PubMed Health⌕ Search

Biomedical subjects

C Rotimi

Publications and source records attributed to C Rotimi.

35 records · Page 2Linked to original sources
PubMed1997

The prevalence of hypertension in seven populations of west African origin.

OBJECTIVES: This study was undertaken to describe the distribution of blood pressures, hypertension prevalence, and associated risk factors among seven populations of West African origin. METHODS: The rates of hypertension in West Africa (Nigeria and Cameroon), the Caribbean (Jamaica, St. Lucia, Barbados), and the United States (metropolitan Chicago, Illinois) were compared on the basis of a highly standardized collaborative protocol. After researchers were given central training in survey methods, population-based samples of 800 to 2500 adults over the age of 25 were examined in seven sites, yielding a total sample of 10014. RESULTS: A consistent gradient of hypertension prevalence was observed, rising from 16% in West Africa to 26% in the Caribbean and 33% in the United States. Mean blood pressures were similar among persons aged 25 to 34, while the increase in hypertension prevalence with age was twice as steep in the United States as in Africa. Environmental factors, most notably obesity and the intake of sodium and potassium, varied consistently with disease prevalence across regions. CONCLUSION: The findings demonstrate the determining role of social conditions in the evolution of hypertension risk in these populations.

Adult↗
PubMed1996

Standardization of blood pressure measurement in an international comparative study.

In the context of a collaborative study on the epidemiology of hypertension in populations of West African origin procedures for standardization of the measurement of blood pressure were evaluated. Comparisons of mean levels of blood pressure, which in large part determine prevalence rates, are highly sensitive to differences in technique. While rotating a single field team may be the ideal approach to multisite studies, it is not practical in international collaborative research. Appropriate techniques to standardize multiple teams over a long period of time have not been well developed, however. In the present study 8981 individuals were examined in eight sites in six countries with the standard mercury sphygmomanometer. An evaluation of the effectiveness of central training, site visits, monitoring of digit preference, and the use of an electronic device for internal standardization is described. In all but one of the sites reliability was high and comparable to the observers at the Coordinating Center. Digit preference for the entire set of measurements was limited (frequency of terminal zero = 23.5% for systolic and 28.9% for diastolic readings) and could be shown to have virtually no effect on prevalence rates or correlation estimates. Mean differences among observers within a given site and between sites were small (+/- 0-5 mmHg). While logistically complex, these methods can provide the basis for standardization in international comparative blood pressure surveys.

Adult↗
PubMed1996

Is hypertension more severe among U.S. blacks, or is severe hypertension more common?

It is frequently stated that the risk of sequelae from hypertension at a given level of severity is higher among blacks than whites, although little empirical evidence supports that supposition. In this work we examined the basis for accepting the existence of a black: white differential in hypertension outcomes in a representative biracial sample of the U.S. population followed in the First National Health and Nutrition Examination Survey (NHANES-1) Epidemiologic Follow-up Study. As well recognized, the risk associated with increasing blood pressure is not dichotomous but varies across the entire distribution in a curvilinear fashion. The rightward skew of the blood pressure distribution with increasing mean levels affects comparisons between populations, since the change in shape results in a change in the mix of case severity. These considerations can influence estimates of the relative population-attributable risk from hypertension, considered as a dichotomous classification in blacks and whites. Although the relative risk of death associated with a systolic blood pressure of > or = 140 mmHg in this study was higher for blacks than for whites (1.7 and 1.5, respectively), with all-cause mortality as the outcome, the logistic coefficient for systolic blood pressure was not significantly different among white as compared with black men (beta = 0.016 vs. 0.010; p = 0.320 for race interaction term) and was slightly greater among white vs. black women (beta = 0.013 vs. 0.010; P = 0.05). After strata-specific blood pressure adjustment, the principal determinant of increased population risk for both black men and women was the higher prevalence of hypertension, not differential severity. The population-attributable risk for hypertension was at least two times higher among blacks because of the higher prevalence among them; moreover, the increased prevalence accounted for 10% of the interethnic difference in mortality. Data from this study indicate that hypertension was not more severe among individual blacks, simply more common in the population.

