were included in the meta-analysis. Linear regression models adjusted for covariates were fitted to examine the association between the number of household smokers in postnatal life (0, 1, 2+) and child blood DNAm. Sensitivity models without adjusting for MSDP and restricted to mothers who did not smoke during pregnancy were evaluated.

RESULTS

Our analysis revealed significant associations (False Discovery Rate < 0.05) between household postnatal SHS exposure and DNAm at 11 CpGs in exposed children. Nine CpGs were mapped to genes (MYO1G, FAM184B, CTDSPL2, LTBP3, PDE10A, and FIBCD1), while 2 CpGs were located in open sea regions. Notably, all except 2 CpGs (mapped to FIBCD1 and CTDSPL2) have previously been linked to either personal smoking habits or in utero exposure to smoking. The models restricted to non-smoking mothers provided similar results. Importantly, several of these CpGs and their associated genes are implicated in conditions exacerbated by or directly linked to SHS.

CONCLUSIONS

Our findings highlight the potential biological effects of SHS on blood DNAm. These findings support further research on epigenetic factors mediating deleterious effects of SHS on child health and call for public health policies aimed at reducing exposure, particularly in environments where children are present.

[Influence of smoking, nutrition and other modifiable environmental factors on rheumatoid arthritis]

Numerous reports in recent years have focused on the influence of environmental factors on rheumatoid arthritis. This article provides an overview of the current study situation on the influence of modifiable environmental factors on the development and course of rheumatoid arthritis. Lifestyle factors, such as cigarette smoking, diet, exercise and body weight can be individually influenced. Factors such as air pollution and socioeconomic status can be influenced by environmental and sociopolitical measures at a public level. Epidemiological studies have identified nicotine abuse, an unhealthy diet and obesity as well as a low level of education and social status as risk factors for the development of rheumatoid arthritis. Numerous factors are also associated with a poorer response to treatment and a worse prognosis. As randomized interventional studies on most environmental factors are hardly feasible, the causal relationship of the individual factors to the incidence and progression of rheumatoid arthritis is difficult to quantify. Nevertheless, the current evidence already enables the provision of appropriate counselling to patients with rheumatoid arthritis with respect to a healthy lifestyle including abstaining from cigarette smoking, maintaining a healthy diet, physical activity and avoiding obesity.

The Impact of Rheumatoid Arthritis on First Nations and How We Can Work With Communities to Prevent It

Rheumatoid arthritis (RA) is prevalent in many Indigenous North American First Nations (FN) and tends to be seropositive, familial, and disabling, as well as associated with highly unfavorable outcomes such as early mortality. The risk of developing RA is based on a perfect storm of gene-environment interactions underpinning this risk. The gene-environment interactions include a high frequency of shared epitope encoding HLA alleles, particularly HLA-DRB1*1402, in the background population, and prevalent predisposing environmental factors such as smoking and periodontal disease. Together, these provide a compelling rationale for an RA prevention agenda in FN communities. Our research team has worked in partnership with several FN communities to prospectively follow the first-degree relatives of FN patients with RA, with the aim of better understanding the preclinical stages of RA in this population. We have focused on specific features of the anticitrullinated protein antibodies (ACPA) and other proteomic biomarkers as predictors of future development of RA. These studies have now led us to consider interventions having a favorable risk-benefit ratio if applied at a stage prior to a hypothetical "point of no return," when the autoimmunity potentially becomes irreversible. Based on a supportive mouse model and available human studies of curcumin, omega-3, and vitamin D supplements, we are undertaking studies where we screen communities using dried blood spot technology adapted for the detection of ACPA, and then enrolling ACPA-positive individuals in studies that use a combination of these supplements. These studies are guided by shared decision-making principles.

Association of Sleep Quality and General, Mental, and Oral Health with Lifestyle Traits (Dietary Intake, Smoking Status) in Arthritis: A Cross-Sectional Study from the Canadian Community Health Survey (CCHS)

Arthritis is associated with health challenges. Lifestyle traits are believed to influence arthritis development and progression; however, data to support personalized treatment regimens based on holistic lifestyle factors are missing. This study aims to provide a comprehensive list of associations between lifestyle traits and the health status of individuals with arthritis in the Canadian population, using binary logistic regression analysis on data from the Canadian Community Health Survey, which includes 104,359 respondents. Firstly, we explored the association between arthritis and various aspects of health status including self-reported lifestyle factors. Secondly, we examined the associations between self-reported dietary intake and smoking status with general, mental, and oral health, and sleep disturbance among individuals both with and without arthritis. Our analysis revealed that individuals with arthritis reported considerably poorer general, mental, and oral health, and poorer sleep quality compared to those without arthritis. Associations were also found between self-reported dietary intake and various measures of health status in individuals with arthritis. Smoking and exposure to passive smoking were associated not only with arthritis but also with compromised sleep quality and poorer general, mental, and oral health in people with and without arthritis. This study highlights the need for personalized and holistic approaches that may include a combination of dietary interventions, oral health improvements, sleep therapies, and smoking cessation for improved arthritis prevention and care.

Molecular and functional changes in neutrophilic granulocytes induced by nicotine: a systematic review and critical evaluation

Background

Over 1.1 billion people smoke worldwide. The alkaloid nicotine is a prominent and addictive component of tobacco. In addition to tumors and cardiovascular disorders, tobacco consumption is associated with a variety of chronic-inflammatory diseases. Although neutrophilic granulocytes (neutrophils) play a role in the pathogenesis of many of these diseases, the impact of nicotine on neutrophils has not been systematically reviewed so far.

Objectives

The aim of this systematic review was to evaluate the direct influence of nicotine on human neutrophil functions, specifically on cell death/damage, apoptosis, chemotaxis, general motility, adhesion molecule expression, eicosanoid synthesis, cytokine/chemokine expression, formation of neutrophil extracellular traps (NETs), phagocytosis, generation of reactive oxygen species (ROS), net antimicrobial activity, and enzyme release.

Material and methods

This review was conducted according to the PRISMA guidelines. A literature search was performed in the databases NCBI Pubmed® and Web of Science™ in February 2023. Inclusion criteria comprised English written research articles, showing in vitro studies on the direct impact of nicotine on specified human neutrophil functions.

Results

Of the 532 originally identified articles, data from 34 articles were finally compiled after several evaluation steps. The considered studies highly varied in methodological aspects. While at high concentrations (>3 mmol/l) nicotine started to be cytotoxic to neutrophils, concentrations typically achieved in blood of smokers (in the nmol/l range) applied for long exposure times (24-72h) supported the survival of neutrophils. Smoking-relevant nicotine concentrations also increased the chemotaxis of neutrophils towards several chemoattractants, elevated their production of elastase, lipocalin-2, CXCL8, leukotriene B4 and prostaglandin E2, and reduced their integrin expression. Moreover, while nicotine impaired the neutrophil phagocytotic and anti-microbial activity, a range of studies demonstrated increased NET formation. However, conflicting effects were found on ROS generation, selectin expression and release of β-glucuronidase and myeloperoxidase.

Conclusion

Nicotine seems to support the presence in the tissue and the inflammatory and selected tissue-damaging activity of neutrophils and reduces their antimicrobial functions, suggesting a direct contribution of nicotine to the pathogenesis of chronic-inflammatory diseases via influencing the neutrophil biology.