13
3Volume 69 December 1976
935
Section of Epidemiology & Community Medicine Presidenit R E 0 Williams MD Meeting 11 March 1976
Research Reports on MFCM and MSc Projects Dr P F Grundy (Department of Community Medicine, Welsh National School of Medicine, Heath Park, Cardiff, CF4 4XN)
likely to have occurred among those over the age of 35 at the time of the original survey, thus rendering follow up easier.
A Cohort Study of Mortality in Relation to Lung Function In 1964, a study of the etiology, prevalence and progression of respiratory disability among the men employed at the Steel Works of Richard Thomas & Baldwins Ltd (now British Steel Corporation), Ebbw Vale, was initiated by the Department of Social and Occupational Medicine (now the Department of Community Medicine) of the Welsh National School of Medicine, with financial support from the Nuffield Foundation.
During the Easter vacation of that year, student volunteers collected information on respiratory symptoms, smoking habits, ventilatory capacity, height, weight. and social and occupational history from 8081 employees of the Steel Works. Each employee answered questions on the MRC short questionnaire on respiratory symptoms (1960) and a Garthur Vitalograph was used to record forced ventilatory output. Weight (in light clothing), standing height and sitting height were also recorded for each individual (Lowe et al. 1968). For
the
purpose
of
the
ten-year
follow
up,
only
those employees who were aged 35 years or more on I March 1964 will be traced. It was considered justifiable to reduce the cohort size from about 8000 to about 5000 for two reasons: (1) It is at about 45 years of age that mortality from the major causes of death amongst males in this country begins to rise steeply. (2) In the Ebbw Vale community, emigration from the area is less
Each person examined was allotted a survey number and his surname and initials, together with his date of birth, address and general practitioner at that time, were recorded. All clinical, social and occupational information was collected in such a way that, together with the survey number, it could be transferred to punch cards and subsequently to magnetic tape. The first stage of the follow up is to ascertain which of the 4911 persons originally interviewed and qualifying for the survey were alive on I March 1974. A computer print-out of the current employment register of the Ebbw Vale Steel Works enabled us to ascertain if persons in the survey were still alive and working in March 1975 and, similarly, information from the British Steel Corporation's pension register as it stood on 1 March 1974 showed which of those persons who had retired were still receiving pension on
Table I Men employed at Steel Works, Ebbw Vale. State of the follow up in February 1976 No. ofmen
Number known to be alive on 1.3.74: On current employment register In receipt of pension on 1.3.74
2393 720
3113 Number known to have died
487
(737%)
Total identified
3600
Number thought to be dead but not accurately identified Not known if alive or dead
1181
Total for field follow up
1311
Total included in the investigation
4911 (100%)
130
(27 %)
14
936 Proc. roy. Soc. Med. Vohime 69 December 1976 that date. In addition, the Ebbw Vale works record the cause and date of death of most of those who have been employed at the works. By the rigid matching of surname, initials and exact date of birth we have been able to extract 3600 persons from the original survey list (see Table 1), leaving 1311 persons to be traced. This is at present being done by two field workers (a Social Worker and a Health Visitor) who know Ebbw Vale and its neighbourhood well. Our initial impression is that we shall be able to obtain over 95 % follow up. For all those in the cohort who are known to have died, the date and cause of death are being ascertained and the latter is being coded on a separate punch card, according to the 1968 revision of the International Classification of Diseases. Full forenames and date of birth are to be recorded on these cards and will provide the means by which this information will be linked to the original survey information, which is filed on punch cards by survey number only, through a 'linkage card' on which is recorded surname, initials, date of birth, survey number and a check digit. All infoimation for each individual, whether alive or dead, is being transferred to magnetic tape. Results will yield death rates in the cohort in relation to respiratory symptoms, lung function and obesity index. Respiratory symptoms, as recorded on the questionnaire, will enable us to stratify within each age group by mutually exclusive bronchitis grade (Khosla & Lowe 1974). Similarly, indices of lung function adjusted for height and age (Khosla 1971) and obesity adjusted for height (Khosla & Lowe 1967) will be computed within each age category. The influence of smoking habit will be taken into account wherever relevant. It is expected that, by means of multivariate and life-table analysis, it will be possible to construct predictive indices of mortality risk relating to the parameters chosen. There is a relative paucity in the medical literature of large-scale prospective cohort studies relating premature mortality and cause of death to lung function, respiratory symptoms and indices of body build and it is felt that this study will make a valuible contribution in this field. In addition, it will prepare the way for the more comprehensive follow-up study of all the steelworkers interviewed and examined at Ebbw Vale and Port Talbot in 1964/65. REFERENCES
