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 (AU)

Serum insulin and blood sugar levels in a rural population of Jamaican adults

Serum insulin and blood sugar concentrations were measured in 538 rural Jamaican adults aged 25-64 yr living in a defined area (77.3 percent response). The measurements were made in blood samples taken from the respondents in the fasting state and 1 hr after a drink equivalent to 100 g of glucose (Glucola). Insulin values measured in fasting and one hour post challenge sera are given by age and sex. The one hour insulin values were much higher in women than men. This difference was not completely explained by the effects of age, obesity, blood sugar or smoking habit, and it is suggested that the higher levels in women may be related in part to their higher levels of oestrogens and growth hormone. This finding has implications for the selection of control groups of normal people for use in comparative studies (AU)

Quantitative aspects of electrocardiograms of adults in a Jamaican rural population

The values of selected measurements from scalar electrocardiograms of a representative Jamaican population are reported. The tracings were obtained from 1067 adults aged 35 to 64 years, just under 90 percent of 1200 men and women selected randomly from a defined community of a hilly inland rural area. The participants were mostly small farmers, and their womenfolk, and they were of African origin. Measurements included intervals, axes, and amplitudes and three indices of left heart involvement-Morris's index of left atrial disease, Estes' score for left ventricular hypertrophy, and the Sokolow-Lyon criteria. Their distributions are compared with data from similar epidemiological studies and provide values for an ethnic group for which there are few population-based reports. The striking feature of these tracings was the high proportion with evidence of left ventricular hypertrophy, particularly those of men. The relation between certain electrocardiographic characteristics and age, body built, arterial pressure, and heart rate was investigated by multiple regression analysis, and this showed that little of the variation of most electrocardiographic measurements were explained by these variables. (AU)

The prevalence of diabetes in a rural population of Jamaican adults

The prevalence of diabetes mellitus and significance of related variables are described for a rural Jamaican community. The population of the defined survey area was enumerated by private census and all 696 persons aged 25-64 were requested to participate. A response rate of 77.3 percent was achieved. Blood samples were drawn after respondents and fasted and 1 hour after consumption of a 100 G glucose load (Glucola). Blood tests included blood glucose, serum cholesterol and triglycerides. Anthropometric and blood pressure measurements, a 12 lead electrocardiogram and a PA chest X-ray were taken and a questionaire administered to elicit the occurrence of effort pain. Persons with 1 hour blood glucose levels of 180mg, percent or more were requested to undergo a 3 hour glucose tolerance test. Age specific rates for diabetes rose to 14.5 percent in males aged 45-54 and 17.0 percent in females aged 55-64. The percentage distribution of 1 hour glucose is given by age and sex. No relationship between number of live births and 1 hour blood glucose was found. In a comparison between non-diabetics, newly diagnosed and previously known diabetics, known diabetics of both sex had thicker infrascapular skinfolds, male new and known diabetics had higher cholesterol, and triglycerides increased from non-to known diabetics of both sexes. The validity of intersurvey comparison of diabetes rates is discussed and a alternative presentation of data is recommended. The lack of relationship between the diagnosis of diabetes and cardiovascular disease is also discussed.(AU)

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 initial 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 and important cause of death in rural Jamaicans.(AU)

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 oclusive atheromatous disease as is found in many other populations.(AU)

Jamaican idiopathic cardiomegaly, a possible variant of the athletic heart syndrome in men with high levels of customary activity - abstract

A cardiovascular survey in a rural Jamaican community identified a group with suspected early idiopathic cardiomegaly. Forty and seven normotensive men and women respectively were investigated for further evidence of this disease, and to search for clues to its aetiology. There were: 12 men with large Q waves, 6 men with short P-R interval (pre-excitation), 8 men with prolonged A-V conduction, 9 men with very unusual electrocardiograms, considered most likely to have idiopathic cardimegaly, 5 men with positive responses to an angina questionnaire, 7 women with T-wave inversion in precordial leads. Their results were compared with those of twelve men without evidence of cardiovascular disease. After interview, examination and anthropometry, cardio-respiratory and electrocardiographic excercise responses were measured on a cycle ergometer while subjects exercised to a pulse rate 90 percent of the predicted maximum. Fourteen men performed maximal exercise studies. The great majority of men, but no women, had high levels of customary activity imposed by the terrain of their working environment, and correspondingly athletic responses to the excercise test. No subject developed angina or ECG ischaemia, but five men had a significant excercise arrythmia. At an oxygen intake of 1.51/min the means of cardiac frequency (Cf1.5) and minute ventilation (VE1.5) for the 52 men were 114/min and 43.4 litres respectively. Corresponding values for women were 151/min and 52.7 litres. Mean maximal oxygen intakes/kg lean body mass were 51.5 ml for men and 42.9 ml for women. The athletic performance, low resting pulse, radiographic cardiomegaly, and distinctive electrocardiogram of these men are all features of the athletic heart syndrome, in which potentially dangerous arrythmias can lead to sudden death. It is suggested that some examples of Jamaican idiopathic cardiomegaly in men may be due to a disorder of cardiac rhythm that develops in subjects with ventricular hypertrophy (AU)

A survey of blood glucose and serum lipoprotein in adults in a rural area of Jamaica - abstract

