Cigarette smoking, tar yields, and non-fatal myocardial infarction: 14,000 cases and 32,000 controls in the United Kingdom. The International Studies of Infarct Survival (ISIS) Collaborators

Large-scale test of hypothesised associations between the angiotensin-converting-enzyme insertion/deletion polymorphism and myocardial infarction in about 5000 cases and 6000 controls. International Studies of Infarct Survival (ISIS) Collaborators

BACKGROUND

The original report of a possible association between myocardial infarction and the insertion/deletion (I/D) polymorphism of the gene for the angiotensin-1-converting enzyme (ACE) indicated a risk ratio for myocardial infarction with the DD genotype of 1.34 (95% CI 1.05-1.70), and the association was claimed to be particularly strong in a retrospectively defined low-risk subgroup (3.2 [95% CI 1.7-5.9). Subsequent investigations reached varying conclusions, but all were small, and much larger studies were needed.

METHODS

4629 myocardial infarction cases and 5934 controls were compared. Cases were UK men aged 30-54 years and women aged 30-64 years recruited on presentation to hospital with confirmed myocardial infarction. Controls were aged 30-64 years with no history of cardiovascular disease, but were siblings or children of myocardial infarction survivors, or spouses of such relatives. All risk-ratio calculations allow for this relatedness of some of the controls. An updated meta-analysis of previous studies was also conducted.

FINDINGS

The ACE DD genotype was found in 1359 (29.4%) of the myocardial infarction cases and in 1637 (27.6%) of the controls (risk ratio 1.10 [95% CI 1.00-1.21]). The association between myocardial infarction and the DD genotype did not seem to be stronger in the subgroup defined as low risk by previously used criteria (234 [28%] of 836 cases and 911 [28%] of 3253 controls: risk ratio 1.04 [95% CI 0.87-1.24]), or in any other subgroup. Nor was the ACE I/D genotype predictive of subsequent survival.

INTERPRETATION

This study involved many more cases than any previously reported study of this question, but did not confirm the existence of any substantial association. In an updated meta-analysis of these results with those of previously published studies, the risk ratio for myocardial infarction with the DD genotype seems to lie in the range 1.0 to about 1.1. Although an increase in risk of up to about 10-15% cannot be ruled out, substantially more extreme risks can be. Moreover, there are not especially strong associations in the subgroups previously selected for emphasis. These findings illustrate the need for some studies of candidate genes to involve much larger populations than is customary, without undue emphasis on retrospectively defined subgroups.

Helicobacter pylori infection and early onset myocardial infarction: case-control and sibling pairs study

OBJECTIVES

To examine the association between coronary heart disease and chronic Helicobacter pylori infection.

DESIGN

Case-control study of myocardial infarction at young ages and study of sibling pairs with one member affected and the other not.

SETTING

United Kingdom.

PARTICIPANTS

1122 survivors of suspected acute myocardial infarction at ages 30-49 (mean age 44 years) and 1122 age and sex matched controls with no history of coronary heart disease; 510 age and sex matched pairs of siblings (mean age 59 years) in which one sibling had survived myocardial infarction and one had no history of coronary heart disease.

MAIN OUTCOME MEASURES

Serological evidence of chronic infection with H pylori.

RESULTS

472 (42%) of the 1122 cases with early onset myocardial infarction were seropositive for H pylori antibodies compared with 272 (24%) of the 1122 age and sex matched controls, giving an odds ratio of 2.28 (99% confidence interval 1.80 to 2.90). This odds ratio fell to 1.87 (1.42 to 2.47; P<0.0001) after smoking and indicators of socioeconomic status were adjusted for and to 1.75 (1.29 to 2.36) after additional adjustment for blood lipid concentrations and obesity. Only 158 of the 510 pairs of siblings were discordant for H pylori status; among these, 91 cases and 67 controls were seropositive (odds ratio 1.33 (0.86 to 2.05)). No strong correlations were observed between H pylori seropositivity and measurements of other risk factors for coronary heart disease (plasma lipids, fibrinogen, C reactive protein, albumin, etc).

