Cardiovascular DiseasesNCT00005340
Hypertension in Blacks of West African Origin
An observational study of Cardiovascular Diseases and Heart Diseases, run by National Heart, Lung, and Blood Institute (NHLBI).
Trial summary
To continue an international collaborative study on hypertension in populations of West African origin. Read more about this study
- Who is it for?
- Ages Up to 100 years, men only
- Conditions the study is for
- Cardiovascular Diseases, Heart Diseases, Hypertension
- How many people
- Not given
- Where
- No sites listed yet
- Study dates
- Sep 1991to Aug 2005
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Up to 100 years
- Men only
- No healthy volunteers
- Child, Adult, Older adult
No eligibility criteria
About this study
To continue an international collaborative study on hypertension in populations of West African origin.
Read the detailed description
BACKGROUND:
The increased risk of hypertension in United States Blacks remains a major unsolved public health problem. Comparisons between macro-population groups in the United States suffer from confounding by social factors and genetic admixture. The study's international comparative design provides a unique opportunity to ascertain the evolution of hypertension among populations with a common genetic background currently living in widely varied social conditions. A well-organized network of investigators currently exists in the societies of the Black diaspora and provides for the first time an opportunity to conduct cross-national research on this question.
DESIGN NARRATIVE:
During the first phase of the project over 12,000 adults between the ages of 25 and 74 were sampled from seven communities: West Africa (Nigeria, urban \& rural; Cameroon, urban \& rural), the West Indies (St. Lucia, Barbados) and Maywood (lllinois). The screening examination provided information on blood pressure (BP), height, weight, waist/hip ratio, alcohol use, education/occupation, sodium/potassium excretion and social stress. These data provided estimates of hypertension prevalence in each geographic region and the contribution of the known risk factor to higher rates among United States Blacks. In the first phase considerable effort was directed toward establishing a strong research infrastructure in each of the sites and demonstrating the feasibility of cross-national blood pressure comparisons.
In the second phase the research was continued and extended in three areas: 1) Population studies on risk factors. At the start of the study in 1991, it was not clear that adequate procedures were available to allow standardization of mean blood pressure across sites, especially since differences between some sites might be as little as 2 mmHg. Experience since that time suggested that it would be feasible to collect definitive data on this question. In-depth studies were carried out at one of the African sites to investigate the earliest stages of hypertension risk for a population. Investigators in Jamaica and the United Kingdom joined the collaborative group to examine the effect of migration from the Caribbean to the United Kingdom. 2) Prospective study of blood pressure and mortality. It was well known that hypertension accounted for much of the excess mortality among United States Blacks. It was less well recognized, however, that death rates among Blacks in the United States were higher than reported in the Caribbean or Africa. Hypertension was likely to account for that differential. A follow-up study in each region estimated the relative and attributable risk from hypertension. 3) Heredity/Genetics. The populations in this study shared a common ancestral origin in West Africa. Family studies were undertaken to determine the heritability of blood pressure/hypertension within and between sites. In addition, pilot studies on genetic distance and candidate genes for hypertension were conducted.
The study was renewed in FY 1999 to examine in further detail the role of the two most potent hypertensive risk factors, namely dietary sodium and obesity. Randomized studies will be carried out in Nigeria, Jamaica, and Chicago to determine the relative sodium sensitivity of these populations and the factors which condition the blood pressure response. The renin-angiotensin system and renal sodium handling will be compared as causal mechanisms. In addition, body composition will be studied in a large sample of each of the three populations to determine the role of body fat versus lean body mass. Insulin and leptin will be examined and physical activity will be measured by stable isotopes to assess the role of a sedentary lifestyle as a contributor to the hypertension risk experienced by the obese. Existing cohorts will be followed to determine hypertension sequelae and to examine changes in blood pressure with age.
- Conditions
- Cardiovascular Diseases, Heart Diseases, Hypertension, Obesity
- Medical subject headings
- Cardiovascular Diseases, Heart Diseases, Hypertension, Obesity
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 May 2000 (estimated)
- Study startSep 1991
- Primary completionAug 2005
- Study completionAug 2005
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (67)Papers the sponsor has linked to this study.
- Other trials for Cardiovascular DiseasesStudies of the same condition, open and under way.
