Impact of habitual cocaine smoking on the physiologic response to maximum exercise

BACKGROUND: Habitual smoking of alkaloidal cocaine (crack) has been reported to be associated with a number of cardiopulmonary complications that may not be clinically obvious but could potentially interfere with normal physiologic responses to exercise and thus impair maximum exercise performance. STUDY OBJECTIVE: To evaluate the impact of regular use of cocaine on maximum exercise. DESIGN: Observational study in crack users and age- and gender-matched control subjects. SUBJECTS: Thirty-five habitual cocaine smokers (21 male and 14 female) and 29 age-matched sedentary control nonsmokers of cocaine (15 male and 14 female), all of whom were in good general health. METHODS: In these subjects, we compared physiologic responses to symptom-limited, incremental maximal exercise performed on a cycle ergometer using a ramp protocol. Comparisons were made for men and women separately. RESULTS: For both men and women, long-term cocaine smokers had a reduced aerobic capacity (maximum oxygen consumption) compared with control nonsmokers but did not show evidence of ventilatory limitation, reduced gas exchange threshold, increased physiologic dead space, or gas exchange abnormality at maximum exercise compared with the healthy control subjects. Although cocaine smokers had reduced maximum heart rates compared with control subjects, the relationship between submaximal heart rate and oxygen uptake was normal, indicating a normal cardiovascular response pattern. However, effort perception was similar between the two groups despite the difference in heart rate at maximum exercise, suggesting the possibility of perceptual dysfunction for effort. Differences in aerobic capacity between the crack users and nonusers could not be explained by differences in physical fitness or altered perception of dyspnea. CONCLUSION: In the subjects we studied, long-term cocaine smoking was associated with reduced maximum exercise performance, probably due to poor motivation or altered effort perception. No other identifiable physiologic abnormality appeared to limit exercise in the habitual crack users.     

The effect of smoking and light activity on metabolism in men.

This experiment examined the metabolic effects of smoking during rest and light activity under naturalistic conditions. Thirty-nine male subjects first completed a submaximal graded exercise treadmill test to standardize activity level. Then 3 groups of subjects—smokers smoking (SS), smokers not smoking (SNS), and nonsmokers (NS)—were exposed to 3 stages of rest or 3 stages of light activity with order of rest or activity randomly determined over 2 different days. Energy expenditure was monitored continuously during these sessions. Significant increases in smokers' energy expenditure were observed during light activity when compared with smokers not smoking and nonsmokers. No differences were identified among groups at rest. These findings strengthen the conclusion that smoking or its components contribute to metabolic changes during typical levels of daily activity and suggest a mechanism for the frequently observed relationship between smoking status and body weight. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intensity, duration, and frequency of physical activity and coronary risk factors

Relationships between coronary risk factors and intensity, duration, and frequency of leisure activity were studied in 5943 men and 6039 women, ages 25-69. Age, smoking, socioeconomics, season, body mass index (BMI), urbanization, occupational activity, and liquid, alcohol, and saturated/total fat intake were adjusted using multivariate regressions. Among men each 100 kcal.kg-1.wk-1 spent on vigorous activities (7.5-9.0 MET) was associated with: significant (P < 0.01) average differences of -0.36 mmol.L-1 total cholesterol, +0.17 mmol.L-1 HDL cholesterol (P < 0.001), +0.05 HDL/total cholesterol (P < 0.001), -0.33 mmol.L-1 triglycerides, -3 mm Hg diastolic blood pressure, -10 beats.min-1 heart rate (P < 0.001), +30 L.min-1 peak flow, and -1.1 kg.m-2 BMI. Among women it was associated with: -7 mm Hg systolic blood pressure, -6 beats.min-1 heart rate (P < 0.001), +50 L.min-1 peak flow (P < 0.001), and -1.4 kg.m-2 BMI (P < 0.05). Moderate activity (either 3.0-4.5 MET or 5.0-7.0 MET) was significantly (P < 0.05) associated with HDL cholesterol, BMI, and, for men, heart rate; for women, it was associated with HDL/total cholesterol, triglycerides, diastolic blood pressure, and peak flow. With duration and intensity constant, increasing frequency by one time per wk was significantly (P < 0.05) associated with -0.014 mmol.L-1 total cholesterol, +0.001 HDL/total cholesterol, -0.36 beats.min-1 heart rate, -0.093 kg.m-2 BMI among men, and +0.009 mmol.L-1 HDL cholesterol, +0.001 HDL/total cholesterol, -0.014 mmol.L-1 triglycerides, -0.31 beats.min-1 heart rate, and -0.098 kg.m-2 BMI among women. Serum lipids and BMI showed stronger associations with frequency than with intensity or duration.     