Adult↗
PubMed1996

Angiotensinogen and blood pressure among blacks: findings from a community survey in Jamaica.

OBJECTIVE: To examine the association between blood pressure, angiotensinogen levels, angiotensin converting enzyme activity and polymorphisms of the angiotensinogen and angiotensin converting enzyme genes in a population-based sample. METHOD: Five hundred participants were recruited in a house-to-house survey of three communities in metropolitan areas of Kingston and St Andrew, in Jamaica. Demographic data, anthropometric and blood pressure measurements were obtained for each participant during a brief clinic visit. Circulating levels of angiotensinogen and angiotensin converting enzyme activity were measured in venous blood samples. Polymorphisms of the angiotensinogen and angiotensin converting enzyme genes were determined. RESULTS: A weak association between angiotensinogen level, angiotensin converting enzyme activity and blood pressure was identified in this population, but substantial joint effect of angiotensin converting enzyme activity and angiotensinogen level on blood pressure was apparent. Variants of the angiotensinogen gene had inconsistent effects on blood pressure and on the risk of hypertension. Angiotensinogen level and angiotensin converting enzyme activity were significantly related to several measures of obesity, including body mass index, waist circumference and skin fold thickness. CONCLUSION: The angiotensinogen and angiotensin converting enzyme genetic variants which were studied appear to have only a modest relationship with blood pressure and associated anthropometric risk factors among blacks.

Adult↗
PubMed1996

Polymorphisms of renin-angiotensin genes among Nigerians, Jamaicans, and African Americans.

Within the context of an international collaborative study of the evolution of hypertension in the black diaspora, we determined the allelic distribution of hypertension candidate genes for the renin-angiotensin system in three populations of African origin. The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) and the M235T and T174M variants of the angiotensinogen (AGT) gene were examined in individuals from Nigeria, Jamaica, and the United States. Large differences in the prevalence of hypertension were recorded in door-to-door surveys, ranging from 16% in Nigeria to 33% in the United States. The frequency of the D allele was similar in all groups (54%, 59%, and 63% in Nigeria, Jamaica, and the United States, respectively). The 235T allele of the AGT gene was found in 81% of US and Jamaican blacks and 91% of Nigerians; very little variation was seen for the T174M marker. Despite large differences in hypertension rates, genetic variation at the index loci among these groups was modest. Overall, the frequency of the ACE*D allele was only slightly higher than that reported for European and Japanese populations, whereas the AGT 235T allele was twice as common. Compared with blacks in the western hemisphere, Nigerians had a higher frequency of the 235T allele, which is consistent with 25% European admixture in Jamaica and the United States. The results indicate the potential for etiologic heterogeneity in genetic factors related to hypertension across ethnic groups while suggesting that environmental exposures most likely explain the gradient in risk in the comparison among black populations.

Alleles↗
PubMed1996

A comparative study of hypertension prevalence, awareness, treatment and control rates in St Lucia, Jamaica and Barbados.

BACKGROUND: Cardiovascular diseases represent the most common cause of death in the English-speaking Caribbean, and hypertension represents the most important predisposing condition. However, direct between-country comparative studies in the Caribbean have not previously been undertaken. OBJECTIVE: To obtain estimates of hypertension prevalence, awareness, treatment and control in three countries in the Caribbean. DESIGN: Population-based samples of adults aged 25-74 years in St Lucia, Barbados and Jamaica were surveyed regarding their cardiovascular health and their blood pressures were measured using a highly standardized protocol. A reference site was available from a collaborative study among blacks in metropolitan Chicago, Illinois, USA. RESULTS: At the 160/95 mmHg threshold, age-adjusted hypertension prevalence estimates for Jamaica, St Lucia and Barbados were 17.5, 18.3 and 21.5%, respectively, and 24.7, 26.9 and 27.9%, respectively, at the 140/90 mmHg threshold. The corresponding estimate for the Chicago site at the 140/90 mmHg threshold was 33.2%. The gradient in prevalence resembled the gradient in body mass index (25.7 kg/m2 in Jamaica to 29.3 kg/m2 in the USA). At the 160/95 mmHg threshold, the proportion of all hypertensives who were aware of their disease, pharmacologically treated and controlled was highest in Barbados (90, 85 and 72%, respectively) and lowest in St Lucia (74, 59 and 35%, respectively). Men, particularly those aged less than 55 years, were less likely to have their hypertension treated and controlled. CONCLUSIONS: Compared with estimates from earlier independent surveys, considerable progress has been made in hypertension detection and control in these countries, which should lead to sizable reductions in the burden of cardiovascular disease.

