Inverted U shaped effect of nicotine on the severity of depressive symptoms: A population-based survey

Effects of Smoking on Short-Term and Long-Term Mortality after Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE

The relationship between smoking and clinical outcomes after aneurysmal subarachnoid hemorrhage (aSAH) is poorly clarified, and current pieces of evidence are inconsistent. The purpose of this multicenter cohort study is therefore to explore the relationship between smoking and mortality as well as several complications after aSAH.

METHODS

Databases of patient records were from 4 tertiary hospitals. We assessed the impact of tobacco use and tobacco dose (categorized based on smoking index [SI]) on several complication and overall outcome variables. The primary outcome was mortality within the longest follow-up. Logistic models were used to investigate univariate and multivariate relationships between predictors and outcomes. We also developed a propensity score matching for smoking status by using all known confounders.

RESULTS

A total of 6,578 patients with aSAH were analyzed. Current smoking and former smoking did not show association with mortality within the longest follow-up (odds ratio [OR], 0.95, 95% confidence interval [CI]: 0.69-1.30, p = 0.726; OR, 0.66, 95% CI: 0.38-1.15, p = 0.139, respectively). In addition, patients who were current smokers showed an independent association with the decreased occurrence of hydrocephalus (OR, 0.60; 95% CI: 0.41-0.88; p = 0.009) after matching all known confounders. We also found moderate smoking (SI between 384 and 625) was associated with reduced mortality in hospital.

CONCLUSIONS

Our results indicated that in patients with aSAH, current smoking or former smoking was not associated with all-cause mortality up to 7-year follow-up.

Suicidality among South Brazilian tobacco growers

OBJECTIVE

To assess prevalence of suicidal ideation and suicide attempt among South Brazilian tobacco growers and to analyze the associated factors related to the suicidal ideation.

METHODS

A cross-sectional study was conducted in 2011 with a random sample of 2469 tobacco growers in São Lourenço do Sul/RS. Suicidal ideation was characterized by the question "Has the thought of ending your life been on your mind?". Suicide attempt was assessed by the question "Have you ever tried to kill yourself?". Investigation of factors associated with suicidal ideation was done by means of Poisson regression.

RESULTS

Prevalence of suicidal ideation and suicide attempt was 2.5 % and 1.2 % respectively. In the adjusted analysis, suicidal ideation was associated with being female, older age, moderate participation in religious activities and difficulty in paying debts. Those who worked in activities that required inadequate postures (hunched over or other forced positions), as well as farmers who performed 6-9 pesticide-related tasks demonstrated greater risk of suicidal ideation. Regarding health conditions, medical diagnosis of asthma, chronic low back pain, number of lifetime green tobacco sickness episodes and lifetime pesticide poisoning were positively associated with suicidal ideation.

CONCLUSION

Suicidal thoughts and attempts are relevant mental health problems among tobacco growers. Reducing pesticide use, as well as exposure to nicotine and improving socio-economic conditions, can reduce suicidal ideation and improve the mental health of exposed workers.

Protein target identification of ginsenosides in skeletal muscle tissues: discovery of natural small-molecule activators of muscle-type creatine kinase

Background

Ginseng effectively reduces fatigue in both animal models and clinical trials. However, the mechanism of action is not completely understood, and its molecular targets remain largely unknown.

Methods

By screening for proteins that interact with the primary components of ginseng (ginsenosides) in an affinity chromatography assay, we have identified muscle-type creatine kinase (CK-MM) as a potential target in skeletal muscle tissues.

Results

Biolayer interferometry analysis showed that ginsenoside metabolites, instead of parent ginsenosides, had direct interaction with recombinant human CK-MM. Subsequently, 20(S)-protopanaxadiol (PPD), which is a ginsenoside metabolite and displayed the strongest interaction with CK-MM in the study, was selected as a representative to confirm direct binding and its biological importance. Biolayer interferometry kinetics analysis and isothermal titration calorimetry assay demonstrated that PPD specifically bound to human CK-MM. Moreover, the mutation of key amino acids predicted by molecular docking decreased the affinity between PPD and CK-MM. The direct binding activated CK-MM activity in vitro and in vivo, which increased the levels of tissue phosphocreatine and strengthened the function of the creatine kinase/phosphocreatine system in skeletal muscle, thus buffering cellular ATP, delaying exercise-induced lactate accumulation, and improving exercise performance in mice.

Conclusion

Our results suggest a cellular target and an initiating molecular event by which ginseng reduces fatigue. All these findings indicate PPD as a small molecular activator of CK-MM, which can help in further developing better CK-MM activators based on the dammarane-type triterpenoid structure.

