Factors Influencing Arterial Pressure in the General Population in Jamaica

Though there is evidence that racial factors are important in determining blood-pressure levels in different populations, little is known of the nature of these factors, and the relative contributions of environment and genetics have still to be defined. The evidence from all available epidemiological studies suggests that the arterial pressure in negro populations in the United States is higher than that for white populations there (Adams, 1932; Gover, 1948; Comstock, 1957). Bloodpressure in the negro population of the West Indies is also high (Saunders and Bancroft, 1942 ; Moser et al., 1959; Johnson and Remington, 1961 ; Schneckloth et al., 1962). Whereas in the white population in the United States death rates for hypertension and hypertensive heart disease are consistently higher in the male than in the female, in negroes the rates are consistently greater for females than for males (Lennard and Glock, 1957; Stamler et al., 1960). The ancestors of most American and West Indian negroes came from West Africa in the second half of the seventpenth century and throughout the eighteenth century. ;No data concerning the blood-pressure levels in the general populations of West Africans are available for comparison, and the lack of accurate knowledge of their ages is likely to make such studies unrewarding at present, so the influence on blood-pressure of the different environments in which negroes live in Africa and in the West remains unexplored. The epidemiological studies of rural and urban communities carried out in Jamaica and reported here were undertaken to determine some of the factors influencing arterial pressure in West Indians ; as similar studies had previously been carried out in Wales (Miall and Oldham, 1955, 1958) a comparison of the magnitude of genetic and environmental influences on arterial pressure in the two races was possible. At the same time the surveys were designed to determine the magnitude of the differences in blood-pressures between negroes in Jamaica and whites in South Wales, using the same observer, the same techniques of examination, and representative populations in both the countries. We thus hoped to determine whether such racial differences in arterial pressure as might be found were exnlicable in terms of differences in the nature or the magnitude of environmental or genetic factors. *Present address: M.R.C. Epidemiological Research Unit (Jamaica), University of the West Indies, Kingston, Jamaica. This paper deals with the results of the Jamaican surveys ; they will be compared with the Welsh results in another paper.