CONCLUSION

In the context of results from other relevant studies, these two studies suggest a moderate association between coronary heart disease and H pylori seropositivity that cannot be fully accounted for by other risk factors. But even if this association is causal and largely reversible by eradication of chronic infection, very large randomised trials would be needed to show this.

The adverse health effects of tobacco and tobacco-related products

Tobacco use continues to occur in epidemic proportions and with it, significant morbidity and mortality. One third of smokers will die prematurely of a smoking-related disease. This article reviews the adverse health effects of tobacco use so that clinicians can be aware of the benefits patients will reap when they stop using this lethal substance.

Comparing smoking and smoking cessation process in the Republic of Karelia, Russia and North Karelia, Finland

STUDY OBJECTIVE

The aims of this study were to assess and validate self reported smoking prevalence and to assess smoking cessation related process variables in the Republic of Karelia, Russia and in North Karelia, Finland.

DESIGN

Comparative population surveys of random population samples from both areas in spring 1992. The study included a self administered questionnaire, physical measurements and laboratory tests. The validity of self reported smoking prevalence was assessed by serum cotinine analyses.

SETTING

The district of Pitkäranta in the Republic of Karelia, Russia and province of North Karelia, Finland.

PARTICIPANTS

The study population was a 25 to 64 year old population in both areas. A stratified random sample of 1000 people in Pitkäranta and 2000 people in North Karelia was drawn from the population registers. In Pitkäranta 380 men and 455 women, and in North Karelia 673 men and 803 women, participated in the survey.

RESULTS

The self reported prevalence rates of daily smoking in Pitkäranta were 65% among men and 10% among women. In North Karelia the respective rates were 29% and 13%. Women in Pitkäranta greatly underreported their smoking status, which was assessed by comparing the self reported data to the serum cotinine measurements. The smoking prevalence among women in Pitkäranta would rise from 10% to 21% if all participants with high cotinine values would be regarded as smokers. Compared with smokers in North Karelia, a higher percentage of smokers in Pitkäranta expressed their wish to quit and believed that they would succeed. However, on average they had fewer previous smoking cessation attempts than smokers in North Karelia. In addition, the health personnel in North Karelia were more active in advising smokers to quit.

CONCLUSIONS

High smoking prevalence among men in Pitkäranta obviously contributes much to the high premature death rate in the Republic of Karelia. There is considerable underreporting of smoking in Pitkäranta, especially among women, which is probably attributable to the cultural unacceptability of female smoking in Russia. The common wish to quit, few previous cessation attempts and much lower rates of ex smokers, together with less smoking cessation counselling from health personnel, need to be considered in tailoring antismoking interventions in the area.

No excess risk of cervical carcinoma among women seropositive for both HPV16 and HPV6/11

Human papillomavirus (HPV) types 16 and 18 are the major risk factors for cervical carcinoma, whereas HPV types 6 and 11 cause benign genital lesions. We wanted to study the joint effect of simultaneous infections with the oncogenic and non-oncogenic HPV types on risk of subsequent development of cervical carcinoma. A cohort of 530,000 women who had donated blood samples to Nordic serum banks between 1973 and 1994 was followed up by linkage to national cancer registries. We identified 182 prospective cases with invasive cervical carcinoma and selected 538 matched controls at random. HPV 6, 11, 16, 18 and 33 seropositivity was used as a marker for the different HPV infections, and seropositivity for Chlamydia trachomatis and cotinine were used as markers for risk-taking sexual behavior and smoking respectively. The adjusted odds ratio (OR) of cervical squamous-cell carcinoma (SCC) was 2.2 for HPV6/11 among HPV16 seronegatives and 5.5 for HPV16 among HPV6/11 seronegatives. Assuming multiplicative joint effect, the expected OR for seropositivity to both HPV6/11 and HPV16 would have been 12, but the observed OR was 1.0. The antagonistic interaction was statistically significant (p = 0.001) and present also under deterministic considerations of possible misclassification bias. Antagonistic interactions were also detected for combinations of HPV16 and HPV18 and of HPV16 and HPV33. The results are in line with the concept that HPV-specific immunity protects against SCC and support primary prevention of SCC by vaccination against the HPVs.

