Acute effects of cigarette smoking on insulin resistance and arterial stiffness in young adults

Association of cigarette smoking with cerebrospinal fluid biomarkers of insulin sensitivity and neurodegeneration

INTRODUCTION

Cigarette smoking increases both the risk for insulin resistance and amyloid-β (Aβ) aggregation, and impaired brain insulin/insulin-like growth factor 1 (IGF1) signaling might increase risk factors for Alzheimer's disease (AD). We aimed to investigate the association among cerebrospinal fluid (CSF) insulin sensitivity/IGF1, glucose/lactate, and Aβ42 and further explore whether insulin sensitivity contributed to the risk for AD in active smokers.

METHODS

In this cross-sectional study, levels of insulin, IGF1, and lactate/glucose of 75 active smokers and 78 nonsmokers in CSF were measured. Three polymorphisms regulating IGF1 were genotyped. Analysis of variance was used to compare differences of variables between groups. Partial correlation was performed to test the relationship between CSF biomarkers and smoking status. General linear models were applied to test the interaction of the effect of single nucleotide polymorphisms and cigarette smoking on CSF IGF1 levels.

RESULTS

In the CSF from active smokers, IGF1 and lactate levels were significantly lower (p = .016 and p = .010, respectively), whereas Aβ42 (derived from our earlier research) and insulin levels were significantly higher (p < .001 and p = .022, respectively) as compared to the CSF from nonsmokers. The AG + GG genotype of rs6218 in active smokers had a significant effect on lower CSF IGF1 levels (p = .004) and lower CSF insulin levels in nonsmokers (p = .016).

CONCLUSIONS

Cigarette smoking as the "at-risk" factor for AD might be due to lower cerebral insulin sensitivity in CSF, and the subjects with rs6218G allele seem to be more susceptible to the neurodegenerative risks for cigarette smoking.

Age-related Muscle Fat Infiltration in Lung Screening Participants: Impact of Smoking Cessation

Rationale

Skeletal muscle fat infiltration progresses with aging and is worsened among individuals with a history of cigarette smoking. Many negative impacts of smoking on muscles are likely reversible with smoking cessation.

Objectives

To determine if the progression of skeletal muscle fat infiltration with aging is altered by smoking cessation among lung cancer screening participants.

Methods

This was a secondary analysis based on the National Lung Screening Trial. Skeletal muscle attenuation in Hounsfield unit (HU) was derived from the baseline and follow-up low-dose CT scans using a previously validated artificial intelligence algorithm. Lower attenuation indicates greater fatty infiltration. Linear mixed-effects models were constructed to evaluate the associations between smoking status and the muscle attenuation trajectory.

Measurements and Main Results

Of 19,019 included participants (age: 61 years, 5 [SD]; 11,290 males), 8,971 (47.2%) were actively smoking cigarettes. Accounting for body mass index, pack-years, percent emphysema, and other confounding factors, actively smoking predicted a lower attenuation in both males (β0 =-0.88 HU, P<.001) and females (β0 =-0.69 HU, P<.001), and an accelerated muscle attenuation decline-rate in males (β1=-0.08 HU/y, P<.05). Age-stratified analyses indicated that the accelerated muscle attenuation decline associated with smoking likely occurred at younger age, especially in females.

Conclusions

Among lung cancer screening participants, active cigarette smoking was associated with greater skeletal muscle fat infiltration in both males and females, and accelerated muscle adipose accumulation rate in males. These findings support the important role of smoking cessation in preserving muscle health.

Cardiac function, myocardial fat deposition, and lipid profile in young smokers: a cross-sectional study

Background

There is a possibility that cardiac morphometric characteristics are associated with the lipid profile, that is, the composition and concentration of triglycerides, total cholesterol, HDL, LDL, and others lipoproteins in young smokers without comorbidities. Thus, this study aimed to evaluate the association of cardiac morphometric characteristics, myocardial fat deposition, and smoking cessation with the lipid profile of young smokers.

Methods

A clinical and laboratory evaluation of lipids and the smoking status was performed on 57 individuals, including both a smoker group and a control group. Cardiac magnetic resonance imaging (MRI) with proton spectroscopy was performed to identify cardiac changes and triglyceride (TG) deposition in myocardial tissue.

