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Biomedical subjects

C G Hames

Publications and source records attributed to C G Hames.

At least 19 recordsLinked to original sources
PubMed1996

Ethnicity and cardiovascular disease: The Evans County heart study.

A long term study of diversity between two ethnic groups was developed in Evans County, Georgia. The findings are predicated on the genotypic-phenotypic interactions, with the multitude of environmental factors. The genetic-environmental interaction ultimately determines the individual's state of health or disease. For example, coronary heart disease prevalence and incidence rates were extremely low for blacks in Africa and four times lower than whites in rural South Georgia in the 1960s. Excessive hypertension and diabetes mellitus, and greater cerebrovascular disease mortality in black men, is now well known. Blood pressure levels studied in rural Africa were normal and did not rise with age, whereas blacks, conversely, demonstrated twice as much hypertension in South Georgia as whites and demonstrated an inverse relation between education and blood pressure (ie, the lower the education the higher the blood pressure). Cultural adaptation has accelerated hypertensive disease and strokes in blacks, while there remains an excess of atherosclerotic coronary heart disease in white men. Secular trends suggest that coronary heart disease is decreasing among white men but may be increasing in black men. Studies of ethnicity and biracial populations provide important cardiovascular disease associations with clinical risk factor studies.

Black or African American↗
PubMed1995

Coronary disease mortality and risk factors in black and white men. Results from the combined Charleston, SC, and Evans County, Georgia, heart studies.

BACKGROUND: Epidemiologic studies begun in the southeastern United States in the 1960s indicated that the prevalence of coronary disease was two to three times greater among white men than black men and also showed an excess incidence of coronary disease among white men, although hypertension was twice as prevalent among blacks. This study was conducted to determine if racial differences exist in coronary heart disease mortality and coronary risk factors. METHODS: Data from the two population-based cohorts of the Charleston, SC, and Evans County, Georgia, Heart Studies were pooled to make comparisons of coronary disease mortality and its risk factors. A total of 726 black men and 1346 white men aged 35 years or older in 1960 in the combined cohort were followed up for 30 years. RESULTS: There were 125 deaths among the black men and 323 deaths among the white men attributable to coronary disease; the age-adjusted rates were 5.0 per 1000 person-years in the black men and 6.5 per 1000 person-years in white men. Black-white coronary mortality risk ratios were 0.8 when age adjusted and 0.7 when also adjusted for other cardiovascular risk factors. Elevated systolic blood pressure and cigarette smoking were significant predictors of coronary mortality in black and white men. Serum total cholesterol level was a statistically significant risk factor only in white men. Higher education level was significantly protective in black and white men. CONCLUSIONS: Black men experienced significantly less coronary disease mortality than white men. Except for cholesterol level, the risk factors for coronary mortality in black and white men were similar.

Adult↗
PubMed1995

Outcomes of black and white hypertensive individuals after 30 years of follow-up.

Outcomes of a 30-year follow-up for the participants of the Charleston Heart Study were studied with elevated blood pressure assessed using various classifications. The traditional categories of > or = 140/90 mmHg, > or = 160/95 mmHg and isolated systolic hypertension, as well as high normal and the four stages of high blood pressure were utilized in analyses. Prevalence rates of hypertension were, in general, higher among blacks compared to whites. Blacks had higher prevalence rates of hypertension and greater prevalence of high blood pressure at younger ages. Risk ratios were higher for black and white hypertensives than their normotensive counterparts. Blacks were found to have substantially higher population attributable risk proportions, particularly at the higher blood pressure categories. The results suggest that the standard clinical classifications of hypertension as related to mortality are appropriate for blacks and white.

Adult↗
PubMed1994

Potential of practice-based research networks: experiences from ASPN. Ambulatory Sentinel Practice Network.

During the past 20 years, the feasibility of practice-based research in networks has been established in the United States. The initial work of these networks has revealed the need for a better understanding of family practice and the rest of primary care in order to address the challenges facing our health care system. This paper explores the nature, potential, and limitations of practice-based research networks based on the results of a dozen studies conducted by the Ambulatory Sentinel Practice Network (ASPN).

Adolescent↗
PubMed1993

Plasma ascorbic acid concentrations relate inversely to blood pressure in human subjects.

This study relates antioxidant status and blood pressure (BP) in 168 healthy residents of Augusta, GA, following usual diets. BP ranges were systolic (S) 84-152, mean 112 +/- 1 mm Hg, and diastolic (D) 52-96, mean 72 +/- 1 mm Hg. Plasma concentrations of ascorbic acid (AA) were significantly inversely related to SBP (r = -0.18, P < 0.05) and DBP (r = -0.20, P < 0.01); with regression equations SBP vs AA = -0.083C + 116 and DBP = -0.077C + 76. Highest and lowest quintiles of AA differed significantly in mean SBP (108 +/- 2, 113 +/- 2 mm Hg) and DBP (69 +/- 1, 74 +/- 2), P < 0.05. Plasma AA concentrations were significantly lower in the smokers. By deleting smokers, the inverse relations of SBP and DBP with plasma AA and the slopes of the equation were enhanced. Plasma selenium, alpha-tocopherol, alpha-tocopherol:cholesterol ratio, retinol and taurine were not related to BP; whereas male gender, body mass index, body fat distribution, plasma cholesterol, low density lipoprotein cholesterol, and triglycerides correlated.

