Lipid intolerance in smokers

Dyslipidemia and associated cardiovascular risk factors in HIV-positive and HIV-negative patients visiting ambulatory clinics: A hospital-based study

Background

Dyslipidemia is a well-known risk factor for cardiovascular disease (CVD), accounting for more than half of all instances of coronary artery disease globally (CAD).

Purpose

The purpose of this study was to determine lipid-related cardiovascular risks in HIV-positive and HIV-negative individuals by evaluating lipid profiles, ratios, and other related parameters.

Methods

A hospital-based study was carried out from January 2019 to February 2021 in both HIV + and HIV- ambulatory patients.

Results

High TG (p = .003), high TC (p = .025), and low HDL (p < .001) were all associated with a two-fold increased risk of CVD in people aged 45 and up. Due to higher TG (p < .001) and lower HDL (p < .001), males were found to have a higher risk of atherogenic dyslipidemia. A twofold increase in the likelihood of higher TG levels has been associated with smoking (p = .032) and alcohol intake (p = .022). A twofold increase in a high TC/HDL ratio and an elevated TG/HDL ratio was observed with an increase in waist-to-height ratio (p = .030) and a high level of FBS (126 mg/dl) and/or validated diabetes (p = .017), respectively. In HIV + participants, central obesity (p < .001), diabetes (p < .001), and high blood pressure (p < .001) were all less common than in HIV- participants.

Conclusions

Dyslipidemia is linked to advanced age, male gender, diabetes, smoking, alcohol consumption, and increased waist circumference, all of which could lead to an increased risk of CVD, according to the study. The study also revealed that the risks are less common in HIV + people than in HIV-negative ambulatory patients.

Acute Running and Coronary Heart Disease Risk Markers in Male Cigarette Smokers and Nonsmokers: A Randomized Crossover Trial

PURPOSE

Cigarette smoking is an independent risk factor for coronary heart disease and is associated with impaired postprandial metabolism. Acute exercise reduces postprandial lipemia and improves other coronary heart disease risk markers in nonsmokers. Less is known about responses in cigarette smokers.

METHODS

Twelve male cigarette smokers (mean ± SD; age = 23 ± 4 yr, body mass index = 24.9 ± 3.0 kg·m-2) and 12 male nonsmokers (age = 24 ± 4 yr, body mass index = 24.1 ± 2.0 kg·m-2) completed two, 2-d conditions (control and exercise) in a randomized crossover design. On day 1, participants rested for 9 h (0800-1700) in both conditions except a 60-min treadmill run (65% ± 7% peak oxygen uptake, 2.87 ± 0.54 MJ) was completed between 6.5 and 7.5 h (1430-1530) in the exercise condition. On day 2 of both conditions, participants rested and consumed two high-fat meals over 8 h (0900-1700) during which 13 venous blood samples and nine resting arterial blood pressure measurements were collected.

RESULTS

Smokers exhibited higher postprandial triacylglycerol and C-reactive protein than nonsmokers (main effect group effect size [Cohen's d] ≥ 0.94, P ≤ 0.034). Previous day running reduced postprandial triacylglycerol, insulin, and systolic and diastolic blood pressure (main effect condition d ≥ 0.28, P ≤ 0.044) and elevated postprandial nonesterified fatty acid and C-reactive protein (main effect condition d ≥ 0.41, P ≤ 0.044). Group-condition interactions were not apparent for any outcome across the total postprandial period (0-8 h; all P ≥ 0.089), but the exercise-induced reduction in postprandial triacylglycerol in the early postprandial period (0-4 h) was greater in nonsmokers than smokers (-21%, d = 0.43, vs -5%, d = 0.16, respectively; group-condition interaction P = 0.061).

CONCLUSIONS

Acute moderate-intensity running reduced postprandial triacylglycerol, insulin, and resting arterial blood pressure the day after exercise in male cigarette smokers and nonsmokers. These findings highlight the ability of acute exercise to augment the postprandial metabolic health of cigarette smokers and nonsmokers.

Tobacco Smoking and Association between Betel Nut Chewing and Metabolic Abnormalities Among Military Males: The CHIEF Study

AIM

To investigate the effect of smoking and alcohol intake on the association between betel nut chewing and each metabolic abnormality.

BACKGROUND

Betel nut chewing has been associated with metabolic syndrome.

OBJECTIVE

Whether the association is affected by tobacco or alcohol use is not clarified so far.

METHODS

The authors conducted a cross-sectional study using 6,657 military males, aged 18-50 years in eastern Taiwan in 2013-2014. Metabolic syndrome was defined according to the International Diabetes Federation's ethnic criteria for Asians. The population was classified as non-betel nut chewers (N =5,749), current chewers with both tobacco and alcohol use (N =615), and current chewers without tobacco and/or alcohol use (N =293). Multiple logistic regression analyses were stepwise adjusted for the confounders including alcohol and tobacco use to determine the association of betel chewing with the metabolic abnormalities.

RESULTS

As compared to the non-current chewers, the current chewers with both tobacco/alcohol use and those without had a higher risk of metabolic syndrome (odds ratios (OR) and 95% confidence intervals: 2.46 (2.00-3.02), and 2.04 (1.53-2.73), respectively) after controlling for age, service specialty, total cholesterol levels ≥200 mg/dL and exercise frequency (model 1). The association did not change much in the two chewing groups after additionally adjusting for alcohol consumption (model 2) (OR: 2.49 (1.99-3.12), and 2.04 (1.52-2.73), respectively), whereas the relationship reduced significantly in the chewers with both tobacco/alcohol use rather than those without after further adjusting for smoking (model 3) (OR: 2.18 (1.71-2.78) and 2.02 (1.51-2.71), respectively). This was in parallel with the pattern for the association of betel nut chewing with serum triglycerides >150 mg/dL in the chewers with both tobacco/alcohol use and those without in model 1 (OR: 2.90 (2.40-3.51) and 1.90 (1.45-2.49), respectively, p =0.011), in model 2 (OR: 2.82 (2.30-3.46) and 1.89 (1.44-2.49), respectively, p =0.040), and in model 3 (2.26 (1.81-2.81) and 1.87 (1.42-2.45), respectively, p =0.76).

CONCLUSION

Our findings suggest that tobacco smoking but not alcohol intake could increase the relationship of betel nut chewing with metabolic syndrome, which is likely mediated by a synergic effect on increasing serum triglycerides levels.

Effects of cigarette smoking on blood lipids in Korean men: Cardiovascular and Metabolic Diseases Etiology Research Center cohort

BACKGROUND/AIMS

Cigarette smoking and abnormal blood lipids are major risk factors for cardiovascular disease. The results of previous studies on the relationship between cigarette smoking and dyslipidemia are controversial. In the present study, we investigated the independent association between cigarette smoking and blood lipid levels in a male Korean population.

METHODS

A total of 1,932 men aged from 30 to 64 years old participated in the Cardiovascular and Metabolic Diseases Etiology Research Center cohort study. Smoking history was obtained by in-person interviews. In all regression models, measurements of triglyceride levels were log-transformed.

RESULTS

Triglyceride levels were higher in current smokers than in never-smokers (median: 149 mg/dL vs. 115 mg/dL, p < 0.001) even after adjusting age, body mass index, alcohol intake, systolic blood pressure, fasting glucose, physical activity, and nutrition intake (β = 0.14, p < 0.001). We further divided people into heavy and light smokers using 20 pack-years as the cut-off. Higher triglyceride were found in current heavy smokers (β = 0.18, p < 0.001), current light smokers (β = 0.13, p < 0.001), as well as in past heavy smokers (β = 0.08, p = 0.037), as compared to never-smokers. Moreover, significantly lower high-density lipoprotein cholesterol (HDL-C) were observed in current heavy smokers (β = -2.27 mg/dL, p = 0.009).

