Mortality from smoking worldwide

Estimates are made of the numbers and proportions of deaths attributable to smoking in 44 developed countries in 1990. In developed countries as a whole, tobacco was responsible for 24% of all male deaths and 7% of all female deaths, rising to over 40% in men in some former socialist economies and 17% in women in the USA. The average loss of life for all cigarette smokers was about 8 years and for those whose deaths were attributable to tobacco about 16 years. Trends in mortality attributable to tobacco differed between countries. In some the mortality in middle age (35-69 years) had decreased by half in men since 1965; in others it was continuing to increase. In women, the proportion was mostly increasing, almost universally in old age. Mortality not attributable to smoking decreased since 1955 in all OECD (Organization for European Collaboration and Development) countries, by up to 60% in men and more in women. No precise estimate can be made of the number of deaths attributable to smoking in undeveloped countries, but the prevalence of smoking suggests that it will be large. In the world as a whole, some 3 million deaths a year are estimated to be attributable to smoking, rising to 10 million a year in 30-40 years' time.

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

OBJECTIVES

To assess the effects of cigarette smoking on the incidence of non-fatal myocardial infarction, and to compare tar in different types of manufactured cigarettes.

METHODS

In the early 1990s responses to a postal questionnaire were obtained from 13,926 survivors of myocardial infarction (cases) recently discharged from hospitals in the United Kingdom and 32,389 of their relatives (controls). Blood had been obtained from cases soon after admission for the index myocardial infarction and was also sought from the controls. 4923 cases and 6880 controls were current smokers of manufactured cigarettes with known tar yields. Almost all tar yields were 7-9 or 12-15 mg/cigarette (mean 7.5 mg for low tar (< 10 mg) and 13.3 for medium tar (> or = 10 mg). The cited risk ratios were standardised for age and sex and compared myocardial infarction rates in current cigarette smokers with those in non-smokers who had not smoked cigarettes regularly in the past 10 years.

RESULTS

At ages 30-49 the rates of myocardial infarction in smokers were about five times those in non-smokers (as defined); at ages 50-59 they were three times those in non-smokers, and even at ages 60-79 they were twice as great as in non-smokers (risk ratio 6.3, 4.7, 3.1, 2.5, and 1.9 at 30-39, 40-49, 50-59, 60-69, 70-79 respectively; each 2P < 0.00001). After standardisation for age, sex, and amount smoked, the rate of non-fatal myocardial infarction was 10.4% (SD 5.4) higher in medium tar than in low tar cigarette smokers (2P = 0.06). This percentage was not significantly greater at ages 30-59 (16.6% (7.1)) than at 60-79 (1.0% (8.5)). In both age ranges the difference in risk between cigarette smokers and non-smokers was much larger than the difference between one type of cigarette and another (risk ratio 3.39 and 3.95 at ages 30-59 for smokers of similar numbers of low and of medium tar cigarettes, and risk ratio 2.35 and 2.37 at ages 60-79). Most possible confounding factors that could be tested for were similar in low and medium tar users, with no significant differences in blood lipid or albumin concentrations.

CONCLUSION

The present study indicates that the imminent change of tar yields in the European Union to comply with an upper limit of 12 mg/cigarette will not increase (and may somewhat decrease) the incidence of myocardial infarction, unless they indirectly help perpetuate tobacco use. Even low tar cigarettes still greatly increase rates of myocardial infarction, however, especially among people in their 30s, 40s, and 50s, and far more risk is avoided by not smoking than by changing from one type of cigarette to another.

Migraine and subsequent risk of stroke in the Physicians' Health Study

OBJECTIVE

To evaluate, in a prospective design, whether migraine is an independent risk factor for subsequent stroke.

DESIGN

Evaluated as part of the Physicians' Health Study, a randomized, double-blind, placebo-controlled trial of aspirin and beta-carotene in the primary prevention of cardiovascular disease and cancer begun in 1982. The aspirin component of the study was terminated in 1988, with average follow-up of 60.2 months.

