Showing papers in "Journal of Epidemiology and Community Health in 1987"

Methods for the economic evaluation of health care programmes

Abstract: Public health in the Victorian era had two major concerns: housing conditions and sanitation. These two elements were seen as crucial in improving the health status of the population. This Victorian notion of public health was, therefore, centred upon the prevention rather than cure ofdisease. The early years ofthis century saw a narrowing of this Victorian vision with an increased emphasis on personal hygiene and individual action in the prevention of disease. Thus there was a shift in the focus of disease prevention from society as a whole to its individual members. This influenced the role of public health doctors whose administrative responsibilities were increasing as they assumed responsibility for municipal hospitals. These administrative and preventive roles brought public health doctors into conflict with family doctors about the scope and objectives of public health. The establishment of the National Health Service, which left public health doctors in charge ofa range of community services, only served to heighten the conflicts within the medical profession about the role of public health within a socialised medical system. The emergence of the social work profession created a further area of conflict. Although the 1974 reorganisation of the NHS created the specialty of community medicine, thereby providing public health doctors with a career structure similar to that of other specialties within medicine, the role of the new specialty was emasculated. The fledgling specialty was given the responsibility for planning and coordinating health care delivery within local areas. However, few resources were provided and little opportunity has arisen for the new community physicians to implement their plans. The provision of a medicalised career structure has done little to overcome the negative image of community medicine within the rest of the medical profession. This book presents an historical view of the development of one branch of the medical profession. Using archival material supplemented by interviews with community physicians, Jane Lewis shows how 'public health' and 'preventive medicine' have been supplanted as the central concern of medicine by curative and acute specialties. The much vaunted current policies of prevention and community care have not served to rescue community medicine from languishing in obscurity. This book provides an interesting account of the development of the medical 355

Lumbar disc syndrome in Finland.

Abstract: The prevalence of lumbar disc syndrome (herniated disc or typical sciatica) and its consequences in terms of disability, handicap, and need for medical care were studied as part of the Mini-Finland Health Survey. A sample of 8000 persons representative of the Finnish population aged 30 or over was asked to come for examination, and 7217 (90%) participated. A diagnosis of lumbar disc syndrome based on medical history, symptoms, and standardised physical examination was made for 5.1% of the men and for 3.7% of the women. Half of these patients were assessed to be in need of medical care, over 80% of which was considered to be adequately met. One third of all patients with lumbar disc syndrome had been previously hospitalised for that syndrome, and one fifth of the patients had undergone lumbar surgery. At least slight disability was found in almost 60% of the patients, though severe functional limitations were rare. About 6% of the population's work disability was estimated to be attributable to lumbar disc syndrome.

Mortality in relation to cigarette and pipe smoking: 16 years' observation of 25,000 Swedish men.

Abstract: In a random sample of 25,129 Swedish men who responded to a questionnaire on smoking habits in 1963 the cause specific mortality was followed through 1979. In the cohort, 32% smoked cigarettes, 27% a pipe, and 5% cigars. There were clear covariations (p less than 0.001) between the amount of tobacco smoked and the risk of death due to cancer of the oral cavity and larynx, oesophagus, liver, pancreas, lung, and bladder as well as due to bronchitis and emphysema, ischaemic heart disease, aortic aneurysm, and peptic ulcer. Pipe smokers showed similar risk levels to cigarette smokers. There was a close to linear increase in lung cancer risk in relation to the amount of tobacco smoked for cigarette, pipe, and cigar smokers, respectively. An increasing risk of ischaemic heart disease with amount smoked was seen among both cigarette and pipe smokers. A similar fraction of inhalers in Swedish cigarette and pipe smokers may explain the similarity in risks.

Testicular cancer in young men: the search for causes of the epidemic increase in the United States.