Gender differences in the sequelae of hospitalization for acute myocardial infarction among older adults

OBJECTIVE

To examine the effect of gender differences among older adults hospitalized for an acute myocardial infarction (AMI) on subsequent health outcomes.

DESIGN

Secondary analysis of the Longitudinal Study on Aging. Data from baseline interviews (1984) and three biennial (1986, 1988, and 1990) re-interviews were linked to Medicare hospitalization and National Death Index records for 1984-1991.

PARTICIPANTS

A total of 6071 community-dwelling adults aged 70 years or older at baseline.

METHODS

Pooled and stratified multivariable models were used to examine gender differences in the independent effects of being hospitalized for an AMI on all-cause mortality, the risk and volume of subsequent hospitalization, and increases in the number of functional limitations. Two comparison groups were used.

RESULTS

Three hundred fifty-seven AMI cases (6%; 172 women and 185 men) were compared with 3976 hospitalized controls and 1738 nonhospitalized controls. The risk of all-cause mortality for AMI cases was greater than that for either hospitalized controls or nonhospitalized controls (referent), and this increased risk was significantly (P < .001) stronger for women (adjusted hazards ratio (AHR) = 14.24, 95%CI = 10.99, 18.46) than for men (AHR = 9.91, 95%CI = 7.75, 12.67). Overall, AMI cases were also more likely to be hospitalized subsequently than the hospitalized controls (referent; adjusted odds ratio (AOR) = 1.47, 95%CI = 1.17, 1.85), although in the stratified analysis this association held for men (AOR = 1.73, 95%CI = 1.25, 2.41) but not for women (AOR = 1.25, 95%CI = .90, 1.73). Among those subsequently hospitalized, both women and men AMI cases consumed more hospital resources than the hospitalized controls, and there were gender differences suggesting that the effects on total charges and length of stay were greater for women than for men with AMI. Finally, although the AMI cases had greater adjusted mean increases in the number of instrumental activities of daily living limitations and lower body limitations than the nonhospitalized controls, they were no worse off than the hospitalized controls, and there were no gender differences in those effects.

CONCLUSION

Relative to the appropriate comparison groups, hospitalization for an AMI increases the risk of death and the total costs and lengths of stay of subsequent hospitalizations for women more than for men. Therefore, increased primary prevention, diagnosis, and treatment efforts should be directed toward women.

Need for a paradigm shift: the importance of risk factor reduction therapy in treating patients with cardiovascular disease

Cardiovascular disease remains the number one killer in the United States, despite advances made in diagnosis and therapy. A major shift to expand treatment beyond symptomatic obstructions and infarctions toward comprehensive therapies aimed at treatment of the underlying disease process could decrease the death rate and cost of cardiovascular disease enormously. In the past 5 years, major trials have clearly demonstrated that aggressive intervention with lipid-lowering therapy can dramatically alter the course of disease. Aspirin, smoking cessation, exercise, diet, and other medical and lifestyle interventions can also decrease risk. Successful therapies are not being implemented, however. Making prevention the primary approach to treatment will require increased resource allocation, use of health provider teams, integration of healthcare delivery systems, and expanded emphasis on educating patients about prevention.

Emerging tobacco hazards in China: 1. Retrospective proportional mortality study of one million deaths

OBJECTIVE

To assess the hazards at an early phase of the growing epidemic of deaths from tobacco in China.

DESIGN

Smoking habits before 1980 (obtained from family or other informants) of 0.7 million adults who had died of neoplastic, respiratory, or vascular causes were compared with those of a reference group of 0.2 million who had died of other causes.

SETTING

24 urban and 74 rural areas of China.

SUBJECTS

One million people who had died during 1986-8 and whose families could be interviewed.

MAIN OUTCOME MEASURES

Tobacco attributable mortality in middle or old age from neoplastic, respiratory, or vascular disease.

