Smoking related diseases: the central role of monoamine oxidase

The impact of electronic and conventional cigarettes on periodontal health-a systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis examined the effects of electronic cigarettes on periodontal health compared to conventional cigarette smoke and a non-smoking population.

MATERIALS AND METHODS

MEDLINE, Embase, Web of Science, CENTRAL, and ClinicalTrials.gov were screened for literature. Eligibility criteria included clinical studies published between 2006 and 2022 that compare e-cigarettes and conventional cigarettes on periodontal health (bleeding on probing (BoP), plaque index (PI), probing depth (PD), attachment loss (AL), marginal bone loss (MBL), tooth loss, molecular inflammation markers, salivary flow rate). Meta-regression analysis was used to examine the influence of moderator variables.

RESULTS

Sixteen studies were found to be eligible for qualitative synthesis. Individual analyses showed that cigarette smokers had significantly higher PI, PD, AL, and MBL and increased concentrations of proinflammatory mediators than e-cigarette users and non-smokers. Meta-analysis revealed a 0.33-fold lower chance for BoP in e-cigarette users compared to smokers (p = 0.03), whereby meta-regression failed to detect any effects regarding the age of users and frequency of smoking. A 0.01-fold decreased chance for positive BoP in e-cigarette users compared with non-smokers was seen (p < 0.01).

CONCLUSIONS

The current findings suggest that that e-cigarette use might be considered a healthier alternative to cigarette smoking concerning periodontal health. Even so, harmful effects of electronic nicotine delivery system (ENDS) usage on periodontal health were seen as well. However, a definitive decision on this research question remains elusive due to the absence of randomized controlled trials.

CLINICAL RELEVANCE

Electronic cigarettes, marketed as a safer alternative to traditional cigarettes, are becoming increasingly popular. Evidence on the use of electronic cigarettes as a cessation aid and its beneficial impact compared to cigarette smoke remains inconclusive, so the analysis conducted in this review addresses a recent question of high clinical relevance.

Neuroprotective effects of Olea europaea L. fruit extract against cigarette smoke-induced depressive-like behaviors in Sprague-Dawley rats

Depression is broadly acclaimed as a mental health anomaly and despite advancements in the development of antidepressant drugs, they are linked with side effects. Dietary modifications and medicinal plants like olives can be used as effective strategies due to their antioxidant, immune-modulatory, antiinflammatory, and anticonvulsant properties. Considering the compositional alterations in olive fruits during ripening, the antidepressant potential of olive fruits at different degrees of ripeness, that is, un-ripened (green) and ripened (black) was investigated. Rats were randomly divided into five groups: G₀ (Normal diet), G₁ (Normal diet + smoke exposure (SE), G₂ (Normal diet + SE + Citalopram), G₃ (Normal diet + SE + Green olive extract), and G₄ (Normal diet + SE + Black olive extract). Depressive-like behaviors were induced in all groups through cigarette smoke exposure except G₀ . Green and black olive extracts prevented depressive behaviors by reducing the immobility time of rats in forced swim test and tail suspension test while increased the latency to respond in hot plate assay. Moreover, lipid peroxidation in brain tissue was reduced with citalopram, green, and black olive extracts. Additionally, treatments also enhanced the antioxidant pool of brain tissues. Histological examination revealed that olive extracts and citalopram prevented cigarette smoke-induced moderate to severe necrosis and congestion in the brain parenchyma and elucidated antidepressant potential by improving the expression of monoamine oxidase-A, solute carrier family 6 member 4, and brain-derived neurotrophic factor genes. Conclusively, olives may act as a promising antidepressant agent in ameliorating cigarette smoke-induced depressive-like behaviors. PRACTICAL APPLICATIONS: Olive extracts at both ripening stages revealed an antidepressant-like effect almost similar to the standard antidepressant drug and also prevented oxidative damages. Therefore, from the current findings, it can be recommended that food ingredients with antidepressant potential like olives should be incorporated in future interventions to combat depression/psychiatric anomalies and diet therapy should be encouraged to alleviate lifestyle-related disorders.

