Association between atherosclerotic diseases and carboxyhaemoglobin levels in tobacco smokers

Documento de consenso sobre tabaquismo y riesgo vascular

Consensus statement on smoking and vascular risk About 22% of the Spanish population are daily smokers. Men are more likely to smoke than women. In Spain, women between 15-25 years of age smoke as much or more than men. Every smoker should be assessed for: physical dependence on nicotine (Fagerström test), social and psychological dependence (Glover Nilsson test), level of motivation to quit (Richmond test), probability of therapy success (Henri-Mondor and Michael-Fiore tests), and stage of behavioral change development (Prochaska and DiClementi). Advice on smoking cessation is highly cost-effective and should always be provided. Smoking is an enhancer of cardiovascular risk because it acts as a pathogen agent in the development of arteriosclerosis and is associated with ischemic heart disease, stroke, and peripheral artery disease. Smoking increases the risk of chronic lung diseases (COPD) and is related to cancers of the lung, female genitalia, larynx, oropharynx, bladder, mouth, esophagus, liver and biliary tract, and stomach, among others. Combined oral contraceptives should be avoided in women smokers older than 35 years of age due to the risk of thromboembolism. In smoking cessation, the involvement of physicians, nurses, psychologists, etc. is important, and their multidisciplinary collaboration is needed. Effective pharmacological treatments for smoking cessation are available. Combined treatments are recommended when smoker's dependence is high. For individuals who are unable to quit smoking, a strategy based on tobacco damage management with a total switch to smokeless products could be a less dangerous alternative for their health than continuing to smoke.

Clinical and angiographic profiles and six months outcomes of smokers with acute ST segment elevation myocardial infarction undergoing primary percutaneous coronary angioplasty

Background

Outcomes of primary percutaneous coronary intervention (PCI) for acute STEMI (ST-segment elevation myocardial infarction) in smokers are expected to be better than non-smokers as for patients of acute STEMI with or without fibrinolytic therapy.

Objectives

This comparative study was designed to evaluate the outcomes of primary PCI in patients with acute STEMI in smokers and non-smokers. Clinical and angiographic profile of the two groups was also compared.

Methods

Over duration of two year, a total of 150 consecutive patients of acute STEMI eligible for primary PCI were enrolled and constituted the two groups [Smokers (n = 90), Non-smokers (n = 60)] of the study population. There was no difference in procedure in two groups.

Results

In the present study of acute STEMI, current smokers were about a decade younger than non-smokers (p value = 0.0002), majority were male (98.9% vs 56.6%) were male with a higher prevalence of hypertension and diabetes mellitus (61.67% vs 32.28% and 46.67% vs 14.44%, p = 0.001) respectively. Smokers tended to have higher thrombus burden (p = 0.06) but less multi vessel disease (p = 0.028). Thirty day and six month mortality was non-significantly higher in smokers 4.66% vs 1.33% (p = 0.261) and 5.33% vs 2.66% (p = NS) respectively. Rate of quitting smoking among smokers was 80.90% at 6 months.

Conclusion

The study documents that smokers with acute STEMI have similar outcomes as compared to non smokers with higher thrombus burden and lesser non culprit artery involvement. Smokers present at much younger age emphasizing the role of smoking cessation for prevention of myocardial infarction.

"You've Come a Long Way, Baby": The Convergence in Age Patterns of Lung Cancer Mortality by Sex, United States, 1959-2013

We analyze lung cancer mortality by age and sex in the United States, 1959-2013. It is already known that male lung cancer death rates exceed those of women and that tobacco use is the leading reason for the sex difference. We elaborate on this knowledge by showing that unlike most causes of death, lung cancer mortality patterns by age are a very good fit to a quadratic-Gompertz model, i.e., log mortality rates are quadratic by age, with the mode above age 70. With a little additional historical data on sex differences in tobacco use, the quadratic models help to paint a clear quantitative picture of behavior-led convergence in lung cancer mortality by sex. The shape of the sex-specific mortality curves have converged dramatically: since 1983, the sexes have had statistically indistinguishable shapes of their quadratic-Gompertz mortality curves. Female lung cancer mortality patterns have shown a transformation from a nonsmoking to a smoking pattern. The modal age of the quadratic-Gompertzian lung cancer death rates has potential application in countries at earlier stages of the global tobacco epidemic. Where the modal age is falling (year-on-year), we can infer that the local lung cancer epidemic is getting worse, and where it is rising, that it has begun to abate.

An Interesting Cause of Pulmonary Emboli: Acute Carbon Monoxide Poisoning

Carbon monoxide poisoning, a public health problem of considerable significance, is a relatively frequent event today, resulting in thousands of hospitalizations annually. A 70-year-old lady was seen in the emergency department with a provisional diagnosis of carbon monoxide poisoning. The previous night, she slept in a tightly closed room heated with coal ember. She was found unconscious in the morning with poor ventilation. She had a rare presentation of popliteal vein thrombosis, pulmonary emboli, and possible tissue necrosis with carbon monoxide poisoning. Oxygen treatment with low-molecular-weight heparin (nadroparine) and warfarin therapy resulted in an improvement in both popliteal and pulmonary circulations. In conclusion, the presence of pulmonary emboli should be sought in patients with carbon monoxide poisoning.

Clinical trial on the efficacy of exhaled carbon monoxide measurement in smoking cessation in primary health care

BACKGROUND

Smoking cessation is beneficial for our health at any point in life, both in healthy people and in people already suffering from a smoking-related disease. Any help to quit smoking can produce considerable benefits for Public Health. The purpose of the present study is to evaluate the efficacy of the CO-oximetry technique together with brief advice in smoking cessation, in terms of reduction of the number of cigarettes or in the variation of the motivation to quit smoking at month 12 compared with brief advice alone.

METHODS/DESIGN

Randomised, parallel, single-blind clinical trial in a primary health care setting in Majorca (Spain). Smokers in contemplation or pre-contemplation phase will be included in the study.

EXCLUSION CRITERIA

Smokers in preparation phase, subjects with a terminal illness or whose health status does not allow them to understand the study or complete the informed consent, and pregnant or breastfeeding women. The subjects will be randomly assigned to the control group (CG) or the intervention group (IG). The CG will receive brief advice, and the IG will receive brief advice together with a measurement of exhaled CO. There will be follow-up evaluations at 6 and 12 months after inclusion. 471 subjects will be needed per group in order to detect a difference between groups ≥ 5%.

PRIMARY OUTCOME

sustained smoking cessation (at 6 and 12 months) confirmed by urine cotinine test.

