Search

Epidemiology is defined as the medicine of populations rather than, individuals. The thesis deals with the pattern of mortality from cerebrovascular disease in Scotland, England and Wales; the investigation of some possibilities in screening for symptoms of cerebrovascular disease; and a study of blood pressure on the Hebridean Island of Tiree. Chapter I. A Short History of Epidemiology. Chapter II. The Mature of Mortality Data, for Cerebrovascular Disease. As approximately fifty per cent of deaths from cerebrovascular disease take place at home and grouped data show that hospital clinicians have difficulty in distinguishing between cerebral haemorrhage and infarction, death certificate data for these categories of disease are likely to be unreliable. While this finding is supported from the literature, factors which enhance the validity of death certificates for cerebrovascular-disease are discussed and evidence produced indicating ways in which such data may be considered of greater consequence. Chapter III. The Pattern of Nortality from Cerebrovascular Disease and Arteriosclerotic and Degenerative Heart Disease in Scotland, England and Wales (1947-1966). The crude and direct standardised mortality rates for males and females by five year age groups for cerebrovascular disease (I.S.C. 330-334 and 330, 331, 332) and arteriosclerotic and degenerative heart disease (I.S.C. 420-422) axe tabulated for the period 1947-1966 and the data of greatest interest presented in graphical form. Attention is drawn to the apparent recent lack of increase in mortality for cerebral infarction which is in marked contrast to the rise in rates for myocardial infarction especially in the population aged 50-64 years. The relationship of the two conditions is brought into question. Chapter V, The Introduction of a Questionary on Screening for Symptoms of Transient Cerebral Ischaemia. The cardio-respiratory screening unit and its method of operation is described. A simple questionary on loss of power in the upper and lower limbs and on loss of speech and consciousness is evolved, tested and considered suitable for interviewer - administration under the conditions of a screening survey. Chapter VI. An Account of the Administration of the Questionary on Symptoms of Transient Cerebral Ischaemia in Three Samples of the Scottish Population - Clackmannan, Glasgow and Tiree. Individuals v/ho have experienced one or more of the symptoms sought by the questionary have greater experience of symptoms of angina, infarction and claudication and also more signs of electrocardiographic abnormalities as well as greater experience of cigarette smoking than those who have not admitted to such symptoms. If the high prevalence of these symptoms is substantiated this may partially account for the lack of increase in rates for cerebral infarction and the rise in rates for myocardial infarction mentioned in Chapter III. This project is presently being followed-up by a case/control study and a record linkage procedure. Chapter VI. Blood Pressure in a Scottish Island Community. A study of mean blood pressure levels in age-and-sex-matched samples of the population of the Hebridean Island of Tiree appears to support the local belief that blood pressure is higher on the island than on the mainland. This conclusion may be related to the observation of a greater mean' width of the heart measured radiologically in the island population compared with the mainland population. Chapter VIII. The Paradox of Tiree. The Islanders of Tiree appear to have a greater experience of clinical signs of vascular disease while admitting to fewer symptoms than their mainland contemporaries. While mean blood pressure levels are generally higher for those with symptoms and signs of vascular disease than for those without, they occur at higher mean levels of blood pressure in the island population compared to the mainland. Those without symptoms or signs can have higher blood pressure on the island than those with symptoms on the mainland. The hypothesis that island life may protect the individual from the effects of raised blood pressure is explored but not proven. Chapter IX Summary.