Results

No differences were observed between the groups (control vs. smokers) in relation to the amount of myocardial TG deposition (p = 0.47); however, when TG deposition was correlated with cardiac MRI variables, a positive correlation was identified between smoking history and myocardial TG deposition [hazard ratio (95% CI), 0.07 (0.03-0.12); p = 0.002]. Furthermore, it was observed that the smoking group had lower high-density lipoprotein cholesterol [51 (45.5-59.5) mg/dl vs. 43 (36-49.5) mg/dl, p = 0.003] and higher TG [73 (58-110) mg/dl vs. 122 (73.5-133) mg/dl, p = 0.01] and very-low-density lipoprotein cholesterol [14.6 (11.6-22.2) mg/dl vs. 24.4 (14.7-26.6) mg/dl, p = 0.01] values. In the control and smoking groups, a negative correlation between TGs and the diameter of the aortic root lumen and positive correlation with the thickness of the interventricular septum and end-diastolic volume (EDV) of both the right ventricle (RV) and left ventricle (LV) were noted. Moreover, in the RV, positive correlations with the end-systolic volume (ESV) index (ESVI), stroke volume (SV), ESV, and EDV were observed. Regarding serum free fatty acids, we found a negative correlation between their values and the diameter of the lumen of the ascending aortic vessel. Lipoprotein lipase showed a positive correlation with the SV index of the RV and negative correlation with the diameter of the lumen of the ascending aortic vessel.

Conclusion

Several associations were observed regarding cardiac morphometric characteristics, myocardial fat deposition, and smoking cessation with the lipid profile of young smokers.

Chronic cigarette smoking is associated with increased arterial stiffness in men and women: evidence from a large population-based cohort

BACKGROUND

Cigarette smoking is a threat to global human health and a leading cause of the cardiovascular disease (CVD) morbidity and mortality. Importantly, sex-specific differences in smoking-induced arterial stiffness, an early key event in the development of atherosclerotic CVD, remain still elusive. Thus, this study sought out to investigate sex-specific associations between smoking and measures of arterial stiffness.

METHODS AND RESULTS

Overall, 15,010 participants (7584 men and 7426 women aged 35-74 years) of the Gutenberg Health Study were examined at baseline during 2007-2012. Smoking status, pack-years of smoking, and years since quitting smoking were assessed by a standardized computer-assisted interview. Arterial stiffness and wave reflection were determined by stiffness index (SI) and augmentation index (AI). In the total sample, 45.8% had never smoked, 34.7% were former smokers, and 19.4% were current smokers. Median cumulative smoking exposure was 22.0 pack-years in current male smokers and 16.0 in current female smokers. In general, multivariable linear regression models adjusted for a comprehensive set of confounders revealed that smoking status, pack-years of smoking, and years since quitting smoking were dose-dependently associated with markers of arterial stiffness. In sex-specific analyses, these associations were overall more pronounced in men and SI was stronger related to the male sex, whereas differences between men and women in the case of AI appeared to be less substantial.

DISCUSSION

The present results indicate that chronic smoking is strongly and dose-dependently associated with increased arterial stiffness in a large population-based cohort regardless of sex but with a stronger association in men.

Insulin resistance by the triglyceride-glucose index in a rural Brazilian population

Objective

The aim of this study was to estimate the prevalence of insulin resistance (IR) in a rural population in Brazil, to verify its association with sociodemographic, labor, lifestyle, and health factors.

Subjects and methods

This is a cross-sectional study with 790 farmers in the state of Espírito Santo/Brazil. Triglyceride-glucose (TyG) was calculated and a cut-off point of Ln 4.52 was used. A hierarchical logistic regression for the association of insulin resistance with sociodemographic, labor, lifestyle and health variables of farmers living in Espírito Santo was performed.

Results

The prevalence of insulin resistance was 33.7% (n = 266), and the association with insulin resistance was found in the age group 31 to 40 years of age (OR = 1.85; 95% CI 1.19-2.87); in smokers or former smokers (OR = 1.63; 95% CI 1.08-2.48) and overweight (OR = 3.06; 95% CI 2.22-4.23).

Conclusion

The prevalence of insulin resistance was high in a rural population of Brazil, and was mainly associated with age, smoking and obesity. The use of TyG as an instrument for assessing the health of individuals living in areas where access to health services is difficult, such as rural areas, can represent an important advance in terms of health promotion, protection and recovery. In addition, by identifying the risk factors associated with IR, as well as their consequences, a more adequate scheme for the prevention and treatment of these comorbidities can be defined.

