A comparison of cardiovascular measurements in the Gambia, Jamaica, and the United Republic of Tanzania.

Epidemiological studies of the cardiovascular characteristics of three typically rural communities in the Gambia, Jamaica, and the United Republic of Tanzania were carried out by means of standardized methodology. This paper reports comparisons of arterial blood pressure distribution and electrocardiographic findings in relation to age, sex, and body build. Marked differences in blood pressure were found, with higher values in Jamaicans than in Tanzanians, who in turn had higher values than Gambians. These differences are not explicable in terms of body build. Heart rates and ECG amplitudes were also strikingly different, with higher values in Jamaicans than in Tanzanians and Gambians. The differences in ECG amplitudes cannot be explained by differences in body build, heart rate, or blood pressure. The findings agree with the hypothesis that some factor or factors associated with development contributes to the risk of cardiovascular disease in peoples of African origin.

Longitudinal study of heart disease in a Jamaican rural population. 3. Factors influencing changes in serial electrocardiograms.

A longitudinal survey of heart disease in adults in a representative rural population in Jamaica provided an opportunity to study factors influencing the progression and incidence of electrocardiographic abnormalities in serial tracings taken at a 5-year interval. An analysis of changes occurring in those with ECG abnormalities compatible with ischaemia at the first survey showed that progression from a less severe to a more severe category was greater in men than in women, in hypertensive than in normotensive subjects, and, among men, in those with the amplitude criteria of left ventricular hypertrophy. The incidence of abnormal Q/QS patterns was greater in men than in women, and that of all abnormalities suggesting ischaemia was greater in hypertensive than in normotensive persons; in men, it was greater in those with high amplitude R waves. The incidence cases showed S-T and T wave abnormalities, the great majority of which were classified as showing features compatible with ischaemia rather than with strain secondary to hypertrophy. These findings, which are discussed in terms of their possible causes, seem to confirm that much of the heart disease in this Jamaican community has features of myocardial ischaemia despite other evidence that extramural coronary vessels tend to be spared from such severe occlusive atheromatous disease as is found in many other populations.

Longitudinal study of heart disease in a Jamaican rural population. I. Prevalence, with special reference to ECG findings.

A long-term epidemiological study of heart disease in a representative rural community in Jamaica was started in 1962-63 and the first follow-up survey was carried out in 1967-68. This report describes the prevalence of several cardiovascular characteristics at each survey, and their associations with other measurements. The nature of the electrocardiographic abnormalities and their relationship with symptoms of effort pain and prolonged chest pain suggests that much of the disease seen in this population is ultimately ischaemic in origin despite evidence that classical myocardial infarction and severe coronary atheroma are relatively infrequent. Nevertheless both the symptoms and the electrocardiographic abnormalities had features that were not completely typical of occlusive disease of extramural coronary arteries. These findings are discussed in terms of the four conditions-hypertension, conventional coronary heart disease, small artery disease, and cardiomyopathy-that are believed to account for most cases of heart disease in this community, and it is concluded that the overall pattern of disease cannot be explained by any single disorder of overriding importance. The evidence suggests that all may be important contributors.

Longitudinal study of heart disease in a Jamaican rural population. 2. Factors influencing mortality.

The relationship between cardiovascular characteristics and mortality was investigated in an epidemiological study of heart disease in a representative adult rural community in Jamaica. Of 449 men and 469 women followed up for 5 years, 36 men and 28 women died and the data concerning their status as regards arterial pressure, electrocardiographic abnormalities, and histories of effort pain at the intial survey have been analysed. Cardiovascular disease, and heart disease in particular, was the major cause of death in this population. Blood pressure levels exceeding 160/95 mm Hg had been recorded in about one third of the men and half the women who died and a clear trend was found between overall mortality and arterial pressure. Symptoms of effort pain and ECG abnormalities compatible with myocardial ischaemia, both of which were unexpectedly common, appeared to have independent prognostic significance. The prognosis of each was worse when associated with hypertension; hypertension unaccompanied by either effort pain or ECG "ischaemic" abnormality, on the other hand, caused no excess mortality in either sex within the period of follow-up. Although classical myocardial infarction was confirmed to be relatively infrequent, myocardial disorders with many of the features of ischaemic heart disease are an important cause of death in rural Jamaicans.

The prevalence of diabetes in a rural population of Jamaican adults.

PIP: The prevalence of diabetes, the interrelationship of blood glucose, serum insulin, and lipids, and their relationship to ischemic heart dise ase in a rural Jamaican community were investigated. The people were mo stly of West African descent. Occupations were primarily agricultural w ith much physical labor. Approximately 80% of total claories in their d iet were from carbohydrates. Of 696 25-64 year old persons, a response rate of 77.3% was achieved. The patients, after an overnight fast, drank a 7-oz bottle of Glucola which was the equivalent of a 100 gm glucose load. Electrocardiograms (EKGs), blood pressure readings, a chest X-ray, and skinfold tests for obesity were done. A family history was obtained. Blood and urine specimens were taken before the glucose was given. 1 hour after the glucose was given, blood and urine specimens were also taken. Those with blood glucose of 180 mg% or more were given a 3-hour glucose tolerance test. Of the 525 persons who had the 1-hour test, 23 were found to be glycosuric. Of these, 11 were not shown to be diabetic by the 3-hour glucose test. Of the 502 with negative urines, 34 were positive on blood tests. The rates increased with age, except in the oldest age groups (p less than .05 for males and p less than .001 for females). There was no relationship between the number of live births and the 1-hour blood glucose tests. There was neither increase in the diagnosis of diabetes nor increase in variance with number of children. The known diabetics were fatter and had higher triglycerides than others. Cholesterol was higher in all male diabetics but not in females. Only 2 persons experiencing effort pain had EKG changes. Data from this study indicate that no statistically significant association exists between levels of glycemia and blood pressure or prevalence of cardiovascular disease. The physical fitness acquired from walking and working in a hilly area may be a factor.^ieng