Smoking elicits the insulin resistance syndrome: new aspects of the harmful effect of smoking

Associations Between Smoking, Alcohol Consumption, Physical Activity and Depression in Middle-Aged Premenopausal and Postmenopausal Women

Background: Changes in lifestyle factors are known to affect mood. However, there is insufficient evidence supporting the association between smoking, alcohol consumption, physical activity and depression in middle-aged women who are likely to experience rapid hormonal changes. Methods: We used a nationwide database of medical records in South Korea. 901,721 premenopausal and 943,710 postmenopausal women aged 40 years or older included in this study. Information on smoking, alcohol consumption, physical activity was identified from health examination data and followed up for the occurrence of depression using claims data. Results: Compared with never-smokers, ex-smokers and current smokers among premenopausal and postmenopausal women showed an increased risk of depression in a dose-dependent manner (aHR 1.13 for ex-smokers; aHR 1.23 for current smokers). Compared with non-drinkers, mild drinkers showed a decreased risk of depression (aHR 0.98 for premenopausal women; aHR 0.95 for postmenopausal women), and heavy drinkers showed an increased risk of depression both among premenopausal (aHR 1.20) and postmenopausal women (aHR 1.05). The risk of depression due to smoking and heavy alcohol consumption was higher in premenopausal women than in postmenopausal women. Compared with those who had not engaged in regular physical activity, those who had engaged showed a decreased risk of depression both among premenopausal (aHR 0.96) and postmenopausal women (aHR 0.95). Conclusions: Smoking and heavy alcohol consumption increased the risk of depression, and the increased risk was prominent in premenopausal than in postmenopausal women. Regular physical activity decreased the risk of depression both in premenopausal and postmenopausal women.

Factors Associated with Dietary Control and Physical Activity in the Management of Metabolic Syndrome in Korean Menopausal Women

The increased prevalence of metabolic syndrome (MetS) among menopausal women necessitates successful management strategies such as applying dietary restrictions and engaging in physical activity to improve their health and quality of life. We investigate factors associated with dietary control and physical activity in 564 menopausal Korean women classified as having MetS who partook in the 2016 and 2017 Korean National Health and Nutrition Examination Survey (KNHANES). To determine socio-demographic characteristics, lifestyle features, and MetS-related characteristics associated with dietary control and physical activity, multiple logistic regression analysis was performed. Of the women with MetS 36.1% applied diet control and 39.5% engaged in physical activity. Women who applied dietary control strategies to improve their health were more likely to be in the 40–49 age group (odds ratio (OR): 3.38; 95% confidence interval (CI): 1.25–9.18), to engage in physical activity (OR: 2.24; CI: 1.43–3.52), and to take hypertension medication (OR: 1.66; CI: 1.04–2.67) or diabetes mellitus medication (OR: 2.99; CI: 1.80–4.97). Physically active menopausal women with MetS were more likely to also engage in dieting (OR: 2.32; CI: 1.42–3.51). Accordingly, suggestions can be provided to healthcare workers in designing, not only individual approaches to lifestyle modification but also comprehensive interventions including dietary control and physical activity for menopausal MetS women. Health-care interventions like dietary control, which provide additional support to vulnerable MetS women, should target women aged 60 or above or those who do not take medicines for hypertension and diabetes mellitus.

Lower leptin levels in young non-obese male smokers than non-smokers

Since the effect of smoking on plasma leptin has been divergent in clinical trials, which might have occurred due to selection of heterogeneous study populations, we investigated whether there is such an association in a group of healthy, non-obese, young male adults. A total of 54 smokers (mean age: 21.18+/-1.62; body mass index (BMI): 19.60+/-0.85) and 26 non-smokers (mean age 21.69+/-3.0; BMI: 21.59+/-1.39) with similar daily physical activities and diet and without any documented disease were enrolled, and their plasma leptin levels were determined for the comparison between the two groups. The mean BMI and plasma leptin of smokers were significantly lower than in non-smokers. Plasma leptin in the smokers group correlated inversely with BMI and the amount of daily smoking. Below BMI 20 kg/m(2) and between 20.0 and 20.9 kg/m(2) the plasma leptin levels in smokers were significantly lower when compared to non-smokers. Plasma leptin is decreased in healthy, young non-obese male smokers independently of the amount of body fat. High amount of smoking is associated with lower serum leptin as well.