CONCLUSION

Cigarette smoking is associated with higher triglyceride in Korean men, with the most dramatic effect seen in current smokers with a smoking history of more than 20 pack-years. HDL-C were also lower in current smokers with more than 20 pack-years.

Determination of optimal cut-off points after a high-fat meal corresponding to fasting elevations of triglyceride and remnant cholesterol in Chinese subjects

BACKGROUND

Postprandial high triglyceride (HTG), marking elevated level of remnant cholesterol (RC), is an independent risk factor of coronary heart disease (CHD). The postprandial cut-off points for HTG and high RC (HRC) after a daily meal are recommended as 2.0 mmol/L and 0.9 mmol/L, respectively, by the European Atherosclerosis Society (EAS), while those after a high-fat meal in Chinese subjects were not explored.

METHODS

Ninety subjects, including 60 CHD patients (CHD group) and 30 non-CHD controls (CON group), were enrolled in this study. Serum levels of blood lipids, including calculated RC, were monitored at 0, 2, 4 and 6 h after a high-fat meal with 800 kcal and 50 g fat. Analysis of c-statistic was used to determine the cut-off points for postprandial HTG and HRC.

RESULTS

Postprandial levels of triglyceride (TG) and RC significantly increased and peaked at 4 h after a high-fat meal in two groups, although those in CHD group were significantly higher (P < 0.05). The optimal cut-off point to predict HTG at 4 h corresponding to fasting TG ≥ 1.7 mmol/L was 3.12 mmol/L, and that to predict HRC at 4 h corresponding to fasting RC ≥ 0.8 mmol/L was 1.36 mmol/L. According to the new cut-off points, the omissive diagnosis rates of postprandial HTG and HRC decreased obviously.

CONCLUSION

The cut-off points of postprandial HTG and HRC in Chinese subjects after a high-fat meal were higher than those after a daily meal recommended by the EAS, indicating that specific cut-off points should be determined after a certain high-fat meal.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY GUIDELINES FOR MANAGEMENT OF DYSLIPIDEMIA AND PREVENTION OF CARDIOVASCULAR DISEASE

OBJECTIVE

The development of these guidelines is mandated by the American Association of Clinical Endocrinologists (AACE) Board of Directors and American College of Endocrinology (ACE) Board of Trustees and adheres with published AACE protocols for the standardized production of clinical practice guidelines (CPGs).

METHODS

Recommendations are based on diligent reviews of the clinical evidence with transparent incorporation of subjective factors, according to established AACE/ACE guidelines for guidelines protocols.

RESULTS

The Executive Summary of this document contains 87 recommendations of which 45 are Grade A (51.7%), 18 are Grade B (20.7%), 15 are Grade C (17.2%), and 9 (10.3%) are Grade D. These detailed, evidence-based recommendations allow for nuance-based clinical decision-making that addresses multiple aspects of real-world medical care. The evidence base presented in the subsequent Appendix provides relevant supporting information for Executive Summary Recommendations. This update contains 695 citations of which 203 (29.2 %) are EL 1 (strong), 137 (19.7%) are EL 2 (intermediate), 119 (17.1%) are EL 3 (weak), and 236 (34.0%) are EL 4 (no clinical evidence).

CONCLUSION

This CPG is a practical tool that endocrinologists, other health care professionals, health-related organizations, and regulatory bodies can use to reduce the risks and consequences of dyslipidemia. It provides guidance on screening, risk assessment, and treatment recommendations for a range of individuals with various lipid disorders. The recommendations emphasize the importance of treating low-density lipoprotein cholesterol (LDL-C) in some individuals to lower goals than previously endorsed and support the measurement of coronary artery calcium scores and inflammatory markers to help stratify risk. Special consideration is given to individuals with diabetes, familial hypercholesterolemia, women, and youth with dyslipidemia. Both clinical and cost-effectiveness data are provided to support treatment decisions.

ABBREVIATIONS

4S = Scandinavian Simvastatin Survival Study A1C = glycated hemoglobin AACE = American Association of Clinical Endocrinologists AAP = American Academy of Pediatrics ACC = American College of Cardiology ACE = American College of Endocrinology ACS = acute coronary syndrome ADMIT = Arterial Disease Multiple Intervention Trial ADVENT = Assessment of Diabetes Control and Evaluation of the Efficacy of Niaspan Trial AFCAPS/TexCAPS = Air Force/Texas Coronary Atherosclerosis Prevention Study AHA = American Heart Association AHRQ = Agency for Healthcare Research and Quality AIM-HIGH = Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides trial ASCVD = atherosclerotic cardiovascular disease ATP = Adult Treatment Panel apo = apolipoprotein BEL = best evidence level BIP = Bezafibrate Infarction Prevention trial BMI = body mass index CABG = coronary artery bypass graft CAC = coronary artery calcification CARDS = Collaborative Atorvastatin Diabetes Study CDP = Coronary Drug Project trial CI = confidence interval CIMT = carotid intimal media thickness CKD = chronic kidney disease CPG(s) = clinical practice guideline(s) CRP = C-reactive protein CTT = Cholesterol Treatment Trialists CV = cerebrovascular CVA = cerebrovascular accident EL = evidence level FH = familial hypercholesterolemia FIELD = Secondary Endpoints from the Fenofibrate Intervention and Event Lowering in Diabetes trial FOURIER = Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects With Elevated Risk trial HATS = HDL-Atherosclerosis Treatment Study HDL-C = high-density lipoprotein cholesterol HeFH = heterozygous familial hypercholesterolemia HHS = Helsinki Heart Study HIV = human immunodeficiency virus HoFH = homozygous familial hypercholesterolemia HPS = Heart Protection Study HPS2-THRIVE = Treatment of HDL to Reduce the Incidence of Vascular Events trial HR = hazard ratio HRT = hormone replacement therapy hsCRP = high-sensitivity CRP IMPROVE-IT = Improved Reduction of Outcomes: Vytorin Efficacy International Trial IRAS = Insulin Resistance Atherosclerosis Study JUPITER = Justification for the Use of Statins in Primary Prevention: An Intervention Trial Evaluating Rosuvastatin LDL-C = low-density lipoprotein cholesterol Lp-PLA2 = lipoprotein-associated phospholipase A2 MACE = major cardiovascular events MESA = Multi-Ethnic Study of Atherosclerosis MetS = metabolic syndrome MI = myocardial infarction MRFIT = Multiple Risk Factor Intervention Trial NCEP = National Cholesterol Education Program NHLBI = National Heart, Lung, and Blood Institute PCOS = polycystic ovary syndrome PCSK9 = proprotein convertase subtilisin/kexin type 9 Post CABG = Post Coronary Artery Bypass Graft trial PROSPER = Prospective Study of Pravastatin in the Elderly at Risk trial QALY = quality-adjusted life-year ROC = receiver-operator characteristic SOC = standard of care SHARP = Study of Heart and Renal Protection T1DM = type 1 diabetes mellitus T2DM = type 2 diabetes mellitus TG = triglycerides TNT = Treating to New Targets trial VA-HIT = Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial VLDL-C = very low-density lipoprotein cholesterol WHI = Women's Health Initiative.