Adult↗
PubMed1995

Basal and stimulated platelet calcium and sodium in hypertensive versus normotensive black people.

To examine further the potential role of intracellular cations in hypertension a nested case-control study was carried out in conjunction with a population-based survey. Based on a house-to-house sampling scheme, 43 hypertensive and 56 normotensive black residents of Maywood, IL, were recruited. Free cytosolic calcium (Cai) and intracellular stores of calcium after stimulation with ionomycin were determined in platelets with the fluoroprobe Indo-I; intracellular sodium (Nai) measured at rest and after incubation with ouabain was estimated with SBFI. Cell sodium content was also assayed in erythrocytes. Resting Cai and Nai were not different in hypertensives compared with normotensives, although ionomycin-stimulated levels of Cai were correlated with systolic blood pressure (r = 0.3; P = 0.04). A consistent set of inter-relations among the various cation parameters was observed, lending support to the hypothesis that the cellular metabolism of sodium and calcium may be linked in the pathophysiological pathway to hypertension.

Adult↗
PubMed1995

Familial resemblance for anthropometric measurements and relative fat distribution among African Americans.

Obesity has emerged as a major public health problem in the African-American community and its determinants are poorly understood. The purpose of this study was to examine familial patterns of the degree of heaviness and of regional fat deposits. Seven anthropometric measurements (height, weight, body mass index [BMI], waist and hip circumferences, waist-to-hip ratio and arm circumferences) were examined in a population sample of African-American nuclear families recruited from the Chicago area. Participants included 162 parent pairs and 114 sets of siblings (a total of 295 sons and daughters). Adjustments to correct for the effect of age and sex were performed separately for parents and siblings and the residuals were transformed to normalized z-scores to calculate intraclass correlations between family members. With the exception of waist-to-hip ratio, all variables showed positive familial resemblance, although the degree and level of statistical significance varied by type of relationship. Significant familial resemblance was observed for peripheral fat deposit, as measured by hip and arm circumferences (range: 0.04 for spouse pairs to 0.42 for daughter pairs), and obesity, as measured by BMI (range: 0.12 for spouses to 0.33 for mother-daughter comparison). Significant sex and generation differences were observed for height and hip. We conclude that African Americans exhibit significant familial resemblance for stature, degree of heaviness and regional fat deposits. Understanding the relative contributions of shared genes and shared environmental factors to the observed familial patterns could yield important insights into the origins of obesity in this high risk population.

Adolescent↗
PubMed1994

Familial aggregation of cardiovascular diseases in African-American pedigrees.

Familial aggregation of cardiovascular diseases and diabetes has been consistently demonstrated. However, virtually all of the evidence on the familial patterns of these diseases has come from white population samples. This study evaluates the level of familial excess risk among first degree relatives of 232 African-American pedigrees which included 1,420 individuals recruited from the Chicago, IL, area. Excess disease risk was observed among relatives (parents and offsprings) of affected probands compared to relatives of unaffected probands for coronary heart disease (odds ratio [OR] = 5.30; 95% confidence interval [CI] = 2.51-11.23); hypertension (OR = 1.98; CI = 1.41-2.80); stroke (OR = 3.24; CI = 1.08-9.70); and diabetes (OR = 2.95; CI = 1.55-5.62). The results of this study clearly show that coronary heart disease, hypertension, stroke, and diabetes aggregate in some African-American families and not others. Unaffected relatives of persons suffering from these diseases should be encouraged to have their blood pressure, lipid, and blood glucose levels measured at frequent intervals. These recommendations are particularly urgent in African-American communities because of the disproportionately high morbidity and mortality experienced from cardiovascular diseases and diabetes.