Abstract: A case-control study of 271 men with testicular cancer and 259 controls was conducted in the Washington, DC area to evaluate whether suggested risk factors could be responsible for the epidemic increases in testicular cancer in young men. No substantial risks were associated with a history of groin hernia operation, the common childhood diseases, allergies, x rays below the waist, venereal disease, vasectomy, or external means of elevating the temperature of the testis. Excess risks were associated with a history of undescended testis (RR = 3.7, CI = 1.5-9.5), testicular trauma (RR = 2.6, CI = 1.6-4.2), and mumps orchitis (RR = 5.8, CI = 0.7-129.7). It is unlikely, however, that any of these conditions has increased sufficiently over time to markedly affect the testicular cancer incidence patterns. Therefore, while the risk factors identified in this paper are of epidemiological interest, they do not account for the increase in testicular cancer in young men.

Cancer survival and social class in Sweden.

Abstract: A study of 98,000 cases in the Swedish Cancer Registry from 1961 to 1979 was undertaken The relative survival by social class was calculated There was a higher survival probability for white collar workers than for blue collar workers or self-employed farmers for all cancer, as well as for particular cancers, such as, for instance, cancer of the breast and cervix among women and cancer of the rectum among men For lung cancer, cancer of the stomach, and pancreatic cancer there were no detectable differences in survival probability The findings can be considered in the light of various possible explanations, for instance, early detection, differential treatment, and host factors

Is asthma increasing

Abstract: Asthma mortality is again causing concern. An epidemic of deaths occurred in several countries among young people during the 1960s. In Britain, asthma mortality became higher than it had been at any time in the previous hundred years, throughout which it had been fairly stable.' The epidemic subsided, and by 1974 the death rate had returned to its previous level. In view of the advances in treatment and management since the 1950s it might have been expected that mortality would now be well below pre-epidemic rates. But, in fact, the death rate during the later 1970s remained at about the same level as before. Currently it is showing an alarming tendency to drift upwards again (fig 1). What is going wrong? International comparisons reveal some striking differences in the pattern ofasthma mortality. Caution is obviously required in comparing data from different countries which may use different diagnostic criteria. Death rates among children and young adults are least liable to diagnostic confusion, however, since in this age group the mortality from acute and chronic bronchitis is very low. It appears to be a fact that the epidemic in the 1960s occurred in some countries (eg, Britain, Ireland, Australia, New Zealand and Norway) but not in others (eg, the United States, Canada, Belgium, and West Germany).2 It was noticed that the countries affected had licensed the use ofpressurised aerosols containing high concentrations of sympathomimetic amines, and this led to the suggestion that over use of these drugs had caused the excess mortality.3 This explanation has since been challenged, however, 4 5 and the issue continues to be debated. The present rise in mortality is not occurring in all countries. New Zealand seems to have experienced a particularly sharp rise since 1975, and death rates there are now even higher than they were during the previous epidemic.6 American and Canadian rates have been remarkably low and stable for many years,6 although among children under 14 years of age there has been a recent tendency for asthma deaths to rise in the United States from 1.0 per million in 1977 to 2.2 per million in 1983.7 West Germany, which was also ICD I ICD ' ICD 7th revision 8th revision 9th revision

Epidemiology of multiple sclerosis in the north-east (Grampian region) of Scotland--an update.

Abstract: The north-east of Scotland (Grampian Region) has undergone three incidence and prevalence surveys, including the present one, since 1970. Results from these indicate a true increase in the prevalence of the disease in the region. The incidence of the disease has remained continuously high and shows a slightly upward trend. Literature on the subject of repeated surveys in different regions of the world has been reviewed in detail. The need for a prevalence study from the south of the British Isles has been emphasised in order to enable one to judge if the increase in Scotland is in keeping with the pattern in the whole of the British Isles. The familial incidence of the disease was noted to be virtually unchanged between the three surveys. Certain other aspects of aetiological significance have been analysed, viz, clustering of patients at birth or at onset of the disease; ages of occurrence of childhood viral infections such as measles, mumps, chickenpox and rubella; and the role of canine distemper infection.

