Cigarettes are a major cause of heart disease, but there has been uncertainty as to whether heart attack rates have been decreased, increased, or not changed by alterations in cigarette composition in the United Kingdom over the past few decades. Large epidemiological studies of recent smoking habits are needed to compare low and medium tar cigarettes. On p 471 Parish et al report the relation between non-fatal myocardial infarction, cigarette smoking, and tar yields among 14000 survivors of myocardial infarction from the ISIS trials and 32000 controls. Non-fatal myocardial infarction rates were five times as great among smokers as among non-smokers at ages 30-49 and three times as great at ages 50-59, and even at 60-79 they were twice as great. The rates seemed to be slightly greater with medium tar than with low tar cigarettes, but this difference was not definite. Irrespective of whether low or medium tar cigarettes are used, about three quarters of smokers who have a heart attack in their 30s, 40s, or 50s need not have had one, and far more heart attacks could be prevented by avoiding cigarettes than by changing from one type of cigarette to another.
The health consequences of maternal smoking on the child have been widely investigated, but less interest has been shown in the prognosis for the women themselves who smoked during pregnancy. The paper by Rantakallio et al (p 477) on mortality among pregnant smokers after an interval of 28 years shows that their risk of death is higher than the average for female smokers and 2-3 times that for non-smokers, despite the fact that smoking was recorded only during pregnancy. Excess mortality was found from diseases usually considered to be related to smoking and also from accidents and suicides. Either women who smoke in pregnancy become very heavy smokers, few of whom stop, or their life is more stressful, with many unhealthy habits which increase the risk of premature death.
In an analysis of 10 studies from developing countries Aaby et al (p 481) found a significant decrease in mortality among children who had been immunised with standard titre measles vaccine. Although this is as expected, they found that the decrease in mortality remained even when specific prevention of acute and long term consequences of measles disease was accounted for. In three studies analysed, diphtheria-tetanus-pertussis and polio vaccines did not confer the same benefits. The non-specific beneficial effects of standard titre measles vaccine have yet to be explained, although a general stimulation of the immune system may be involved. Whatever the cause, however, the effect must be considered in the planning of immunisation programmes as halting measles immunisation after the eradication of the disease may well cause an increase in mortality.
Rectal bleeding is an important early warning symptom of colorectal cancer, yet only a minority of people experiencing rectal bleeding in the community seek advice from general practitioners. In their study of adult patients registered with general practices on Tyneside, Crosland and Jones (p 486) found a 12 month prevalence of rectal bleeding of 19% but discovered that only 41% of respondents with rectal bleeding had ever sought medical advice about their problem. Older patients and those reporting blood mixed with stools were more likely to have consulted a doctor, but the main difference between consulters and non-consulters was concern about the seriousness of the symptoms. Early detection offers one way of reducing the death toll from colorectal cancer, so that these findings have clear health education implications.