El tabaquismo, la obesidad y la distribución de la grasa corporal se asocian de manera independiente con la resistencia a la insulina y con otros factores de riesgo cardiovascular

BACKGROUND AND AIM

In recent years, smoking has been shown to increase insulin resistance. However, other studies have failed to demonstrate this association after correcting for confounding factors such as age, gender, body mass index (BMI) or waist to hip ratio (WHR). This study was conducted to elucidate the relative contributions of smoking, obesity and body fat distribution on insulin resistance and other cardiovascular risk factors.

PATIENTS AND METHODS

Cases and controls matched for age, gender and degree of obesity. Evaluations included anthropometrical and biochemical assessments with body mass index (BMI), waist to hip ratio (WHR), lipid profiles and insulin resistance determined by HOMA (Homeostasis Model Assessment).

RESULTS AND CONCLUSION

A total of 126 patients (52 smokers and 74 non-smokers) participated in the study. Of all the patients, 22 (17.5%) were lean, 49 (38.9%) overweight and 55 (43.7%) obese. Multivariate stepwise linear regression showed an association of WHR (beta = 0.414, p < 0.001), BMI (beta = 0.211, p = 0.012), the number of smoked cigarettes per day (beta = 0.200, p = 0.011) and serum triglycerides levels (beta = 0.241, p = 0.007) on insulin resistance (R = 0.628, F = 13.841, p < 0.001). An independent effect of smoking on triglycerides levels was also shown. Therefore, smoking, obesity and body fat distribution are independently associated with insulin resistance and lipid profile.

Influence of smoking on predictors of vascular disease

Beyond the already well-established strong causative relationship with cancer, smoking increases the risk for vascular disease. Smoking may act directly or adversely influence risk factors contributing to the development of vascular disease. Smoking causes endothelial dysfunction, dyslipidemia (decreased high-density lipoprotein cholesterol levels, hypertriglyceridemia and increased oxidation of low-density lipoprotein cholesterol) and platelet activation leading to a prothrombotic state. Smoking increases emerging risk factors (eg, fibrinogen, homocysteine, and high-sensitivity C-reactive protein) and increases insulin resistance and the risk of developing type 2 diabetes mellitus. The beneficial effects of statins and antioxidants (eg, vitamins C and E, beta-carotene) are counteracted by smoking. Smoking-induced alterations in growth factors, adhesion molecules, and even in genes can accelerate the progression of atherosclerosis. The aim of this review is to consider the adverse consequences of smoking on the factors predisposing to vascular disease and to emphasize the beneficial effects of smoking cessation.

Smoking diminishes the beneficial effect of statins: observations from the landmark trials

The landmark statin trials showed a significant reduction in morbidity and mortality associated with ischemic heart disease. However, it may not be widely appreciated that smoking had a marked adverse effect on outcome in these trials. In both the primary and secondary prevention setting, the effect of smoking was broadly similar. Smoking markedly increased the risk of events in the placebo and treatment groups. For example, in the primary prevention trials, this risk was 74-86% higher when smokers were compared with nonsmokers in the placebo groups. The corresponding figures for the secondary prevention trials were 23-61%. The risk of events in untreated nonsmokers was of a similar order to that seen in smokers taking statins. Although statin treatment was associated with a significant reduction in events in smokers, the best outcome was observed in nonsmokers treated with statins (primary prevention: lovastatin or pravastatin; secondary prevention: pravastatin or simvastatin). The highest risk of events in any group was in the smokers on placebo. This information may increase clinician and patient awareness as to the marked harmful effect of smoking relative to effective, evidence-based treatment (ie, the use of statins).

Cigarette smoking, alcohol use, and physical activity in relation to serum leptin levels in a multiethnic population: The Miami Community Health Study

PURPOSE

To examine the correlates of plasma leptin, including fasting insulin, adiposity, and several health habits and behaviors among a nondiabetic multiethnic population.