SECONDARY OUTCOMES

point smoking cessation at 6 and 12 months both confirmed by urine cotinine analysis and self-reported, reduction in cigarette consumption, and variation in phase of smoking cessation.

DISCUSSION

CO-oximetry is an inexpensive, non-invasive, fast technique that requires little technical training; making it a technique for risk assessment in smokers that can be easily applied in primary care and, if proven effective, could serve as a reinforcement aid in smoking cessation intervention activities.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN67499921.

Smoking in pregnancy

During nine months of pregnancy, a woman who smokes 20 cigarettes each day will inhale nicotine, tar and carbon monoxide more than 50 000 times. This smoke contains chemicals known to be mutagenic and carcinogenic and will interfere with the normal growth and development of her child. Recent studies have revealed disturbing long-term consequences for the offspring. This article reviews the constituents of cigarette smoke, the effects of tobacco usage on the pregnancy, child and placenta, and strategies by which smoking during pregnancies may be prevented.

Carboxyhaemoglobin levels and their determinants in older British men

Background

Although there has been concern about the levels of carbon monoxide exposure, particularly among older people, little is known about COHb levels and their determinants in the general population. We examined these issues in a study of older British men.

Methods

Cross-sectional study of 4252 men aged 60–79 years selected from one socially representative general practice in each of 24 British towns and who attended for examination between 1998 and 2000. Blood samples were measured for COHb and information on social, household and individual factors assessed by questionnaire. Analyses were based on 3603 men measured in or close to (< 10 miles) their place of residence.

Results

The COHb distribution was positively skewed. Geometric mean COHb level was 0.46% and the median 0.50%; 9.2% of men had a COHb level of 2.5% or more and 0.1% of subjects had a level of 7.5% or more. Factors which were independently related to mean COHb level included season (highest in autumn and winter), region (highest in Northern England), gas cooking (slight increase) and central heating (slight decrease) and active smoking, the strongest determinant. Mean COHb levels were more than ten times greater in men smoking more than 20 cigarettes a day (3.29%) compared with non-smokers (0.32%); almost all subjects with COHb levels of 2.5% and above were smokers (93%). Pipe and cigar smoking was associated with more modest increases in COHb level. Passive cigarette smoking exposure had no independent association with COHb after adjustment for other factors. Active smoking accounted for 41% of variance in COHb level and all factors together for 47%.

Conclusion

An appreciable proportion of men have COHb levels of 2.5% or more at which symptomatic effects may occur, though very high levels are uncommon. The results confirm that smoking (particularly cigarette smoking) is the dominant influence on COHb levels.

Hearing loss associated with smoking and occupational noise exposure in a Japanese metal working company

The effects of smoking on hearing loss within the context of atherosclerosis was assessed, and the statistical interaction of occupational noise evaluated. A cross-sectional study was conducted in 397 Japanese males working at a metal factory, aged 21-66 years, in a periodical health checkup. The following information was obtained: two smoking indices of smoking status and Brinkman index, occupational noise exposures and atherosclerotic risk factors (body mass index, blood pressure, serum cholesterol, hemoglobin A1c, atherosclerosis index). Hearing acuity was measured at 4 kHz using a pure-tone audiometer in a quiet room. Among the total subjects, 55 (13.9%) were identified as having hearing loss at 4 kHz, and 151 (38.0%) were currently exposed to occupational noise. When adjusted for age and occupational noise exposure, odds ratios (95% confidence intervals) of hearing loss were 3.16 (1.04, 9.62) for past smokers and 3.39 (1.05, 11.01) for heavy smokers (Brinkman index >750 cigarettes per day x number of years), compared with never-smokers. Statistical interaction of occupational noise exposure was insignificant with the association between smoking and hearing loss. When including atherosclerotic risk factors in a multiple model, there were no significant associations between hearing loss and either smoking or any other factors (i.e., occupational noise and atherosclerotic factors). Smoking was found to be associated with hearing loss beyond occupational noise exposure, and this association seemed to be masked by atherosclerotic factors, suggesting that the direction of the atherosclerotic effect on the relationship might need to be explored between smoking and hearing impairment.

Smoking behaviour and toxin exposure during six weeks use of a potential reduced exposure product: Omni

OBJECTIVE

To determine smoking behaviour, acceptability, and toxin exposure when smokers switch to the potential reduced exposure product-Omni cigarette.

DESIGN

12 week randomised, crossover study of Omni versus own cigarettes.

PARTICIPANTS

19 light/ultralight and 15 regular smokers.

OUTCOMES

Cigarettes/day, smoking topography, craving, withdrawal symptoms, urinary cotinine plus its glucuronide (total cotinine), nicotine plus its glucuronide (total nicotine), and carcinogen metabolites (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol plus its glucuronides and 1-hydroxypyrene).

RESULTS

When switched to Omni, smokers smoked the same number of cigarettes/day, smoked Omni cigarettes less intensely (total puff volume = -11%) and had slightly lower total cotinine (-18%) levels than their own cigarettes, but had a slightly greater carbon monoxide boost/cig (+21%). Craving and withdrawal ratings were similar with Omni and own cigarettes. Carcinogen metabolite levels were somewhat but not significantly lower with Omni. About half of smokers rated Omni as better for their health and about two thirds stated it was weaker and worse tasting than their own cigarettes.

CONCLUSIONS

Although Omni may be an adequate behavioural and pharmacological substitute for traditional cigarettes, it may not decrease carcinogen exposure and may increase carbon monoxide. Replications with larger sample sizes and longer follow up are needed. These results indicate the need for regulation of reduced exposure and reduced risk claims.

Influence of smoking on incidence and prevalence of peripheral arterial disease

OBJECTIVE

Many studies have been published regarding the influence of smoking on the incidence and prevalence of peripheral arterial disease (PAD). A systematic review was performed to establish the magnitude of the effect of smoking on the development of PAD, and a possible dose-response relationship.

METHODS

English-language articles were reviewed by 2 observers using a standardized form, and were summarized in tabular form. Data were extracted by 2 independent observers. Where possible, outcome data, expressed in terms of prevalence or incidence, were recalculated as odds ratio or relative risk, with never-smokers as the reference group, or if this was not available the nonsmoker group. Most studies did not provide primary data. Therefore the weighted means were reported as a summary estimate, provided that a funnel plot between sample size and observed effect size made publication bias unlikely.