Adolescent Substance Use and the Brain: Behavioral, Cognitive and Neuroimaging Correlates

Adolescence is an important ontogenetic period that is characterized by behaviors such as enhanced novelty-seeking, impulsivity, and reward preference, which can give rise to an increased risk for substance use. While substance use rates in adolescence are generally on a decline, the current rates combined with emerging trends, such as increases in e-cigarette use, remain a significant public health concern. In this review, we focus on the neurobiological divergences associated with adolescent substance use, derived from a cross-sectional, retrospective, and longitudinal studies, and highlight how the use of these substances during adolescence may relate to behavioral and neuroimaging-based outcomes. Identifying and understanding the associations between adolescent substance use and changes in cognition, mental health, and future substance use risk may assist our understanding of the consequences of drug exposure during this critical window.

Design, synthesis, molecular modelling and in vitro screening of monoamine oxidase inhibitory activities of novel quinazolyl hydrazine derivatives

A new series of N'-substituted benzylidene-2-(4-oxo-2-phenyl-1,4-dihydroquinazolin-3(2H)-yl)acetohydrazide (5a-5h) has been synthesized, characterized by FT-IR, NMR spectroscopy and mass spectrometry and tested against human monoamine oxidase (MAO) A and B. Only (4-hydroxy-3-methoxybenzylidene) substituted compounds gave submicromolar inhibition of MAO-A and MAO-B. Changing the phenyl substituent to methyl on the unsaturated quinazoline ring (12a-12d) decreased inhibition, but a less flexible linker (14a-14d) resulted in selective micromolar inhibition of hMAO-B providing insight for ongoing design.

Tobacco consumption and premenstrual syndrome: A case-control study

Objective

To assess whether tobacco smoking is associated with Premenstrual Syndrome (PMS) and its most severe form, Premenstrual Dysphoric Disorder (PMDD).

Design

Case-control study with incident cases using the Spanish public healthcare system.

Setting

3 major public hospitals and one family counseling and planning center.

Population

Women consulting for troubles related to menstruation and for other motives such as screening for uterine cancer, contraception counseling or desire for pregnancy.

Methods

Logistic regression.

Main outcome measures

Odds Ratios of PMS and PMDD.

Results

285 incident PMS cases and 285 age-matched controls on the one hand, and 88 incident PMDD cases and 176 controls on the other hand participated in the study. The odds of premenstrual disorders was higher in current smokers compared with never smokers: Odds Ratio (OR) = 1.78, 95% Confidence Interval (CI): 1.20–2.63 for PMS and OR = 2.92, 95%CI: 1.55–5.50 for PMDD. For PMS, women who smoke 1 to 5 cigarettes/day presented an OR = 2.82, 95%CI: 1.57–5.06 and those who smoke more than 15 cigarettes/day an OR = 2.52, 95%CI: 0.99–6.40.

Compared to non-smokers, current and ex-smokers who smoked < 3 pack-years presented an OR = 1.79, 95%CI: 1.04–3.08 for PMS, and an OR = 3.06, 95%CI: 1.27–7.35 for PMDD. Smokers of 3 to 8 pack-years presented an OR = 2.34, 95%CI: 1.33–4.13 for PMS and OR = 3.56, 95%CI: 1.55–8.17 for PMDD.

These results were confirmed by the exposure-effect curve obtained from a cubic spline model.

Conclusions

This study shows that smokers are more likely to develop PMS and PMDD.

Crosstalk between oral and general health status in e-smokers

Electronic cigarette (e-cigarette) simulates the act of tobacco smoking by vaporizing a mixture of propylene glycol, nicotine, and flavoring agents. e-cigarette has been proposed as a product able to aid to stop smoking. The aim of the study is to verify the clinical variations of periodontal health induced by e-cigarettes use and, moreover, to investigate about the awareness of the e-smokers about their health variations and about their hypothetical need to turn back to smoke combustible cigarettes.This clinical observational pilot study involved 110 out of 350 smokers, who switched to e-cigarette. Patients were subjected to oral examinations. A questionnaire to self-assess the variations of some parameters of general health, and to self-assess the need to smoke combustible cigarettes, was distributed to such subjects involved in the study.At the end of the study, we registered a progressive improvement in the periodontal indexes, as well as in the general health perception. Finally, many patients reported an interesting reduction in the need to smoke.In the light of this pilot study, the e-cigarette can be considered as a valuable alternative to tobacco cigarettes, but with a positive impact on periodontal and general health status.