Gut microbiota as a target for prevention and treatment of type 2 diabetes: Mechanisms and dietary natural products

Type 2 diabetes mellitus (T2DM) is among the most remarkable public health concerns globally. Accumulating research evidence documents that alteration of gut microbiota has an indispensable role in the onset and progression of obesity and T2DM. A reduced microbial diversity is linked to insulin resistance and energy metabolism, especially for the rise of the Firmicutes/Bacteroidetes ratio. Changes in metabolites followed by the gut dysbacteriosis are linked to the presence of T2DM. Moreover, endotoxin leakage and gut permeability caused by gut dysbacteriosis is more of a trigger for the onset and progression of T2DM. Research documents that natural products are remarkable arsenals of bioactive agents for the discovery of anti-T2DM drugs. Many studies have elucidated that the possible mechanisms of the anti-T2DM effects of natural products are remarkably linked to its regulation on the composition of gut microflora and the successive changes in metabolites directly or indirectly. This review presents a brief overview of the gut microbiota in T2DM and several relevant mechanisms, including short-chain fatty acids, biosynthesis and metabolism of branched-chain fatty acids, trimethylamine N-oxide, bile acid signaling, endotoxin leakage, and gut permeability, and describes how dietary natural products can improve T2DM via the gut microbiota.

Smoking and Endothelial Dysfunction

Cigarette smoking is one of the most important health concerns worldwide. Even though the rate of smoking is declining in developed countries, it is still experiencing growth in developing regions. Many studies have examined the relationship between smoking, as an established risk factor, and cardiovascular diseases. We provide an updated review of the underlying mechanisms of smokinginduced cardiovascular diseases, with a focus on the relationship between smoking and oxidative stress, particularly from the perspective of endothelial cell dysfunction. We review smoking-induced oxidative stress as a trigger for a generalized vascular inflammation associated with cytokine release, adhesion of inflammatory cells and, ultimately, disruption of endothelial integrity as a protective barrier layer. We also briefly discuss the harms related to the vaping of electronic cigarettes, which many erroneously consider as a safe alternative to smoking. We conclude that even though e-cigarette could be a helpful device during the transition period of cigarette quitting, it is by no means a safe substitute.

Association between Cigarette Smoking and New-Onset Diabetes Mellitus in 78,212 Koreans Using Self-Reported Questionnaire and Urine Cotinine

BACKGROUND

No study has assessed association between cigarette smoking and new-onset diabetes mellitus (NODM) incidence using two different smoking classification systems: self-reported questionnaire and urine cotinine. The objective of this longitudinal study was to evaluate NODM risk using the above two systems in Korean adults.

METHODS

Among individuals enrolled in Kangbuk Samsung Health Study and Cohort Study who visited between 2011 and 2012 at baseline and 2014 at follow-up, 78,212 participants without baseline diabetes mellitus were followed up for a median of 27 months. Assessment of NODM incidence was made at the end of follow-up period. Cotinine-verified current smoking was having urinary cotinine ≥50 ng/mL.

RESULTS

Percentages of self-reported and cotinine-verified current smokers were 25.9% and 23.5%, respectively. Overall incidence of NODM was 1.5%. According to multivariate regression analyses, baseline self-reported current smoking (relative risk [RR], 1.33; 95% confidence interval [CI], 1.07 to 1.65) and cotinine-verified current smoking (RR, 1.27; 95% CI, 1.08 to 1.49) increased NODM risk compared to baseline self-reported never smoking and cotinine-verified current non-smoking. Higher daily amount and longer duration of smoking were also associated with increased NODM risk (P for trends <0.05). In particular, self-reported current smokers who smoked ≥20 cigarettes/day (RR, 1.62; 95% CI, 1.25 to 2.15) and ≥10 years (RR, 1.34; 95% CI, 1.08 to 1.67) had the highest RRs for NODM. These results remained significant in males, although there was no gender interaction.

CONCLUSION

This longitudinal study showed that baseline self-reported and cotinine-verified current smoking were associated with increased risks of NODM, especially in males.

Chronic Tobacco Exposure by Smoking Develops Insulin Resistance

BACKGROUND AND OBJECTIVES

The present review critically discusses the high occurrence rate, insulin resistance and type-2 diabetes in tobacco exposed individuals. Tobacco extracts and smoke contain a large number of toxic materials and a significant number of those are metabolic disintegrators.

