Gerald A. C Grell

Social factors mediating social class differences in blood pressure in a Jamaican community

Research on the factors mediating social class differences in blood pressure was carried out in a Jamaican community. It was found in a previous report that higher social class is related to lower blood pressure for females, while for males higher social class is related to higher blood pressure. These differences are examined in greater detail here, especially in terms of the historical context of the specific community studied, which is on the fringe of the Kingston urban area, and in terms of the continuing importance of a social class system established under colonial rule. In the current study it is shown that social class differences in blood pressure for males are mediated by perceptions of social support. Social class differences in blood pressure for females are mediated by perceptions of economic stress. It is suggested that specific patterns of the growth of the city, and the historically-based social class system, have resulted in the juxtaposition of lower and middle class Jamaicans within this community, who in turn are influenced by different factors affecting blood pressure.

A survey of parasites in primary school children in Dominica, West Indies.

A study of Dominican school children aged four to twelve years showed that infection with gastrointestinal parasites was very common. Trichuris was found in the stools in 92% of the children, Ascaris in 38%, Necator in 11%, Giardia in 18% and E. histolytica in 1%. In spite of the high prevalence of parasites, the general health of the children studied was remarkably good, and only 18 of the 1000 children were found to have a haemoglobin level below 10 g/dl.

Blood pressure and social class in a Jamaican community.

A study of social factors and blood pressure was conducted in a Jamaican community among a sample of 199 persons ages 30 to 50. After controlling for obesity, age, and respondent tension (and other covariates), interaction effects of social class x sex for systolic and diastolic blood pressure were found. Blood pressure increased with increasing social class for males and decreased with increasing social class for females.

AGT and RH blood group polymorphisms affect blood pressure and lipids in Afro-Caribbeans

Population blood pressure variation is most likely due to multiple genes. This is likely the reason why monogenic testing with the angiotensinogen (AGT) gene polymorphisms on chromosome 1 (1q42–43), especially M235T, has met with negative results, especially in those of African descent. The RH blood group system, also on chromosome 1 (1 p36.2–34), has likewise been associated with blood pressure variation in African-Americans and with the rise in blood pressure with age in whites. Using a random sample of the population, we investigated the combined effects of single and combined variation of the AGTN M235T and RH genotypes on blood pressure, lipids, and lipoprotein concentrations in Afro-Caribbeans aged 18–60 years from the island nation of Dominica. In monogenic analysis, AGT M235T was not associated with blood pressure. However, it was associated with HDL (MM 42±23, MT 44±12, TT 52±14 (P=0.002)). RH genotype was significantly associated with systolic blood pressure (P=0.006) and Apo-A (P=0.003). These effects remained after adjustment for age, gender, weight, and BMI. In the polygenetic analysis, AGT M235T and RH were significantly associated with systolic blood pressure (P=0.037; interaction effects, P=0.068). The association of the AGT M235T with blood pressure across RH blood group haplotypes was then tested. Of the five RH haplotypes available for analysis, the AGT M235T was significantly associated with blood pressure within the “D” haplotype (P=0.01). The RH blood group and gender were significantly associated with systolic blood pressure and Apo-A levels (P=0.005 and 0.012, respectively). All interactions were independent of age and weight. In conclusion, we demonstrate a significant association of AGT M235T with blood pressure and cholesterol metabolism in an Afro-Caribbean population in the “genetic context” of the RH blood group system. Further investigation of these interactions may help understand the effects of genetic factors on cardiovascular risk in African-derived and other populations.

Health care system: chronic disease control in the english-speaking caribbean, with special reference to hypertension

Health systems and services in all islands in the English-speaking Caribbean have evolved from the British Colonial prototype with a ministry of health, a large central hospital, several district hospitals, and peripheral health centers and government clinics. Hyptertension is today the single most important contributor to deaths in adults in the Caribbean, and heart diseases and cerebrovascualr diseases are the 2 commonest causes of death overall. Currently, the management of chronic diseases in the West Indies is determined to a large extent by individual physician preference. Much work needs to be done. Some 40% of hypertensive patients are largely unaware of the diagnosis and only 13% were on therapy in a study performed in Barbados. Thus, there is urgent need to implement a hypertension detection and treatment program. The need for patient education is equally great. Education of all levels of health personnel should also be an important requirement for guaranteeing the necessary level of enthusiasm and for produucing a uniformity of management approach throughout the Caribbean. The success of a chronic disease program, in its implementation phase, will depend upon the extent to which it can be integrated into existing health care delivery systems. The current proposals for developing services to streamline the management of hypertension in the Caribbean recognize the need to centralize programs both nationally and regionally. In order to ensure continuity, the Caribbean coordinating committee has as its terms of reference: 1) to define and monitor the problem of hypertension in the region, 2) to initiate and maintain a regional management program, 3) to disseminate information, and 4) to produce a regionally applicable treatment protocol.