Effect of present versus previous smoking on non-invasive haemodynamics

We examined cardiovascular function in 637 volunteers (19-72 years) without antihypertensive medication in never smokers (n = 365), present smokers (n = 81) and previous smokers (n = 191, median abstinence 10 years). Haemodynamics during passive head-up tilt were recorded using whole-body impedance cardiography and radial pulse wave analysis. Results were adjusted for age, sex, body mass index, LDL cholesterol and alcohol use. Systolic and diastolic blood pressure, heart rate, and pulse wave velocity were not different between the groups. Supine aortic reflection times did not differ, while upright values were shorter in present versus previous smokers (p = 0.04). Heart rate adjusted augmentation index was increased in the supine position in present smokers versus controls (p = 0.045), and in present (p < 0.001) and previous (p = 0.031) smokers versus controls in the upright position. Supine and upright cardiac output was higher (p ≤ 0.016) and systemic vascular resistance lower (p ≤ 0.001) in present versus previous smokers. In spite of the long abstinence, in the upright position previous smokers had lower cardiac output (p = 0.032) and higher systemic vascular resistance (p = 0.014) than never smokers. In the absence of differences in blood pressure and arterial stiffness, present smokers presented with hyperdynamic circulation and enhanced wave reflection compared with previous smokers.

Fasting Lipoprotein Lipase Protein Levels Can Predict a Postmeal Increment of Triglyceride Levels in Fasting Normohypertriglyceridemic Subjects

BACKGROUND

Although a postprandial increment in triglyceride (TG) levels is considered to be a risk factor for atherogenesis, tests (e.g., fat load) to assess postprandial changes in TG levels cannot be easily applied to clinical practice. Therefore, fasting markers that predict postprandial TG states are needed to be developed. One current candidate is lipoprotein lipase (LPL) protein, a molecule that hydrides TGs. This study investigated whether fasting LPL levels could predict postprandial TG levels.

METHODS

A total of 17 subjects (11 men, 6 women, mean age 52 ± 11 years) with normotriglyceridemia during fasting underwent the meal test. Several fasting parameters, including LPL, were measured for the area under the curve of postprandial TGs (AUC-TG).

RESULTS

The subjects' mean fasting TG level was 1.30 mmol/l, and their mean LPL level was 41.6 ng/ml. The subjects' TG levels increased after loading (they peaked after two postprandial hours). Stepwise multiple regression analysis demonstrated that fasting TG levels were a predictor of the AUC-TG. In addition, fasting LPL mass levels were found to be a predictor of the AUC-TG (β = 0.65, P < 0.01), and this relationship was independent of fasting TG levels.

CONCLUSION

Fasting LPL levels may be useful to predict postprandial TG increment in this population.

Cigarette smoking and albuminuria are associated with impaired arterial smooth muscle function in patients with type 2 diabetes mellitus: a FIELD substudy

AIM

Impaired arterial function has been implicated in diabetes-related atherosclerosis, but its determinants in high-risk adults have not been well characterised. We investigated factors associated with impaired arterial function in adults with type 2 diabetes.

METHODS

Flow-mediated dilatation (a marker of endothelial function) and dilator response to glyceryl trinitrate (to assess smooth muscle function) of the brachial artery were assessed at baseline in 193 patients with type 2 diabetes from the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study. Traditional risk factors were assessed and a multivariable model was constructed to identify factors independently associated with impaired arterial function.

RESULTS

Median age was 64 years (interquartile range, 58-69; 61% male) and duration of diabetes was 4 years (interquartile range, 2-9). Flow-mediated dilatation (3.06 ± 0.25%, mean ± SEM) was severely impaired but not significantly associated with other risk factors. Dilator responses to glyceryl trinitrate (10.56 ± 0.52%) were significantly and independently impaired in past and present cigarette smokers (P = 0.005) and in subjects with increased urinary albumin/creatinine ratio (P = 0.01).

CONCLUSIONS

In adults with type 2 diabetes and known or suspected atherosclerosis, arterial smooth muscle-dependent dilatation was shown to be significantly impaired in cigarette smokers and those with elevated urinary albumin levels.

Comparison of postprandial lipemia between women who are on oral contraceptive methods and those who are not

BACKGROUND

Postprandial Lipemia (PPL) is a physiological process that reflects the ability of the body to metabolize lipids. Even though the influence of oral contraceptives (OC) on PPL is not known, it is a known fact that their use increases fasting lipid values.

OBJECTIVE

To compare the PPL between women who are on OC and those who are not.

METHODS

A prospective analytical study which assessed eutrophic women, aged between 18 and 28 years old, who were irregularly active and with fasting triglycerides ≤ 150 mg/dL. They were divided into two groups: oral contraceptive group (COG) and non-oral contraceptive group (NCOG). Volunteers were submitted to the PPL test, in which blood samples were collected in time 0 (12-hour fasting) and after the intake of lipids in times 180 and 240 minutes. In order to compare the triglyceride deltas, which reflect PPL, the two-tailed Mann-Whitney test was used for independent samples between fasting collections and 180 minutes (Δ1) and between fasting and 240 minutes (Δ2).

RESULTS

Forty women were assessed and equally divided between groups. In the fasting lipid profile, it was observed that HDL did not present significant differences and that triglycerides in COG were twice as high in comparison to NCOG. Medians of Δ1 and Δ2 presented significant differences in both comparisons (p ≤ 0.05).

CONCLUSION

The results point out that women who are irregularly active and use OC present more PPL in relation to those who do not use OC, which suggests that in this population, its chronic use increases the risk of heart conditions.

Postprandial lipaemia and vascular disease

PURPOSE OF REVIEW

In this review we discuss the postprandial pathophysiological mechanisms that promote vascular disease, the evidence for a role of postprandial lipaemia (PPL) in vascular disease and the effect of modifiable and nonmodifiable factors in PPL.

RECENT FINDINGS

PPL refers to the dynamic changes in serum lipids and lipoproteins (mainly in serum triglycerides) that occur after a fat load or a meal. Recent data indicate that postprandial or nonfasting triglyceride levels are better predictors of cardiovascular risk, suggesting that efficiency of postprandial handling of triglyceride-rich lipoproteins plays a role in the causation of vascular disease.

SUMMARY

The recent finding that postprandial serum triglyceride levels are even better than fasting serum triglyceride levels as predictors of vascular disease indicate that it is better to measure an index of triglyceride-rich lipoproteins (in most cases serum triglyceride levels) in the postprandial period than in the postabsorptive fasting state. Moreover, by the time the postabsorptive state is reached, some of these proatherogenic triglyceride-rich lipoprotein changes may be missed in the measurement.

The latest on the effect of prior exercise on postprandial lipaemia

This review examines the effect of prior exercise on postprandial triacylglycerol (pTAG) concentrations, an independent risk factor for cardiovascular diseases. Numerous studies have shown that a single bout of exercise reduces pTAG concentrations; however, several modulators such as exercise energy expenditure/deficit, mode of exercise (aerobic/resistance/high intensity/intermittent exercise or combinations), type of meal (moderate or high fat), time frame between exercise and meal and target group may individually or in conjunction influence this effect. On the other hand, at least for aerobic exercise, training reduces pTAG concentrations transiently (~2 days); therefore, exercise sessions should be frequent enough to maintain this clinically significant improvement. For the healthy population, it seems that a subject's preference and ability determine which type of exercise to undertake to attenuate pTAG concentrations; an energy expenditure of ~30 kJ/kg of body mass (or ~2-2.5 MJ) not combined with a corresponding increase in energy intake is required; for resistance or intermittent exercise, for those following a moderate rather than a high-fat diet, and for those with obesity (expressed as kJ/kg of body mass), a smaller energy expenditure is probably sufficient. More studies are needed to investigate dose-response/plateau effects, as well as the threshold of energy expenditure in those with diabetes mellitus and other high-risk populations. Finally, investigation of the underlying mechanisms may be clinically helpful in individualizing the appropriate intervention.

Lifestyle-related risk factors, smoking status and cardiovascular disease

BACKGROUND

Cardiovascular disease represents one of the most important causes of morbidity and mortality in highly developed countries and is known to be associated with some lifestyle-related risk factors (e.g. alcohol consumption, smoking status, diet, physical activity, bodyweight). There is still incomplete information about their combined effect on cardiovascular risk in hypertensive patients with optimal pharmacological blood pressure control.