Relationship of physical characteristics and life habits to treadmill exercise capacity

Apparently healthy middle-aged men (n = 175) were recruited from a population sample and completed questionnaires about habitual physical activity, smoking, beverage consumption and sleep habits. Body mass index (BMI), heart rate and blood pressure were measured at rest and during submaximal exercise; frequency of ventricular premature beats (VPB) on an ECG rhythm strip; hand grip strength; and serum cholesterol. These characteristics were correlated with duration of treadmill exercise by the Bruce protocol. Univariate analysis indicated that treadmill performance was significantly and positively correlated with leisure-time physical activity and personal reports of sweating and/or dyspnea occurring regularly during such physical activity. Performance was negatively correlated with age, BMI, resting heart rate, cigarette smoking, and consumption of caffeine-containing beverages, but was insignificantly related to job physical activity, hand grip strength, alcohol consumption, sleep habits, blood pressure, cigar smoking, serum cholesterol, and the frequency of VPB. A 0.75 multiple correlation coefficient was found between treadmill performance and 11 of the above variables and the r is increased to 0.81 by adding heart rate during submaximal exercise. It is concluded that substantial prediction of work capacity and physical fitness of population is achieved by questionnaires and easily obtained, noninvasive physical measures.     

L-Arginine normalizes coronary vasomotion in long-term smokers

BACKGROUND: Noninvasive measurements of myocardial blood flow (MBF) with PET revealed an abnormal coronary vasomotor response to cold pressor test in healthy long-term smokers. If coronary endothelial dysfunction accounted for this abnormality, we hypothesized that it could be reversed by L-arginine as the substrate for NO synthase. METHODS AND RESULTS: MBF was quantified with 13N-labeled ammonia and PET in 11 healthy smokers (age, 45+/-10 years; 27+/-10 years of smoking) and in 12 age-matched nonsmokers on 2 separate days. On day 1, MBF was measured at rest and, after intravenous L-arginine, during cold pressor test. On day 2, MBF was measured during cold pressor test and then at rest during L-arginine. Baseline rate-pressure product (RPP) (6559+/-1590 versus 7144+/-1157 bpmxmm Hg) and MBF (0.65+/-0.14 versus 0.73+/-0.13 mL x g-1 x min-1) were similar in nonsmokers and smokers. Cold pressor test increased RPP similarly in both groups (53+/-26% versus 46+/-26%), whereas MBF increased in nonsmokers (to 0.93+/-0.25 mL x g-1 x min-1; P<0.05) but not in smokers (0.80+/-0.16 mL x g-1 x min-1). The percent MBF increase differed between nonsmokers and smokers (44+/-25% versus 11+/-14%; P=0.0017). However, after L-arginine, the magnitude of MBF response to cold pressor test no longer differed between groups (48+/-36% versus 48+/-28%), whereas RPP again increased similarly in the 2 groups (59+/-30% versus 44+/-16%). L-Arginine had no effect on resting MBF in smokers or nonsmokers. CONCLUSIONS: Our findings implicate the coronary endothelium as the major site of the abnormal vasomotor response in long-term smokers. Cold pressor test combined with PET imaging may allow the noninvasive identification of coronary endothelial dysfunction in humans.     