RESULTS

Sixteen articles describing 17 studies were included in the analysis. Four of the studies were prospective, and 13 were cross-sectional. The prevalence of symptomatic PAD was increased 2.3-fold in current smokers. Even in former smokers the prevalence was substantially increased by a factor of 2.6. A clear dose-response relationship, with a strong increase in risk for PAD in heavy smokers was observed. In countries where approximately 30% of the population are smokers, 50% of PAD can be attributed to smoking.

CONCLUSIONS

Smoking is a potent risk factor for symptomatic PAD, with an important and consistent dose-response relationship. With the persistence of high risk for PAD in former smokers, tobacco control programs should continue to advocate smoking cessation, but focus even more on preventing future generations from ever starting to smoke.

Sustained ventricular tachycardia or fibrillation in the cardiac catheterization laboratory among patients receiving primary percutaneous coronary intervention: incidence, predictors, and outcomes

OBJECTIVES

We sought to evaluate the incidence, predictors, and outcomes of ventricular tachycardia and/or ventricular fibrillation (VT/VF) in the cardiac catheterization laboratory among patients undergoing primary percutaneous coronary intervention (PCI).

BACKGROUND

Although VT/VF has been known to occur during primary PCI, the current data do not identify patients at risk for these arrhythmias or the outcomes of such patients.

METHODS

We evaluated 3065 patients enrolled in the Primary Angioplasty in Myocardial Infarction (PAMI) trials, who underwent primary PCI to evaluate the associations of VT/VF and the influence of these arrhythmias on in-hospital and one-year outcomes.

RESULTS

In patients undergoing primary PCI, VT/VF occurred in 133 (4.3%). Multivariate analysis identified the following as independent correlates of VT/VF: smoking (odds ratio [OR] 1.95, 95% confidence interval [CI] 1.26 to 3.02), lack of preprocedural beta-blockers (OR 2.34, 95% CI 1.35 to 4.07), time from symptom onset to emergency room of <or=180 min (OR 2.63, 95% CI 1.42 to 4.89), initial Thrombolysis In Myocardial Infarction (TIMI) flow grade 0 (OR 2.06, 95% CI 1.23 to 3.47), and right coronary artery-related infarct (OR 1.93, 95% CI 1.25 to 2.99). Although patients with VT/VF had a higher incidence of bradyarrhythmias, hypotension, cardiopulmonary resuscitation, and endotracheal intubation in the catheterization laboratory, their in-hospital and one-year adverse outcomes were similar to those of the cohort without these arrhythmias.

CONCLUSIONS

Our findings suggest that the incidence of VT/VF during primary PCI is low, indicating that these arrhythmias do not influence PCI success or in-hospital or one-year outcomes. Our data further help identify patients at risk of VT/VF during primary PCI and suggest that pretreatment with beta-blockers should be strongly considered to reduce these arrhythmias.

Paradoxical Effect of Smoking in the Spanish Population With Acute Myocardial Infarction or Unstable Angina

OBJECTIVES

The paradoxical effect of smoking after acute myocardial infarction (AMI) is a phenomenon consisting of a reduction in the mortality of smokers compared to nonsmokers. However, it is not known whether the benefit of this reduction in mortality is due to smoking itself or to other covariables. Despite acceptance of the paradoxical effect of smoking in AMI, it is not known whether a similar phenomenon occurs in unstable angina. The objective of this study was to investigate the paradoxical effect of smoking in AMI and unstable angina, and to study specifically whether smoking is an independent prognostic variable.

METHODS AND RESULTS

The study population was selected from the multicentric ARIAM (Análisis del Retraso en el Infarto Agudo de Miocardio [analysis of delay in AMI]) Register, a register of 29,532 patients with a diagnosis of unstable angina or AMI. Tobacco smokers were younger, presented fewer cardiovascular risk factors such as diabetes or hypertension, fewer previous infarcts, a lower Killip and Kimball class, and a lower crude and adjusted mortality in AMI (odds ratio, 0.774; 95% confidence interval, 0.660 to 0.909; p = 0.002). Smokers with unstable angina were younger, with less hypertension or diabetes. In the multivariate analysis, no statistically significant difference in mortality was found.

CONCLUSIONS

The reduced mortality observed in smokers with AMI during their stay in the ICU cannot be explained solely by clinical covariables such as age, sex, other cardiovascular factors, Killip and Kimball class, or treatment received. Therefore, smoking may have a direct beneficial effect on reduced mortality in the AMI population. The lower mortality rates found in smokers with unstable angina are not supported by the multivariate analysis. In this case, the difference in mortality can be explained by the other covariables.

Randomised trial investigating effect of a novel nicotine delivery device (Eclipse) and a nicotine oral inhaler on smoking behaviour, nicotine and carbon monoxide exposure, and motivation to quit

OBJECTIVE

To monitor the effect of a novel nicotine delivery device that may produce fewer carcinogens (Eclipse) on cigarette smoking, carbon monoxide and nicotine concentrations, and motivation to give up smoking. The smoker's own brand of cigarette and a nicotine replacement product (Nicotrol inhaler) were used as comparisons.

DESIGN

After baseline data were recorded, smokers were randomised to either Eclipse or inhaler for two weeks and then switched to the other product for another two weeks. Thereafter a second baseline was obtained.

SETTING AND PARTICIPANTS

Fifty smokers were included and data are reported for the 40 with complete data sets. The smokers were not trying to quit but were interested in trying a new product to reduce their risk. They visited a smoking clinic 10 times during the six week period of the trial.

INTERVENTION

No counselling to aid reduction by Eclipse or inhaler was given.

MAIN OUTCOME MEASURES

At each visit smoking status and carbon monoxide concentrations were recorded. In half of the visits withdrawal symptoms, attitudes towards smoking, heart rate, and blood nicotine concentrations were also recorded.

RESULTS

Eclipse use decreased the number of cigarettes smoked per day (cpd) from 19.1 cpd at baseline to 2.1 cpd (p < 0.001), but increased carbon monoxide concentrations in parts per million (ppm) from 21.0 ppm to 33.0 ppm (p < 0.001). A similar decrease in cigarettes smoked per day was seen with the Nicotrol inhaler, from 19.1 cpd to 4.8 cpd (p < 0.001), but carbon monoxide decreased from 21.0 ppm to 12.7 ppm (p < 0.001). The blood nicotine concentration remained fairly stable with Eclipse, increasing slightly from 16.8 ng/ml to 18.0 ng/ml, while for the inhaler a significant drop was noted, from 16.8 ng/ml to 12. 2 ng/ml (p < 0.002). Craving and withdrawal did not increase with Eclipse. Few significant adverse events occurred with Eclipse.