AIM

The objective of this study was to evaluate the correlation of some lifestyle behaviours, using a specific questionnaire, with development of cardiovascular disease in treated hypertensive patients.

METHODS

617 hypertensive, non-diabetic participants (aged 53.1 ± 7.6 years, 44.9% male; mean age 53.1 ± 7.6 years) free of prevalent cardiovascular disease, cancer, liver cirrhosis and/or failure, chronic kidney disease more than grade 3 (glomerular filtration rate by the Modification of Diet in Renal Disease study <30 mL/min/1.73 m2) were analysed. Metabolic syndrome was defined according to the Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). Left ventricular hypertrophy was defined when left ventricular mass index was >51 g/m2. Carotid artery atherosclerosis was assessed as an increased intima medial thickness (IMT) by B-mode ultrasonography. IMT values between 0.9 and 1.3 mm were defined as 'thickening' and those >1.3 mm as 'plaque'. Assessment of smoking status, dietary and non-dietary factors was established by administration of a specific questionnaire.

RESULTS

In the initial population of examined patients, 288 were smokers and 329 were non-smokers. At baseline, the patients belonging to smoking group were less often overweight than those belonging to the non-smoking group, showing a lower initial body mass index (BMI) [27.54 ± 4.0 vs 28.28 ± 4.3; p < 0.029], lower plasma levels of high-density lipoprotein cholesterol (HDL-C) [48.14 ± 12.6 vs 51.39 ± 14.1 mg/dL; p < 0.006] and were more often affected by carotid artery atherosclerosis (93.9 % vs 86.1%; p < 0.002) than non-smoking patients. When analysed for dietary and other lifestyle-related risk factors, we found a higher prevalence of carotid atherosclerotic disease in patients consuming less than two meals per day than in those consuming more than two meals per day (96.6% vs 85.7%; p < 0.001), without any significant difference in the mean number of medications taken and in specific classes of medications. Total amount of cigarettes smoked, calculated as packs per year (39.14 ± 16.5 vs 20.81 ± 13.6; p < 0.0001) was higher in patients with a diagnosis of atherosclerotic disease of the carotid artery than in patients free of this disorder, whereas the average age at which people began smoking was lower (17.58 ± 6.3 vs 21.53 ± 10.2 years). In a binary model of logistic regression adjusted for BMI, HDL-C, smoking status and number of daily meals, only smoking status was confirmed to be strongly correlated to clinical evidence of carotid atherosclerosis (p < 0.025).

CONCLUSIONS

In hypertensive patients, in optimal blood pressure control, smoking status has been shown to be independently associated with an increased maximum arterial IMT (IMTmax). In particular, an increase of the IMT was associated with the total amount of cigarettes smoked (calculated as packs per year) and the average age at which people began smoking.

Smoking cessation: the role of the foot and ankle surgeon

Tobacco cigarette smoking causes many negative effects on the body, and it is the leading preventable cause of death in the United States. These negative effects are a concern for the foot and ankle surgeon, as smoking can increase the risk of diabetes and peripheral artery disease and delay healing of surgical incisions and ulcerations of the lower extremities. Tobacco cigarette smoking can also increase the risk of avascular necrosis and delayed union and nonunions of fractures and osteotomies. Smoking cessation is an important component in the overall treatment of conditions affecting the foot and ankle. Smoking cessation can be a difficult goal to achieve, but proper education and support can help patients reach this goal.

The role of exercise in minimizing postprandial oxidative stress in cigarette smokers

Cigarette smoking continues to pose a significant health burden on society. Two well-described mechanistic links associating smoking with morbidity and mortality include elevated blood lipids and increased oxidative stress. These variables have traditionally been measured while an individual is fasting, but evidence suggests that postprandial lipemia and oxidative stress provide more important information concerning susceptibility to disease, in particular cardiovascular disease. Cigarette smokers have elevated levels of biomarkers of oxidative stress at rest and experience impaired postprandial lipid and glucose metabolism. We have confirmed these findings while noting an exaggerated oxidative stress response to high-fat feeding. Smoking cessation is without question the best approach to minimizing smoking-induced ill health and disease, but success rates among those who attempt to quit are dismal. Other means to decrease a smoker's susceptibility to oxidative stress-related disease are needed. We propose that exercise may aid in attenuating postprandial oxidative stress, and we do so in 3 distinct ways. First, exercise stimulates an increase in endogenous antioxidant enzyme activity. Second, exercise improves blood triglyceride clearance via a reduced chylomicron-triglyceride half-life and an enhanced lipoprotein lipase activity. Third, exercise improves blood glucose clearance via an enhanced glucose 4 transport protein translocation and protein content, as well as insulin-insulin receptor binding and postreceptor signaling. Improvements in antioxidant status, as well as lipid and glucose processing, may aid greatly in minimizing feeding-induced oxidative stress in smokers. If so, and in accordance with the recent joint initiative of the American College of Sports Medicine and the American Medical Association, exercise may be viewed as a "medicine" for cigarette smokers at increased risk for postprandial oxidative stress. Research into this area may provide insight into the potential benefits of exercise for this purpose.

Postprandial oxidative stress in exercise trained and sedentary cigarette smokers

Cigarette smokers experience an exaggerated triglyceride (TAG) and oxidative stress response to high fat feeding. Exercise training may serve to attenuate the rise in these variables, by improving TAG clearance and antioxidant defense. We compared blood TAG, antioxidant capacity, and oxidative stress biomarkers in exercise trained (>2 hrs per wk) and untrained smokers matched for age, in response to a high fat test meal. We report here that low volume exercise training can attenuate postprandial lipid peroxidation, but has little impact on blood TAG and other markers of oxidative stress. Higher volumes of exercise may be needed to allow for clinically meaningful adaptations in postprandial lipemia and oxidative stress.

Smoking selectively accelerates carotid atherosclerosis in hypertensive patients

BACKGROUND AND OBJECTIVES

Left ventricular hypertrophy, carotid atherosclerosis and renal dysfunction are indicators of target organ damage in hypertension, and independent risk factors for both fatal and non-fatal cardio- and cerebrovascular events. In the general population, smoking is associated with increases in left ventricular mass and carotid intima-media thickness (IMT), and impaired renal function. The aim of the present study was to evaluate whether smoking affects the development of target organ damage in patients with arterial hypertension.

METHODS

3192 hypertensive patients referred to the Hypertension Clinic of the "Federico II" University of Naples from January 2000 to July 2006 were retrospectively analysed. Subjects were aged from 18 to 75 years. Among these patients, 1391 were smokers and 1801 non-smokers.

RESULTS

The duration and severity of hypertension was significantly shorter in smokers when compared with non-smokers. The maximum arterial IMT was significantly higher in smokers compared with non-smokers (1.7 ± 0.1 mm vs 1.5 ± 0.1, p < 0.0001), while left ventricular mass index was comparable between the two groups. In contrast, glomerular filtration rate was observed to be higher in smokers compared with non-smokers. Logistic regression analysis showed that smoking, age, sex, duration of hypertension, systolic blood pressure and diastolic blood pressure were significantly correlated with IMT. Furthermore, a strong correlation was found between the number of cigarettes smoked per day and IMT.

CONCLUSIONS

Together, these data indicate that in hypertensive patients who have a high risk of developing atherosclerosis, smoking could potentiate the development of atherosclerotic plaques.

Postprandial lipaemia in patients with impaired fasting glucose, impaired glucose tolerance and diabetes mellitus

AIMS

To compare the postprandial lipid responses in subjects with prediabetes (IFG and IGT), newly detected diabetes mellitus (NDDM) and normal glucose tolerance (NGT).