Effects of a muscle exercise program on exercise capacity in subjects with osteoarthritis

Maximal aerobic power and muscle function have been shown to decrease with age and to be even lower in patients with osteoarthritis (OA). This study was designed to determine if subjects with OA who underwent only a muscle exercise program had improved exercise capacity and cardiovascular fitness. A maximal graded exercise test was given before and after 3 months of exercise (isometric, isotonic, and isometric force generated as a function of time contractions, three times a week). Maximal strength and the tension-time index improved significantly. Peak aerobic power increased from 15.99 +/- 3.96 mL.kg-1.min-1 to 20.34 +/- 3.29 mL.kg-1.min-1. On average, maximal walking speed increased from 2.0 +/- 0.6 mph to 2.4 +/- 0.7mph. Exercise time increased 22%, from 9.2 +/- 2.3 minutes to 11.2 +/- 2.7 minutes. There were significant reductions in submaximal heart rate (15b.min-1) and systolic blood pressure (15mmHg) after training. It would appear that the reduction in aerobic fitness of subjects with OA is secondary to their reduced muscle function. By improving muscle function, increases in exercise capacity and aerobic fitness occurred.     

Ambulatory 24-h blood pressure monitoring in healthy, middle-aged smokeless tobacco users, smokers, and nontobacco users

Ambulatory 24-h blood pressure monitoring was conducted in 135 healthy, normotensive, middle-aged (35 to 60 years) men, with no antihypertensive medication, to study the influence of habitual smokeless tobacco use (n = 47) and smoking (n = 29) on diurnal blood pressure and heart rate. Comparisons were made with nonusers of tobacco (n = 59). Adjustments were made for differences in age, body mass index, waist-hip ratio, physical fitness, and alcohol intake. Daytime ambulatory heart rates were significantly (P < .05) elevated in both smokeless tobacco users and smokers compared with nonusers (69 +/- 14 and 74 +/- 13 beats/min, respectively, versus 63 +/- 12 beats/min). In subjects > or = 45 years old, ambulatory daytime diastolic blood pressures were significantly elevated, on average by 5 mm Hg, in both smokeless tobacco users and smokers (P < .001) compared with nonusers. Clinical measurements of heart rate and systolic blood pressure in smokers were significantly lower compared with the ambulatory mean values. Nighttime measurements showed only minor differences between the tobacco habit groups. The higher heart rates and blood pressures noted during the daytime in smokers and smokeless tobacco users were most likely due to the effects of nicotine. A strong positive relationship was found between cotinine (major nicotine metabolite) and blood pressure in smokeless tobacco users (systolic blood pressure, r = 0.48, P < .001; diastolic blood pressure, r = 0.41, P = .005), whereas an inverse relationship was found in smokers (systolic blood pressure, r = -0.12, P = .47; diastolic blood pressure, r = -0.03, P = .84), indicating additional and more complex influences on vascular tone in smokers than the influence of nicotine in smokeless tobacco users.     

Exercise mode and gender comparisons of energy expenditure at self-selected intensities

The purpose of this study was to compare oxygen consumption (VO2) and energy expenditure after 20 min of self-selected submaximal exercise for four modes of exercise. Eighteen subjects (9 male and 9 female) first completed a test of VO2max during treadmill running. On separate days, subjects then completed 20 min submaximal treadmill running (TR), simulated cross-country skiing (XC), cycle ergometry (CE), and aerobic riding (AR) exercise. Total VO2 and energy expenditure were significantly higher for TR than all other modes for both males and females (43.6 +/- 10.4, 39.1 +/- 9.7, 36.1 +/- 7.6, 28.4 +/- 6.1 LO2, for TR, XC, CE, and AR, respectively, P < 0.0001). For males and females, heart rate was similar during TR and XC and lower during CE and AR (154.8 +/- 14.2, 152 +/- 13.1, 143.4 +/- 14.9, and 126.2 +/- 12.0 beats.min-1 for TR, XC, CE, and AR, respectively, P < 0.0001). Compared with females, males had significantly greater VO2 (P < 0.005) and energy expenditure (P < 0.004), while females had higher heart rates (P < 0.003). Ratings of perceived exertion (RPE) were not different between TR, XC, and CE, but were significantly lower during AR (13.4 +/- 1.3, 13.6 +/- 0.8, 13.2 +/- 0.9, and 12.6 +/- 1.0 for TR, XC, CE, and AR, respectively, P < 0.003). TR elicited the greatest VO2 and energy expenditure during self-selected exercise despite and RPE similar to XC and CE. Therefore, treadmill exercise may be the modality of choice for individuals seeking to improve cardiorespiratory endurance and expend a larger number of kjoules.     