CONCLUSIONS

Eclipse can dramatically decrease cigarette consumption without causing withdrawal symptoms or decreases in nicotine concentrations or motivation to quit altogether. Unlike the inhaler, Eclipse produces an increase in carbon monoxide concentration. Thus Eclipse may not be a safer cigarette.

Neural circulatory responses to carbon monoxide in healthy humans

The contribution of carbon monoxide (CO) to the acute cardiovascular effects of smoking is not clear. Using a double-blind, randomized, vehicle-controlled study design, we examined the sympathetic and vascular responses to modest increases in carboxyhemoglobin in 10 healthy humans. We measured muscle sympathetic nerve activity (microneurography), forearm blood flow (plethysmography), heart rate, blood pressure, and minute ventilation at baseline and during 60 minutes of CO inhalation (1000 ppm during the first 30 minutes and 100 ppm during the last 30 minutes). The same measurements were made in a vehicle session (room air inhalation) on a separate day. During the first 30 minutes of CO inhalation, carboxyhemoglobin levels increased progressively from 0.2 +/- 0.1% to 8.3 +/- 0.5% and were maintained at about this level for a further 30 minutes. Forearm vascular resistance did not change with CO but increased slightly with vehicle; the effects of CO on muscle sympathetic nerve activity, forearm blood flow, blood pressure, heart rate, and minute ventilation were not significantly different from the effects of vehicle. Modest increases in carboxyhemoglobin levels equivalent to those resulting from cigarette smoking are unlikely to contribute to the acute sympathetic and hemodynamic effects of smoking in healthy humans.

Is preconditioning by nicotine responsible for the better prognosis in smokers with acute myocardial infarction?

Cigarette smoking is a well-known risk factor for acute myocardial infarction and sudden death. However, a history of smoking consistently has been associated with better hospital outcome in patients with acute myocardial infarction. The mechanism for the better outcome in smokers is not clear. It has been suggested that nicotine may have a "preconditioning-like" effect. This study assesses whether nicotine attenuates myocardial infarct size. Anesthetized rabbits were randomized to receive infusion of nicotine 80 micrograms/kg (n = 13), or saline (n = 12) over 10 min. Twenty minutes after termination of infusion all rabbits underwent 30 min of coronary artery occlusion and 4 h of reperfusion. Risk zone was assessed by blue dye and infarct size by tetrazolium staining. Nicotine did not affect regional myocardial blood flow 15 min after treatment, during occlusion or during reperfusion. Heart rate and mean systemic blood pressure were similar between the groups. Nicotine serum levels during occlusion were 9.5-22.0 ng/ml in the treated group, which are comparable to levels found in human smokers. No differences were found in the risk zone of nicotine compared to control rabbits (26 +/- 2% vs. 23 +/- 2% of the left ventricle, respectively), or infarct size (31 +/- 5% vs. 37 +/- 4% of risk zone). Since no effect on infarct size was found, a third group receiving higher dose of nicotine, 320 micrograms/kg (n = 6), was added. Infarct size was not different from the control group (39 +/- 6% of risk zone). Nicotine, given intravenously before ischemic insult, does not protect the myocardium. A "preconditioning-like" effect of nicotine is probably not the mechanism of reduced mortality in smoking patients with myocardial infarction.

Influence of carbon monoxide (CO) on the early course of acute myocardial infarction

OBJECTIVE

To clarify the influence of an elevated carboxyhemoglobin (COHb) blood level on the course of acute myocardial infarction and to evaluate the administration of supplemental oxygen on the COHb level and the incidence of complications.

DESIGN

Prospective clinical study with randomized, unblinded intervention.

SETTING

Coronary Care Unit of a university hospital.

PATIENTS

78 consecutive patients with acute myocardial infarction. Excluded were patients with severe dyspnea, pulmonary edema or any other medical indication for supplemental oxygen therapy.

INTERVENTIONS

Randomized therapy with 41/min oxygen in 35 patients.

MEASUREMENTS AND RESULTS

COHb was measured at admission and 4 h later. The incidence of serious arrhythmias and the maximal creatine kinase (CK) values were recorded. In patients with initial COHb > or = 5%, there were significantly more arrhythmias and significantly higher maximal CK values than in those with normal COHb admission (89 vs 33%, p < 0.001; and 1897 +/- 1602 u/l vs 960 +/- 1097 u/l, p=0.05). This effect was seen only in patients with Q-wave infarction, not in those with non-Q-wave infarction. Supplemental oxygen had no effect on the incidence of arrhythmias.

CONCLUSIONS

We conclude that myocardial infarction patients with acute Q-wave infarction and increased COHb levels at admission suffer a more severe course of the disease. This outcome was not influenced by oxygen therapy. Whether this finding indicates a casual relationship and whether higher oxygen concentrations would favorably alter the course of acute myocardial infarction remains to be determined.

Effect of cigarette smoking on outcome after thrombolytic therapy for myocardial infarction

BACKGROUND

Smoking is known to be a strong risk factor for premature atherosclerosis, myocardial infarction, and sudden cardiac death. Unexpectedly, in the reperfusion era, investigators have reported that patients who smoke have a more favorable prognosis after thrombolysis compared with non-smokers. Since smoking is associated with a relatively hyper-coagulable state, we hypothesized that the coronary occlusion responsible for infarction may be primarily thrombotic, with improved outcome relating to enhanced patency or the absence of a residual stenosis after thrombolytic therapy.

METHODS AND RESULTS

To examine this issue, we evaluated 1619 patients treated with TPA, urokinase, or both in six consecutive myocardial infarction trials, of whom 878 (54%) were currently smoking. Patients underwent 90-minute and predischarge catheterizations, which were quantified blinded to the patients' smoking status. As expected, baseline fibrinogen (2.8 [2.5,3.6] versus 2.7 [2.4,3.5] g/dL, P = .003) and hematocrit (44% [41%, 47%] versus 43% [40%, 45%], P = .0001) levels were greater in smokers. Although there were no differences between smokers and nonsmokers with regard to 90-minute patency (73% versus 74%), smokers were more likely to have TIMI-3 flow (41.1% versus 34.6%, P = .034), with a larger minimum lumen diameter of the infarct stenosis both acutely (0.82 [0.51, 1.11] versus 0.72 [0.43, 1.04] mm, P = .0432) and at follow-up (1.2 [0.8, 1.74] versus 1.0 [0.7, 1.5], P = .002). Although smokers tended to have reduced in-hospital mortality compared with nonsmokers in univariate analysis (4.0% versus 8.9%, P = .0001), after adjustment for baseline differences between smokers and nonsmokers in age (54 [47, 62] versus 60 [54, 68] years, P < .0001), inferior infarct location (60% versus 53%, P < .0001), three-vessel disease (16% versus 22%, P < .001), and baseline ejection fraction (53% [44%, 60%] versus 50% [42%, 58%], P = .0069), smoking history was of no independent prognostic significance.