SETTING

Conducted by mail among male physicians throughout the United States.

PARTICIPANTS

A total of 22,071 US male physicians aged 40 to 84 years in 1982 with no prior history of cancer or cardiovascular diseases who were enrolled in the Physicians' Health Study.

INTERVENTIONS

Participants were randomized to receive 325 mg of aspirin or aspirin placebo every other day and to receive 50 mg of beta-carotene or placebo on alternate days.

MAIN OUTCOME MEASURES

The primary outcomes of the Physicians' Health Study were cardiovascular disease and cancer. Because stroke was a main outcome, this provided the opportunity to evaluate the association between migraine headaches and stroke.

RESULTS

Physicians reporting migraine (n = 1479) had significantly increased risks of subsequent total stroke and ischemic stroke compared with those not reporting migraine. After adjustment for age, aspirin and beta-carotene treatment assignment, and a number of cardiovascular risk factors, the relative risks were 1.84 (95% confidence interval, 1.06 to 3.20) for total stroke and 2.00 (95% confidence interval, 1.10 to 3.64) for ischemic stroke. There were too few hemorrhagic strokes in the study to evaluate this end point. No associations were seen between ordinary nonmigraine headache and subsequent stroke or between migraine and subsequent myocardial infarction or cardiovascular death.

CONCLUSION

These data raise the possibility that vascular events associated with migraine may also have causative importance in stroke but require confirmation in other studies specifically designed to evaluate this question.

Mortality in relation to smoking: 40 years' observations on male British doctors

OBJECTIVE

To assess the hazards associated with long term use of tobacco.

DESIGN

Prospective study of mortality in relation to smoking habits assessed in 1951 and again from time to time thereafter, with causes sought of deaths over 40 years (to 1991). Continuation of a study that was last reported after 20 years' follow up (1951-71).

SUBJECTS

34,439 British male doctors who replied to a postal questionnaire in 1951, of whom 10,000 had died during the first 20 years and another 10,000 have died during the second 20 years.

RESULTS

Excess mortality associated with smoking was about twice as extreme during the second half of the study as it had been during the first half. The death rate ratios during 1971-91 (comparing continuing cigarette smokers with life-long non-smokers) were approximately threefold at ages 45-64 and twofold at ages 65-84. The excess mortality was chiefly from diseases that can be caused by smoking. Positive associations with smoking were confirmed for death from cancers of the mouth, oesophagus, pharynx, larynx, lung, pancreas, and bladder; from chronic obstructive pulmonary disease and other respiratory diseases; from vascular diseases; from peptic ulcer; and (perhaps because of confounding by personality and alcohol use) from cirrhosis, suicide, and poisoning. A negative association was confirmed with death from Parkinson's disease. Those who stopped smoking before middle age subsequently avoided almost all of the excess risk that they would otherwise have suffered, but even those who stopped smoking in middle age were subsequently at substantially less risk than those who continued to smoke.

CONCLUSION

Results from the first 20 years of this study, and of other studies at that time, substantially underestimated the hazards of long term use of tobacco. It now seems that about half of all regular cigarette smokers will eventually be killed by their habit.

Mortality in relation to consumption of alcohol: 13 years' observations on male British doctors

OBJECTIVE

To assess the risk of death associated with various patterns of alcohol consumption.

DESIGN

Prospective study of mortality in relation to alcohol drinking habits in 1978, with causes of death sought over the next 13 years (to 1991).

SUBJECTS

12,321 British male doctors born between 1900 and 1930 (mean 1916) who replied to a postal questionnaire in 1978. Those written to in 1978 were the survivors of a long running prospective study of the effects of smoking that had begun in 1951 and was still continuing.