Heart rate response and perceived exertion during twenty consecutive karate sparring matches

This study investigated the changes in heart rate (HR) and perceived exertion ratings (RPE) of 20 consecutive karate sparring matches each of 2 minutes duration. The resting and maximal HR (HRmax) responses to the maximal treadmill test were 69.8 +/- 2.9 beats.min-1 and 198.5 +/- 8.2 beats.min-1, respectively. The resting HR before the 20 sparring matches was 83.5 +/- 11.3 beats min-1. The mean HR during the 20 sparring matches was 191.8 +/- 9.4 beats.min-1 which was equal to 96.7 +/- 4.2% of HRmax. At the end of the 20 sparring matches, the mean RPE obtained was 19 +/- 2. The results of this study suggest that the subjects could continue the 20 sparring matches for about 40 minutes at the intensity close to the HRmax.     

The influence of desmopressin on blood loss during spinal fusion surgery in neuromuscular patients

PURPOSE: Fatigue and impairment of physical performance are common and severe problems of cancer patients. We describe the effect of an aerobic exercise program designed for cancer patients suffering from these symptoms. METHODS: Five cancer patients (4 female, 1 male, age 18 to 55), participated in the training program. Fatigue had been present for a time ranging between 5 wk and 18 months and hindered the patients from carrying out normal daily activities. The training program consisted of walking daily on a treadmill with an intensity corresponding to a lactate concentration of 3 +/- 0.5 mmol.L-1 and was carried out for 6 wk. RESULTS: By the end of the exercise program we observed an improvement in maximal physical performance (from 6.4 +/- 0.4 km.h-1 to 7.5 +/- 0.9 km.h-1, P < 0.05) and maximal walked distance (from 1640 +/- 724 m to 3300 +/- 953 m, P < 0.05). Heart rate and lactate concentration by an equivalent submaximal workload (5 km.h-1) were significant reduced (from 138 +/- 21 beats.min-1 to 113 +/- 20 beats.min-1, P < 0.05, and from 2.6 +/- 1.4 mmol.L-1 to 1.3 +/- 0.6 mmol.L-1, P < 0.05); all patients experienced a clear reduction of fatigue and could carry out normal daily activities again without substantial limitations. CONCLUSION: We conclude that an aerobic exercise program of precisely defined intensity, duration, and frequency can be prescribed as therapy for primary fatigue in cancer patients.     

Acetylator phenotype, aminobiphenyl-hemoglobin adduct levels, and bladder cancer risk in white, black, and Asian men in Los Angeles, California