CONCLUSIONS

Therefore, smokers have a relatively hypercoagulable state, documented by increased hematocrit and fibrinogen levels. Quantitative coronary angiographic analysis suggests that the mechanism of infarction in smokers is more often thrombosis of a less critical atherosclerotic lesion compared with nonsmokers. Enhanced perfusion status, as well as favorable baseline clinical and angiographic characteristics, may be responsible for the more benign prognosis of current smokers.

Coronary vessel alterations following chronic carbon monoxide exposure in the adult rat

Adult male rats were exposed to 500 ppm CO continuously for 30 days, while litter-mate controls remained in room air (AIR). Heart weight-to-body weight ratio and hematocrit were increased significantly. Right ventricle (RV) free wall thickness was increased significantly as was right to left heart diameter and average heart diameter. Cross-sectional areas of the left ventricle (LV) free wall, interventricular septum (S) and RV midway between the apex and base were increased significantly. Morphometric analysis of the CO-exposed and AIR hearts revealed no significant differences in the number of small (27-114 microns) or larger (> 114 microns) blood vessels in any region; however, there was a trend towards an increased number of the smaller vessels, both arterioles and venules, in the CO-exposed rats. The larger arteries in the S and RV were significantly larger in the CO-exposed rats. There was a significant overall effect of CO on larger artery diameter across all heart regions, consistent with the appearance of heart radiographs taken. There were no differences in the diameter of the small vessels in any region of the heart between the CO-exposed and AIR rats. The vessel cross-sectional area of the larger vessels tended to be increased in all regions of the heart. The cross-sectional area of the large arteries in the LV was increased significantly. Arterial wall thickness was decreased significantly in RV and there was a significant overall effect of CO in decreasing wall thickness and the ratio of wall thickness-to-vessel luminal diameter in these vessels. No vascular pathology was observed. The results of this study suggest changes in coronary vessel architecture during chronic CO-induced cardiac hypertrophy and are consistent with earlier hemodynamic and morphometric studies of CO-exposed hearts.

Chronic carbon monoxide exposure in young rats alters coronary vessel growth

The goal of this study was to determine whether chronic monoxide exposure in the developing heart produces long-lasting coronary vasculature alterations. One-day-old male rat pups were exposed to 500 ppm CO continuously for 30 d, while littermate controls remained in room air (AIR). At 61 and 110 d of age hearts were removed, perfusion fixed, x-rayed, and processed for analysis of coronary vessel architecture. Body weight (BW) and heart weight (HW) increased with age; the ratio of HW/BW decreased. There were no differences in HW and ventricular dimensions at either age due to prior CO exposure. Morphometric analysis of the fixed hearts from CO-exposed and AIR rats revealed no significant individual group differences in the number of small (27-114 microns) or larger (> 114 microns) vessels in any heart region. The septum (S) in CO rats was an exception: There were more small veins at 61 d of age and more larger veins at 110 d of age. There was a significant increase in the number of small arteries at both ages in the CO rats across all heart regions, and in the smaller veins at 61 d of age. The large vessels in the S at 61 d of age had a significantly greater diameter in CO compared to AIR rats. This was also true for the large arteries in the S and right ventricle (RV) of the 110-d-old rats. Taking all heart regions together, the large arteries in CO rats were larger than in AIR rats. Previous CO exposure significantly increased large artery and total cross-sectional area in the S and RV at 61 d of age, and in RV at 110 d of age. Total cross-sectional area of veins in the S was also increased. Taking all heart regions together, CO significantly increased small artery cross-sectional area at 61 d of age, and small, large, and total artery cross-sectional area at 110 d of age. With one exception (small veins, 110 d of age), there was no effect of CO on vein cross-sectional area. These changes resulted in the percentage of total cross-sectional area contributed by the larger vessels being increased. Pathological examination showed nothing abnormal. The results suggest profound and persistent changes in coronary vessel architecture following chronic neonatal CO exposure.

Self-titration of nicotine: evidence from the Scottish Heart Health Study

Data from 2754 cigarette smokers who smoke no other forms of tobacco are extracted from the baseline cross-sectional survey of the Scottish Heart Health Study. Carbon monoxide in expired-air (CO-E), serum thiocynate and serum cotinine measurements from these smokers are compared with the carbon monoxide (CO), nicotine and tar yields of the cigarettes which they smoke, controlling for daily cigarette consumption, the sex of the smoker and the other cigarette yields. CO-E is found to increase positively with CO and tar yield, but inversely with nicotine yield. Thiocyanate increases positively with CO, is not significantly affected by tar, but increases inversely with nicotine. Cotinine is affected only by tar, in a positive direction for women. We conclude that smokers appear to self-titrate their consumption of nicotine by more aggressive smoking of lower-strength cigarettes.

Relation of passive smoking as assessed by salivary cotinine concentration and questionnaire to spirometric indices in children

BACKGROUND

Previous studies of the effects of passive exposure to smoke on spirometric indices in children have largely relied on questionnaire measures of exposure. This may have resulted in underestimation of the true effect of passive smoking. Biochemical measures offer the opportunity to estimate recent exposure directly.

METHODS

The relation between spirometric indices and passive exposure to tobacco smoke was examined in a large population sample of 5-7 year old children from 10 towns in England and Wales. The effects of passive exposure to smoke on lung function were assessed by means of both salivary cotinine concentration and questionnaire measurements of exposure. Analyses of the relation between spirometric values and cotinine concentrations were based on 2511 children and of the relation between spirometric values and questionnaire measures on 2000 children.

RESULTS

Cotinine concentration was negatively associated with all spirometric indices after adjustment for confounding variables, which included age, sex, body size, and social class. The strongest association was with mid expiratory flow rate (FEF50), the fall between the bottom and top fifths of the cotinine distribution being 6%, equivalent to a reduction of 14.3 (95% confidence limits (CL) 8.6, 20.0) ml/s per ng/ml cotinine. Salivary cotinine concentrations were strongly related to exposure to cigarette smoke at home but 88% of children who were from non-smoking households and not looked after by a smoker had detectable cotinine concentrations, 5% being in the top two fifths of the cotinine distribution. A composite questionnaire score based on the number of regular sources of exposure was as strongly related to mid and end expiratory flow rates as the single cotinine measure. The fall in FEF50 per smoker to whom the child was exposed was 51.0 (26.5, 75.5) ml/s. The relationships between the questionnaire score and forced vital capacity (FVC) or forced expiratory volume in one second (FEV1) were not statistically significant.