Non-participation and mortality in a prospective study of cardiovascular disease.

Abstract: Men who did not participate in a prospective study of cardiovascular disease (The British Regional Heart Study) were younger than the participants, more likely to be unmarried, and more likely to be less skilled workers. In the first three years of follow-up, their total mortality rate was significantly higher than that of the participants; thereafter it declined to levels not significantly different from those of the participants. This excess of early deaths could not be attributed to age. There was a small but non significant excess mortality in non-participants due to neoplasms and cardiovascular disease and a somewhat greater excess from all other causes combined. The social characteristics of the non-participant population appear to contribute to their significantly higher total mortality rate, and allowance needs to be made for this in interpreting the study findings. However the death rate from cardiovascular disease was similar in participants and non-participants, suggesting that any analysis related to this particular cause of death should not be biased by non-participation.

Toxicity of car exhausts and opportunity for suicide: comparison between Britain and the United States.

Abstract: The rate of car exhaust suicides in the United States has declined following the introduction of emission controls in the mid-1960s, though not as much as the decline in CO emitted by cars. In Britain, where emission controls have not been introduced, the rate of these suicides, initially much lower than in the United States, has greatly increased since the beginning of the 1970s and is now about double that of the United States. This rise cannot be explained simply on the basis of an increase in the opportunities for suicide as represented by an increase in the number of cars but may be due to increased knowledge of the method. While these results are interpreted as generally supporting the potential for opportunity-reducing preventive measures, they also demonstrate that much more research is needed into the complex nature of the opportunity structure for suicide.

Adult body height and childhood socioeconomic group in the Swedish population.

Abstract: Cross-sectional data from interviews of a sample of the Swedish population aged 16 to 74 years in 1980-81 were used to obtain information on the relation between father's socioeconomic status during the childhood of the participants and the adult body height of the latter. A difference in height between members of higher and lower socioeconomic groups was found. The difference diminished over falling age but was still noticeable among men born in the early and mid 1950s. The mean difference in height between sons of senior salaried employees and sons of unskilled workers was 2.9 cm. The difference was less for women.

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

Abstract: 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.

Education, prevalence of disease, and frequency of health care utilisation. The 1983 Italian National Health Survey.

Abstract: The relation between education, prevalence of 17 chronic diseases or groups of diseases, and pattern of health care utilisation was evaluated from data from the 1983 Italian National Health Survey, based on 58 462 individuals aged 25 or over randomly selected within strata of geographical area, size of place of residence, and size of household, in order to be representative of the whole Italian population. Most of the diseases considered, including diabetes, hypertension, myocardial infarction and other heart disease, haemorrhoids or varices, chronic respiratory disease, anaemias, gastroduodenal ulcer, cholelithiasis and liver cirrhosis, kidney and urological diseases, arthritis, and psychiatric and neurological disturbances, were consistently less prevalent among more educated individuals. The age and sex adjusted risk estimates for individuals educated in high school or university compared with those with only a primary school education or less ranged between 0.21 for liver cirrhosis and 0.80 for anaemias. The sole exception was allergy, which was more prevalent among the more educated individuals (relative risk = 1.42). General practitioner visits and hospital admissions were reported less frequently by the more educated individuals, but specialist consultations of potential preventive value were less frequent among the less well educated. The results were similar when occupation was utilised as an indicator of social class. Thus, the findings of this national survey provide confirmation and quantitative assessment of considerable differences in health and health service utilisation according to indicators of social class.

Sudden infant death syndrome and environmental temperature: an analysis using vital statistics.