Adult↗
PubMed1994

Angiotensinogen gene in human hypertension. Lack of an association of the 235T allele among African Americans.

The frequency of the 235T and 174M alleles of the angiotensinogen gene, previously reported to be associated with hypertension in Caucasians and Japanese, was compared between 57 hypertensive African Americans and 130 normotensive African Americans sampled as part of a community survey of hypertension in the Chicago area. The frequency of the 235T allele was unrelated to hypertension status (cases, 83%, control subjects, 82%), as was true for the 174M allele. Compared with Caucasians, the frequency of the 235T allele was twice as high in this African American population, while the frequency of the 174M allele was similar. Even higher frequencies of the 235T allele (93%) were noted in a sample of 122 Nigerians. It appears that the 235T allele is very common in populations of West African origin, although we found no evidence that it confers risk of hypertension.

Adult↗
PubMed1993

Retrospective follow-up study of foundry and engine plant workers.

A retrospective follow-up study of 21,013 workers employed at a foundry and two engine manufacturing plants was conducted to determine if these workers had an unusual mortality experience. A total of 2,235 deaths occurred during the follow-up period of 1970-1987. Mortality from all causes was lower than expected. Men experienced a 6-13% excess of lung cancer deaths, depending on the choice of the comparison group. The data displayed evidence of a positive trend between lung cancer mortality and increasing duration of employment (p = 0.008). White men experienced a statistically significant excess of deaths from stomach cancer (standardized mortality ratio [SMR] = 158; 95% confidence interval [CI] = 101-234). Black men had increased mortality from pancreatic cancer, especially among engine plant workers (SMR = 303; CI = 121-624), and an excess of prostate cancer, concentrated among foundry workers (SMR = 234; CI = 112-430).

Adult↗
PubMed1993

Hypertension, diabetes, and obesity in Barbados: findings from a recent population-based survey.

A stratified random sample of 464 persons aged 40 to 79 years, drawn from enumeration registers in the Bridgetown area of Barbados, participated in this survey. The prevalence of hypertension (defined as systolic blood pressure of at least 160 mm Hg, diastolic blood pressure of at least 95 mm Hg, or use of antihypertensive medication) was 47% and 43% for women and men, respectively. Diabetes was present in 17% of all subjects (18% of women and 15% of men). Of the 209 hypertensive subjects, 82% were aware of their blood pressure status. The proportion of previously diagnosed hypertensive subjects on medication was 72% for men and 68% for women. Fifty-three percent of men and 42% of women were overweight (body mass indices [weight in kilograms divided by height in meters squared] between 25 and 30). However, 30% of women and 10% of men were obese (body mass indices over 30), supporting the growing recognition of the marked gender disparity in obesity among persons of African origin in the Caribbean. Body mass index was positively associated with hypertension (OR = 1.33; 95% CI: 1.1-1.6). Obese persons experienced a 2.6 times greater risk of hypertension compared to those with body mass indices below 25. Similar statistically significant associations were observed between diabetes and body mass index: OR comparing body mass index over 30 with body mass index under 25 was 2.5 (95% CI: 1.3-5.1) for all subjects, 1.0 (0.3-4.1) for men only, and 5.2 (1.9-14) for women only. Preventing obesity in this population could reduce the incidence of hypertension and diabetes by approximately 30% and 33% among men and women, respectively.

Adult↗
PubMed1993

Establishing the epidemiologic basis for prevention of cardiovascular diseases in Africa.

A child born today in the rich countries of the world will inherit the expectation of living into the mid-70s. In Africa, of those surviving to the age of 5 years, the expectation of reaching the mid-50s remains in doubt. Inequality in the opportunity to experience life itself remains the cruelest inequality of all. As in many other fields, the technological experience accumulated by the economically wealthy countries can be put to useful purposes in underdeveloped regions. Given the longer history of chronic disease epidemiology in wealthy societies, much has been learned and many successes have been achieved. These lessons are, to a large extent, exportable. An opportunity to avoid the transition to high rates of CVDs and cancer therefore exists through implementation of primary prevention programs. Despite the competing priorities, a coordinated and sustained effort to achieve this goal should be initiated without further delay.