CONCLUSIONS

These effects of passive smoking on respiratory function are consistent with the results of previous studies and, although small in absolute magnitude, may be important if the effects of exposure are cumulative. In children aged 5-7 years the use of a single salivary cotinine concentration as a marker of passive exposure to smoke resulted in clear relationships between exposure and FVC and FEV1, whereas the associations were much weaker and not significant when based on the questionnaire score. The associations between exposure and mid or end expiratory flow rates were of similar magnitude for cotinine concentration and the questionnaire score. The use of salivary cotinine concentration in longitudinal studies may help to determine the extent to which these effects are cumulative or reversible.

Discrepancies between self-reported smoking and carboxyhemoglobin: an analysis of the second national health and nutrition survey

Environmental, self-report, and demographic factors mediated the relationship between self-reported cigarette smoking and carboxyhemoglobin among 2114 smokers and 3918 nonsmokers. Self-reported nonsmokers with carboxyhemoglobin levels between 2% and 3% were more likely to be self-reported ex-smokers, to live in a larger community, and to be younger, less educated, and male than were self-reported nonsmokers with carboxyhemoglobin levels of less than 2%. Self-reported nonsmokers with strong evidence of cigarette consumption (carboxyhemoglobin level greater than 3%) were more likely to be self-reported ex-smokers, younger, less educated, and non-White than were nonsmokers with carboxyhemoglobin levels of less than 2%.

Oxygen-dissociation kinetics in the blood of smokers and non-smokers: interaction between oxygen and carbon monoxide at the hemoglobin molecule

The importance of smoking as a possible factor in coronary heart disease (CHD) may be related to the effect of carbon monoxide (CO) on oxygen exchange at the hemoglobin molecule (Hb). We examined the kinetics of this process in vitro and ex vivo using a fast-reaction technique (stopped-flow) whereby the dissociation-rate constant of oxygen was determined in the blood of smokers and non-smokers and at fixed HbCO-concentrations in non-smokers blood. In non-smokers, carbon monoxide saturated blood was obtained by gassing with carbon monoxide and mixing the samples with appropriate carbon monoxide free blood to achieve HbCO-concentration in the range of 10-60%. The reaction time course for the oxygen-dissociation was divided into a non-linear-initial phase (loss of the first oxygen molecule) and a subsequent linear phase. The oxygen-dissociation velocity decreased from 96.5 x 10(3) ms-1 to 42.7 x 10(3) ms-1 in the linear phase at pH 7.4 and decreased from 29.2 x 10(3) ms-1 to 20.9 x 10(3) ms-1 at pH 9.2 when the HbCO-concentration was increased to 63%. For the initial phase at pH 7.4, the dissociation velocity decreased depending on the HbCO-concentration. In non-smokers 50% of the bound oxygen was released in 17.5 +/- 2.3 ms (n = 13) whereas in smokers 19.4 +/- 1.8 ms (n = 14) (p less than 0.05) was required.(ABSTRACT TRUNCATED AT 250 WORDS)

Is there a connection between carbon monoxide exposure and hypertension?

Exposure to carbon monoxide in our society is a frequent occurrence, from auto exhaust, industrial effluents, and cigarette smoke, and takes place over a wide range of concentrations. It has been suggested that chronic CO inhalation may alter blood pressure, even possibly provoking hypertension by acting alone or in combination with other environmental stressors. Some studies examining the response to CO exposure have reported decreases in blood pressure, whereas others have found increases or no change. Blood pressure in long-term cigarette smokers is generally decreased relative to nonsmokers, albeit a slight decrease. The strength of this finding is somewhat clouded by the effect of the lower body weight in smokers. The increases in blood pressure observed acutely with smoking are mainly due to nicotine. Chronically, the hypertensive action of nicotine is largely offset by the hypotensive action of CO. Several studies support the notion that environmental CO exposure or smoking accelerates or exacerbates hypertension in some people. It has been asserted that chronic CO exposure increases the development of atherosclerotic disease; however, convincing evidence from animal experiments is lacking. Nevertheless, CO may elevate plasma cholesterol and does appear to enhance atherosclerosis when serum cholesterol is greatly elevated by diet. Using the borderline hypertensive rat, an animal model reputed to have increased sensitivity to environmental stimuli, we found no evidence to suggest a provocatory role for CO in the development of hypertension; instead, CO exposure produced hypotension. On the whole, the human and animal literature, as well as our studies, fail to support the hypothesis that long-term CO exposure is capable of provoking an increase in blood pressure, even in borderline hypertensive or sensitive individuals.

The peripheral vascular consequences of smoking

Cigarette smoking is associated with an increased risk and extent of advanced atherosclerotic vascular disease in peripheral as well as coronary arteries. The likelihood of claudication, amputation, stroke, abdominal aortic aneurysm, and failure of vascular reconstruction is higher in smokers than nonsmokers. Smoking exerts its deleterious effects through many interactive mechanisms. Nicotine and carbon monoxide produce acute cardiovascular consequences, including altered myocardial performance, tachycardia, hypertension, and vasoconstriction. Smoking injures blood vessel walls by damaging endothelial cells, thus increasing permeability to lipids and other blood components. Among metabolic and biochemical changes induced by smoking are elevated plasma, free fatty acids, elevated vasopressin, and a thrombogenic balance of prostacyclin and thromboxane A2. Chronic smoking is associated with a tendency for increased serum cholesterol, reduced high density lipoprotein, and other lipid effects that contribute to atherosclerosis. In addition to rheologic and hematologic changes from increased erythrocytes, leukocytes, and fibrinogen, smokers have alterations in platelet aggregation and survival that produce thrombosis. Considering the ubiquitous repercussions of this menace, vascular surgeons should play an active role in motivating their patients to quit smoking.

Prevention of cardiovascular disease in women: role of the obstetrician-gynecologist

Cardiovascular disease poses a major threat to women's health. Obstetrician-gynecologists dominate the adult health care field in preventive services in the United States, and the scope of their preventive services should be broadened to encompass cardiovascular disease in women. Endogenous and exogenous risk factors jointly contribute to a woman's cardiovascular risk profile; the risk of cardiovascular disease should be viewed as a multifactorial phenomenon with a continuous gradient of response. Three important risk factors--serum cholesterol, hypertension, and cigarette smoking--are amenable to change and should become a principal focus of women's health care. Although preventive medicine lacks the glamour and immediate rewards of obstetric and gynecologic interventions, the long-term benefits to the health of women are compelling.