DISCUSSION

Glucose and lipid homeostasis is severely impaired by this compound. Tobacco exposure contributes to adverse effects by impairing the physical, biochemical and molecular mechanisms in the tissues. The immunological components are damaged by tobacco with high production of proinflammatory cytokines (IL-6, TNF-∞) and augmentation of inflammatory responses. These events result in damages to cytoskeletal structures of different tissues. Degradation of matrix structure (by activation of different types of MMPs) results in the permanent damages to the tissues and their metabolic functions. Cellular antioxidant defense system mostly cannot or hardly nullify CS-induced ROS production that activates polymorphonuclear neutrophils (PMNs), which are a major source of cytokines and chemokines (TNFα, IL6, IL8, INFγ). Additive effects of these immediately promote the low energy-metabolism as well as inflammation. Oxidative stress, mitochondrial dysfunction, and inflammation contribute to the direct nicotine toxicity via nAChRs in diabetes. The investigator identified that skeletal muscle insulin-resistance occurs in smokers due to phosphorylation of insulin receptor substrate1 (IRS1) at Ser-636 position.

CONCLUSION

Tobacco exposure initiates free radical related immunological impairment, DNA damage, and inflammation. So, the present analysis is of importance to figure out the mechanistic layout of tobacco-induced tissue damage and its possible therapeutic interventions.

Clinical guidelines for type 1 diabetes mellitus with an emphasis on older adults: an Executive Summary

We present a summary of a guideline produced by an international group of experts for managing type 1 diabetes in adults with an emphasis on the special needs of older people with this condition. The rationale for delivering high-quality diabetes care for adults with type 1 diabetes, why it is important to include older people in our considerations, and the key underpinning principles of the guideline are included. The structure of the recommendations given is described and consists of 'general' recommendations followed by 'specific' recommendations according to three categories depending on the characteristics of adults addressed, such as functional level or self-management ability. Recommendations are provided in the areas of: clinical diagnosis, establishing management plans and glucose regulation, diabetes self-management education, nutritional therapy, physical activity, exercise and lifestyle modification, insulin treatments and regimens, use of technology in diabetes management, hypoglycaemia, managing cardiovascular risk, management of microvascular risk, and inpatient management of type 1 diabetes and ketoacidosis.

Association and interaction between triglyceride-glucose index and obesity on risk of hypertension in middle-aged and elderly adults

AIMS

To investigate the association between triglyceride-glucose(TyG) index and the risk of hypertension.

METHOD

A cross-sectional study was conducted in Bengbu, China. The participants received relevant questionnaire survey, anthropometric tests, and laboratory examination. Multivariate logistic regression analysis was performed to estimate the possible association between TyG index and hypertension risk. The additive interaction evaluated by the relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and synergy index(SI) was calculated.

RESULTS

A total of 1777 participants (748 men and 1029 women) were investigated. There was a significant increase in the risk of hypertension and isolated systolic hypertension (ISH) when comparing the highest TyG index (the fourth quartile) to the lowest TyG index (the first quartile) and corresponding ORs were 2.446 (95% CI: 1.746-3.426) and 2.621(95%CI: 1.627-4.224), respectively. However, no significant relationship was observed between TyG index and isolated diastolic hypertension (IDH). In males, significant interactions between TyG index and WHtR (RERI:1.978, 95%CI: 0.162-3.792; AP: 0.359, 0.113-0.605; SI:1.782, 1.017-3.122), smoking (AP: 0.437, 95%CI: 0.048-0.825), family history of hypertension (AP:0.433, 95%CI: 0.203-0.662; SI:2.248, 95%CI: 1.333-3.791) were observed. As for females, there were also significant interactions between TyG index and WHtR (RERI:1.415, 95%CI: 0.693-2.136; AP: 0.198, 95%CI: 0.104-0.291; SI:1.298, 95%CI:1.101-1.530), family history of hypertension (RERI:1.744, 95%CI: 0.221-3.267; AP:0.405, 95%CI: 0.113-0.697) on risk of hypertension.

CONCLUSIONS

Increased TyG index was significantly associated with higher risk of hypertension and ISH, but not for IDH in middle-aged and elderly adults. Our results also demonstrated interactions of TyG index and abdominal obesity and family history of hypertension on hypertension risk.