BACKGROUND: There is a large body of epidemiologic and experimental data that have identified a number of arylamines as human bladder carcinogens. Metabolic activation is required to biotransform these arylamines into their carcinogenic forms, and N-hydroxylation, which is catalyzed by the hepatic cytochrome P4501A2 isoenzyme, is generally viewed as the first critical step. On the other hand, the N-acetylation reaction, catalyzed by the hepatic N-acetyltransferase enzyme, represents a detoxification pathway for such compounds. The N-acetyltransferase enzyme is coded by a single gene displaying two phenotypes, slow and rapid acetylators. In the United States, cigarette smoking is a major cause of bladder cancer in men, and carcinogenic arylamines present in cigarette smoke are believed to be responsible for inducing bladder cancer in smokers. PURPOSE: Our purpose was to test the differences in three ethnic/racial groups for the prevalence of acetylator phenotypes and to ascertain whether slow acetylators actually have higher levels of activated arylamines in comparison with rapid acetylators. METHODS: One hundred thirty-three male residents of Los Angeles County who were either white, black, or Asian (Chinese or Japanese) and over the age of 35 years were assessed for their acetylator phenotype and levels of 3- and 4-aminobiphenyl (ABP) hemoglobin adducts. Subjects were either lifetime nonsmokers (n = 72) or current cigarette smokers of varying intensity (n = 61). RESULTS: The proportion of slow acetylators was highest among whites (54%), intermediate among blacks (34%), and lowest among Asians (14%). Similarly, geometric mean levels of both 3- and 4-ABP-hemoglobin adducts were highest in whites (1.80 and 49.2 pg/g hemoglobin [Hb], respectively), intermediate in blacks (1.54 and 38.5 pg/g Hb), and lowest in Asians (0.73 and 36.0 pg/g Hb). As expected, cigarette smokers had significantly higher mean levels of both 3- and 4-ABP-hemoglobin adducts relative to nonsmokers, and the levels increased with the number of cigarettes smoked per day (P < .0005 for both adducts). Slow acetylators consistently exhibited higher mean levels of ABP-hemoglobin adducts relative to rapid acetylators, independent of race and level of smoking. CONCLUSION: The present cross-sectional survey supports acetylation phenotype as an important determinant of bladder cancer risk and a possible major factor in the varying bladder cancer risk among whites, blacks, and Asians.     

Cardiorespiratory drift during exercise in the horse

The purpose of the present study was to measure the time-course and degree of cardiovascular and respiratory 'drift' during constant submaximal exercise in the horse. One Thoroughbred and four Morgan mares were instrumented for simultaneous measurement of respiratory and blood gases which also enabled cardiac output (Q) to be calculated. Data were collected at rest, and at 10, 20 and 30 mins during a constant workload which elicited an initial exercising heart rate (HR) of 150 beats/min, and an approximate 15-fold increase in oxygen consumption (VO2). Significant cardiac and respiratory drift during exercise were observed over time so that ventilation increased from 750 +/- 58 to 910 +/- 49 litres/min (21 per cent increase) from the 10 to 30 min time-point (P < 0.05) and HR went from 154 +/- 4 to 173 +/- 9 beats/min (mean +/- se) over the same time period (P < 0.05). Q also rose from 142 +/- 5 to 177 +/- 17 litres/min (P < 0.05) during the same interval while stroke volume (SV) was maintained. Rectal temperature (TR) and mixed venous lactate (LA) also showed significant increases during exercise while PaO2 and PaCO2 remained constant. The results indicate a significant degree of cardiac and respiratory drift in the horse in response to strenuous submaximal exercise. At the constant exercise work rate chosen, a levelling off, or plateauing of the selected parameters of interest was not observed. Therefore if a true exercising 'steady-state' was achieved, it must have occurred very early in the exercise bout.     

Cigarette smoking is associated with unhealthy patterns of nutrient intake: a meta-analysis

The aim of this investigation was to assess the relationship between smoking status and nutrient intakes using a meta-analysis. Publications in English were sought through a Medline search using the following key words: food habits, eating, feeding behavior, diet, food, nutrition, nutritional status or assessment, tobacco use disorder, tobacco, nicotine and smoking. Scanning relevant reference lists of articles and hand searching completed the data collection. No attempt was made to search for unpublished results. Paper selection was based on nutritional surveys including comparisons of smokers with nonsmokers. Fifty-one published nutritional surveys from 15 different countries with 47,250 nonsmokers and 35,870 smokers were used in the analysis. The estimates of size effects were calculated with the mean and variance values of each nutrient intake and the size of the sample. Smokers declared significantly (all P < 10(-5)) higher intakes of energy (+4.9%), total fat (+3.5%), saturated fat (+8.9%), cholesterol (+10.8%) and alcohol (+77.5%) and lower intakes of polyunsaturated fat (-6.5%), fiber (-12.4%), vitamin C (-16.5%), vitamin E (-10.8%) and beta-carotene (-11.8%) than nonsmokers. Protein and carbohydrate intakes did not differ between smokers and nonsmokers. There was no evidence of heterogeneity among studies. In conclusion, the nutrient intakes of smokers differ substantially from those of nonsmokers. Some of these differences may exacerbate the deleterious effects of smoke components on cancer and coronary heart disease risk.     