Cholesteryl ester accumulation in macrophages incubated with low density lipoprotein pretreated with cigarette smoke extract

Although cigarette smoking is one of the major risk factors for atherosclerosis and coronary heart disease, the precise mechanisms of its adverse effects have not been fully elucidated. We incubated low density lipoprotein (LDL) with cigarette smoke (CS) extract and examined the incorporation of the lipoprotein by macrophages in vitro. When incubated with macrophages, LDL pretreated with CS extract (100 micrograms/ml) stimulated cholesteryl [14C]oleate synthesis approximately equal to 12.5-fold that with unmodified LDL and transformed macrophages to cells rich in lipid droplets positively stained with oil red O. Enhancement in cholesteryl ester synthesis was dependent on the concentration of CS-modified LDL and exhibited saturation kinetics. When subjected to electrophoreses, CS-modified LDL migrated to a more anionic position than did unmodified LDL and showed extensive fragmentation of apolipoprotein B. This LDL modification depended upon the incubation time and concentration of the CS extract. Superoxide dismutase inhibited modification of LDL by 52%, suggesting that superoxide anion is, at least in part, involved. These results suggest that CS extract alters LDL into a form recognized and incorporated by macrophages. Such modification if it occurs in vivo, could explain the increased incidence of atherosclerosis and coronary heart disease in smokers.

Behavioral and biochemical effects of gradual reductions in cigarette yields in pregnant and nonpregnant smokers

Smoking-related risks have been well-documented for both the smoker and the pregnant smoker's unborn child, but the risks associated with low tar/nicotine cigarette smoking are still controversial. The present study examined some of the behavioral and biochemical effects of gradual reductions in tar and nicotine yields in six pregnant and six nonpregnant smokers. Over four sessions spanning a 6-week period, smokers switched to cigarette brands progressively lower in tar and nicotine. Examination of the topographical variables assessed both during (cigarette frequency, puff frequency, and cigarette duration) and between sessions (daily cigarette rate and nicotine intake) revealed significant decreases in both pregnant and nonpregnant smokers' cigarette duration and nicotine intake. Also observed were significantly lower and less variable carboxyhemoglobin (COHb) levels among the pregnant smokers when they smoked the lowest tar and nicotine brands. However, even the pregnant smokers' lower mean COHb levels did not drop below the 3% minimal cardiovascular risk level. The pregnant smokers also tended to have lower and less variable salivary thiocyanate (SCN) levels, but these differences were nonsignificant. The results were discussed in terms of implications for controlled smoking treatment programs for pregnant smokers.

Cigarette consumption and serum cotinine in relation to birthweight

The concentration of serum cotinine (the major metabolite of nicotine) was measured in sera from 4211 women at between 15 and 21 weeks gestation to determine whether a serum cotinine level was a better predictor of low birthweight than the self-reported number of cigarettes smoked per day. Both cotinine levels and smoking history were significantly associated with reduced birthweight, but cotinine correlated significantly better. Smokers of greater than or equal to 25 cigarettes per day, representing the 2.7% of women with the greatest cigarette consumption, had infants 289 g lighter than the 68% of women who were nonsmokers. Women with serum cotinine levels in the top 2.7% (greater than or equal to 284 ng/ml) had infants 441 g lighter than the 68% of women with the lowest cotinine levels (less than or equal to 24 ng/ml). Our results strengthen the evidence linking smoking with low birthweight and also demonstrate that cotinine can be satisfactorily used to assess and monitor cigarette smoking in pregnancy.

Response and acclimatisation of symptomless smokers on changing to a low tar, low nicotine cigarette

Ten symptomless smokers were switched from their usual cigarette to a low tar, low nicotine test cigarette for two weeks to investigate their immediate response and subsequent acclimatisation to the test cigarette. The tar (T) and nicotine (N) yields of the test cigarettes were T = 3.8 mg, N = 0.6 mg; the median yields of the usual cigarettes were T = 16.4 mg, N = 1.4 mg. The subjects were monitored over a six week period comprising a control period (usual cigarette), a test period (test cigarette), and a return period (usual cigarette), each lasting two weeks. The inhaled smoke volume (smoke from the burning tip of the cigarette which is subsequently inhaled) was measured with a non-invasive radiotracer technique. Puffing indices were recorded using an electronic smoking analyser and flowhead cigarette holder. Measurements were made at the beginning of the control period, at the beginning and end of the test period, and at the end of the return period. Subjects kept records of their cigarette consumption during each of the three periods. Apart from a small change in puff duration, cigarettes were smoked in the same way during the control and return periods. Mean and total puff volumes increased with the low tar, low nicotine cigarette but did not change from the beginning to the end of the test period. There was no significant change between the control, test, and return periods for mean inhaled smoke volume, total inhaled smoke volume, or cigarette consumption. It is concluded that when smokers are switched to a low tar, low nicotine cigarette the puff volume increases but there is no change in the inhaled smoke volume or daily consumption.

Effect of chronic smoking on fibrinolysis

The aim of the study was to investigate the long-term chronic effects of smoking on the fibrinolytic enzyme system by comparing two groups of healthy male volunteers (aged 30 to 40 years). One group consisted of 15 habitual smokers who consumed 20 or more cigarettes a day; the other consisted of 15 nonsmokers. Fibrinolysis was studied at rest (baseline) and after infusion of 1-desamino-8-D-arginine vasopressin (DDAVP; 0.4 micrograms/kg body weight). Smokers had significantly lower baseline blood fibrinolytic activity as determined by the overall assays: dilute blood clot lysis (p less than or equal to 0.05) and euglobulin-fibrin plate assay (p less than or equal to 0.05). Further analysis showed that these low activities could be attributed to a lower baseline level of extrinsic tissue-type plasminogen activator (t-PA) activity (p less than or equal to 0.05) in the smokers. There were no significant differences between the groups in various fibrinolytic inhibitors or in the intrinsic fibrinolytic activation pathways. The increased levels of t-PA activity and factor VIII R:Ag in response to DDAVP were also reduced in the smokers (p less than or equal to 0.01). The relative increase (ratio of post-DDAVP activity/baseline activity) for these parameters was not significantly different for the two groups. Smokers also had significantly higher levels of the acute phase reactants, alpha 1-antitrypsin (p less than or equal to 0.02) and plasminogen (p less than or equal to 0.02) and C-reactive protein (p less than or equal to 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Cigarette smoking as a risk for cardiovascular disease V: Biochemical parameters with increased and decreased nicotine content cigarettes