METHODS

A cross-sectional study was conducted among 25-44 year old African-Americans (n = 126), Cuban-Americans (n = 107), and non-Hispanic whites (n = 189) randomly selected from Dade County Florida. Fasting leptin levels were correlated with fasting insulin, percent body fat, smoking, alcohol use, and physical activity within each sex. Multiple linear regression and analysis of covariance were used to estimate the independent determinants of plasma leptin concentration separately among men and women.

RESULTS

Stepwise linear regression analyses revealed statistically significant associations of leptin with percent body fat, fasting insulin, cigarette smoking, and physical activity (both inversely) among men (p < 0.05 for each). Among women, percent body fat, fasting insulin (both positively), cigarette smoking, and alcohol use (inversely) were independent predictors of leptin levels explaining over 70% of the variance. Analyses of covariance revealed that women had higher adjusted mean leptin levels than men (13.1 ng/ml vs. 5.9 ng/ml; p < 0.001), whereas no separate effect of ethnicity was noted.

CONCLUSIONS

Although adiposity was the strongest correlate of leptin levels, fasting insulin and several health habits and behaviors were independently associated with leptin. After adjustment for these factors, women had significantly higher mean leptin levels than men. The independent association among leptin and insulin levels is intriguing and suggests additional avenues for epidemiologic research.

Intracellular starvation in the insulin resistance syndrome and type II diabetes mellitus

Statistical associations of insulin resistance, type II diabetes, hypertension and hyperlipidemia have been well documented, but the pathophysiology of the 'insulin resistance syndrome' is unknown. This article explores the hypothesis that intracellular starvation plays a central role in the development of type II diabetes, hypertension and hyperlipidemia. According to this hypothesis, insulin resistance leads to inadequate intracellular glucose, which in turn leads to insufficient amounts of adenosine triphosphate needed for ion transfer, and to drive energy-requiring reactions. Indirect evidence supporting this hypothesis is presented. Intracellular starvation is also discussed as an alternative to the 'glucose hypothesis' to explain certain complications of diabetes.

Associations of smoking, alcohol and physical activity with risk factors for coronary heart disease and diabetes in the first follow-up cohort of the Heart Disease and Diabetes Risk Indicators in a Screened Cohort study (HDDRISC-1)

OBJECTIVES

To investigate the associations between risk factors for cardiovascular disease and cigarette smoking, alcohol intake, and physical activity in a group of predominantly healthy men.

DESIGN

Cohort study with baseline characterisation, clinical follow-up, and identification of predictors of coronary artery disease and diabetes.

SETTING

University hospital metabolic day ward.

SUBJECTS

Participants in a company health programme (n=742).

MAIN OUTCOME MEASURES

Routine haematology and biochemistry, cholesterol, triglycerides, high density lipoprotein (HDL) cholesterol (on a subset of 522 subjects), and glucose and insulin levels during a 3 h oral glucose tolerance test (OGTT).

RESULTS

Independent associations with previous cigarette smoking included high uric acid and low HDL cholesterol, and with current cigarette smoking, high haemoglobin and white cell count and low OGTT insulin. Increasing alcohol intake was associated with increasing blood pressure, uric acid, HDL cholesterol and fasting glucose. The moderate range of exercise intensity in this cohort was associated with decreasing systolic blood pressure, fasting insulin and OGTT glucose and insulin. Factor analysis distinguished principal factors comprising features of the metabolic syndrome with low physical activity, and high white cell count, high haemoglobin concentration and low HDL cholesterol with increasing previous and current cigarette smoking and alcohol intake.

CONCLUSIONS

Some characteristics of the metabolic syndrome were seen with previous but not current smoking habit. Regular alcohol consumption was associated with mainly unfavourable metabolic characteristics, although there was an independent beneficial association with HDL cholesterol. The improved metabolic syndrome profile seen with increasing exercise is consistent with even moderate degrees of physical activity having beneficial effects on metabolism.