The impact of smoking on the development of diabetes and its complications

Diabetes is one of the most common metabolic disorders and emerges secondary to an interaction between genetic, environmental and lifestyle factors. This work provides an overview of the impact of smoking on the development of vascular complications in this condition and also provides an overview of the potential role of smoking in predisposition to diabetes. There are many studies documenting the impact of smoking on health (not focused on patients with diabetes), suggesting that the health exposure in these individuals is at least comparable to that observed in the general population. Distinct studies of smoking in patients with diabetes have unambiguously confirmed an increased prevalence and a higher risk of early death associated with the development of macrovascular complications. Smoking is also associated with premature development of microvascular complications and may contribute to the pathogenesis of type 2 diabetes. It has been shown that smoking is a predictor of the progression of glucose intolerance at both the transition from normoglycaemia to impaired glucose tolerance status and the increased risk of developing diabetes. The mechanisms explaining the relationship between smoking and the development of diabetes are not fully understood, although a number of hypotheses have been put forward. Current evidence indicates that smoking cessation is not only important to prevent macrovascular complications in diabetes, but also has a role in limiting microvascular disease and may also facilitate glycaemic management in this condition.

Gender Differences of Arterial Stiffness and Arterial Age in Smokers

The present study aimed to find gender differences for arterial stiffness and arterial aging in smokers. A total of 147 smokers (71 male and 76 female, matched for age) were explored using an Arteriograph in a cross-sectional survey. Pulse wave velocity (PWV), arterial age (AA), brachial and aortic augmentation index (AixBrach, AixAo), and blood pressure variables were assessed. Data about smoking intensity, such as the number of cigarettes smoked daily, smoking period, and smoking pack years (SPY) were used. No significant differences were found for PWV, AA, AixBrach and AixAo. Significant correlations were found between SPY and PWV, augmentation indices, and AA, respectively. The cut-off values for SPY were higher for an increased arterial stiffness in male compared to female smokers (18.5 and 7.5 pack year, respectively). SPY is significantly associated with an increased arterial stiffness in smokers regardless of gender, and with an increased SBPAo only in female smokers. The results of our study indicate gender differences for arterial stiffness and arterial age in smokers.

Sources of inaccuracy in the measurement of adult patients' resting blood pressure in clinical settings: a systematic review

BACKGROUND

To interpret blood pressure (BP) data appropriately, healthcare providers need to be knowledgeable of the factors that can potentially impact the accuracy of BP measurement and contribute to variability between measurements.

METHODS

A systematic review of studies quantifying BP measurement inaccuracy. Medline and CINAHL databases were searched for empirical articles and systematic reviews published up to June 2015. Empirical articles were included if they reported a study that was relevant to the measurement of adult patients' resting BP at the upper arm in a clinical setting (e.g. ward or office); identified a specific source of inaccuracy; and quantified its effect. Reference lists and reviews were searched for additional articles.

RESULTS

A total of 328 empirical studies were included. They investigated 29 potential sources of inaccuracy, categorized as relating to the patient, device, procedure or observer. Significant directional effects were found for 27; however, for some, the effects were inconsistent in direction. Compared with true resting BP, significant effects of individual sources ranged from -23.6 to +33 mmHg SBP and -14 to +23 mmHg DBP.

CONCLUSION

A single BP value outside the expected range should be interpreted with caution and not taken as a definitive indicator of clinical deterioration. Where a measurement is abnormally high or low, further measurements should be taken and averaged. Wherever possible, BP values should be recorded graphically within ranges. This may reduce the impact of sources of inaccuracy and reduce the scope for misinterpretations based on small, likely erroneous or misleading, changes.

Substance Use Disorders among Patients with Type 2 Diabetes: a Dangerous but Understudied Combination

PURPOSE OF REVIEW

This paper reviews research on substance use and disorders (SUDs) among adults with diabetes. It describes epidemiological data on SUDs in persons with type 2 diabetes, overviews effects of substance use on diabetes outcomes, and discusses treatments for SUDs in patients with diabetes.