Cigarette smokers were assessed for customary smoking behavior and then were assigned a cigarette which was 0.4 mg higher or lower in nicotine and after 4 weeks, were returned to their customary brand. Biochemical indices of smoking behavior including blood carboxyhemoglobin (COHb), plasma nicotine, cotinine and thiocyanate (-SCN) were measured every 2 weeks. When nicotine availability was increased, smokers received an increased nicotine bolus per puff as determined by plasma nicotine and did not alter smoking topography or cigarettes per day. Over the 4 weeks, plasma cotinine increased without corresponding increases in COHb and -SCN. The return to standard brand resulted in declining cotinine levels but increasing COHb and -SCN, suggesting altered inhalation patterns. In smokers switched to a low yield cigarette, there was a decrease in the nicotine obtained per cigarette followed by a steady rise in plasma cotinine, -SCN and blood COHb over the 4-week period. A positive correlation was observed between cotinine and the gas phase constituents during the change to lower yield and back to standard brand cigarettes. These results indicate that cigarette smokers compensate for decreased nicotine yield with concomitant increases in gas phase components. In addition, increased nicotine availability results in an increased body burden of nicotine and "tar," but not gas phase constituents. The relative risks of cardiovascular disease under these two situations, which increase exposure to nicotine or gas phase components, deserve careful consideration.

Carbon monoxide yield of cigarettes and its relation to cardiorespiratory disease

Estimates of the carbon monoxide yield of their cigarettes have been obtained for 4910 smokers (68% of all smokers) in the Whitehall study of men aged 40 to 64. In the 10 years after examination 635 men died. When men smoking cigarettes with high carbon monoxide yield were compared with those smoking cigarettes with a low yield, and after adjusting for age, employment grade, amount smoked, and tar yield, the risk of death was 32% lower for coronary heart disease, 49% higher for lung cancer, and 10% lower for total mortality; these differences were not statistically significant. Among men who said that they inhaled the risk of fatal coronary heart disease was 51% lower in the high carbon monoxide group (p less than 0.01), while the risk of lung cancer was 75% higher. These results provide no evidence that a smoker can reduce his risk of death by smoking a brand with a low carbon monoxide yield; he might even increase it. The complex interactions between characteristics of the smoker, smoking behaviour, constituents of tobacco smoke, and health are again demonstrated.

Cigarette smoking and renovascular hypertension

A retrospective cohort study to investigate the association between smoking and renal artery stenosis compared 71 patients with documented renovascular hypertension and 308 age-matched control patients with essential hypertension. 94% (30/32) of men and 74% (29/39) of women with renal artery stenosis had smoked cigarettes compared with only 43% (64/150) of men and 41% (65/158) of women in the control group. This striking relation was true for both patients with fibromuscular disease (71% smokers; 15/21) and patients with atherosclerotic lesions (88% smokers; 44/50). All renal artery stenosis groups had significantly higher systolic and diastolic blood pressures than the relevant control group. When the groups were stratified according to blood pressure, there were significantly more smokers in the renal artery stenosis group at every level of blood pressure.

Influence of carboxyhemoglobin, gamma-glutamyl-transferase, body weight, and heart rate on blood pressure in middle-aged men

Carboxyhemoglobin (COHb%) and gamma-glutamyl-transferase (GGT) are indicators of tobacco and alcohol consumption; similarly, body weight broadly reflects dietary habits. Relationships between COHb%, GGT, relative body weight, heart rate and blood pressure were studied in 242 48-year-old men attending a general health screening program in Malmö, Sweden. All were without treatment for high blood pressure. Positive correlations were found between blood pressure and body weight, GGT, and pulse, and a reciprocal correlation between blood pressure and COHb%. Use of objective markers for known or suspected risk factors, such as alcohol consumption, smoking, or overweight, were studied to elucidate their usefulness for further prospective studies.

Atherosclerosis: pathology, pathogenesis, and role of risk factors

Atherosclerosis is a complex disease that represents the end product of the interaction of many different causative agents. Those that originate external to the arterial wall usually are called primary risk factors. Many other influences, the secondary risk factors, modulate the primary factors. The penetrance of the secondary factors is variable. They can have a major effect in some people but not in others. The idea of risk factor is important because it provides the conceptual framework upon which to build an intervention program for prevention of atherosclerosis. The development of atherosclerosis can be viewed as a two-step process (Table 2). The first is injury to the arterial wall. The second is response to injury. The primary risk factors can be regarded as the injurious agents. Examples are factors causing endothelial damage, influx of plasma lipoproteins, toxic products of smoking, hemodynamic injury of hypertension, and perhaps microvascular injury from diabetes mellitus. The response to injury represents typical pathologic changes--proliferation of smooth muscle cells, mononuclear infiltration, phagocytosis of products of injury, secretion of connective tissue elements, neovascularization, and necrosis. Regulation of these latter processes is poorly understood and is a worthy subject for future research. Modulation of the primary injurious factors through alteration of secondary risk factors is currently the only significant approach to prevention of atherosclerosis. Future investigation may provide more direct ways to prevent or retard atherogenesis, either by more effective modification of primary factors or by reducing the magnitude of response to these factors.

The effect of cessation of smoking on the accumulative survival rates of patients with symptomatic peripheral vascular disease

A study of the accumulative survival rates of 133 patients with symptomatic peripheral vascular disease was carried out comparing the survival rates of tobacco smokers and non-smokers. Within the smoking group, those who continued to smoke after the surgery were compared to those who ceased smoking. Of these patients with peripheral vascular disease, 86% were, or had been, smokers. Their survival rates were less than for those who had never been smokers. Of the smoking group, those who claimed to have ceased smoking had almost twice the chance of surviving five years than those who continued to smoke. From these data, we conclude that it is never too late to stop the smoking habit.

Carboxyhemoglobin Levels in New York City Runners

In brief: Carboxyhemoglobin (COHb) blood levels were measured in 16 New York City runners before and after one-half hour of exercise. Subjects exercised along a highway and in a park under similar weather conditions during rush-hour traffic. These COHb levels were compared to those of ten healthy, nonsmoking volunteers who stood quietly for the same time period at one of the exercise locations. The runners' COHb rose during exercise at both locations from 1.7% to 5.1% and from 1.3% to 4.2% (p <.001). COHb levels also increased in the nonrunners but to a lesser extent (from 0.83% to 2.44%, p <.05). The data indicate that running or standing near traffic in an urban area raises COHb to the levels found in chronic cigarette smokers. These findings quantify potentially harmful exposure to carbon monoxide fumes in an urban environment.