RESULTS

Men were divided on the basis of their response to the 1978 questionnaire into two groups according to whether or not they had ever had any type of vascular disease, diabetes, or "life threatening disease" and into seven groups according to the amount of alcohol they drank. By 1991 almost a third had died. All statistical analyses of mortality were standardised for age, calendar year, and smoking habit. There was a U shaped relation between all cause mortality and the average amount of alcohol reportedly drunk; those who reported drinking 8-14 units of alcohol a week (corresponding to an average of one to two units a day) had the lowest risks. The causes of death were grouped into three main categories: "alcohol augmented" causes (6% of all deaths: cirrhosis, liver cancer, upper aerodigestive (mouth, oesophagus, larynx, and pharynx) cancer, alcoholism, poisoning, or injury), ischaemic heart disease (33% of all deaths), and other causes. The few deaths from alcohol augmented causes showed, at least among regular drinkers, a progressive trend, with the risk increasing with dose. In contrast, the many deaths from ischaemic heart disease showed no significant trend among regular drinkers, but there were significantly lower rates in regular drinkers than in non-drinkers. The aggregate of all other causes showed a U shaped dose-response relation similar to that for all cause mortality. Similar differences persisted irrespective of a history of previous disease, age (under 75 or 75 and older), and period of follow up (first five and last eight years). Some, but apparently not much, of the excess mortality in non-drinkers could be attributed to the inclusion among them of a small proportion of former drinkers.

CONCLUSION

The consumption of alcohol appeared to reduce the risk of ischaemic heart disease, largely irrespective of amount. Among regular drinkers mortality from all causes combined increased progressively with amount drunk above 21 units a week. Among British men in middle or older age the consumption of an average of one or two units of alcohol a day is associated with significantly lower all cause mortality than is the consumption of no alcohol, or the consumption of substantial amounts. Above about three units (two American units) of alcohol a day, progressively greater levels of consumption are associated with progressively higher all cause mortality.

Cause-specific mortality in long-term survivors of breast cancer who participated in trials of radiotherapy

PURPOSE

To examine long-term cause-specific mortality in patients irradiated for breast cancer as part of a randomized clinical trial.

PATIENTS AND METHODS

We studied all available information from randomized trials initiated before 1975 in which radiotherapy was the randomized option and surgery was the same for both treatment arms. Eight such trials were identified.

RESULTS

The increased all-cause mortality rate in 10-year survivors previously reported is no longer significant, although a numerical difference in favor of non-irradiated patients remains. This result was strongly influenced by the earliest trials, and more recent trials have found a nonsignificant net benefit in overall mortality associated with radiation therapy. An excess of cardiac deaths was apparent in both early and more recent trials (P < .001), but this was offset by a reduced number of deaths due to breast cancer, especially in more recent trials.

CONCLUSION

The reduction of breast cancer deaths suggests that radiation therapy may have a value beyond the clearly established improvements obtainable for local control. Use of techniques that minimize cardiac dose is important in reducing the risks of adjuvant radiotherapy, especially in good-prognosis patients.

Geographic association between urinary excretion of N-nitroso compounds and oesophageal cancer mortality in China

Overnight urine samples were collected from approximately 60 male adults in each of 69 counties of China in 1989. Two specimens were collected from each subject--one after a loading dose of proline and ascorbic acid and another after a loading dose of proline only. Levels of N-nitrosamino acids and nitrate were measured in urine samples and correlated with cumulative mortality rates for subjects aged between 0 and 64 years in the 1970s. Oesophageal cancer mortality rates were positively and significantly associated with (i) urinary levels of excreted N-nitrosoproline (NPRO) (after proline and ascorbic acid loading or proline loading only), (ii) N-nitrososarcosine levels, and (iii) nitrosation potential (the decrease in the amount of urinary NPRO after adding ascorbic acid to the proline load). There were also positive correlations between the urinary level of NPRO or other N-nitrosamino acids and that of nitrate. The urinary excretion of nitrate was associated with consumption of various nitrate-rich vegetables. The results suggest that N-nitroso compounds (NOC) or other nitrite-derived carcinogens are implicated in the aetiology of oesophageal cancer in China.