Smoking habits and coenzyme Q10 status in healthy European adults

INTRODUCTION

Coenzyme Q10 (CoQ10) is a lipophilic endogenously synthesised antioxidant that is present in nearly all human tissues and plays an important role in mitochondrial energy production. It has been postulated that smoking has a consumptive effect on CoQ10.

MATERIAL AND METHODS

To further define the relation between smoking and the serum CoQ10 status, 276 healthy volunteers aged 19 to 62 years were grouped into non-smokers (n = 113; 77 male, 36 female) and smokers (n = 163; 102 male, 61 female). Serum lipid profile was analysed by standard clinical chemistry. Coenzyme Q10 concentration and redox status were analysed by high-pressure liquid chromatography with electrochemical detection.

RESULTS

Male smokers showed higher serum CoQ10 levels than female smokers. This sex-related difference was accounted for when CoQ10 was related to low-density lipoprotein (LDL) cholesterol as the main carrier of CoQ10 in the circulation. Neither LDL-adjusted CoQ10 concentration nor redox status significantly differed when smokers and non-smokers were compared. Regarding the smoking history, the number of cigarettes consumed per day did not significantly affect the CoQ10 status. Interestingly, with increasing time of smoking habit we observed increasing levels of LDL-adjusted serum CoQ10 concentration (Spearman's p < 0.002) and of the reduced form of CoQ10 (Spearman's p < 0.0001).

CONCLUSIONS

As an adaptive response to oxidative stress in long-term smokers an increased demand for antioxidant capacity may be covered by increasing levels of LDL-adjusted CoQ10 serum concentrations and by a concomitantly increased availability of the reduced, active form of CoQ10, possibly by induction of enzymes that are involved in converting CoQ10ox to CoQ10red.

Association among smoking, depression, and anxiety: findings from a representative sample of Korean adolescents

This study investigated the relationship between smoking and depression and anxiety using data from a nationwide survey representing Korean adolescents. Subjects were 6,489 adolescents in middle and high school (age 13-18) who had participated in the 2011 Korean Study of Promotion Policies on Children and Adolescents-Mental Health (KSPCAM). Daily smoking number of times for current smokers was classified as 1-2 times, 2-4 times and over 5 times. The odds ratio for the statistical test was presented using hierarchical logistic regression. When adjusted for covariates (gender, age, household economy, type of residing city, type of school, school record, satisfaction with school life, subjective health status, satisfaction with relationship with parents, and drinking experience), smokers more significantly likely to have depression (OR = 1.27, 95% CI [1.02-1.57]), and anxiety (OR = 1.49, 95% CI [1.14-1.96]) than non-smokers (p < 0.05). In addition, adolescents who smoke more than 5 cigarettes a day were 1.5 times more likely to have depression (OR = 1.48, 95% CI [1.13-1.92]) and anxiety (OR = 1.49, 95% CI [1.07-2.08]) than those who do not smoke. Smoking in adolescence was found to be significantly related with depression and anxiety. To promote the mental health of adolescents, effective smoking cessation programs are required.

Bacoside A: Role in Cigarette Smoking Induced Changes in Brain

Cigarette smoking (CS) is a major health hazard that exerts diverse physiologic and biochemical effects mediated by the components present and generated during smoking. Recent experimental studies have shown predisposition to several biological consequences from both active and passive cigarette smoke exposure. In particular, passive smoking is linked to a number of adverse health effects which are equally harmful as active smoking. A pragmatic approach should be considered for designing a pharmacological intervention to combat the adverse effects of passive smoking. This review describes the results from a controlled experimental condition, testing the effect of bacoside A (BA) on the causal role of passive/secondhand smoke exposure that caused pathological and neurological changes in rat brain. Chronic exposure to cigarette smoke induced significant changes in rat brain histologically and at the neurotransmitter level, lipid peroxidation states, mitochondrial functions, membrane alterations, and apoptotic damage in rat brain. Bacoside A is a neuroactive agent isolated from Bacopa monnieri. As a neuroactive agent, BA was effective in combating these changes. Future research should examine the effects of BA at molecular level and assess its functional effects on neurobiological and behavioral processes associated with passive smoke.