Abstract: We examined the relation between the daily numbers of deaths ascribed to sudden infant death syndrome (SIDS) (n = 6226) and daily temperature in England and Wales over the five year period 1979-83. When the data were filtered to remove the dominant seasonal trend, and residual autocorrelation, we found a significant negative correlation of deaths with both the level and rate of change of temperature four to six days earlier, irrespective of age at death. Place of usual residence was obtained for 909 SIDS cases occurring during the unusually severe winter of 1981-82, and, using space-time clustering techniques, we confirmed previous findings of the lack of 'epidemicity' for this condition. These results are compatible with several previous hypotheses of the relation between the weather and SIDS and directly incriminate drops in temperature in the occurrence of the condition.

Multiple sclerosis and motor neurone disease: survival and how certified after death.

Abstract: This study assesses the outcome of a random sample of patients with multiple sclerosis (MS) and motor neurone disease (MND) selected from a previous study carried out between the years 1960 and 1972. Of the MND patients who are now dead, 20% of the women and 27% of the men lived longer than five years after hospitalised diagnosis, and two of these patients lived up to 19 years after diagnosis in hospital. Also, 10.7% of the random sample of MND patients were still alive in June 1985. Of the MS deaths 26.4% and of the MND deaths 20.4% did not have these respective conditions recorded on the death certificates.

Can hospital use be a measure of need for health care

Abstract: To achieve an equitable distribution of health service resources between geographical areas requires a measure of the relative needs of populations. For 11 years the methods of the Resource Allocation Working Party (RAWP) have been employed in England for this purpose. ' RAWP uses mortality rates in the form ofstandardised mortality ratios (SMRs) as a proxy for morbidity, to take account ofdifferences in the relative needs of populations for hospital care in excess of those 'explained' by the age/sex structure of the population. In this way RAWP aims gradually to redistribute National Health Service (NHS) resources more fairly in relation to need at both Regional and sub-Regional levels. A major criticism ofthe RAWP formula has centred on its use ofSMRs as an indicator of need for hospital care.2 In particular, it is argued that the relatively high level of morbidity experienced by 'deprived' populations may not be adequately reflected in their SMRs. Hospitals in deprived areas may also experience greater demands on their services at similar levels of morbidity, arising from the populations' social needs for in-patient care due to their poor housing conditions, living alone, etc. The greater needs ofdeprived populations have their major impact at a sub-Regional level. This is due to the concentration of deprived areas in some inner city health Districts. The Thames Regions, which include a number of deprived inner city Districts, have responded to the perceived inadequacies of SMRs in subregional RAWP by using socioeconomic classifications as measures ofneed for hospital care. Their approach has been to examine rates of hospital use by different socioeconomic groups to generate 'deprivation weights' as opposed to mortality weights. Recently, the NHS Management Board Review of National RAWP has called for research along similar lines in the hope of improving the needs element in the RAWP formula.5 Current interest in developing measures of need based on rates of hospital use raises questions concerning the interpretation of utilisation data and its relation to population need. Of particular significance are the large geographical variations in utilisation rates. For example, McPherson and colleagues found that rates of hospital utilisation for common surgical procedures (standardised by age and sex) varied as much as twofold within England and Wales and up to sevenfold between England and Wales, Canada, and the United States.6 Data assembled by the London Health Planning Consortium (LHPC) similarly show marked variations in hospital admission rates for all acute specialties (excluding Regional acute specialties) between the 14 Regions in England. For example, there was a 25% difference in admission rates between the Trent and Yorkshire Regions. Although the four Thames Regions all had relatively high admission rates, there was considerable variation within these Regions, with 115 admissions per 1000 resident population in inner London, 100 per 1000 in outer London, and 86 per 1000 in the remainder of the four Thames Regions. This compares with a figure of91 per 1000 in England as a whole. An analysis ofadmissions to medical specialties in the 15 health districts in South East Thames Region similarly shows that rates range from 19 to 57 admissions per 1000 population aged 0-14 years, from 41 to 81 per 1000 population aged 65-74 years, and from 35 to 119 per 1000 population aged 75 and over.8 In addition to these geographical variations in admission rates are important variations in the length of time patients spend in hospital in different areas of the country'9-O Differences in rates of hospital use between Regions and Districts are partly accounted for by differences in morbidity, associated with the economic circumstances and social conditions of their populations. However, variations in overall hospitalisation rates appear too large to be accounted for by differences in morbidity alone. Studies of operation rates for particular conditions, such as hysterectomy,' glue ear'2 and cataract extraction, 3 also indicate that the substantial geographical variations cannot be explained entirely by differences in the prevalence of these disorders.