RECENT FINDINGS

Rates of current smoking range from 10 to 26% and alcohol use disorders are 0-5%. Rates of illicit SUDs are 3-4%, but there are no population-based studies using nationally representative samples. Smoking increases the risk for long-term diabetes complications and premature death. Alcohol and illicit drug use can also impact long-term diabetes complications by impairing glucose homeostasis and adversely influencing self-management behaviors. There is mixed evidence about psychosocial smoking cessation interventions in adults with diabetes and little on alcohol and illicit SUD interventions. Limited data exist on pharmacotherapies for SUDs in this population, but a recent study suggests that varenicline is safe and effective for treating smoking in patients with diabetes. Substance use is an understudied problem in type 2 diabetes, and addressing substance use holds potential for improving outcomes. Additional large population-based epidemiological studies in those with type 2 diabetes are needed, particularly for alcohol and illicit SUDs. Longitudinal studies should be conducted to better understand the time course of diabetes onset and outcomes in relation to SUDs. Randomized controlled trials are needed to assess safety and efficacy of promising psychosocial and pharmacological interventions.

A Japanese cross-sectional multicentre study of biomarkers associated with cardiovascular disease in smokers and non-smokers

We performed a cross-sectional, multicentre study in Japan to detect the differences in biomarkers of exposure and cardiovascular biomarkers between smokers and non-smokers. Several clinically relevant cardiovascular biomarkers differed significantly between smokers and non-smokers, including lipid metabolism (high-density lipoprotein cholesterol concentrations – lower in smokers), inflammation (fibrinogen and white blood cell count – both higher in smokers), oxidative stress (8-epi-prostaglandin F_2α – higher in smokers) and platelet activation (11-dehydro-thromboxane B₂ – higher in smokers) (p ≤ 0.0001). These results provide further evidence showing that cardiovascular biomarkers can discriminate smokers from non-smokers, and could be used to evaluate the risks associated with tobacco products.

Smoking and progression of diabetic nephropathy in patients with type 1 diabetes

AIMS

To evaluate the effect of cumulative smoking on the development of diabetic nephropathy.

METHODS

Study included 3613 patients with type 1 diabetes, participating in the Finnish Diabetic Nephropathy Study. The 12-year cumulative risk of microalbuminuria, macroalbuminuria and end-stage renal disease (ESRD) was estimated for current, ex- and nonsmokers. Cox regression analyses, with multivariable adjustments for other risk factors for diabetic nephropathy, were used to evaluate the risk at different stages of diabetic nephropathy based on the cumulative amount of smoking in pack-years.

RESULTS

The 12-year cumulative risk of microalbuminuria was 18.9 % (95 % CI 14.6-23.0, P < 0.0001) for current smokers and 15.1 % (10.3-19.6, P = 0.087) for ex-smokers, compared with 10.0 % (7.8-12.1) for nonsmokers. The corresponding risks of macroalbuminuria were 14.4 % (95 % CI 10.8-17.9, P < 0.0001), 6.1 % (3.5-8.6, P = 0.082) and 4.7 % (3.0-6.4), respectively. The 12-year cumulative risk of ESRD was 10.3 % (95 % CI 8.4-12.4, P < 0.0001) for current smokers and 10.0 % (7.9-12.3, P < 0.0001) for ex-smokers, compared with 5.6 % (4.6-6.7) for nonsmokers. In the current smokers, one pack-year increased the risk of macroalbuminuria with a HR of 1.025 (1.010-1.041) and the risk of ESRD with a HR of 1.014 (1.001-1.026) compared with nonsmokers, in the fully adjusted model. In the ex-smokers, the risk of macroalbuminuria and ESRD was no different from the risk in nonsmokers after multivariable adjustment.

CONCLUSIONS

Current smoking is a risk factor for the progression of diabetic nephropathy and the risk increases with the increasing dose of smoking. Ex-smokers seem to carry a similar risk of progression of diabetic nephropathy as nonsmokers.

Tobacco Use, Insulin Resistance, and Risk of Type 2 Diabetes: Results from the Multi-Ethnic Study of Atherosclerosis

INTRODUCTION

Tobacco use is associated with insulin resistance and incident diabetes. Given the racial/ethnic differences in smoking patterns and incident type 2 diabetes our objective was to evaluate the association between tobacco use and insulin resistance (IR) as well as incident type 2 diabetes mellitus in a contemporary multiethnic cohort.