METHODS

Postprandial lipid responses to a standard oral fat challenge was studied in forty-four subjects who were divided after an OGTT into NGT, pure impaired fasting glucose (PIFG), pure impaired glucose tolerance (PIGT) and NDDM.

RESULTS

There was a significantly higher postprandial triglyceride (PPTg) response with a higher PPTg area under curve (p=0.004) and peak PPTg levels (p=0.003) in patients with NDDM but not with either PIFG (p>0.05) or PIGT (p>0.05) when compared with NGT. Overall, PPTg responses correlated significantly with fasting plasma glucose (p=0.001) and 2h plasma glucose (p=0.001) but not with age, sex, body mass index, waist, or insulin resistance.

CONCLUSION

Subjects with newly detected diabetes mellitus displayed postprandial hypertriglyceridemia after a standard oral fat meal challenge while no such abnormality could be demonstrated in subjects with IFG or IGT. This defect is probably related to glycemic status and insulin resistance.

Dietary, physiological, genetic and pathological influences on postprandial lipid metabolism

Most of diurnal time is spent in a postprandial state due to successive meal intakes during the day. As long as the meals contain enough fat, a transient increase in triacylglycerolaemia and a change in lipoprotein pattern occurs. The extent and kinetics of such postprandial changes are highly variable and are modulated by numerous factors. This review focuses on factors affecting postprandial lipoprotein metabolism and genes, their variability and their relationship with intermediate phenotypes and risk of CHD. Postprandial lipoprotein metabolism is modulated by background dietary pattern as well as meal composition (fat amount and type, carbohydrate, protein, fibre, alcohol) and several lifestyle conditions (physical activity, tobacco use), physiological factors (age, gender, menopausal status) and pathological conditions (obesity, insulin resistance, diabetes mellitus). The roles of many genes have been explored in order to establish the possible implications of their variability in lipid metabolism and CHD risk. The postprandial lipid response has been shown to be modified by polymorphisms within the genes for apo A-I, A-IV, A-V, E, B, C-I and C-III, lipoprotein lipase, hepatic lipase, fatty acid binding and transport proteins, microsomal triglyceride transfer protein and scavenger receptor class B type I. Overall, the variability in postprandial response is important and complex, and the interactions between nutrients or dietary or meal compositions and gene variants need further investigation. The extent of present knowledge and needs for future studies are discussed in light of ongoing developments in nutrigenetics.

Weight loss and metabolic effects of topiramate in overweight and obese type 2 diabetic patients: randomized double-blind placebo-controlled trial

OBJECTIVE

To examine the metabolic effects and body composition changes after topiramate treatment of obese type 2 diabetic patients (DM2) for 11 months.

DESIGN AND SUBJECTS

Thirty-eight DM2 on diet or sulfonylurea treatment participated in this randomized double-blind placebo-controlled trial. Thirteen placebo-treated and nine topiramate-treated patients completed the trial. Patients were randomized to treatment with topiramate 96 mg b.i.d. or placebo (6-week run-in phase, 2-months titration phase, 9-months maintenance phase).

MEASUREMENTS

Insulin sensitivity was measured with euglycaemic hyperinsulinemic clamps. Weight, HbA1c, fasting glucose, blood lipids and safety variables were measured at regular intervals. Body composition was determined with computerized tomography. Meal tests were performed to evaluate postprandial glucose and insulin levels. Three-day diet recalls were carried out to evaluate energy ingestion.

RESULTS

The mean age was 58.6+/-7.1 years, body weight 98.1+/-16.1 kg, BMI 33.0+/-4.5 kg/m(2), and glycosylated hemoglobin (HbA1c) 7.3+/-0.9%. In topiramate-treated patients, there were significant reductions in HbA1c (1.1+/-0.9%), fasting plasma glucose, body weight (-6.6+/-3.3%), as well as body fat, lean body mass, postprandial glucose and free fatty acid levels but there were no significant changes in insulin sensitivity. The daily average energy intake decreased more in the topiramate group than in the placebo group. Paresthesia and central nervous system-related side effects were the main causes for the dropout rate.

CONCLUSIONS

Topiramate treatment of overweight DM2 reduced body weight and body fat, and was associated with a marked improvement in glycaemic control whereas no significant improvement in insulin-stimulated glucose uptake was demonstrated. Further studies are required to clarify whether this effect might occur through changes in insulin sensitivity in the liver and/or pancreatic insulin secretion.

Metabolic syndrome and gender differences in postprandial lipaemia

BACKGROUND

Postprandial hyperlipidaemia may be a predictor of vascular risk.

DESIGN

We evaluated postprandial lipaemia after an oral fat tolerance test (OFTT) in men (n=41) and women (n=21) with metabolic syndrome (MetS).

METHODS

Triglyceride (TG) levels were measured before and 2, 4, 6 and 8 h after the fat load.

RESULTS

Men showed a greater plasma TG response 8 h after the fat load (284+/-117 versus 224+/-126 mg/dl, P=0.029). Only fasting TG levels significantly predicted the TG area under the curve (AUC) and incremental AUC.

CONCLUSIONS

Men had a more pronounced postprandial hypertriglyceridaemia and seem to have delayed TG clearance.

Pathogenesis and treatment of diabetic vascular disease - illustrated by two cases

This publication is a summary of the presentations given at the First JIM Grand Round held at the Sahlgrenska University Hospital on 15 March 2006. The Grand Round was based on two case reports; a patient with type 2 diabetes and pronounced macrovascular disease and another patient with early microvascular disease combined with the macrovascular complications. The pathogenesis of the vascular complications and the current treatment regimens were discussed in relation to the history and examinations performed in these patients.

Biomarkers to assess the utility of potential reduced exposure tobacco products

To date, we have no valid biomarkers that serve as proxies for tobacco-related disease to test potential reduced exposure products. This paper represents the deliberations of four workgroups that focused on four tobacco-related heath outcomes: Cancer, nonmalignant pulmonary disease, cardiovascular disease, and fetal toxicity. The goal of these workgroups was to identify biomarkers that offer some promise as measures of exposure or toxicity and ultimately may serve as indicators for future disease risk. Recommendations were based on the relationship of the biomarker to what is known about mechanisms of tobacco-related pathogenesis, the extent to which the biomarker differs among smokers and nonsmokers, and the sensitivity of the biomarker to changes in smoking status. Other promising biomarkers were discussed. No existing biomarkers have been demonstrated to be predictive of tobacco-related disease, which highlights the importance and urgency of conducting research in this area.

Biomarkers to assess the utility of potential reduced exposure tobacco products

To date, we have no valid biomarkers that serve as proxies for tobacco-related disease to test potential reduced exposure products. This paper represents the deliberations of four workgroups that focused on four tobacco-related heath outcomes: Cancer, nonmalignant pulmonary disease, cardiovascular disease, and fetal toxicity. The goal of these workgroups was to identify biomarkers that offer some promise as measures of exposure or toxicity and ultimately may serve as indicators for future disease risk. Recommendations were based on the relationship of the biomarker to what is known about mechanisms of tobacco-related pathogenesis, the extent to which the biomarker differs among smokers and nonsmokers, and the sensitivity of the biomarker to changes in smoking status. Other promising biomarkers were discussed. No existing biomarkers have been demonstrated to be predictive of tobacco-related disease, which highlights the importance and urgency of conducting research in this area.

Lipolysis in smokers during tobacco withdrawal: a pilot study

OBJECTIVE

Nicotine has an influence on several metabolic events, such as lipid metabolism. Habitual smoking increases plasma levels of glycerol as well as noradrenaline, which is the main stimulating hormone of adipose tissue lipolysis. However, the long-term effect of smoking on lipolysis is unclear. We compared nocturnal lipolysis in habitual smokers during short-term tobacco withdrawal with a control group of non-smokers.