The menopause and breast cancer.

Abstract: It is usually accepted that an older age of menopause is associated with an increased risk of breast cancer. This is often interpreted as a statement about postmenopausal women; however, some authors, eg ref. 1, explicitly and others, eg ref. 2, implicitly take it as embracing both an increased risk for postmenopausal women who have had a late menopause and an increased risk for older premenopausal women who are still menstruating. We have recently examined the role of menstrual status and age at menopause in a study of risk factors in a population of screened women.3 Our results there and the difficulties we encountered in relating them to the literature have motivated this study. We begin with a survey of the literature: comparison of reported studies is difficult because of considerable variations in the definitions of menstrual status (as well as absence and vagueness of definitions), the frequent absence of any "menopausal" category, and a lack of age-specific figures. The only clear consensus is that there is a higher risk among women aged 50-54 who are still menstruating than among those who are postmenopausal. Later we propose a modification of the "two linear component" model for age incidence: this includes increased incidence at the time of the menopause and a subsequent deficit. The intention is to test this model using data from the Edinburgh Breast Screening Trial, and the suitability for this purpose of the data which are being collected is discussed.

The Copenhagen case-control study of bladder cancer: role of smoking in invasive and non-invasive bladder tumours.

Abstract: A population based study of 388 cases of bladder cancer including papillomas and 787 controls in Greater Copenhagen confirmed the role of smoking in the aetiology of bladder cancer. Significantly increased relative risks were found for persons who had smoked only cigarettes (RR = 2.9; both sexes combined) and for mixed smokers including cigarettes (RR = 3.6; both sexes combined). Multiple logistic regression analysis showed significant influences of the amount (pack years) of cigarettes smoked and a reduced risk among persons who had stopped smoking. No significant effects of smoking pipe or cigars/cigarillos were apparent, and the present study does not confirm previous suggestions of associations between the smoking of cigars/cigarillos and bladder cancer in Denmark. Only a slight increase in relative risk with the amount smoked was found. The influence of smoking on bladder cancer risk was similar for tumours in stages T1 and T2-4 at diagnosis and also for tumours of grades 1-2 and grades 3-4 at diagnosis.

Diet, alcohol, body mass, and social factors in relation to blood pressure: the Caerphilly Heart Study.

Abstract: Data for 387 men who had completed seven-day weighed dietary records as part of the Caerphilly Heart Study were examined for relations of alcohol, diet, body mass index (BMI), and other variables to blood pressure. These included age, smoking, exercise, and social class. For men not on antihypertensive treatment (n = 356) regression analysis showed that age (p less than 0.001), BMI (p less than 0.05), and alcohol intake (p less than 0.01) were significantly related to systolic blood pressure, and BMI (p less than 0.001) and alcohol intake (p less than 0.01) to diastolic blood pressure. In addition, protein intake (p less than 0.05) was significantly and inversely related to the risk of being hypertensive, but other dietary variables were not related to blood pressure. For men on antihypertensive treatment (n = 31) significant inverse correlations were observed between diastolic blood pressure and the intakes of potassium (p less than 0.01), fibre (p less than 0.001), polyunsaturated fat (p less than 0.01), and a number of other dietary variables. Reasons for these differences are discussed.

Coffee consumption is correlated with serum cholesterol in middle-aged Finnish men and women.