METHODS AND RESULTS

We studied 5,931 Multi- Ethnic Study of Atherosclerosis (MESA) participants who at baseline were free of type 2 diabetes (fasting glucose ≥7.0 mmol/l (126 mg/dl) and/or use of insulin or oral hypoglycemic medications) categorized by self-reported tobacco status and reclassified by urinary cotinine (available in 58% of participants) as never, current or former tobacco users. The association between tobacco use, IR (fasting plasma glucose, insulin, and the homeostatic model assessment of insulin resistance (HOMA-IR)) and incident diabetes over 10 years was evaluated using multivariable linear regression and Cox proportional hazards models, respectively. Mean age of the participants was 62 (±10) years, 46% were male, 41% Caucasian, 12% Chinese, 26% African American and 21% Hispanic/Latino. IR biomarkers did not significantly differ between current, former, and never cigarette users (P >0.10) but showed limited unadjusted differences for users of cigar, pipe and smokeless tobacco (All P <0.05). Fully adjusted models showed no association between dose or intensity of tobacco exposure and any index of IR. When stratified into participants that quit smoking vs. those who continued smoking during the 10-year study there was no difference in serum glucose levels or frequency of diabetes. In fully adjusted models, there was no significant difference in diabetes risk between former or current cigarette smokers compared to never smokers [HR (95% CI) 1.02 (0.77,1.37) and 0.81 (0.52,1.26) respectively].

CONCLUSION

In a contemporary multi-ethnic cohort, there was no independent association between tobacco use and IR or incident type 2 diabetes. The role smoking plays in causing diabetes may be more complicated than originally thought and warrants more in-depth large contemporary multi-ethnic studies.

Effect of cigarette smoking on insulin resistance risk

OBJECTIVES

Smoking is one of the main risk factors for cardiovascular disease (CVD). The mechanism(s) of the effects of smoking on CVD are not clearly understood; however, a number of atherogenic characteristics, such as insulin resistance have been reported. We aim to investigate the effects of cigarette smoking on insulin resistance and to determine the correlation between this parameter with smoking status characteristics.

STUDY DESIGN

This study was conducted on 138 non-smokers and 162 smokers aged respectively 35.6±16.0 and 38.5±21.9 years. All subjects are not diabetic.

METHODS

Fasting glucose was determined by enzymatic methods and insulin by chemiluminescence method. Insulin resistance (IR) was estimated using the Homeostasis Model of Assessment equation: HOMA-IR=[fasting insulin (mU/L)×fasting glucose (mmol/L)]/22.5. IR was defined as the upper quartile of HOMA-IR. Values above 2.5 were taken as abnormal and reflect insulin resistance.

RESULTS

Compared to non-smokers, smokers had significantly higher levels of fasting glucose, fasting insulin and HOMA-IR index. These associations remained significant after adjustment for confounding factors (age, gender, BMI and alcohol consumption). A statistically significant association was noted between the smoking status parameters, including both the number of cigarettes smoked/day and the duration of smoking, and fasting insulin levels as well for HOMA-IR index. Among smokers, we noted a positive correlation between HOMA-IR index and both plasma thiocyanates and urinary cotinine.

CONCLUSION

Our results show that smokers have a high risk to developing an insulin resistance and hyperinsulinemia, compared with a matched group of non-smokers, and may help to explain the high risk of cardiovascular diseases in smokers.

A single serving of blueberry (V. corymbosum) modulates peripheral arterial dysfunction induced by acute cigarette smoking in young volunteers: a randomized-controlled trial

Cigarette smoking causes oxidative stress, hypertension and endothelial dysfunction. Polyphenol-rich foods may prevent these conditions. We investigated the effect of a single serving of fresh-frozen blueberry intake on peripheral arterial function and arterial stiffness in young smokers. Sixteen male smokers were recruited for a 3-armed randomized-controlled study with the following experimental conditions: smoking treatment (one cigarette); blueberry treatment (300 g of blueberry) + smoking; control treatment (300 mL of water with sugar) + smoking. Each treatment was separated by one week of wash-out period. The blood pressure, heart rate, peripheral arterial function (reactive hyperemia and Framingham reactive hyperemia), and arterial stiffness (digital augmentation index, digital augmentation index normalized for a heart rate of 75 bpm) were measured before and 20 min after smoking with Endo-PAT2000. Smoking impaired the blood pressure, heart rate and peripheral arterial function, but did not affect the arterial stiffness. Blueberry consumption counteracted the impairment of the reactive hyperemia index induced by smoking (-4.4 ± 0.8% blueberry treatment vs. -22.0 ± 1.1% smoking treatment, p < 0.01) and Framingham reactive hyperemia (+28.3 ± 19.2% blueberry treatment vs. -42.8 ± 20.0% smoking treatment, p < 0.0001), and the increase of systolic blood pressure (+8.4 ± 0.02% blueberry treatment vs. +13.1 ± 0.02% smoking treatment, mmHg, p < 0.05) after cigarette smoking. No effect was observed for arterial stiffness and other vital signs. In conclusion, data obtained suggest a protective role of blueberry on reactive hyperemia, Framingham reactive hyperemia, and systolic blood pressure in subjects exposed to smoke of one cigarette. Future studies are necessary to elucidate the mechanisms involved.