A community survey in Lawrence Tavern was started in October, 1969 in which all 544 perons aged 25-54 living in a particular area were requested to participate. Measurements taken included fasting and 1 hour blood glucose and insulin, serum cholesterol and triglycerides, lipoprotein electrophoresis, heamoglobin concentration, packed cell volume and haemoglobin type as well as blood pressure and anthropometric data. A chest X-ray and ECG were also taken. The aim of the study is to investigate the single joint distributions of the measurements and the relationships existing between glucose tolerance and cardiovascular parameters. Mean fasting blood glucose levels of the first 379 respondents show no trend with age in males and little evidence of any trend in females. However mean 1-hour post-Glucola levels show a striking trend with age. Of the 30 persons qualifying for the diagnosis of diabetes based on a 1-hour blood level of 180 mgm percent or greater, 6 were known diabetics, 13 were confirmed as newly discovered diabetics and 5 confirmed as non-diabetics by a full glucose tolerance test 6 refused the full test. Confirmed diabetic were more common among females than males aged 35-44 (6/92 as against 1/50) but no difference was found in the decade 45-54 (5/65 as against 7/65). Only one case (unconfirmed) eas found below age 35. Results for the other measurements made on blood constituents are not yet available (AU)

Malnutrition, infection and child growth in Jamaica

A semi-longitudinal study of factors influencing child growth in a rural community in Jamaica provided an opportunity to explore the relationships between diarrhoea, respiratory infections and body weight. Respiratory infections and diarrhoea both reached peak incidences between the ages of 6 and 24 months when children are at highest risk of malnutrition. Respiratory infections had no demonstrable influence on growth. Diarrhoea was more common in boys than in girls and more common in underweight children. It had no influence on long-term weight increases, though it did have the expected influence on short-term increments. The findings suggested that much of the diarrhoea seen in this community of children may have been secondary to undernutrition rather than a cause of it. (AU)

Socio-economic and cultural influences on child growth in rural Jamaica

A semi-longitudinal study of growth in children up to 5 years of age in a rural Jamaican community is described. One of its aims was to investigate the relationship between growth and factors in the social environment such as family structure, parental characteristics, housing and income. A strong relationship between growth and socio-economic variables was found. This apparently masked whatever effects the quality of care or separation from the parents may have upon child growth. (Summary)

A five-year study of infant growth in rural Jamaica

Growth patterns observed in a cohort of 229 children followed from birth to 5 years of age, are described cross-sectionally and longitudinally. The children were probably representative of those in other parts of rural Jamaica and the results, though not showing ideal growth, could be used as reference standards for similar communities. About half the children failed to make any net any net weight gain during at least one 6-month period, and 13 (6 percent) had no net weight gain for a whole year or more. The limited usefulness of good or poor weight increments as guides to long-term progress is discussed (Summary)

A comparison between the characteristics of Jamaican adults with normal hemoglobin and those with sickle cell trait

In surveys of representative samples of Jamaicans aged 35-64 years living in rural and suburan communities, no significant differences in heights, weights, hematological indices, cardiothoracic ratios, blood pressures, glycosuria, proteinuria, parity or electrocardiographic abnormalaties were apparent between 167 subjects with the sickle cell trait, AS, and 1,282 subjects with normal hemoglobin, AA. Older women with the trait had a significantly higher prevalence of bacteriuria without other evidence of urinary tract pathalogy. The findings suggest that the trait is not appreciably associated with chronic disease. (AU)

Cardiothoracic ratios in two Jamaican communities

Ashcroft, M. T. and W. E. Maill (Med. Research Council's Epidemological Research Unit, Univ. of the West Indies, Kingston 7, Jamaica). Cardiothoracic ratios in two Jamaican communities. Amer. J. Epid., 1969, 89: 161-167.-Cardiothoracic ratios were estimated from 929 full-sized chest radiographs of representative samples of men and women of predominantly African origin aged 35-64 years living in rural and suburban communities in Jamaica. CTRs were greater in women than in men and increased with age; they were orrelated with weight and with blood pressure levels. Mean CTRs were substantially greater in Jamaica than in a comparable sample of white persons living in Wales. These differences could not be explained by the prevalence of cardiovascular disorders including hypertension or by differences in weight or physical activity. An ethnic difference, possibly in the position of the heart within the chest or in the size of the thoracic diameter, is suggested. The greater CTR of the Negro should be taken into account when assessing heart size from chest films. (AU)

Degenerative joint disease in a Jamaican rural population

The prevalence of degenerative joint disease has been measured in a random sample of adults aged 35-64 years living in a rural area in Jamaica and compared with that found in similar surveys in the United Kingdom. Radiological evidence of osteo-arthrosis in general showed the same prevalence in the two races, with the exception of certain joints which showed significant differences. Lumbar disk degeneration was also found to have a similar prevalence, though the involvement of multiple disks was significantly more common in Jamaica. Cervical disk degeneration was both more common and more severe in Jamaica. Symptoms in Jamaica were less frequent in relation to all sites of osteo-arthrosis except the cervical spine, and Jamaicans seemed to have fewer symptoms and less incapacity than Englishmen with the same degree of disk degeneration.(Summary)

Jamaica: the social background of malnutrition

A study is described in which anthropometric measurements were made on a cohort of infants born in a rural area in Jamaica, and repeated at frequent intervals since birth. Growth, by the standards of infants in industrial countries, is much retarded from three months of age till about two years of age; by eighteen months of age less than 20 percent of children have attained their expected weight for age, or their expected weight for height. Comparisons were made of the social backgrounds of children whose quarterly weight increments were above the 90th and below the 10th percentiles. The findings confirm the influence of factors associated with poverty and rapid reproduction and suggest that unstable parental relationships may be a major cause of infant malnutrition in Jamaica. (Summary)