- More trials run by National Heart, Lung, and Blood Institute (NHLBI)The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
Sponsor and investigators
- Sponsor type
- US National Institutes of Health
- Investigators
- Richard Cooper, Loyola University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00005340
- Sponsor's protocol ID
- 4202
- Other IDs
- R01HL045508
- Status last verified
- Jan 2008
- First submitted
- 25 May 2000
- Last updated
- 29 Jul 2016
- Results posted
- No
Publications
Rotimi C, Cooper R, Cao G, Sundarum C, McGee D. Familial aggregation of cardiovascular diseases in African-American pedigrees. Genet Epidemiol. 1994;11(5):397-407. doi: 10.1002/gepi.1370110502.
PubMed 7835686Rotimi C, Morrison L, Cooper R, Oyejide C, Effiong E, Ladipo M, Osotemihen B, Ward R. Angiotensinogen gene in human hypertension. Lack of an association of the 235T allele among African Americans. Hypertension. 1994 Nov;24(5):591-4. doi: 10.1161/01.hyp.24.5.591.
PubMed 7960018Cooper RS, Rotimi CN, Kaufman JS, Muna WF, Mensah GA. Hypertension treatment and control in sub-Saharan Africa: the epidemiological basis for policy. BMJ. 1998 Feb 21;316(7131):614-7. doi: 10.1136/bmj.316.7131.614. No abstract available.
PubMed 9518920Luke AH, Rotimi CN, Cooper RS, Long AE, Forrester TE, Wilks R, Bennett FI, Ogunbiyi O, Compton JA, Bowsher RR. Leptin and body composition of Nigerians, Jamaicans, and US blacks. Am J Clin Nutr. 1998 Mar;67(3):391-6. doi: 10.1093/ajcn/67.3.391.
PubMed 9497181Kaufman JS, Asuzu MC, Rotimi CN, Johnson OO, Owoaje EE, Cooper RS. The absence of adult mortality data for sub-Saharan Africa: a practical solution. Bull World Health Organ. 1997;75(5):389-95.
PubMed 9447773Kaufman JS, Asuzu MC, Mufunda J, Forrester T, Wilks R, Luke A, Long AE, Cooper RS. Relationship between blood pressure and body mass index in lean populations. Hypertension. 1997 Dec;30(6):1511-6. doi: 10.1161/01.hyp.30.6.1511.
PubMed 9403575Kaufman JS, Durazo-Arvizu RA, Rotimi CN, McGee DL, Cooper RS. Obesity and hypertension prevalence in populations of African origin. The Investigators of the International Collaborative Study on Hypertension in Blacks. Epidemiology. 1996 Jul;7(4):398-405. doi: 10.1097/00001648-199607000-00010.
PubMed 8793366Rotimi C, Luke A, Li Z, Compton J, Bowsher R, Cooper R. Heritability of plasma leptin in a population sample of African-American families. Genet Epidemiol. 1997;14(3):255-63. doi: 10.1002/(SICI)1098-2272(1997)14:33.0.CO;2-4.
PubMed 9181355Rotimi CN, Cooper RS, Marcovina SM, McGee D, Owoaje E, Ladipo M. Serum distribution of lipoprotein(a) in African Americans and Nigerians: potential evidence for a genotype-environmental effect. Genet Epidemiol. 1997;14(2):157-68. doi: 10.1002/(SICI)1098-2272(1997)14:23.0.CO;2-4.
PubMed 9129961Forrester T, McFarlane-Anderson N, Bennett FI, Wilks R, Cooper R, Rotimi C, Morrison L, Ward R. The angiotensin converting enzyme and blood pressure in Jamaicans. Am J Hypertens. 1997 May;10(5 Pt 1):519-24. doi: 10.1016/s0895-7061(97)00049-6.
PubMed 9160762Cooper RS, Rotimi CN, Kaufman JS, Owoaje EE, Fraser H, Forrester T, Wilks R, Riste LK, Cruickshank JK. Prevalence of NIDDM among populations of the African diaspora. Diabetes Care. 1997 Mar;20(3):343-8. doi: 10.2337/diacare.20.3.343.
PubMed 9051385Rotimi C, Cooper R, Ogunbiyi O, Morrison L, Ladipo M, Tewksbury D, Ward R. Hypertension, serum angiotensinogen, and molecular variants of the angiotensinogen gene among Nigerians. Circulation. 1997 May 20;95(10):2348-50. doi: 10.1161/01.cir.95.10.2348.
PubMed 9170394Luke A, Durazo-Arvizu R, Rotimi C, Prewitt TE, Forrester T, Wilks R, Ogunbiyi OJ, Schoeller DA, McGee D, Cooper RS. Relation between body mass index and body fat in black population samples from Nigeria, Jamaica, and the United States. Am J Epidemiol. 1997 Apr 1;145(7):620-8. doi: 10.1093/oxfordjournals.aje.a009159.