Citation for the Distinguished Physician Award of the Endocrine Society to Dr. John P. Bilezikian

OBJECTIVE: To elucidate the molecular mechanism of smoking cessation and its relationship to body weight gain, the effects of smoking on the serum levels of leptin were studied in Japanese patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: The serum levels of leptin after an overnight fast in 37 adult male Japanese patients with type 2 diabetes (17 smokers and 20 nonsmokers) were assayed using radioimmunoassay. In addition, the serum leptin levels in four nondiabetic smokers were measured before and 2 weeks after quitting smoking. RESULTS: Smokers and nonsmokers did not differ in age, BMI, or levels of blood glucose and fasting insulin but did differ in HDL cholesterol levels (1.07 +/- 0.18 vs. 1.32 +/- 0.24 mmol/l for smokers and nonsmokers, respectively, P = 0.002). The mean serum leptin level of smokers did not differ from that of nonsmokers (3.8 +/- 1.9 vs. 3.8 +/- 1.6 ng/ml). The leptin level correlated with the fasting insulin level and BMI (r = 0.55 and 0.56, P < 0.001 and 0.001, respectively). The leptin levels in four heavy smokers showed no change after the subjects quit smoking (3.3 +/- 1.0 vs. 3.8 +/- 1.8 ng/ml, before and after quitting, respectively). CONCLUSIONS: Because smoking did not affect the leptin levels, the effects of quitting smoking on the fuel metabolism appear to be due to some other factors.     

Effects of cigarette smoking on the angiographic evolution of coronary atherosclerosis. A Canadian Coronary Atherosclerosis Intervention Trial (CCAIT) Substudy. CCAIT Study Group

BACKGROUND: Although smoking increases both the risk of developing coronary disease and the risk of coronary events in patients with known coronary atherosclerosis, the effect of smoking on the evolution of coronary atherosclerosis as assessed by serial angiography is poorly defined. METHODS AND RESULTS: Ninety smokers with coronary atherosclerosis shown on a recent angiogram and with fasting cholesterol levels between 220 and 300 mg/dL were enrolled in a randomized, double-blind, placebo-controlled trial of cholesterol-lowering therapy, along with 241 nonsmokers and exsmokers. Lovastatin at a mean dose of 36 mg/d lowered total and LDL cholesterol by 21 +/- 11% and 29 +/- 11%, respectively, but these levels changed by < 2% in placebo-treated patients. Coronary arteriography was repeated after 2 years in 72 smokers and their 557 lesions were measured blindly with an automated quantitative system, along with 1752 lesions in 227 nonsmokers. Coronary change score, the per-patient mean of the minimal lumen diameter changes for all qualifying lesions, worsened by 0.16 +/- 0.16 mm in smokers and by 0.07 +/- 0.15 mm in nonsmokers in the placebo group (P < .001). Lovastatin-treated smokers had less worsening (0.07 +/- 0.15 mm) than placebo-treated smokers (P = .024). One or more coronary lesions progressed in 16 of 34 lovastatin-treated smokers and in 28 of 38 placebo-treated smokers (47% versus 74%, P < .001). In the placebo group, new coronary lesions developed in 21 of 38 smokers and in 28 of 115 nonsmokers (55% versus 24%, P < .001); fewer lovastatin-treated smokers developed new lesions (15% versus 55%, P < .001). CONCLUSIONS: Smoking accelerates coronary progression and new lesion formation as assessed by serial quantitative coronary arteriography. Lovastatin slows the progression of coronary atherosclerosis and prevents the development of new coronary lesions in smokers.     