MATERIAL AND METHODS

Sixteen healthy subjects (9 heavy smokers and 7 non-smokers) were recruited in the study. The smokers were not permitted to smoke for at least 7 h before the test. The microdialysis technique was used to measure glycerol levels, the end-product of lipolysis, in subcutaneous adipose tissue. Variations in adipose tissue blood flow were measured using the ethanol technique. Glycerol, lactate and glucose concentrations as well as ethanol outflow/inflow ratio were measured between 2400 and 0600 h.

RESULTS

There were no significant differences in subcutaneous glycerol or glucose concentrations between smokers and non-smokers. Between 0300 and 0600 h, lactate levels in smokers were lower than those in non-smokers. Adipose tissue blood flow did not differ between the groups.

CONCLUSIONS

Despite potent acute and direct effects of smoking on lipolysis, we could not find any significant differences in basal lipolysis rate between smokers during short-term tobacco withdrawal and non-smokers.

Obesity and smoking: relationship with waist circumference and obesity-related disorders in men undergoing a health screening

This study investigated whether smoking habits had a differential influence on waist circumference and obesity-related disorders in nonobese and obese men. We investigated 359 men with smoking habits confirmed by their spouses, including 172 nonobese men (BMI<25) and 187 obese men (BMI>or=25). There were 113 nonobese smokers and 129 obese smokers. Obesity-related disorders were defined as hypertension, dyslipidemia, hyperglycemia, hyperuricemia, or treatment for one or more of these disorders. Nonobese subjects showed no differences of age, BMI, and waist circumference between smokers and nonsmokers, but smokers had a higher incidence of obesity-related disorders. Obese smokers were younger than obese nonsmokers and had a larger waist circumference, but a similar prevalence of obesity-related disorders. The prevalence of obesity-related disorders was similar between obese nonsmokers and smokers, but the smokers were younger. In nonobese subjects, smoking may increase obesity-related disorders by a mechanism other than visceral fat accumulation. In obese subjects, however, smoking may promote visceral fat accumulation. Further investigations will be necessary to better elucidate the relationship between the promotion of visceral fat accumulation in obese subjects by smoking and obesity-related disorders.

Educational disparities in the metabolic syndrome in a rapidly changing society--the case of South Korea

BACKGROUND

Most of the evidence about socioeconomic inequalities in the metabolic syndrome comes from Western industrialized societies. The aim of this study is to examine how the inequalities appear and what could explain them in Korea, a rapidly changing society.

METHODS

We analysed the nationwide survey data of 1998 and 2001 with a sample of 4630 men and 5896 women (> or = 25 years). The subjects were grouped into four birth cohorts based on the historical context: born before 1946, 1946-53, 1954-62, and since 1963. Socioeconomic position was defined by education level: high school graduation or above as the more educated group, and below that as the less educated one. The syndrome was defined according to ATP III criteria using abdominal obesity for Asians. The covariates included family history of diabetes, smoking, drinking, daily physical activity, regular exercise, suicidal ideation, weight change, and carbohydrates intake. The associations were examined by stratified logistic regression models across cohorts and gender.

RESULTS

Less-educated women had higher prevalence with widening gaps across successive cohorts; the age-adjusted odds ratios of the less-educated group were 1.22 (0.86-1.71), 1.41 (1.01-1.97), 2.50 (1.87-3.35), and 2.64 (1.69-4.14). They hardly changed after covariate adjustment, and remained significant with considerable attenuation after controlling body mass index. However, educational disparities were not observed in men.

CONCLUSIONS

We could observe the complex pattern of disparities in the metabolic syndrome across cohorts and gender. An equity-sensitive health promotion programme to prevent further spread of social inequalities may have beneficial effects on the metabolic syndrome and its components in Korea.

Metabolic response to oral lipid overload in diabetes and impaired glucose tolerance

Post-prandial hyperglycemia and hypertriglyceridemia have been related to atherogenesis. The aim of this study was to evaluate the response of plasma lipoproteins to a lipid overload in subjects with diabetes (DM), impaired glucose tolerance (IGT) and normals (N). Seventy-seven subjects were selected, 36-85 years, plasma glucose (G)<140 mg/dl and triglycerides (TG)<150 mg/dl; those without diabetes underwent a glucose tolerance test (GTT), which classified them into three groups: N, 2h G<140 mg/dl, n=37; IGT, 2h G 140-200mg/dl, n=20; and DM, previous diabetes or 2h G>200mg/dl, n=20. They were submitted to a clinical evaluation and an oral lipid overload (1000 kcal, 58% fat). Fasting, 4 and 6-h blood samples after the meal were collected for G, insulinaemia (I), TG, cholesterol and their fractions, and HOMA-IR. Fasting and post-lipid overload lipoproteins were similar between groups, but 6h TG was still high in DM versus IGT and N as compared to their 4h values. There was a positive correlation between fasting TG versus 6h TG (r=0.78, p<0.001). We conclude that individuals with impaired glucose tolerance and with diabetes mellitus have a slower plasma reduction of triglycerides after lipid overload, as well as an altered glucose and post-prandial insulin response.

Do cigarette smokers with erectile dysfunction benefit from stopping?: a prospective study

OBJECTIVE

To assess whether stopping smoking can improve erectile dysfunction (ED) in smokers, as cigarette smoking is a known risk factor for ED.

PATIENTS AND METHODS

Smokers who requested nicotine replacement therapy (NRT) and complained of ED were first evaluated for hypertension, dyslipidaemia, diabetes, psychiatric disorders and drug history. The grade of ED in smokers with none of these risk factors was then determined using the five-item version of the International Index of Erectile Function (IIEF-5) before NRT, and the grading repeated after 1 year of follow-up. The correlation between the exposure to smoking (pack-years) and severity of ED was assessed before the follow-up. The ED status between patients who stopped smoking after NRT and those who continued during the follow-up was then compared before and after the follow-up.

RESULTS

The severity of ED correlated significantly with the level of exposure to smoking. Age and ED status before the follow-up were not significantly different between 118 patients who stopped (ex-smokers) and 163 who continued smoking (current smokers). After 1 year the ED status improved in > or = 25% of ex-smokers but in none of the current smokers; 2.5% of ex-smokers and 6.8% of current smokers had a deterioration in ED. Ex-smokers had a significantly better ED status after the follow-up (P = 0.009). Among ex-smokers, patients with advanced ED and those who were older had less improvement.

CONCLUSION

There is a strong association between the intensity of cigarette smoking and degree of ED. Stopping cigarette smoking can improve ED in a considerable proportion of smokers. Age and the severity of ED before stopping are inversely related to the chance of improvement.

Smoking accelerates biotin catabolism in women

BACKGROUND

Smoking accelerates the degradation of many nutrients, including lipids, antioxidants, and certain B vitamins. Accelerated biotin catabolism is of concern in women because marginal biotin deficiency is teratogenic in mammals.

OBJECTIVE

The objective was to assess the effect of smoking on the biotin status of women.

DESIGN

A preliminary study of 7 women and 3 men examined the urinary concentrations of biotin and its metabolites biotin sulfoxide and bisnorbiotin in smokers. The interpretation of the results of this study was limited by the lack of a contemporaneous control group; consequently, we conducted a cohort-controlled study. Smoking women (n = 8) and nonsmoking control subjects (n = 15) provided 24-h urine samples; excretion rates of biotin, the biotin metabolites, and 3-hydroxyisovaleric acid were determined. Increased urinary excretion of 3-hydroxyisovaleric acid, which reflects a reduced activity of the biotin-dependent enzyme 3-methylcrotonyl-Co A carboxylase, is a sensitive indicator of biotin depletion at the tissue level.

