Certification and coding of two underlying causes of death in The Netherlands and other countries of the European Community.

Differences in certification and coding of causes of death between countries of the European Community were studied by sending sets of case histories to samples of certifying physicians. Completed certificates were coded by national coding offices and by by a WHO reference centre. Detection fractions ranged from 60% to 92% in a first study (concerning cases of chronic obstructive pulmonary disease) and from 80% to 94% in a second study (concerning cases of cancer). A detailed analysis of the findings for the Netherlands, which performed very well in both studies, reveals a substantial frequency of errors in certification (as opposed to errors in diagnosis). Comparison of national and reference centre coding suggests that the Dutch coding process is to a certain extent adapted to the frequency of these certification errors, leading to deviations from WHO coding rules. It is concluded that certification and coding practices should be studied together and that further international standardisation of coding practices will not necessarily improve the validity of national cause of death statistics.

Descriptive epidemiology of bronchial reactivity in an adult population: results from a community study.

The bronchial response to inhaled histamine has been suggested as an epidemiological tool for assessing the prevalence of asthma, though the exact relationship between reactivity and asthma is unknown. Tests of bronchial reactivity to histamine were carried out in 511 subjects aged 18-64 years, randomly selected from the population in two areas of the South of England, who had returned questionnaires on respiratory symptoms. Bronchial reactivity to less than or equal to 8 mumol histamine was present in 14% and was associated with positive skin test responses to common allergens and with smoking history. Both of these relationships were in turn dependent on age, skin sensitivity being the more important determinant of reactivity in the young and smoking the more important in older subjects. Bronchial reactivity was least prevalent in the 35-44 year age group. No independent effect on reactivity of sex, social class, or area of residence was detected, and no significant effect from recent respiratory tract infections. Interpretation of the bronchial response to histamine in selected groups of subjects must take account of age, atopic state, and smoking history.

Response to inhaled histamine and 24 hour sodium excretion.

A relation between the prevalence of asthma and economic development has been suggested by studies in migrants and other surveys in developing countries. That this correlation might be partially explained by an increased intake of salt in the diet is supported by the observation that sales of table salt in the different regions of England and Wales are independently correlated with mortality from asthma for men and for children. As part of a wider survey of asthma 138 men living in two Hampshire villages and aged 18-64 were given a bronchial histamine challenge test and had their 24 hour urinary excretion of sodium measured. Bronchial reactivity was strongly related to 24 hour excretion of sodium after allowing for the effects of age, atopy, and cigarette smoking, there being on average a 10-fold difference in reactivity over the 95% range of sodium excretion recorded in the study. The data suggest that a high sodium diet may potentiate bronchial reactivity.

Death certification of farmer's lung and chronic airway diseases in different countries of the EEC.

An EEC Working Party has investigated death certification of respiratory disease in eight EEC countries by sending ten standard case histories to a sample of certifying doctors in each country. Results of interest to clinicians with reference to certification of farmer's lung, and of obstructive airway diseases, are presented. For a case of farmer's lung, a majority of certifying doctors in all countries certified an interstitial lung disease, but the proportion certifying farmer's lung ranged from 70% to 0% (overall 26%). Rural doctors certified farmer's lung more frequently than others only in some countries. For four cases of different types of airways disease (chronic obstructive bronchitis, emphysema or asthma) there were wide differences between countries of certification of these conditions or of unspecified chronic airways obstruction. Some countries certify more emphysema, and others, particularly younger doctors in English speaking countries, more unspecified chronic airways obstruction. There are also large differences in the certification of asthma. The differences are presumed to be attributable to differences of medical education. Epidemiological studies and patient care might be helped by more uniformity of diagnostic criteria within the EEC.

Family history in "low risk" men with coronary heart disease.

A detailed family history was obtained from men who had earlier been participants in a longitudinal study of coronary heart disease (CHD). Men who developed CHD during the 5-6 years' course of that study were matched with those who had remained free of CHD, using age and initial risk characteristics (blood pressure, plasma cholesterol concentration, smoking habits, and physical activity at work) for the matching criteria. Men who developed CHD were more likely to report a family history of CHD than their controls, and the excess was greater in those who had been at low risk initially than in those at initially high risk. This suggests that a clue to the reason why men at low conventional risk develop CHD may lie in their family history, and that there may be an explanation other than the familial aggregation of conventional risk factors for CHD to run in families.

The effect of death certification and coding practices on observed differences in respiratory disease mortality in 8 E.E.C. countries.

National differences in respiratory disease mortality have been observed in eight member countries of the European Economic Community (E.E.C.). To investigate the extent to which death certification and coding practices explain such differences, a representative sample of certifying doctors in each country was asked to complete specimen death certificates for a bank of ten written case histories. The certificates from each country were coded firstly by their own offices and subsequently by the W.H.O. Reference Centre in the U.K. Large within- and between-country differences in the coded causes of death were found. Some of these differences were due to variations in the ways doctors certify deaths, others to the way certificates are coded in each country. These discrepancies explain part of the between-country differences in mortality in some disease categories. Comparisons of mortality statistics for respiratory diseases between different countries should therefore be viewed with caution. There is a need for further standardisation of death certification and coding practices in the E.E.C.

Respiratory disease Mortality in Agricultural workers in eight member countries of the European community.

A co-operative study by representatives of eight member countries of the EEC into the problem of respiratory disease among agricultural workers is reported. From each country mortality data (routinely collected but often unpublished) were obtained for seven disease categories in the country as a whole, and separately where possible for urban and rural areas, and agricultural workers. The results indicate that comparable data can be collected from different countries despite variations in local methods of data collection and coding. There are large between country differences in respiratory disease mortality rates, and data for agricultural workers in France and England and Wales suggest an excess respiratory disease deaths (mainly pneumonia and influenza) among agricultural workers.

Practices in STD clinics in England and Wales. A reassessment based on the numbers of cases seen.

Data previously collected on the facilities and diagnostic criteria used in clinics for sexually transmitted diseases in England and Wales were reanalysed to established how different consultant policies affected the management of individual cases. Several discrepancies were found between conclusions based on percentages of clinics and those based on numbers of cases. Full-time facilities for contact tracing were available to more cases than previously suggested and rectal sampling in women was more widespread. Laboratory facilities were limited and cultural facilities lacking in small clinics, which thus affected only a small number of cases. Previous indications that diagnostic criteria were fairly standardised in the diagnosis of non-specific urethritis were found to be invalid. Variation in the management of individual cases was found to lead to inconsistencies in the notification of STDs to the Department of Health and Social Security.