Influence of lifestyle on the course of type 1 diabetes mellitus

Type 1 diabetes (T1DM) is an autoimmune disease that requires insulin treatment from the time of diagnosis. Its clinical course depends on both genetic and environmental factors, and the lifestyle of a patient modulates their interaction. The evidence about the influence of lifestyle on the course of T1DM is increasing. In this paper, we present evidence on the relationship between lifestyle parameters and diabetes-related outcomes. We discuss the most commonly addressed factors associated with lifestyle, such as physical activity, nutrition and smoking, and those with sparse evidence in T1DM, such as socioeconomic status, sleep duration, psychological stress and illicit drugs intake.

Favorable effects of concord grape juice on endothelial function and arterial stiffness in healthy smokers

BACKGROUND

Smoking is associated with impaired vascular function. Concord grape juice (CGJ), a rich source of flavonoids, can modify cardiovascular risk factors. Endothelial function and arterial stiffness are surrogate markers of arterial health. We examined the impact of CGJ on arterial wall properties in healthy smokers.

METHODS

We studied the effect of a 2-week oral treatment with CGJ in 26 healthy smokers on 3 occasions (day 0 (baseline), day 7, and day 14) in a randomized, placebo-controlled, double-blind, crossover study. Measurements were taken before (pSm), immediately after (Sm0), and 20 minutes after (Sm20) cigarette smoking. Endothelial function was evaluated by flow-mediated dilation (FMD) of the brachial artery. Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic stiffness.

RESULTS

Compared with placebo, treatment with CGJ resulted in a significant improvement in pSm values of FMD (P = 0.02) and PWV (P = 0.04). At baseline, smoking decreased FMD in both the CGJ group (P < 0.001) and the placebo group (P < 0.001). Compared with placebo, CGJ treatment prevented the acute smoking-induced decrease in FMD on day 7 (P = 0.02) and day 14 (P < 0.001). Moreover, at baseline, smoking induced a significant elevation in PWV in both the CGJ group (P = 0.02) and the placebo group (P = 0.04). Treatment with CGJ prevented the smoking-induced elevation in PWV on day 7 (P = 0.003) and day 14 (P < 0.001).

CONCLUSIONS

CGJ consumption improved endothelial function and vascular elastic properties of the arterial tree in healthy smokers and attenuated acute smoking-induced impairment of arterial wall properties.

Effect of tobacco smoking and smoking cessation on plasma lipoproteins and associated major cardiovascular risk factors: a narrative review

Cigarette smoking, active or passive, kills about 6 million people each year worldwide. Cardiovascular disease (CVD) is responsible for 40% of all smoking-related deaths, lung cancer accounts for 20% of all smoking-related deaths, and chronic obstructive pulmonary disease is related to another 20% of deaths. In this narrative review we consider the relationship between cigarette smoking and CVD. We discuss disease states and/or CVD risk factors related to smoking, such as dyslipidaemia, vascular inflammation, endothelial dysfunction, arterial stiffness, insulin resistance, type 2 diabetes mellitus (T2DM), chronic kidney disease (CKD), and non-alcoholic fatty liver disease (NAFLD) as well as their complex interrelations. Smoking cessation can correct abnormalities related to smoking; however, success rates are relatively low. In cases of inability to quit, measures to minimize the adverse effects of smoking specifically related to CVD should be taken. Smokers should receive best practice treatment, according to guidelines, as for non-smokers.

Smoking and type 2 diabetes mellitus

Cigarette smoking is a well-known risk factor in many diseases, including various kinds of cancer and cardiovascular disease. Many studies have also reported the unfavorable effects of smoking for diabetes mellitus. Smoking increases the risk of developing diabetes, and aggravates the micro- and macro-vascular complications of diabetes mellitus. Smoking is associated with insulin resistance, inflammation and dyslipidemia, but the exact mechanisms through which smoking influences diabetes mellitus are not clear. However, smoking cessation is one of the important targets for diabetes control and the prevention diabetic complications.