Work Stress and Depressive Symptoms in Fishermen With a Smoking Habit: A Mediator Role of Nicotine Dependence and Possible Moderator Role of Expressive Suppression and Cognitive Reappraisal

This study examined pathways of influence between work stress, depressive symptoms, nicotine dependence, expressive suppression, and cognitive reappraisal in fishermen with smoking habits in Qionghai, Hainan province, China (N = 1068). These fishermen responded to multiple assessments a week before leaving on a deep-sea fishing trip, including a Mental Stressor Investigation Questionnaire (MSIQ), the Center for Epidemiological Studies Depression Scale (CES-D), the Russell Reason for Smoking Questionnaire (RRSQ), and an Emotion Regulation Questionnaire (ERQ). Structural equation modeling (SEM) analyses of the collected data in Mplus 7 showed that work stress and nicotine dependence were independent predictors of depressive symptoms. The relationship between work stress and depressive symptoms was found to be partially mediated by nicotine dependence and be moderated by cognitive reappraisal. The evidence suggests it advantageous to examine the need of work stress, nicotine dependence, and cognitive reappraisal when attempting to understand depressive symptoms in fishermen with a smoking habit. These findings suggest that improving nicotine dependence through work stress management and training in cognitive reappraisal could be utilized as effective modalities for improving depressive symptoms.

Persistent behavioral effects following early life exposure to retinoic acid or valproic acid in zebrafish

BACKGROUND

Moderate to severe dysregulation in retinoid signaling during early development is associated with a constellation of physical malformations and/or neural tube defects, including spina bifida. It is thought that more subtle dysregulation of this system, which might be achievable via dietary (i.e. hypervitaminosis A) or pharmacological (i.e. valproic acid) exposure in humans, will manifest on behavioral domains including sociability, without overt physical abnormalities.

METHODS

During early life, zebrafish were exposed to low doses of two chemicals that disrupt retinoid signaling. From 0 to 5dpf, larvae were reared in aqueous solutions containing retinoic acid (0, 0.02, 0.2 or 2nM) or valproic acid (0, 0.5, 5.0 or 50μM). One cohort of zebrafish was assessed using a locomotor activity screen at 6-dpf; another was reared to adulthood and assessed using a neurobehavioral test battery (startle habituation, novel tank exploration, shoaling, and predator escape/avoidance).

RESULTS

There was no significant increase in the incidence of physical malformation among exposed fish compared to controls. Both retinoic acid and valproic acid exposures during development disrupted larval activity with persisting behavioral alterations later in life, primarily manifesting as decreased social affiliation.

CONCLUSIONS

Social behavior and some aspects of motor function were altered in exposed fish; the importance of examining emotional or psychological consequences of early life exposure to retinoid acting chemicals is discussed.

Occupational exposure to pesticides, nicotine and minor psychiatric disorders among tobacco farmers in southern Brazil

INTRODUCTION

Exposure to pesticides has been associated with psychiatric problems among farm workers, although there is still controversy as to chemical types, intensity and forms of exposure that represent risk factors for neuropsychological problems. Furthermore, tobacco workers are exposed to dermal absorption of nicotine, although its effect on mental health has not yet been studied.

OBJECTIVES

To identify the prevalence of minor psychiatric disorders (MPD) among tobacco farmers and associated factors, paying special attention to pesticide and nicotine exposure.

METHODS

This is a cross-sectional study with a representative sample of tobacco growers, characterizing economic indicators of the farms, socio-demographic factors, lifestyle habits and occupational exposures. Multivariate analysis was performed using a hierarchical Poisson regression model.

RESULTS

A total of 2400 tobacco farmers were assessed and MPD prevalence was 12%. MPD was higher among women (PR 1.4), workers aged 40 or over, tenants/employees (PR 1.8) and those who reported having difficulty in paying debts (PR 2.0). Low socioeconomic status was inversely associated with MPD prevalence. Tasks involving dermal exposure to pesticides showed risk varying between 35% and 71%, whereas tobacco growers on farms using organophosphates had 50% more risk of MPD than those not exposed to this kind of pesticide. The number of pesticide poisoning and green tobacco sickness episodes showed linear association with MPD.

CONCLUSIONS

The study reinforces the evidence of the association between pesticide poisoning and mental health disorders. It also points to increased risk of MPD from low socioeconomic status, dermal pesticide exposure as well as from exposure to organophosphates. Furthermore, the study reveals intense nicotine exposure as a risk for tobacco farmers' mental health.