Association between monoamine oxidase gene polymorphisms and smoking behavior: A meta-analysis

BACKGROUND

A number of studies have researched the association between monoamine oxidase gene (MAO) polymorphisms and smoking behavior, but the conclusion is quite inconsistent. A meta-analysis was conducted to assess the association of MAO-A C1460T, MAO-A VNTR and MAO-B G644A polymorphisms with smoking behavior.

METHODS

A comprehensive search was performed to identify all eligible studies. Meta-analysis was applied to calculate the pooled effect values and their 95% confidence intervals. Meta-regression and the 'leave one out' sensitivity analysis were used to explore potential sources of heterogeneity. The risk of bias was assessed by the Egger regression asymmetry test.

RESULTS

11 articles conformed to the inclusion criteria. The meta-analysis showed T allele in MAO-A C1460T reduced the risk of heavy smoking (OR=0.66, 95% CI: 0.52-0.84; I(2)=0.0%), especially in Caucasians; the active group in MAO-A VNTR increased the likelihood of failed smoking cessation in males (OR=1.49, 95% CI: 1.01-2.22; I(2)=0.0%); A allele in MAO-B G644A reduced the risk of heavy smoking in males (OR=0.20, 95% CI: 0.04-0.98).

CONCLUSION

Our findings indicate that the low activity of monoamine oxidase gene polymorphisms has a protective effect on smoking cessation and heaviness. Some associations and applications should be further confirmed.

Does quitting smoking decrease the risk of midlife hot flashes? A longitudinal analysis

Epidemiological studies have shown that cigarette smoking is associated with an increased risk of midlife hot flashes; however, the effect of quitting smoking on this risk is unclear. The purpose of this study was to examine the effect of quitting smoking on hot flashes using data from 761 women aged 45 to 54 years of age at baseline followed for 1 to 7 years. Results showed that women who quit smoking were less likely to suffer from hot flashes, less likely to have severe hot flashes, and less likely to have frequent hot flashes than women who continued to smoke (OR=0.55, 0.80, 0.76), but were more likely to suffer from any hot flashes, more severe hot flashes, and more frequent hot flashes than women who never smoked (OR=2.55, 1.68, 1.46). Subset analysis of the 353 women who had ever smoked found that women who had quit smoking for longer than 5 years had significantly lower odds, severity, and frequency of hot flashes than women who had continued smoking (OR=0.36, 0.62, 0.63) or women who had quit in the previous 5 years (OR=0.66, 0.77, 0.69). These findings suggest that that early smoking cessation programs may improve women's well-being during the menopausal transition.

Influence of Altered Hormonal Status on Platelet 5-HT and MAO-B Activity in Cigarette Smokers

The present study was designed to understand the cigarette smoking-induced alterations in hormones and the resulting changes in platelet serotonin (5-hydroxytryptamine, 5-HT) and monoamine oxidase (MAO-B) activity in chronic smokers. Human male volunteers aged 35 ± 8 years, were divided into two groups, namely controls and smokers (12 ± 2 cigarettes per day for 7-10 years). Results showed that cigarette smoking significantly (p < 0.05) elevated plasma triiodothyronine (T3), cortisol and testosterone levels with significant (p < 0.05) reduction in plasma tryptophan and thyroxin (T4). Moreover, smokers showed reduced platelet 5-HT levels and MAO-B activity. In smokers, plasma cortisol was negatively correlated with tryptophan (r = -0.386), platelet MAO-B (r = -0.264), and 5-HT (r = -0.671), and positively correlated with testosterone (r = 0.428). However, testosterone was negatively correlated with platelet MAO-B (r = -0.315), and 5-HT (r = -.419) in smokers. Further, smokers plasma T3 levels were negatively correlated with platelet MAO-B (r = -0.398), and 5-HT (r = -0.541), whereas T4 levels were positively correlated with platelet MAO-B (r = 0.369), and 5-HT (r = 0.454). In conclusion, our study showed that altered testosterone and cortisol levels may aggravate behavior, mood disturbances and symptoms of depression by decreasing platelet 5-HT and MAO-B activity in smokers.