RESULTS

Compared with control subjects from previous studies, the smoking women in the preliminary study excreted significantly less urinary biotin (P = 0.02). Moreover, the ratio of urinary biotin sulfoxide to biotin increased (P = 0.04) in these women. In the cohort-controlled study, the urinary excretion of biotin decreased by 30% (P = 0.04), and the ratios of urinary bisnorbiotin and biotin sulfoxide to biotin increased significantly, which indicated accelerated catabolism in smokers. Moreover, the urinary excretion of 3-hydroxyisovaleric acid was greater in the smokers than in the control subjects (P = 0.04), which indicated biotin depletion in the smokers at the tissue level.

CONCLUSION

These data provide evidence of accelerated biotin metabolism in smoking women, which results in marginal biotin deficiency.

Smoking cessation and weight gain

Cigarette smoking is the single most important preventable cause of death and illness. Smoking cessation is associated with substantial health benefits. Weight gain is cited as a primary reason for not trying to quit smoking. There is a great variability in the amount of weight gain but younger ages, lower socio-economic status and heavier smoking are predictors of higher weight gain. Weight change after smoking cessation appears to be influenced by underlying genetic factors. Besides, weight gain after smoking cessation is largely because of increased body fat and some studies suggest that it mostly occurs in the subcutaneous region of the body. The mechanism of weight gain includes increased energy intake, decreased resting metabolic rate, decreased physical activity and increased lipoprotein lipase activity. Although there is convincing evidence for the association between smoking cessation and weight gain, the molecular mechanisms underlying this relationship are not well understood. This review summarizes current information of the effects of nicotine on peptides involved in feeding behaviour. Smoking was shown to impair glucose tolerance and insulin sensitivity and cross-sectional studies have demonstrated that smokers are insulin-resistant and hyperinsulinaemic, as compared with non-smokers. Smoking cessation seems to improve insulin sensitivity in spite of the weight gain. Nicotine replacement - in particular nicotine gum - appears to be effective in delaying post-cessation weight gain. In a group of women who failed to quit smoking because of weight gain, a dietary intervention (intermittent very-low-calorie diet) plus nicotine gum showed to both increase success rate in terms of smoking cessation and prevent weight gain. On the other hand, body weight gain at the end of treatment was significantly lower in the patients receiving bupropion or bupropion plus nicotine patch, compared with placebo. Studies with new drugs available for the treatment of obesity - sibutramine and orlistat - are warranted.

Visceral fat accumulation determines postprandial lipemic response, lipid peroxidation, DNA damage, and endothelial dysfunction in nonobese Korean men

Visceral fat has been associated with multiple cardiovascular disease (CVD) risk factors. The aim of this study was to identify anthropometrical measures most closely associated with some well-known CVD risk factors. Because most Asians at risk have normal body mass index (BMI) according to Western standards, we studied healthy nonobese Korean males (n = 102; age: 36.5 +/- 0.8 years, BMI: 23.8 +/- 0.2 kg/m2). Visceral fat area (VFA) at the fourth lumbar vertebra was associated with increased postprandial triglyceride (TG) response (r = 0.53, P < 0.001) and with plasma malondialdehyde (MDA) (r = 0.36, P < 0.01) and PGF2alpha (r = 0.24, P < 0.05). When matched for BMI and age, men with high VFA (HVFA) (>/=100 cm2; n = 27) had higher blood pressure (P < 0.01), increased consumption of cigarettes (P < 0.01), and lower ratio of energy expenditure to calorie intake (P < 0.01) as compared with low VFA men (<100 cm2; n = 27). Men with HVFA showed higher TG, glucose, and insulin responses following fat and oral glucose tolerance tests respectively higher plasma concentrations of MDA (P < 0.001), urinary PGF2alpha (P < 0.05), and lymphocytes deoxyribonucleic acid tail moments (P < 0.01). Conversely, HVFA was associated with lower testosterone, insulin-like growth factor-1, and brachial artery flow-mediated dilation (P < 0.001). In conclusion, our data indicate that visceral fat accumulation, even in nonobese men, is a major factor contributing to increased CVD risk.

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.

Cigarette smoking and diabetes

Smokers are insulin resistant, exhibit several aspects of the insulin resistance syndrome, and are at an increased risk for type 2 diabetes. Prospectively, the increased risk for diabetes in smoking men and women is around 50%. Many patients with type 1 and type 2 diabetes mellitus are at risk for micro- and macrovascular complications. Cigarette smoking increases this risk for diabetic nephropathy, retinopathy, and neuropathy, probably via its metabolic effects in combination with increased inflammation and endothelial dysfunction. This association is strongest in type 1 diabetic patients. The increased risk for macrovascular complications, coronary heart disease (CHD), stroke, and peripheral vascular disease, is most pronounced in type 2 diabetic patients. The development of type 2 diabetes is another possible consequence of cigarette smoking, besides the better-known increased risk for cardiovascular disease. In diabetes care, smoking cessation is of utmost importance to facilitate glycemic control and limit the development of diabetic complications.

Cigarette smoking and rheumatoid arthritis

OBJECTIVES

To examine and explore the potential relationships among the following: the incidence/severity of rheumatoid arthritis (RA), the extra-articular manifestations of RA, vascular disease, certain specific malignancies, the p53 tumor suppressor gene, and cigarette smoking.

METHODS

The medical literature was reviewed from 1985 to 2001 with the assistance of a MEDLINE search using the key words vascular disease, smoking, protein p53, RA, rheumatoid vasculitis, cancer, and malignancies. A qualitative review was performed after all articles were abstracted and new information summarized.

RESULTS

Cigarette smoking has been increasingly shown in epidemiologic and case-control studies to be an important risk factor for both the incidence and severity of RA, especially in seropositive men. Further, there is evidence of a downward trend in incidence of extra-articular manifestations of RA, especially RA vasculitis, observed with a decrease in worldwide tobacco use and overall improved mortality in RA. The association of cigarette smoking with lung and other cancers and its link to vascular disease (including Buerger's disease) and atherosclerosis appears secure. Mutations or alterations in p53, a suppressor gene that regulates cell growth, have been found in certain cancers, cigarette smokers, and in patients with RA.

CONCLUSIONS

Cigarette smoking appears to have an undeniable link to the pathogenesis of vascular disease of many types, including the possibility of a strong causal connection to rheumatoid vasculitis. The observations worldwide of decreasing tobacco use along with secular trends of diminished RA vasculitis and extra-articular manifestations, and with improved survival, points to a better outcome for our patients. The example of p53 may be a first step in the discovery of additional links between environmental triggers and phenotypic expression of chronic illness.

Acute in vivo chylomicron metabolism and postalimentary lipoprotein alterations in normolipidemic male smokers

Increased postprandial lipemia has been stated as one of the mechanisms responsible for atherogenesis in smokers. We measured the postalimentary lipid response and the in vivo intravascular delipidation index of an artificial chylomicron emulsion in healthy adult smokers and controls. The blood was collected in the fasting state immediately after the smokers smoked one cigarette. The lipemia was measured 2, 4, 6 and 8 h postalimentarily in smokers (S, n = 8) and in non-smoking controls (C, n = 8) and the chylomicron metabolism rate was measured 2, 4, 6, 8, 12, 16, 20, 24 and 30 min after the injection of an artificial emulsion to S (n = 10) and to C (n = 10). The lipoproteins were isolated in the fasting period and 4 h after the fatty meal and their chemical composition in cholesterol, triglycerides, phospholipids and protein was determined. Smokers showed an increased lipolysis percentage value (mean +/- S.E.M.) of the artificial chylomicron (39.1 +/- 3.1) compared to controls (26.5 +/- 3.3) and higher levels of HDL(2)-PL: 28.4 +/- 4.3 (S) versus 16.2 +/- 2.0 (C) mg/dl (mean +/- S.E.M.). In conclusion, the oral fat tolerance was not altered in smokers but an upregulation of the rate of metabolism of the TG-rich lipoproteins was elicited immediately after smoking one cigarette.