The effect of chronic fluvoxamine on hormonal and psychological responses to buspirone in normal volunteers

Because of previously reported associations between a high leukocyte count and risk of ischemic heart disease (IHD), we examined the relation of leukocyte counts to various characteristics among 3591 white and 506 black 31- to 45-year-old men. The mean leukocyte count was approximately 1000 cells/microL higher among whites than among blacks, and approximately 1900 cells/microL higher among current smokers than among nonsmokers. The leukocyte count was also higher among men who had recently stopped smoking and among men who reported their general health as poor or fair. Independent of these relations, the leukocyte count was associated positively with the platelet count (r = 0.29), triglyceride level (r = 0.21), heart rate (r = 0.15), and use of corticosteroids and beta-blockers; and inversely with alcohol consumption and prothrombin time (r = -0.10). The examined characteristics could together account for 37% of the variability in leukocyte counts. These relatively strong associations indicate that it may be difficult to disentangle the relation of the leukocyte count to IHD from that of other risk factors.     

Establishment of xenografts and cell lines from well-differentiated human thyroid carcinoma

OBJECTIVE: To investigate the acute effect of cigarette smoking on glucose tolerance, insulin sensitivity, serum lipids, blood pressure, and heart rate. RESEARCH DESIGN AND METHODS: This nonrandomized experimental control trial in a tertiary care center included 20 healthy chronic smokers and 20 age-, sex-, and BMI-matched healthy volunteers. Two oral glucose tolerance tests (OGTTs) were performed on each subject. Three cigarettes were smoked during the first 30 min in one of the tests. Serum glucose, insulin, and C-peptide levels were measured every 30 min; the area under the curve (AUC) and the insulin sensitivity index (ISI) were calculated; serum total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride levels were measured at 0 and 180 min; and blood pressure and heart rate were recorded every 5 min throughout 180 min. RESULTS: Smoking acutely impaired glucose tolerance: the AUC for glucose in smokers was 25.5 +/- 1.03 mmol/l (mean +/- SE) (95% CI 22.9-28) during the smoking OGTT and 21.8 +/- 0.85 mmol/l (CI 19.2-24.3) in the control OGTT (P < 0.01); in nonsmokers, it was 19.7 +/- 0.3 mmol/l (CI 18.8-20.5) in the smoking OGTT and 18.7 +/- 0.35 mmol/l (CI 17.8-19.5) in the control OGTT (P < 0.05). Smoking acutely increased serum insulin and C-peptide levels and decreased ISI only in smokers: ISI in smokers was 55 +/- 2.8 (CI 47.4-62.6) in the control OGTT and 43 +/- 2.7 (CI 35.4-50.6) in the smoking OGTT (P < 0.05). Smoking acutely caused a rise of serum total cholesterol levels in both groups and increased LDL cholesterol and triglyceride serum levels significantly only in smokers (P < 0.05). A significant rise of blood pressure and heart rate while smoking was present in all the subjects. CONCLUSIONS: Smoking acutely impaired glucose tolerance and insulin sensitivity, enhanced serum cholesterol and triglyceride levels, and raised blood pressure and heart rate. These findings support the pathogenetic role of cigarette smoking on cardiovascular risk factors.     

Ascorbic acid and dehydroascorbic acid as biomarkers of oxidative stress caused by smoking