Symptoms of depression and anxiety in anorexia nervosa: links with plasma tryptophan and serotonin metabolism

Depressive, anxiety and obsessive symptoms frequently co-occur with anorexia nervosa (AN). The relationship between these clinical manifestations and the biological changes caused by starvation is not well understood. It has been hypothesised that reduced availability of tryptophan (TRP) could reduce serotonin activity and thus trigger these comorbid symptoms. The aim of this study, during re-feeding in individuals with AN, was to analyse covariations across measures of nutritional status, depressive and anxiety symptoms, and peripheral serotonin markers. Depressive and anxiety symptoms, nutritional status and serotonin markers--whole blood serotonin content, plasma TRP and the ratio between TRP and large neutral amino acids--were assessed for 42 AN participants at admission to inpatient treatment and after re-feeding. Biological measures were compared to those obtained in 42 non-eating disordered subjects. For those with AN, psychological, nutritional and biological parameters improved significantly during hospitalisation. Levels of serotonin markers were significantly lower in the AN group compared to the control group, at admission and at discharge. Increase in the TRP/LNAA ratio was correlated with a decrease in depressive symptoms. In addition, there was a positive correlation between serotonin levels and symptoms of both anxiety and depression at discharge. We speculate that enhanced TRP availability during re-feeding, as a result of the increase in the TRP/LNAA ratio, could restore serotonin neurotransmission and lead to a decrease in depressive symptoms. The association between serotonin and anxiety and depressive symptoms would be consistent with numerous observations indicating abnormal functioning of the serotoninergic system in AN.

Attenuation of smoke induced neuronal and physiological changes by bacoside rich extract in Wistar rats via down regulation of HO-1 and iNOS

Bacopa monniera is well known herbal medicine for its neuropharmacological effects. It alleviates variety of disorders including neuronal and physiological changes. Crackers smoke is a potent risk factor that leads to free radical mediated oxidative stress in vivo. The aim of the current study is to evaluate the protective efficacy of B. monniera extract (BME) against crackers smoke induced neuronal and physiological changes via modulating inducible nitric oxide synthase (iNOS) and hemeoxygenase-1 (HO-1) expression in rats. Rats were exposed to smoke for 1h for a period of 3 weeks and consecutively treated with BME at three different dosages (i.e., 10, 20 and 40 mg/kg b.wt.). Our results elucidate that BME treatment ameliorates histopathalogical changes, reactive oxygen species levels, lipid peroxidation, acetylcholine esterase activity and brain neurotransmitter levels to normal. BME supplementation efficiently inhibited HO-1 expression and nitric oxide generation by down-regulating iNOS expression. Smoke induced depletion of antioxidant enzyme status, monoamine oxidase activity was also replenished by BME supplementation. Thus the present study indicates that BME ameliorates various impairments associated with neuronal and physiological changes in rats exposed to crackers smoke by its potent neuromodulatory, antioxidant and adaptogenic propensity.

How cigarette smoking may increase the risk of anxiety symptoms and anxiety disorders: a critical review of biological pathways

Multiple studies have demonstrated an association between cigarette smoking and increased anxiety symptoms or disorders, with early life exposures potentially predisposing to enhanced anxiety responses in later life. Explanatory models support a potential role for neurotransmitter systems, inflammation, oxidative and nitrosative stress, mitochondrial dysfunction, neurotrophins and neurogenesis, and epigenetic effects, in anxiety pathogenesis. All of these pathways are affected by exposure to cigarette smoke components, including nicotine and free radicals. This review critically examines and summarizes the literature exploring the role of these systems in increased anxiety and how exposure to cigarette smoke may contribute to this pathology at a biological level. Further, this review explores the effects of cigarette smoke on normal neurodevelopment and anxiety control, suggesting how exposure in early life (prenatal, infancy, and adolescence) may predispose to higher anxiety in later life. A large heterogenous literature was reviewed that detailed the association between cigarette smoking and anxiety symptoms and disorders with structural brain changes, inflammation, and cell-mediated immune markers, markers of oxidative and nitrosative stress, mitochondrial function, neurotransmitter systems, neurotrophins and neurogenesis. Some preliminary data were found for potential epigenetic effects. The literature provides some support for a potential interaction between cigarette smoking, anxiety symptoms and disorders, and the above pathways; however, limitations exist particularly in delineating causative effects. The literature also provides insight into potential effects of cigarette smoke, in particular nicotine, on neurodevelopment. The potential treatment implications of these findings are discussed in regards to future therapeutic targets for anxiety. The aforementioned pathways may help mediate increased anxiety seen in people who smoke. Further research into the specific actions of nicotine and other cigarette components on these pathways, and how these pathways interact, may provide insights that lead to new treatment for anxiety and a greater understanding of anxiety pathogenesis.