Adult↗
PubMedDate not supplied

Prevalence of cardiovascular risk factors in an African, urban inner city community.

With the epidemiological transition phenomenon, more countries are expected to move from a disease pattern dominated by infectious diseases to one characterised by non-communicable diseases. Many developing countries are contending with infectious diseases as well as non-communicable diseases, yet little is known about the prevalence of cardiovascular risk factors in poor urban communities in developing countries. The objective of this community based study was to determine the prevalence of selected cardiovascular risk factors in an urban inner city community which had been followed up prospectively from 1993 to 1998. Results show that the prevalence of hypertension (Blood Pressure BP > 160/95 mm Hg) was 12.4 percent with an age-adjusted rate of 7.4 percent. This is higher than what is found in the rural parts of the country but much lower than what is generally observed in industrialized countries of the world. Though there was no significant difference in the proportion with hypertension by gender (P > 0.05), the mean systolic BP was significantly higher for men (123.9 +/- 23.9) mm Hg) than for women (120.6 +/- 26.8 mg Hg) t = 2.93, p < 0.01. The mean diastolic BP was similarly higher for men (75.8 +/- 14.9) mm Hg than women (74.0 +/- 14.9) mm Hg t = 2.76 p < 0.01). Eight percent of the study population were obese (BMI > 30), and generally, more women than men were obese. However, at ages 15-19 significantly more males than females were obese (X2 = 73, p < 0.01). Both mean systolic and diastolic BP increased with increasing weight. When adjusting for gender, the association between hypertension and other CVD risk factors remained similar for males and females and gender was not a modifier of the factors. Of the CVD risk factors studied, Age > 40 years and obesity, were significantly associated with the presence of hypertension in this community (P < 0.0001 and P < 0.0001), smoking, alcohol intake and gender were not (P > 0.05). It is necessary to implement a national plan for the control of cardiovascular diseases in order to reduce and keep to minimum cardiovascular diseases and its complications in the country.

Adolescent↗
PubMedDate not supplied

Hypertension prevalence, awareness, treatment, and control among African Americans in the 1990s: estimates from the Maywood Cardiovascular Survey.

During the last decade, the decline in cardiovascular disease mortality slowed among African Americans, compared to the general population. Hypertension control is likely to play an important role in determining these trends. The Maywood Cardiovascular Survey provides estimates of the prevalence, awareness, treatment, and control of hypertension among African Americans. Between 1991 and 1993, we conducted a cardiovascular disease survey among 1,524 African Americans living in the Chicago suburb of Maywood, Illinois. Estimates of the prevalence, awareness, treatment, and control of hypertension (defined as blood pressure [BP] > or = 140/90 mm Hg or self-reported taking of antihypertensive medications) were calculated and compared to U.S. population estimates for African Americans from NHANES II and III. The prevalence of hypertension in our sample was 32.7% (30.3, 35.1). After age-adjustment to the U.S. population, prevalence was 29.9% (27.9, 31.9), which is nonsignificantly lower than that reported for African Americans in NHANES III (32.4% [30.2, 34.6]). Awareness, pharmacologic treatment, and control on pharmacologic treatment were 81%, 56%, and 55%, respectively. These estimates are, respectively, 15%, 27%, and 42% higher than NHANES II and 7%, 9%, and 11% higher than NHANES III. Nonpharmacologic treatment alone may have accounted for up to 34% of hypertension control overall. Among previously diagnosed hypertensive subjects, risk factors for being untreated were male gender (odds ratio [OR] = 5.3 [1.3, 21.3]) and age < 45 years (OR = 3.8 [1.1, 12.8]), and for being uncontrolled was age > or = 65 years (OR = 1.9 [1.1, 3.0]). Rates of hypertension awareness, pharmacologic treatment, and control on pharmacologic treatment are higher in this sample of African Americans than among African Americans in NHANES II and are comparable to those in NHANES III. The impact of nonpharmacologic treatments on control needs further consideration. Medical Subject Headings (MeSH): hypertension, nonpharmacologic treatment, African-American males.

Adult↗