Using a reliable, newly developed assay for ascorbic acid (reduced form) and dehydroascorbic acid (DHAA; the oxidized form) in plasma, we studied the influence of age, sex, and smoking on 219 healthy, age-stratified, and randomly selected subjects representing the Danish population. The mean (+/-SD) plasma total ascorbic acid (ascorbic acid + DHAA) concentration was lower in smokers (62.8 +/- 24.9 mumol/L) than in nonsmokers (74.9 +/- 23.6 mumol/L) (P < 0.001) and the DHAA content was 1.8 +/- 4.0% of the total ascorbic acid in smokers compared with 0.1 +/- 3.1% in nonsmokers (P < 0.001). A significant inverse correlation between the DHAA fraction and the total ascorbic acid concentration was found in smokers (P < 0.002) but not in smokers; the slopes of the linear regressions were significantly different in the two groups (P < 0.005). The mean plasma concentration of total ascorbic acid was higher in females than in males (P < 0.005); this difference persisted in multivariate analysis when smoking was adjusted for. No age dependence could be identified. The data show that smoking results in severe oxidative stress, depletion of the ascorbic acid pool, and insufficient reduction capacity to maintain ascorbic acid in the reduced form in plasma. We suggest that the additional analysis of DHAA allows further differentiation in the assessment of oxidative stress and may provide an objective way of determining vitamin C requirements in smokers. Preliminary findings suggest that a vitamin C dose that results in a plasma concentration of approximately 70 mumol/L or higher is required in smokers.     

Trimethoprim-sulfamethoxazole for the prevention of methicillin-resistant Staphylococcus aureus pneumonia in severely burned patients

This study sought to examine the association between cigarette smoking and serum bilirubin antioxidant concentrations in 715 middle-aged men undergoing coronary angiography. The study involved 153 current smokers, 251 who quit smoking and 311 who never smoked. Serum bilirubin concentrations were divided into the following quartiles; 0.20-0.57, 0.58-0.73, 0.74-0.95 and 0.96-3.26 mg/dl. The percentage of individuals within each quartile were as follows; current smokers (42, 22, 24, 12), former smokers (22, 27, 23, 28), nonsmokers (16, 28, 27, 29). A total of 42% of the current smokers had bilirubin concentrations in the lowest quartile compared to 16% of the nonsmokers. Also, 12% of the current smokers had bilirubin concentrations in the highest quartile compared to 29% in the nonsmoking group. The Mantel-Haenszel chi-square test for association between ordered categorical variables was 30.6 (P < 0.0001). Subdividing the subjects according to maximum percent stenosis on angiography (< 10, 10-49, 50-100%) revealed a significant inverse association between smoking and bilirubin (< 0.01) within each subset. The data shows that smoking is associated with decreased serum bilirubin concentrations. In addition, it supports the hypothesis that cigarette smoking may increase the risk of coronary artery disease by lowering antioxidant concentrations and raising oxidized lipid and lipoprotein concentrations.     

Passive cigarette smoking and reduced HDL cholesterol levels in children with high-risk lipid profiles

BACKGROUND: HDL cholesterol levels are known to be lower in smokers than in nonsmokers. Previous studies have demonstrated an association of decreased HDL cholesterol with passive smoking in children but have not adjusted for potential confounding factors. METHODS AND RESULTS: In a cross-sectional, pilot-scale study, we examined the relationship of HDL cholesterol levels to passive smoking in children and adolescents referred to a tertiary hyperlipidemia clinic. Eligibility criteria included (1) first visit to a lipid clinic, (2) LDL cholesterol >95th percentile for age or HDL cholesterol <5th percentile, (3) age between 2 and 18 years, and (4) absence of secondary causes of hyperlipidemia. Sociodemographic information, diet record, medical history, and fasting lipid profiles were obtained. Of 109 eligible patients, 103 (94%) were studied. Twenty-seven percent came from households with cigarette smokers. HDL cholesterol levels were 38.7+/-1.2 mg/dL (mean+/-SEM) in passive smokers versus 43.6+/-1.2 mg/dL in children without smoke exposure (P=.005). Smoking exposure was not significantly associated with other lipid values. The effect of smoking on HDL cholesterol was minimally affected by potential confounders. In multivariate regression adjusting for body mass index, age, sex, exercise, and dietary fat intake, passive smoking remained a significant risk factor for decreased HDL cholesterol (P=.012). CONCLUSIONS: Mean HDL cholesterol levels are lower in dyslipidemic children from households with smokers than in those without household smoke exposure. Passive smoking may worsen the risk profile for later atherosclerosis among high-risk young persons.