Ultrastructural changes in platelet membranes due to cigarette smoking

It is estimated that 1.3 billion people currently smoke cigarettes or other tobacco products. Smoking is becoming an epidemic worldwide and is a major risk factor for atherosclerosis and heart disease. Research has shown that smoking causes changes in platelet membrane fluidity and Na(+)/K(+)ATPase activity. The aim of the current research is to determine if these changes in membrane fluidity are ultrastructurally visible. Thirty-five experimental and control subjects were selected for the study. Smokers had smoked on average 2 cigarettes per day for 5-10 years. Smears of platelet-rich plasma were prepared for scanning electron microscopy and viewed with a Zeiss ULTRA plus FEG-SEM with InLens capabilities. Platelet surface morphology was viewed at 1 kV and micrographs were taken at 80,000-200,000× machine magnification. A difference in the globular nature of the platelet membrane of smokers was visible; additionally, it seemed as if surface pseudopodia were more pronounced than in healthy individuals. No apoptotic or necrotic platelet morphology was noted. Research has noted changed membrane fluidity and the study concludes by suggesting that this is visible ultrastructurally. Therefore, changes in membrane fluidity are structurally visible and translate into a more globular and bulbous appearance of the membrane surface.

Key players in major and bipolar depression--a retrospective analysis of in vivo imaging studies

In the present study, we evaluated the contribution of the individual synaptic constituents of all assessed neurotransmitter systems by subjecting all available in vivo imaging studies on patients with unipolar major depressive disorder (MDD) and bipolar depression (BD) to a retrospective analysis. In acute MDD, findings revealed significant increases of prefrontal and frontal DA synthesis, decreases of thalamic and midbrain SERT, increases of insular SERT, decreases of midbrain 5-HT(1A) receptors and decreases of prefrontal, frontal, occipital and cingulate 5-HT(2A) receptors, whereas, in remission, decreases of striatal D₂ receptors, midbrain SERT, frontal, parietal, temporal, occipital and cingulate 5-HT(1A) receptors and parietal 5-HT(2A) receptors were observed. In BD, findings indicated a trend towards increased striatal D₂ receptors in depression and mania, decreased striatal DA synthesis in remission and decreased frontal D₁ receptors in all three conditions. Additionally, there is some evidence that ventrostriatal and hippocampal SERT may be decreased in depression, whereas in remission and mania elevations of thalamic and midbrain SERT, respectively, were observed. Moreover, in depression, limbic 5-HT(1A) receptors were elevated, whereas in mania a decrease of both cortical and limbic 5-HT(2A) receptor binding was observed. Furthermore, in depression, prefrontal, frontal, occipital and cingulate M2 receptor binding was found to be reduced. From this, a complex pattern of dysregulations within and between neurotransmitter systems may be derived, which is likely to be causally linked not only with the subtype and duration of disease but also with the predominance of individual symptoms and with the kind and duration of pharmacological treatment(s).

Reduced coenzyme Q(10) in female smokers and its association with lipid profile in a young healthy adult population

INTRODUCTION

Cigarette smoking has a negative effect on body reserve of antioxidants and cholesterol metabolism. Coenzyme Q(10) (CoQ(10)), a potent antioxidant synthesized as part of the cholesterol pathway, is a potential biomarker for systemic oxidative stress. We aimed to investigate gender variation in plasma lipid profile and CoQ(10) concentrations in healthy non-smokers and in smokers.