PubMed 9098179Kaufman JS, Rotimi CN, Brieger WR, Oladokum MA, Kadiri S, Osotimehin BO, Cooper RS. The mortality risk associated with hypertension: preliminary results of a prospective study in rural Nigeria. J Hum Hypertens. 1996 Jul;10(7):461-4.
PubMed 8880560Rotimi C, Cooper R. Familial resemblance for anthropometric measurements and relative fat distribution among African Americans. Int J Obes Relat Metab Disord. 1995 Dec;19(12):875-80.
PubMed 8963355
Study at a glance
From the registry record, last updated by the sponsor on 29 Jul 2016. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Hypertension in Blacks of West African Origin
- ClinicalTrials.gov ID
- NCT00005340
- Acronym / sponsor ID
- 4202
- Conditions
- Cardiovascular Diseases, Heart Diseases, Hypertension, Obesity
- Study type
- Observational
- Recruitment status
- Completed
- Lead sponsor
- National Heart, Lung, and Blood Institute (NHLBI)US National Institutes of Health
- Study start
- Sep 1991
- Primary completion
- Aug 2005 (actual)
- Study completion
- Aug 2005 (actual)
- First posted
- 26 May 2000 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
To continue an international collaborative study on hypertension in populations of West African origin.
Detailed description
BACKGROUND:
The increased risk of hypertension in United States Blacks remains a major unsolved public health problem. Comparisons between macro-population groups in the United States suffer from confounding by social factors and genetic admixture. The study's international comparative design provides a unique opportunity to ascertain the evolution of hypertension among populations with a common genetic background currently living in widely varied social conditions. A well-organized network of investigators currently exists in the societies of the Black diaspora and provides for the first time an opportunity to conduct cross-national research on this question.
DESIGN NARRATIVE:
During the first phase of the project over 12,000 adults between the ages of 25 and 74 were sampled from seven communities: West Africa (Nigeria, urban \& rural; Cameroon, urban \& rural), the West Indies (St. Lucia, Barbados) and Maywood (lllinois). The screening examination provided information on blood pressure (BP), height, weight, waist/hip ratio, alcohol use, education/occupation, sodium/potassium excretion and social stress. These data provided estimates of hypertension prevalence in each geographic region and the contribution of the known risk factor to higher rates among United States Blacks. In the first phase considerable effort was directed toward establishing a strong research infrastructure in each of the sites and demonstrating the feasibility of cross-national blood pressure comparisons.
In the second phase the research was continued and extended in three areas: 1) Population studies on risk factors. At the start of the study in 1991, it was not clear that adequate procedures were available to allow standardization of mean blood pressure across sites, especially since differences between some sites might be as little as 2 mmHg. Experience since that time suggested that it would be feasible to collect definitive data on this question. In-depth studies were carried out at one of the African sites to investigate the earliest stages of hypertension risk for a population. Investigators in Jamaica and the United Kingdom joined the collaborative group to examine the effect of migration from the Caribbean to the United Kingdom. 2) Prospective study of blood pressure and mortality. It was well known that hypertension accounted for much of the excess mortality among United States Blacks. It was less well recognized, however, that death rates among Blacks in the United States were higher than reported in the Caribbean or Africa. Hypertension was likely to account for that differential. A follow-up study in each region estimated the relative and attributable risk from hypertension. 3) Heredity/Genetics. The populations in this study shared a common ancestral origin in West Africa. Family studies were undertaken to determine the heritability of blood pressure/hypertension within and between sites. In addition, pilot studies on genetic distance and candidate genes for hypertension were conducted.
The study was renewed in FY 1999 to examine in further detail the role of the two most potent hypertensive risk factors, namely dietary sodium and obesity. Randomized studies will be carried out in Nigeria, Jamaica, and Chicago to determine the relative sodium sensitivity of these populations and the factors which condition the blood pressure response. The renin-angiotensin system and renal sodium handling will be compared as causal mechanisms. In addition, body composition will be studied in a large sample of each of the three populations to determine the role of body fat versus lean body mass. Insulin and leptin will be examined and physical activity will be measured by stable isotopes to assess the role of a sedentary lifestyle as a contributor to the hypertension risk experienced by the obese. Existing cohorts will be followed to determine hypertension sequelae and to examine changes in blood pressure with age.
Study design
Who may qualify
- Ages
- Up to 100 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Not reported in the source record.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Jul 2016.