Khosla T (1971) British Journal ofPreventive and Social Medicine 25, 203 Khosda T & Lowe C R (1967) British Journal ofPreventive and Social Medicine 21, 122 (1974) British Journal ofPreventive and Social Medicine 28, 156 Lowe C R, Pelmear P L, Campbell H, Hitchens R A N, Khosla T & King T L (1968) British Journac ofPreventive and Social Medicine 22, 1
Dr Godfrey Walker (Department of Commiuniity Health, London School of Hygiene and Tropical Medicine, Lonidon WCIE 7HT)
Primary Health Care in Botswana: A Study in Cost-effectiveness Many developing countries experience difficulties in the provision of even the most basic primary health services. Several attempts have been made to increase their availability and accessibility by means of mobile land and air services. While the use of such services to deliver primary health care has been questioned (Paddock & Paddock 1973, Korte & Patel 1974) they have seldom been examined with regard to the most effective use of limited resources. This paper describes how the techniques of cost-efficiency1 and cost-effectiveness2 were used in Botswana to help in choosing between alternative ways of delivering primary health care, by mobile air and land services or by static permanently-staffed clinics. Botswana The Republic of Botswana, formerly the Bechuanaland Protectorate, was under British rule until it attained independence in 1966. It is a large country of about 220 000 square miles (569 800 kM2) - approximately twice the size of the United Kingdom. The population of almost 650 000 is more than 90% rural and 55% live in villages of fewer than .500 people. Forty-eight per cent of the inhabitants are under 15 years of age and the rate of natural increase is just over 3 % per annum. Patterns of disease are similar to those of many other developing countries and are largely determined by inadequate diets, limited access to clean water and a generally low standard of hygiene. During 1974, reports (Government of Botswana 1975) of new out-patients aged less than 15 years showed that 31 % were suffering from respiratory infections, 23 % from gastroenteritis and 21 % from ear, eye or skin infections. Infant mortality is estimated at 105 per 1000 live births. Specific infectious diseases, of which the commonest were tuberculosis, measles, meningitis and tetanus, accounted for more deaths in hospital during 1974 than any other category of disease. About 17% of deaths in Botswana occur in hospital but, of these, over two-thirds occur in people who have travelled less than five miles for admission, a proportion similar to that for all hospital admissions. 1 Cost-efficiency is based on the number of patients with whom contact is made ' Cost-effectiveness is based on the number of patients whose diseases are likely to be diagnosed and treated effectively
3Volume 69 December 1976
935
Section of Epidemiology & Community Medicine Presidenit R E 0 Williams MD Meeting 11 March 1976
Research Reports on MFCM and MSc Projects Dr P F Grundy (Department of Community Medicine, Welsh National School of Medicine, Heath Park, Cardiff, CF4 4XN)
likely to have occurred among those over the age of 35 at the time of the original survey, thus rendering follow up easier.
A Cohort Study of Mortality in Relation to Lung Function In 1964, a study of the etiology, prevalence and progression of respiratory disability among the men employed at the Steel Works of Richard Thomas & Baldwins Ltd (now British Steel Corporation), Ebbw Vale, was initiated by the Department of Social and Occupational Medicine (now the Department of Community Medicine) of the Welsh National School of Medicine, with financial support from the Nuffield Foundation.
During the Easter vacation of that year, student volunteers collected information on respiratory symptoms, smoking habits, ventilatory capacity, height, weight. and social and occupational history from 8081 employees of the Steel Works. Each employee answered questions on the MRC short questionnaire on respiratory symptoms (1960) and a Garthur Vitalograph was used to record forced ventilatory output. Weight (in light clothing), standing height and sitting height were also recorded for each individual (Lowe et al. 1968). For
the
purpose
of
the
ten-year
follow
up,
only
those employees who were aged 35 years or more on I March 1964 will be traced. It was considered justifiable to reduce the cohort size from about 8000 to about 5000 for two reasons: (1) It is at about 45 years of age that mortality from the major causes of death amongst males in this country begins to rise steeply. (2) In the Ebbw Vale community, emigration from the area is less
Each person examined was allotted a survey number and his surname and initials, together with his date of birth, address and general practitioner at that time, were recorded. All clinical, social and occupational information was collected in such a way that, together with the survey number, it could be transferred to punch cards and subsequently to magnetic tape. The first stage of the follow up is to ascertain which of the 4911 persons originally interviewed and qualifying for the survey were alive on I March 1974. A computer print-out of the current employment register of the Ebbw Vale Steel Works enabled us to ascertain if persons in the survey were still alive and working in March 1975 and, similarly, information from the British Steel Corporation's pension register as it stood on 1 March 1974 showed which of those persons who had retired were still receiving pension on
Table I Men employed at Steel Works, Ebbw Vale. State of the follow up in February 1976 No. ofmen