Abstract: The association between coffee consumption and serum cholesterol was studied in a cross-sectional epidemiological study in Finland where the annual per capita consumption of coffee (13.0 kg) is the highest in the world. Coffee consumption was assessed by a questionnaire in a representative population sample of 4744 men and 4495 women aged 25 to 64 years. Serum total cholesterol and HDL-cholesterol concentrations were determined in fresh sera by the enzymatic method. Data on a large number of potential confounding variables were also collected. In the age group 25 to 44 years, the level of serum total cholesterol increased linearly with increasing coffee consumption in both sexes, but in people aged 45 to 64 the peak level of serum cholesterol was found in those who consumed 4 to 6 cups of coffee per day. In the analysis of covariance controlling for age, body mass index, intake of fat, sugar, and alcohol, smoking, physical activity, and fasting time, the mean level of serum cholesterol of men was lower (p less than 0.001) in those who drank no coffee (5.9 mmol/l) than in those who drank 1 to 3 cups (6.1 mmol/l) or 4 or more cups (6.2 mmol/l) per day. In women, the corresponding mean serum cholesterol values were 5.8 mmol/l, 6.1 mmol/l, and 6.1 mmol/l (p less than 0.05). Serum HDL-cholesterol levels did not vary significantly with coffee consumption. There was a slight inverse association between tea drinking and serum total cholesterol in men (p less than 0.05) but not in women. Although our results suggest a positive association, the impact of coffee drinking on serum cholesterol seems to be minimal. The results also indicate that the possible mechanisms do not include caffeine.

A longitudinal study on the significance of environmental and individual factors associated with the development of essential hypertension.

Abstract: Altogether 379 men of the same age have been followed for more than 40 years, mainly as regards socioeconomic conditions during the first 10 years as well as cognitive ability measured at the ages of 10 and 20, education, income development, and psychosocial conditions in adulthood. At the age of 48 a health investigation was performed. In order to identify possible risk factors associated with the development of raised blood pressure 38 subjects with essential hypertension were compared with 155 men without any obvious mental or somatic diseases. No differences regarding socioeconomic conditions during childhood could be observed between the two groups. However, there was a very strong difference between father's education and the son's cognitive ability in the group with hypertension. The low income development for the group with hypertension can probably be explained partly by the lower cognitive ability. In the total group there was a positive correlation between IQ at the age of 10 and income at the age of 43 (r = 0.42; p less than 0.001). The hypertensive men were psychosocially disadvantaged with respect to divorce rate and job dissatisfaction, and furthermore they reported low physical activity during leisure time. Hypertensive men were more obese and had inferior respiratory function. The observation that a lower cognitive ability seems to be related to the development of hypertension is compatible with the observation that early mortality in this investigated group has a correlation of a low IQ with poor socioeconomic conditions in childhood.

Relation between cigarette smoking and use of hormonal replacement therapy for menopausal symptoms.

Abstract: The aim of this study was to characterise new users of hormonal replacement therapy (HRT) for the relief of menopausal symptoms and to compare these women with never-users of HRT; 402 new users and 804 never-users were studied. Hot flushes were the most common symptom in both users and non-users and were the most frequent reason for prescribing HRT. The prevalence of menopausal symptoms in non-users of HRT was high although substantially lower than that in users. HRT users were more likely to be current cigarette smokers than were never-users. There was also, within smokers, a significant relation between the number of cigarettes smoked and the likelihood of using HRT. This relation between HRT use and smoking could result from an anti-oestrogen effect of smoking, intensifying menopausal symptoms. Of potential clinical relevance is the suggestion that a proportion of women using HRT may be doing so in order to alleviate smoking-induced symptoms. Users of HRT were also more likely to have used oral contraceptives than were never-users; this relation was probably behavioural.

Association of infant alimentary and respiratory illness with parental smoking and other environmental factors.