Smoking, diabetes and hyperlipidaemia

The epidemiological evidence linking smoking with insulin resistance is considerable. This evidence is even more convincing because there is a dose response relationship between smoking and the risk of non-insulin dependent diabetes (NIDDM). Similarly, there is a time-dependent decrease in risk of NIDDM for those who quit smoking. Insulin resistance (in the form of impaired glucose tolerance, IGT) may precede the development of NIDDM. There is a biochemical basis for the smoking-IGT/NIDDM relationship. Smoking increases the risk of developing diabetic complications like nephropathy, neuropathy and retinopathy Smoking is also an independent risk factor for myocardial infarction and all-cause mortality in NIDDM. Smokers are both insulin resistant and lipid intolerant. Smoking cessation increases circulating high density lipoprotein (HDL) and reduces low density lipoprotein (LDL) levels, despite weight gain. Those providing advice or treatment to improve cardiovascular risk factors should be aware of these smoking-related harmful effects. This is especially true if IGT is underdiagnosed despite the fact that this condition increases the risk of vascular events. Explaining that smoking increases the chance of developing diabetes as well as raising 'blood fat' levels may convince more smokers to quit.

Predictors of smoking cessation after percutaneous coronary revascularization

OBJECTIVE

To identify factors predictive of smoking cessation after successful percutaneous coronary revascularization.

MATERIAL AND METHODS

We undertook a case-control study of the smoking status of all patients at Mayo Clinic Rochester from September 1979 through December 1995 who were smokers at the time of an index percutaneous coronary revascularization procedure in the non-peri-infarction setting (no myocardial infarction within 24 hours). Maximal duration of prospective follow-up was 16 years. Patients were classified into those who permanently quit smoking immediately after the procedure (N = 435; mean follow-up, 5.1 +/- 3.7 years) or those who continued to smoke at some time during follow-up (N = 734; mean follow-up, 5.3 +/- 3.7 years). Logistics regression models were formulated to determine independent predictors of smoking cessation.

RESULTS

Predictors of continued smoking were greater prior cigarette consumption (odds ratio [OR] = 1.009 for each pack-year; 95% confidence interval [CI] = 1.004 to 1.014) and having one or more risk factors for coronary artery disease other than cigarette smoking (OR = 1.49; 95% CI = 1.15 to 1.93). Older age (OR = 0.98 for each additional year; 95% CI = 0.97 to 0.99) and unstable angina at time of initial assessment (OR = 0.69; 95% CI = 0.52 to 0.91) were associated with less likelihood of continued smoking.

CONCLUSION

Younger patients with a worse risk profile and greater prior cigarette consumption were more likely than other patients to continue smoking after percutaneous coronary revascularization in the non-peri-infarction setting. Patients who had unstable angina were more likely to quit smoking than those who had stable angina. Despite the proven benefits of smoking cessation after percutaneous coronary revascularization, a substantial proportion of smokers (63%) continue to smoke; thus, smoking-cessation counseling should be addressed in this population.

Cigarette smoking is not associated with hyperinsulinemia: evidence against a causal relationship between smoking and insulin resistance

Previous reports of a relationship between cigarette smoking and hyperinsulinemia and insulin resistance provide an important possible mechanism by which smoking could be associated with the metabolic cardiovascular syndrome and hence with ischemic heart disease. However, few previous studies have been able to adjust for all the possible confounding factors related both to smoking and to insulin resistance. Therefore, we examined this association in a population-based cohort study of 1,122 individuals aged 40 to 65 years who underwent a 75-g oral glucose tolerance test with specific measurement of insulin, 32,33-split proinsulin, and intact proinsulin concentrations. Physical activity was quantified using the Paffenbarger questionnaire, and smoking status and alcohol consumption were determined using the Health and Lifestyle Survey questionnaire; 17.4% of the population were current smokers and 32.4% were ex-smokers. Current smoking was associated with reduced overall obesity as indicated by the body mass index (BMI) but an increase in central adiposity as measured by the waist to hip ratio (WHR). There were also significant associations between cigarette smoking and the pattern of alcohol intake and physical inactivity. In unadjusted analyses, current smoking was associated with lower fasting and 120-minute insulin and also 120-minute glucose compared with levels in nonsmokers. Adjustment for confounding by age and BMI reduced these differences, but they were increased by adjustment for central obesity. We conclude from this study that a causal relationship between cigarette smoking and insulin resistance is unlikely.