MATERIAL AND METHODS

The study included 55 cigarette smokers (25 females and 30 males) and 51 non-smokers (25 females and 26 males) with the age range from 21 to 45 years, and who had no history of alcohol abuse or chronic diseases such as diabetes mellitus or obesity. Coenzyme Q(10) plasma concentrations were measured by reverse-phase high performance liquid chromatography (HPLC) with ultraviolet detection. Fasting plasma glucose and lipid levels were determined by standard colorimetric methods.

RESULTS

Our results showed that CoQ(10) concentrations were significantly decreased in smokers, especially in females, than their non-smoker counterparts. Female smokers also exhibited a significant decrease in plasma concentrations of total cholesterol (TC), HDL-C, LDL-C, and atherogenic ratios HDL-C/TC and CoQ(10)/LDL-C than male counterparts. Plasma triglyceride concentrations were increased in smokers irrespective of gender. Plasma CoQ(10) was relatively more associated with TC and LDL-C in female smokers than male smokers.

CONCLUSIONS

The adverse effects of smoking on body reserve of antioxidants and cholesterol metabolism are greater in females than in males, partially as a result of decreased CoQ(10) plasma concentrations, HDL-C and total-cholesterol and abnormal atherogenicity indices.

Genetics of schizophrenia and smoking: an approach to studying their comorbidity based on epidemiological findings

The association between schizophrenia and tobacco smoking has been described in more than 1,000 articles, many with inadequate methodology. The studies on this association can focus on: (1) current smoking, ever smoking or smoking cessation; (2) non-psychiatric controls or controls with severe mental illness (e.g., bipolar disorder); and (3) higher smoking frequency or greater usage in smokers. The association with the most potential for genetic studies is that between ever daily smoking and schizophrenia; it may reflect a shared genetic vulnerability. To reduce the number of false-positive genes, we propose a three-stage approach derived from epidemiological knowledge. In the first stage, only genetic variations associated with ever daily smoking that are simultaneously significant within the non-psychiatric controls, the bipolar disorder controls and the schizophrenia cases will be selected. Only those genetic variations that are simultaneously significant in the three hypothesis tests will be tested in the second stage, where the prevalence of the genes must be significantly higher in schizophrenia than in bipolar disorder, and significantly higher in bipolar disorder than in controls. The genes simultaneously significant in the second stage will be included in a third stage where the gene variations must be significantly more frequent in schizophrenia patients who did not start smoking daily until their 20s (late start) versus those who had an early start. Any genetic approach to psychiatric disorders may fail if attention is not given to comorbidity and epidemiological studies that suggest which comorbidities are likely to be explained by genetics and which are not. Our approach, which examines the results of epidemiological studies on comorbidities and then looks for genes that simultaneously satisfy epidemiologically suggested sets of hypotheses, may also apply to the study of other major illnesses.

Former smoking is a risk factor for chronic kidney disease after lung transplantation

Chronic kidney disease (CKD) is a common complication after lung transplantation (LTx). Smoking is a risk factor for many diseases, including CKD. Smoking cessation for >6 months is required for LTx enlistment. However, the impact of smoking history on CKD development after LTx remains unclear. We investigated the effect of former smoking on CKD and mortality after LTx. CKD was based on glomerular filtration rate (GFR) ((125) I-iothalamate measurements). GFR was measured before and repeatedly after LTx. One hundred thirty-four patients never smoked and 192 patients previously smoked for a median of 17.5 pack years. At 5 years after LTx, overall cumulative incidences of CKD-III, CKD-IV and death were 68.5%, 16.3% and 34.6%, respectively. Compared to never smokers, former smokers had a higher risk for CKD-III (hazard ratio [HR] 95% confidence interval [95%CI]= 1.69 [1.27-2.24]) and IV (HR = 1.90 [1.11-3.27]), but not for mortality (HR = 0.99 [0.71-1.38]). Adjustment for potential confounders did not change results. Thus, despite cessation, smoking history remained a risk factor for CKD in LTx recipients. Considering the increasing acceptance for LTx of older recipients with lower baseline renal function and an extensive smoking history, our data suggest that the problem of post-LTx CKD may increase in the future.