- Background: PubMed 7835686Rotimi C, Cooper R, Cao G, Sundarum C, McGee D. Familial aggregation of cardiovascular diseases in African-American pedigrees. Genet Epidemiol. 1994;11(5):397-407. doi: 10.1002/gepi.1370110502.
- Background: PubMed 7960018Rotimi C, Morrison L, Cooper R, Oyejide C, Effiong E, Ladipo M, Osotemihen B, Ward R. Angiotensinogen gene in human hypertension. Lack of an association of the 235T allele among African Americans. Hypertension. 1994 Nov;24(5):591-4. doi: 10.1161/01.hyp.24.5.591.
- Background: PubMed 9518920Cooper RS, Rotimi CN, Kaufman JS, Muna WF, Mensah GA. Hypertension treatment and control in sub-Saharan Africa: the epidemiological basis for policy. BMJ. 1998 Feb 21;316(7131):614-7. doi: 10.1136/bmj.316.7131.614. No abstract available.
- Background: PubMed 9497181Luke AH, Rotimi CN, Cooper RS, Long AE, Forrester TE, Wilks R, Bennett FI, Ogunbiyi O, Compton JA, Bowsher RR. Leptin and body composition of Nigerians, Jamaicans, and US blacks. Am J Clin Nutr. 1998 Mar;67(3):391-6. doi: 10.1093/ajcn/67.3.391.
- Background: PubMed 9447773Kaufman JS, Asuzu MC, Rotimi CN, Johnson OO, Owoaje EE, Cooper RS. The absence of adult mortality data for sub-Saharan Africa: a practical solution. Bull World Health Organ. 1997;75(5):389-95.
- Background: PubMed 9403575Kaufman JS, Asuzu MC, Mufunda J, Forrester T, Wilks R, Luke A, Long AE, Cooper RS. Relationship between blood pressure and body mass index in lean populations. Hypertension. 1997 Dec;30(6):1511-6. doi: 10.1161/01.hyp.30.6.1511.
- Background: PubMed 8793366Kaufman JS, Durazo-Arvizu RA, Rotimi CN, McGee DL, Cooper RS. Obesity and hypertension prevalence in populations of African origin. The Investigators of the International Collaborative Study on Hypertension in Blacks. Epidemiology. 1996 Jul;7(4):398-405. doi: 10.1097/00001648-199607000-00010.
- Background: PubMed 9181355Rotimi C, Luke A, Li Z, Compton J, Bowsher R, Cooper R. Heritability of plasma leptin in a population sample of African-American families. Genet Epidemiol. 1997;14(3):255-63. doi: 10.1002/(SICI)1098-2272(1997)14:33.0.CO;2-4.
- Background: PubMed 9129961Rotimi CN, Cooper RS, Marcovina SM, McGee D, Owoaje E, Ladipo M. Serum distribution of lipoprotein(a) in African Americans and Nigerians: potential evidence for a genotype-environmental effect. Genet Epidemiol. 1997;14(2):157-68. doi: 10.1002/(SICI)1098-2272(1997)14:23.0.CO;2-4.
- Background: PubMed 9160762Forrester T, McFarlane-Anderson N, Bennett FI, Wilks R, Cooper R, Rotimi C, Morrison L, Ward R. The angiotensin converting enzyme and blood pressure in Jamaicans. Am J Hypertens. 1997 May;10(5 Pt 1):519-24. doi: 10.1016/s0895-7061(97)00049-6.
- Background: PubMed 9051385Cooper RS, Rotimi CN, Kaufman JS, Owoaje EE, Fraser H, Forrester T, Wilks R, Riste LK, Cruickshank JK. Prevalence of NIDDM among populations of the African diaspora. Diabetes Care. 1997 Mar;20(3):343-8. doi: 10.2337/diacare.20.3.343.
- Background: PubMed 9170394Rotimi C, Cooper R, Ogunbiyi O, Morrison L, Ladipo M, Tewksbury D, Ward R. Hypertension, serum angiotensinogen, and molecular variants of the angiotensinogen gene among Nigerians. Circulation. 1997 May 20;95(10):2348-50. doi: 10.1161/01.cir.95.10.2348.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Richard Cooper
Loyola University
Questions about this trial
What is this clinical trial studying?
An observational study of Cardiovascular Diseases and Heart Diseases, run by National Heart, Lung, and Blood Institute (NHLBI).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 29 Jul 2016. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00005340, which also lists 67 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Jul 2016.