RESULTS

Among male smokers aged 35-69 there was a 51% (SE 2) excess of neoplastic deaths, a 31% (2) excess of respiratory deaths, and a 15% (2) excess of vascular deaths. All three excesses were significant (P<0.0001). Among male smokers aged >/70 there was a 39% (3) excess of neoplastic deaths, a 54% (2) excess of respiratory deaths, and a 6% (2) excess of vascular deaths. Fewer women smoked, but those who did had tobacco attributable risks of lung cancer and respiratory disease about the same as men. For both sexes, the lung cancer rates at ages 35-69 were about three times as great in smokers as in non-smokers, but because the rates among non-smokers in different parts of China varied widely the absolute excesses of lung cancer in smokers also varied. Of all deaths attributed to tobacco, 45% were due to chronic obstructive pulmonary disease and 15% to lung cancer; oesophageal cancer, stomach cancer, liver cancer, tuberculosis, stroke, and ischaemic heart disease each caused 5-8%. Tobacco caused about 0.6 million Chinese deaths in 1990 (0.5 million men). This will rise to 0.8 million in 2000 (0.4 million at ages 35-69) or to more if the tobacco attributed fractions increase.

CONCLUSIONS

At current age specific death rates in smokers and non-smokers one in four smokers would be killed by tobacco, but as the epidemic grows this proportion will roughly double. If current smoking uptake rates persist in China (where about two thirds of men but few women become smokers) tobacco will kill about 100 million of the 0.3 billion males now aged 0-29, with half these deaths in middle age and half in old age.

Smokers' misperceptions of light and ultra-light cigarettes may keep them smoking

INTRODUCTION

This study examined smokers' understanding of the relative tar deliveries of Ultra-light, Light, and Regular cigarettes, reasons for smoking Ultra-light/Light cigarettes, and the likelihood of both quitting smoking and switching to Regular cigarettes if they came to learn that one Ultra-light/Light cigarette gave the same amount of tar as one Regular cigarette.

DESIGN

Ten- to fifteen-minute random-digit-dialed, computer-assisted telephone interviews (CATI) were conducted with both a national probability sample (n = 788) and a state random sample (n = 266) of daily smokers over the age of 18.

RESULTS

Less than 10% of smokers in the national sample and only 14% of smokers in the state sample knew that one Light cigarette could give the same amount of tar as one Regular cigarette. Less than 10% of smokers in the state sample knew that one Ultra-light cigarette could give the same amount of tar as one Regular cigarette. Thirty-two percent of the Light and 26% of the Ultra-light smokers in the national sample, and 27% of Light and 25% of Ultra-light smokers in the state sample, said they would be likely to quit smoking if they learned one Light/Ultra-light equaled one Regular.

CONCLUSION

Many Light and Ultra-light smokers are smoking these cigarettes to reduce the risks of smoking and/or as a step toward quitting. However, these smokers are unaware that one Ultra-light/Light cigarette can give them the same amount of tar and nicotine as one Regular cigarette. Many of the Ultra-light/Light smokers sampled in this study stated that they would be likely to quit if they knew this information. Mistaken beliefs about low-yield brands are reducing intentions to quit smoking.

Design, objectives, and lessons from a pilot 25 year follow up re-survey of survivors in the Whitehall study of London Civil Servants

DESIGN

To assess the feasibility of conducting a re-survey of men who are resident in the United Kingdom 25 years after enrollment in the Whitehall study of London Civil Servants.

METHODS

A random sample of 401 study survivors resident in three health authority areas was selected for this pilot study. They were mailed a request to complete a self administered questionnaire, and then asked to attend their general practice to have their blood pressure, weight, and height measured and a blood sample collected into a supplied vacutainer, and mailed to a central laboratory. Using a 2 x 2 factorial design, the impact of including additional questions on income and of an informant questionnaire on cognitive function was assessed.

RESULTS

Accurate addresses were obtained from the health authorities for 96% of the sample. Questionnaires were received from 73% and blood samples from 61% of the sample. Questions on income had no adverse effect on the response rate, but inclusion of the informant questionnaire did. Between 1970 and 1995 there were substantial changes within men in the mean blood pressure and blood total cholesterol recorded, as reflected by correlation coefficients between 1970 and 1995 values of 0.26, and 0.30 for systolic and diastolic blood pressure and 0.38 for total cholesterol.

CONCLUSION

This pilot study demonstrated the feasibility of conducting a re-survey using postal questionnaires and mailed whole blood samples. The magnitude of change in blood pressure and blood total cholesterol concentrations within individuals was greater than anticipated, suggesting that such remeasurements may be required at different intervals in prospective studies to help interpret risks associations properly. These issues will be considered in a re-survey of the remaining survivors of the Whitehall study.