Abstract: The incidences of alimentary and respiratory illnesses were observed during the first year of life in 1565 infants born in Tayside during 1980. Significant correlations (p less than 0.05) were found between each of these outcomes and parental smoking, maternal age, social class, method of infant feeding, and heating fuels. Multiple logistic regression indicated a significant independent effect of parental smoking was related separately to alimentary and to respiratory outcomes, the relative risks being of similar strength.

Myocardial infarction and angina pectoris in young women.

Abstract: The Oxford-Family Planning Association contraceptive study has now followed 17,000 women, predominantly of childbearing age, for a total of more than 200,000 woman-years. The incidence of myocardial infarction and angina in women aged less than 50 years has been low: 0.03/1,000 woman-years at ages 25-34 rising to 0.67/1,000 woman-years at ages 45-49. However, the overall incidence in women who were smokers at entry to the study is more than three times that in women who were non-smokers, the increase in individual risk being proportional to the number of cigarettes smoked. Observations on other risk factors must be treated with caution in view of the small numbers involved: in general, the differences and trends reported are not statistically significant. However, a consistent positive relation is observed between incidence rates and both relative weight and parity after adjustment for age and smoking, while no consistent trend is observed for social class. Ever use of oral contraceptives is associated with a twofold increased risk of myocardial infarction (not statistically significant), but there is no increased risk in current users as was suggested by earlier studies. This may reflect the adoption of lower dose preparations and the positive selection of healthy women for oral contraception.

Is social class standardisation appropriate in occupational studies

Abstract: Social class standardisation has been proposed as a method for separating the effects of occupation and "social" or "lifestyle" factors in epidemiological studies, by comparing workers in a particular occupation with other workers in the same social class. The validity of this method rests upon two assumptions: (1) that social factors have the same effect in all occupational groups in the same social class, and (2) that other workers in the same social class as the workers being studied are free of occupational risk factors for the disease of interest. These assumptions will not always be satisfied. In particular, the effect of occupation will be underestimated when the comparison group also has job-related exposures which cause the disease under study. Thus, although adjustment for social class may minimise bias due to social factors, it may introduce bias due to unmeasured occupational factors. This difficulty may be magnified when occupational category is used as the measure of social class. Because of this potential bias, adjustment for social class should be done only after careful consideration of the exposures and disease involved and should be based on an appropriate definition of social class. Both crude and standardised results should be presented when such adjustments are made.

Measures of social class based on education for use in health studies in developing countries.

Abstract: In this paper we consider the appropriateness of education, compared to occupation and income, as a measure of social class for use in health-related studies in developing societies in transition. Three evaluation criteria were used, namely, the feasibility of constructing the measure, its sensitivity in reflecting relevant social class life conditions, and its ability to produce a family-level measure of social class. We used two data sets from community health surveys in areas of Amman city, Jordan, and in Beirut city, Lebanon, to define a family-based average educational score. We then proceeded, using the Beirut data, to test the score's ability to discriminate social class effects on family health, compared to a more standard representation based on the educational level of the head of the family. It was found that the performance of the average educational score was often better than, but not consistently superior to, the educational level of the head of the family.

Socioeconomic differentials in the uptake of medical care in Great Britain.

Abstract: Socioeconomic differentials in the uptake of medical care in men were investigated using data from the General Household Survey (1974-76 and 1979-80). Hospitalisation, attendance at out patient clinics, and consultation with doctors were higher in local authority tenants than in owner occupiers. Men belonging to the manual socioeconomic groups also used services and consulted doctors more often than those in the non-manual groups. Hospitalisation among men was highest among manual workers living in local authority properties without access to car(s) (OR 1.92). Highest attendance at outpatient clinics (OR 1.60) was seen among local authority tenants in urban areas belonging to manual groups. However, consultation with doctors was highest among urban manual workers living in local authority properties but with access to car(s) (OR 1.72). The implications of these findings for resource allocation are discussed.

Neural tube defects in Beijing-Tianjin area of China. Urban-rural distribution and some other epidemiological characteristics.

