The subjects reported here (Table 3.1) were recruited from semirural primary care clinics on the island of St. Vincent [45] after ethical approval from the Ministry of Health of St. Vincent and the Grenadines. All subjects were of African ancestry as defined by grandparental and parental ethnicity. St. Vincent and the Grenadines are a small group of islands in the West Indies, with a relatively homogenous population. They have the genetic advantage of low migration rates, little raci‘l admixture and a small gene pool. In addition, they have a high prevalence of essential hypertension, making them an ideal group to study. The population of the islands in 1986 was 110,000 of which 40% were under 15 years and 3.9% were over 65 years. Hypertension is the leading cause of death in St. Vincent’s for over 65’s, accounting for 14% of all cause mortality at 89/1000,000 deaths.
139 unrelated individuals with essential hypertension and a recorded family history of parental or sibling hypertension were defined by blood pressure ≥ 95 mm Hg, or by receipt of antihypertensive therapy with documentary evidence of blood pressures ≥ 95 mm Hg diastolic. Blood pressure was measured in accordance with the 1986 British Hypertension Society guidelines [163]. All individuals with clinical evidence of secondary hypertension and diabetes were excluded. 82 unrelated normotensive controls with a negative family history of parents or siblings with hypertension and diastolic blood pressure less than 85 mmHg were also identified from the same primary care clinics.
Age, body mass index, alcohol consumption in units per week, smoking habit, blood pressure, blood glucose (using a glucometer from Boehringer-Mannheim, Mannheim, Germany), and current treatment were recorded. Hypertensive unrelated cases, normotensives, and random controls were drawn from the same population. Genomic DNA was extracted from whole blood taken into potassium EDTA tubes using phenol-chloroform purification after transfer to the United Kingdom.
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© 2001 Alexander Binder