Uncovering the effects of smoking: historical perspective

Tobacco was introduced into Europe from America at the end of the fifteen century. At first used primarily for medicinal purposes it came to be burnt in pipes for pleasure on a large scale nearly 100 years later, at first in England and subsequently in Europe and throughout the world. Pipe smoking gave way to the use of tobacco as snuff and, in turn, to cigars and cigarettes at different times in different countries until cigarette smoking became the dominant form in most of the developed world between the two world wars. Societies were formed to discourage smoking at the beginning of the century in several countries, but they had little success except in Germany where they were officially supported by the government after the Nazis seized power. In retrospect it can now be seen that medical evidence of the harm done by smoking has been accumulating for 200 years, at first in relation to cancers of the lip and mouth, and then in relation to vascular disease and cancer of the lung. The evidence was generally ignored until five case-control studies relating smoking to the development of lung cancer were published in 1950. These stimulated much research, including the conduct of cohort studies, which, by the late 1950s, were beginning to show that smoking was associated with the development of many other diseases as well. The interpretation that smoking caused these various diseases was vigorously debated for some years but came to be generally accepted in respect of lung cancer by the late 1950s and of many other diseases in the subsequent two decades. Cigarette smoking has now been found to be positively associated with nearly 40 diseases or causes of death and to be negatively associated with eight or nine more. In some instances the positive associations are largely or wholly due to confounding, but the great majority have been shown to be causal in character. The few diseases negatively associated with smoking are for the most part rare or nonfatal and their impact on disease incidence and mortality as a result of smoking is less than 1% of the excess of other diseases that are caused by smoking. The most recent observations show that continued cigarette smoking throughout adult life doubles age-specific mortality rates, nearly trebling them in late middle age. All the diseases related to smoking that cause large numbers of deaths should now have been discovered, but further nonfatal diseases may remain to be revealed by cohort studies that are able to link individuals' morbidity data with their personal characteristics.

The prevalence of smoking in Austria

BACKGROUND

A population-based cross-sectional study was performed to assess smoking prevalence in Austria and to compare the results with data from 1986.

METHODS

A representative sample of Austrians (n = 2,400) who in 1995 were > or = 15 years of age was obtained. A total of 2,065 respondents were interviewed about their smoking habits.

RESULTS

Approximately 31% of the population age > or = 15 are regular cigarette smokers, 12% are former smokers, 6% smoke occasionally, and 51% have never smoked. Among males, the prevalence of regular smoking increases with age and reaches its highest level between the ages of 25 and 34. The age distribution among female regular smokers shows a similar pattern, peaking in the same age group (35.7% smokers). No significant differences in smoking prevalence were found according to monthly household income, years of school, and number of inhabitants at place of residence. At the time of interview 45.7% of male and 20.9% of female regular smokers consumed > 20 cigarettes per day. Compared with data from 1986 the prevalence of regular smokers increased from 18.1 to 24.2% among females and from 35.5 to 38.9% among males.

CONCLUSIONS

Smoking prevalence increased in Austria between 1986 and 1995 by 33.7% among females and by 9.6% among males. Patterns of smoking among females (prevalence and cigarettes per day) are approaching those of males.

Effect of smoking cessation on lipoprotein A-I and lipoprotein A-I:A-II levels

Cigarette smoking is associated with low plasma high-density lipoprotein cholesterol (HDL-C) and apolipoprotein (apo) A-I levels, which may explain, in part, its deleterious effects on coronary heart disease (CHD). In a group of ex-smokers, we assessed the influence of smoking cessation on apo A-I particle levels. Plasma lipid, apolipoprotein, and lipoparticle concentrations of 58 subjects who had completely stopped smoking (ex-smokers) were compared with those of 37 subjects who had continued smoking (smokers) before and after a smoking cessation counseling program. Nutritional intake was recorded before and after the program to adjust for potential interaction with plasma lipid variables. Smokers and ex-smokers were similar in gender distribution, age, body mass index (BMI), social status, and nutrient intake. There were significantly greater increases in total cholesterol (P < .04), HDL-C (P < .005), HDL2-C (P < .008), and lipoprotein (Lp) A-I:A-II (P < .04) in ex-smokers than in smokers. After smoking cessation, ex-smokers consumed more vegetable protein (P < .02) and polysaccharides (P < .04) and had higher plasma levels of HDL-C (P < .0004), apo A-I (P < .001), Lp A-I (P < .007), and Lp A-I:A-II (P < .01) than smokers. Adjustments on nutritional variables did not show any additional difference between ex-smokers and smokers, suggesting that smoking per se effects Lp A-I and Lp A-I:A-II levels. In conclusion, HDL particles including Lp A-I and Lp A-I:A-II are higher in ex-smokers than in smokers.