Number known to be alive on 1.3.74: On current employment register In receipt of pension on 1.3.74
2393 720
3113 Number known to have died
487
(737%)
Total identified
3600
Number thought to be dead but not accurately identified Not known if alive or dead
1181
Total for field follow up
1311
Total included in the investigation
4911 (100%)
130
(27 %)
14
936 Proc. roy. Soc. Med. Vohime 69 December 1976 that date. In addition, the Ebbw Vale works record the cause and date of death of most of those who have been employed at the works. By the rigid matching of surname, initials and exact date of birth we have been able to extract 3600 persons from the original survey list (see Table 1), leaving 1311 persons to be traced. This is at present being done by two field workers (a Social Worker and a Health Visitor) who know Ebbw Vale and its neighbourhood well. Our initial impression is that we shall be able to obtain over 95 % follow up. For all those in the cohort who are known to have died, the date and cause of death are being ascertained and the latter is being coded on a separate punch card, according to the 1968 revision of the International Classification of Diseases. Full forenames and date of birth are to be recorded on these cards and will provide the means by which this information will be linked to the original survey information, which is filed on punch cards by survey number only, through a 'linkage card' on which is recorded surname, initials, date of birth, survey number and a check digit. All infoimation for each individual, whether alive or dead, is being transferred to magnetic tape. Results will yield death rates in the cohort in relation to respiratory symptoms, lung function and obesity index. Respiratory symptoms, as recorded on the questionnaire, will enable us to stratify within each age group by mutually exclusive bronchitis grade (Khosla & Lowe 1974). Similarly, indices of lung function adjusted for height and age (Khosla 1971) and obesity adjusted for height (Khosla & Lowe 1967) will be computed within each age category. The influence of smoking habit will be taken into account wherever relevant. It is expected that, by means of multivariate and life-table analysis, it will be possible to construct predictive indices of mortality risk relating to the parameters chosen. There is a relative paucity in the medical literature of large-scale prospective cohort studies relating premature mortality and cause of death to lung function, respiratory symptoms and indices of body build and it is felt that this study will make a valuible contribution in this field. In addition, it will prepare the way for the more comprehensive follow-up study of all the steelworkers interviewed and examined at Ebbw Vale and Port Talbot in 1964/65. REFERENCES
Khosla T (1971) British Journal ofPreventive and Social Medicine 25, 203 Khosda T & Lowe C R (1967) British Journal ofPreventive and Social Medicine 21, 122 (1974) British Journal ofPreventive and Social Medicine 28, 156 Lowe C R, Pelmear P L, Campbell H, Hitchens R A N, Khosla T & King T L (1968) British Journac ofPreventive and Social Medicine 22, 1
Dr Godfrey Walker (Department of Commiuniity Health, London School of Hygiene and Tropical Medicine, Lonidon WCIE 7HT)
Primary Health Care in Botswana: A Study in Cost-effectiveness Many developing countries experience difficulties in the provision of even the most basic primary health services. Several attempts have been made to increase their availability and accessibility by means of mobile land and air services. While the use of such services to deliver primary health care has been questioned (Paddock & Paddock 1973, Korte & Patel 1974) they have seldom been examined with regard to the most effective use of limited resources. This paper describes how the techniques of cost-efficiency1 and cost-effectiveness2 were used in Botswana to help in choosing between alternative ways of delivering primary health care, by mobile air and land services or by static permanently-staffed clinics. Botswana The Republic of Botswana, formerly the Bechuanaland Protectorate, was under British rule until it attained independence in 1966. It is a large country of about 220 000 square miles (569 800 kM2) - approximately twice the size of the United Kingdom. The population of almost 650 000 is more than 90% rural and 55% live in villages of fewer than .500 people. Forty-eight per cent of the inhabitants are under 15 years of age and the rate of natural increase is just over 3 % per annum. Patterns of disease are similar to those of many other developing countries and are largely determined by inadequate diets, limited access to clean water and a generally low standard of hygiene. During 1974, reports (Government of Botswana 1975) of new out-patients aged less than 15 years showed that 31 % were suffering from respiratory infections, 23 % from gastroenteritis and 21 % from ear, eye or skin infections. Infant mortality is estimated at 105 per 1000 live births. Specific infectious diseases, of which the commonest were tuberculosis, measles, meningitis and tetanus, accounted for more deaths in hospital during 1974 than any other category of disease. About 17% of deaths in Botswana occur in hospital but, of these, over two-thirds occur in people who have travelled less than five miles for admission, a proportion similar to that for all hospital admissions. 1 Cost-efficiency is based on the number of patients with whom contact is made ' Cost-effectiveness is based on the number of patients whose diseases are likely to be diagnosed and treated effectively