Abstract: Records in the obstetric wards and nurseries of 18 hospitals were reviewed and studied epidemiologically, covering about 210,000 deliveries and 1000 cases of neural tube defects (NTD). All live and still births occurred in the period 1970-84. Following the NTD classification used by Koch (1984), our case series consisted of anencephalus 50.3%, spina bifida 44.2%, and NTD with other system defects 5.5%. Overall NTD prevalence rate at birth was 4 per thousand, obviously higher than those in most other countries. Marked urban-rural differences in NTD prevalence rate at birth were observed. The rate in rural areas after correction for selection bias was still as high as 7.25 per thousand. As compared with cities and suburbs, the relative risk of NTD born to mothers in rural regions was 2.4. The male-to-female ratios were much less than 1 for various kinds of NTD. Looking at the effect of maternal age and birth order simultaneously in 12 different settings, it can be seen that prevalence of NTD was moderately higher among second and third births to women aged less than or equal to 24 and those greater than or equal to 35 years of age.

Does G6PD deficiency protect against cancer? A critical review.

Abstract: Previous observations on the lower mortality for cancer experienced in populations with a higher frequency of G6PD deficiency support biochemical studies on the role of G6PD during cell proliferation. The general agreement among experimental studies prevented a deeper analysis of the sources of what has been called "epidemiological evidence of the protective role of G6PD deficiency against cancer". This review analyses the methods and findings in those papers, stressing their limitations and emphasising that no final conclusions can be drawn from them. Preliminary results of ongoing epidemiological studies of G6PD deficiency and cancer are presented, although they do not prove or disprove the hypothesis that G6PD deficiency protects against cancer.

The Tromsø Heart Study: serum selenium and risk of myocardial infarction a nested case-control study.

Abstract: The association between serum selenium concentration and the risk of myocardial infarction was studied in a nested case-control study. Altogether 59 men, initially free of disease, aged 28-54 at the time of blood sampling, died suddenly or experienced a fatal or non-fatal myocardial infarction during a six year follow-up period. Case-control pairs came from a population of 9364 persons examined in 1979-80 in the second Tromso Heart Study. No significant difference was observed between serum selenium in cases and controls (p = 0.34). The major determinants of myocardial infarction and sudden death were raised levels of serum cholesterol and triglycerides (p less than or equal to 0.001) and high systolic blood pressure (p less than 0.05). Thus, in this population with intermediate selenium intake, low serum selenium is not associated with an excess risk of myocardial infarction.

Atopy, smoking, and chronic bronchitis.

Abstract: The aim was to test the hypothesis that atopy increases the occurrence of chronic bronchitis. Relations between atopy, smoking, and chronic bronchitis were studied in farmers. The data were from two successive postal surveys and a skin prick tested subsample. The cross-sectional study consisted of 9017 farmers. Those 6899 farmers who did not have chronic bronchitis at the beginning and who continued farming were followed for three years. A sample of 150 farmers was skin-tested with 36 allergens. The prevalence of chronic bronchitis (rate per 1000), standardised for age and sex, was 41 in non-atopic non-smokers, 101 in atopic non-smokers, 106 in non-atopic smokers, and 257 in atopic smokers (effect of atopy: p less than 0.001; effect of smoking: p less than 0.001). The standardised incidence rates of chronic bronchitis (per 1000 farming years) were 14, 34, 36, and 50, respectively (atopy: p less than 0.001; smoking p less than 0.001). The relative risk of chronic bronchitis, calculated from the incidence data adjusting for the effects of age, sex, smoking or atopy by logistic regression analysis was 2.2 for atopy (95% confidence interval 1.8-2.7) and 2.3 for smoking (1.8-2.9). Only 20 farmers had chronic bronchitis in the skin-tested subjects; the results were consistent with the findings in the surveys but did not reach statistical significance for atopy. In conclusion, atopy and smoking have independent and additive effects on the occurrence of chronic bronchitis at least in dusty farming work.