The dose-response relationship between cigarette consumption, biochemical markers and risk of lung cancer

The relationship between the number of cigarettes smoked per day and the incidence of lung cancer is linear but, from the multistage model of carcinogenesis, it should be quadratic (upwards curving). We investigated this anomaly in a study of 11,403 male never smokers and current smokers in whom carboxyhaemoglobin (COHb) was measured in all and serum cotinine in 1175. The relationship between the biochemical markers and the reported number of cigarettes per day was approximately linear up to 20 cigarettes per day as expected. But above 20 cigarettes per day the marker levels increased less steeply and were 35% lower than expected in men who smoked more than 40 cigarettes per day. Less smoke is inhaled from each cigarette by men with high daily cigarette consumption than by men with lower consumption. Allowance for this transforms the observed linear dose-response relationship into one consistent with the expected quadratic relationship. The anomaly is explained by the observation that heavier smokers inhale less smoke from each cigarette.

High prevalence of smoking in young patients with acute myocardial infarction

Of 35 patients with acute myocardial infarction (AMI) at the age of 40 years or less, 32 (91%) smoked and only three patients were non-smokers. The age at AMI related significantly to the extent of smoking (p < 0.001, Kruskall-Wallis test). Five patients with AMI at the age < 30 years smoked more heavily than the 30 with AMI at the age of 30-40 years (p = 0.04, Mann Whitney U test). Heavy smoking men > 30 years at the AMI had a Q-wave infarction as often (11 of 13 (85%)) as those with multivessel disease or a coronary artery occlusion (8 of 9 (89%) and 14 of 16 (88%) respectively) on coronary arteriography after the infarction. Smoking may be the most important modifiable risk factor in young patients with AMI.

Mortality in relation to tar yield of cigarettes: a prospective study of four cohorts

OBJECTIVE

To investigate relation between tar yield of manufactured cigarettes and mortality from smoking related diseases.

DESIGN

Prospective epidemiological study of four cohorts of men studied between 1967 and 1982.

SETTING

Combined data from British United Provident Association (BUPA) study (London), Whitehall study (London), Paisley-Renfrew study (Scotland), and United Kingdom heart disease prevention project (England and Wales).

SUBJECTS

Of the 56,255 men aged over 35 who were included in the studies, 2742 deaths occurred among 12,400 smokers. Average follow up was 13 years.

MAIN OUTCOME MEASURES

Relative mortality from smoking related diseases according to tar yields of cigarettes smoked.

RESULTS

Age adjusted mortality from smoking related diseases in smokers of filter cigarettes was 9% lower (95% confidence interval 1% to 17%) than in smokers related diseases consistently decreased with decreasing tar yield. Relative mortality in cigarette smokers for a 15 mg decrease in tar yield per cigarette was 0.75 (0.52 to 1.09) for lung cancer, 0.77 (0.61 to 0.97) for coronary heart disease, 0.86 (0.50 to 1.50) for stroke, 0.78 (0.40 to 1.48) for chronic obstructive lung diseases, 0.78 (0.65 to 0.93) for these smoking related diseases combined, and 0.77 (0.65 to 0.90) for all smoking related diseases.

CONCLUSION

About a quarter of deaths from lung cancer, coronary heart disease, and possibly other smoking related diseases would have been avoided by lowering tar yield from 30 mg per cigarette to 15 mg. Reducing cigarette tar yields in Britain has had a modest effect in reducing smoking related mortality.