Metabolic and lifestyle determinants of postprandial lipemia differ from those of fasting triglycerides: The Atherosclerosis Risk In Communities (ARIC) study

Despite the reported association of lipoprotein responses to a fatty meal with atherosclerosis, little is known about the determinants of these responses. Plasma triglyceride, retinyl palmitate, and apolipoprotein B-48 responses to a standardized fatty meal containing a vitamin A marker were measured in 602 Atherosclerosis Risk in Communities (ARIC) study participants. To focus on postprandial responses specifically, which have been reported to be related to atherosclerosis independently of fasting triglycerides, analyses for determinants of postprandial responses were adjusted for fasting triglycerides. Major determinants of fasting triglycerides, namely, diabetes, obesity, other factors related to insulin resistance, and male sex, were not independently associated with postprandial responses. Fasting triglycerides were the strongest predictor of postprandial lipids, but independent of triglycerides, the predictors of postprandial responses were smoking, diet, creatinine, and alcohol. Smokers had substantially increased retinyl palmitate and apolipoprotein B-48 responses, indicators of chylomicrons and their remnants. Persons who consume more calories or omega3 fatty acids had reduced chylomicron responses. Triglyceride responses were associated positively with serum creatinine levels and negatively with moderate alcohol consumption. Thus, determinants of fasting and postprandial lipids differ. The independent atherogenic influence of postprandial lipids may relate more to smoking and diet than to obesity and insulin resistance.

Alcohol consumption had no beneficial effect on serum lipids in a substantial proportion of patients with primary hyperlipidemia

The cardioprotective effect of moderate alcohol consumption, which is mediated largely by an elevation of high-density lipoprotein (HDL) levels, may be absent in patients with primary disorders of lipid metabolism. In 881 untreated, unrelated patients with primary hyperlipidemia, we estimated the effect of alcohol on fasting serum HDL cholesterol concentration adjusted for age, gender, diet, and smoking with a multiple linear regression model. The number of abstainers, moderate users (1-30 g daily), and heavy alcohol consumers (> or = 30 g daily) was not different between three types of hyperlipidemia. Among hypercholesterolemic (n = 514) and combined hyperlipidemic (n = 227) patients, consumers of alcohol had higher HDL levels compared to abstainers (P(for trend) = 0.0001 and 0.0002, respectively). Heavy drinkers with combined hyperlipidemia had higher triglyceride levels compared to moderate drinkers and abstainers (P(for trend) = 0.008). Alcohol consumption had no effect on the lipid profiles in 140 patients with hypertriglyceridemia. In conclusion, combined hyperlipidemic and hypertriglyceridemic patients may profit from an encouragement to stop consuming alcohol. On the other hand, moderate use of alcohol may delay the development of coronary artery disease in hypercholesterolemic patients by an elevation of HDL levels.

Oxysterols: modulators of cholesterol metabolism and other processes

Oxygenated derivatives of cholesterol (oxysterols) present a remarkably diverse profile of biological activities, including effects on sphingolipid metabolism, platelet aggregation, apoptosis, and protein prenylation. The most notable oxysterol activities center around the regulation of cholesterol homeostasis, which appears to be controlled in part by a complex series of interactions of oxysterol ligands with various receptors, such as the oxysterol binding protein, the cellular nucleic acid binding protein, the sterol regulatory element binding protein, the LXR nuclear orphan receptors, and the low-density lipoprotein receptor. Identification of the endogenous oxysterol ligands and elucidation of their enzymatic origins are topics of active investigation. Except for 24, 25-epoxysterols, most oxysterols arise from cholesterol by autoxidation or by specific microsomal or mitochondrial oxidations, usually involving cytochrome P-450 species. Oxysterols are variously metabolized to esters, bile acids, steroid hormones, cholesterol, or other sterols through pathways that may differ according to the type of cell and mode of experimentation (in vitro, in vivo, cell culture). Reliable measurements of oxysterol levels and activities are hampered by low physiological concentrations (approximately 0.01-0.1 microM plasma) relative to cholesterol (approximately 5,000 microM) and by the susceptibility of cholesterol to autoxidation, which produces artifactual oxysterols that may also have potent activities. Reports describing the occurrence and levels of oxysterols in plasma, low-density lipoproteins, various tissues, and food products include many unrealistic data resulting from inattention to autoxidation and to limitations of the analytical methodology. Because of the widespread lack of appreciation for the technical difficulties involved in oxysterol research, a rigorous evaluation of the chromatographic and spectroscopic methods used in the isolation, characterization, and quantitation of oxysterols has been included. This review comprises a detailed and critical assessment of current knowledge regarding the formation, occurrence, metabolism, regulatory properties, and other activities of oxysterols in mammalian systems.

The effect of smoking on glucose homeostasis and fetal growth in pregnant women

OBJECTIVE

To examine the relationship between maternal blood glucose levels, cigarette smoking in pregnancy and fetal growth.

DESIGN

A prospective study of healthy parous women from early pregnancy and their infants.

SETTING

Three Scandinavian university hospitals covering all deliveries from well defined geographical areas.

SUBJECTS

Study groups of non-smoking (150), light smoking (131) and heavily smoking mothers (218), para 1 and 2 and with > 37 weeks of gestational length.

MAIN OUTCOME MEASURES

Oral glucose tolerance test performed in pregnancy week 37, glycated hemoglobin measured the 3rd day post partum and neonatal anthropometric parameters including skinfold measurements.

RESULTS

Among heavily smoking mothers 12.4% displayed a 2-hour glucose value in the range of gestational diabetes (> 8.5 mmol/l) compared to 9.2% among light smokers and 6.0% among nonsmokers (p < 0.05). Heavily smoking mothers also had significantly (p < 0.05) higher glycated hemoglobin compared to nonsmokers, 5.01 v.s. 4.86. These changes in glucose parameters in smokers were not associated with higher birthweights.

CONCLUSIONS

Smoking in pregnancy affects parameters of glucose homeostasis in the direction of gestational diabetes. The retarding effect of smoking on fetal growth abolished any expected growth stimulation from the higher blood glucose levels seen in the smokers.

Low cellular IRS 1 gene and protein expression predict insulin resistance and NIDDM

We examined the gene and protein expression of IRS 1 (insulin receptor substrate 1) in adipocytes from two groups of healthy individuals with an increased propensity for non-insulin-dependent diabetes mellitus (NIDDM): those with two first-degree relatives with diabetes and another group with massive obesity. A low expression of IRS 1 (</=50% of the matched control group) was seen in approximately 30% of both groups and these individuals were characterized by insulin resistance and its hallmarks: higher levels of insulin, glucose, and triglycerides. Two individuals with previously unknown NIDDM were diagnosed and both had low IRS 1 expression. Low IRS 1 protein expression was associated with low mRNA levels but not with the common Gly972Arg polymorphism of the IRS 1 gene. Taken together, our present and previous findings show that a low expression of IRS 1 in fat cells predicts insulin resistance and NIDDM. Furthermore, they support the likelihood that an impaired transcriptional activation may play a key role in the pathogenesis of NIDDM.-Carvalho, E., Jansson, P.-A., Axelsen, M., Eriksson, J. W., Huang, X., Groop, L., Rondinone, C., Sjöström, L., Smith, U. Low cellular IRS 1 gene and protein expression predict insulin resistance and NIDDM.