Adipose Tissue↗
PubMed1993

Black-white comparisons of 20-year coronary heart disease mortality in the Evans County Heart Study.

The Evans County Heart Study was initiated to compare the epidemiology of coronary heart disease (CHD) of black and white residents of a southeastern United States community. The study was prompted by a clinical observation that CHD appeared to be less frequent in black than white patients, despite a much higher prevalence and greater severity of hypertension in blacks. A total community-based, closed cohort study was initiated with a prevalence survey in 1960-1962. The 20-year follow-up experience of the Evans County cohort confirmed the importance of the major risk factors of serum cholesterol, smoking and blood pressure for middle age and older, black and white men and women for CHD, cardiovascular disease (CVD) and all-cause mortality. Black men were less likely to die of CHD than white men, and this relative protectiveness increased upon adjusting for risk factors and also increased with age. The relative protectiveness of black men for CHD mortality was also reflected in lower black than white CVD and all-cause mortality in men 65 years of age and older.

Adult↗
PubMed1992

Greater incidence of electrocardiographic left ventricular hypertrophy in black men than in white men in Evans County, Georgia.

Population-based studies of black populations in the United States and Puerto Rico have reported higher prevalences of electrocardiographic left ventricular hypertrophy compared to white or lighter-skinned populations residing in the same areas. This study examines the incidence and correlates of electrocardiographic left ventricular hypertrophy in a population-based, biracial cohort of 435 white and 163 black men from the Evans County, Georgia, Heart Study, who were examined at entry in 1960 and reexamined in 1967. Only men over 35 years of age who were free of cardiovascular disease and had normal electrocardiograms at entry were eligible. Black men had a nearly fourfold greater incidence of electrocardiographic left ventricular hypertrophy compared to white men (13.5% vs 3.7%, respectively; incidence ratio 3.7; 95% CI 3.2-4.4). After statistically adjusting for age, systolic blood pressure, weight, and the change in weight and blood pressure, black men had a threefold greater incidence of electrocardiographic left ventricular hypertrophy compared to white men (logistic odds ratio 3.0; 95% CI 1.6-6.1). In summary, black men showed a significantly greater risk of developing electrocardiographic left ventricular hypertrophy at 7-year follow-up in Evans County compared to their white counterparts. This elevated risk could not be explained by the independent or joint effects of risks factors for electrocardiographic left ventricular hypertrophy.

Adult↗
PubMed1991

Socioeconomic status and morbidity and mortality in hypertensive blacks.

Despite an overall limited range of social and economic opportunities in the recent past, blacks of lower socioeconomic status have experienced marked excesses in hypertension-related burdens compared with their more advantaged peers: the incidence, prevalence, and severity of hypertension and its end-organ sequelae increased with decreasing educational achievement and the 5-year mortality was two times higher for black hypertensives of lower than higher educational achievement under conditions of usual care in U.S. communities in the 1970s. The Stepped Care program of antihypertensive pharmacologic therapy of the HDFP reduced all-cause mortality by 19% for black hypertensive men and 28% for black women. The HDFP also eliminated the association of mortality with educational achievement; the favorable impact of the program was greatest in the group at highest risk, blacks of lowest socioeconomic status.

Adult↗
PubMed1990

Biochemical, endocrine, and mineral effects of indapamide in black women.

Black women with established essential hypertension, without renal insufficiency or diabetes mellitus, were withdrawn from their usual antihypertensive therapy for 2-3 weeks prior to entry into a study to evaluate pertinent biochemical and mineral effects of indapamide treatment. Twenty patients with a sitting diastolic blood pressure greater than 90 mm Hg had baseline measurements of plasma total cholesterol, HDL cholesterol, triglycerides, glucose, uric acid, potassium, magnesium, calcium, selenium, renin, norepinephrine, whole blood ionized calcium, and glycosylated hemoglobin. Low-density lipoprotein (LDL) cholesterol was calculated by the Friedewald equation. The patients were placed on a fixed daily dose of 2.5 mg indapamide. Blood pressure and blood tests were repeated at 4, 8, and 12 weeks of treatment. The systolic and diastolic blood pressure were both lowered significantly at week 12. Plasma renin activity was significantly increased. There was no significant change in norepinephrine, glucose, glycosylated hemoglobin, uric acid, ionized calcium, calcium, triglycerides, potassium, magnesium, or selenium. Total cholesterol increased with an increase in both high-density lipoprotein (HDL) and LDL cholesterol; however, these increases did not alter significantly either the total/HDL cholesterol or LDL/HDL cholesterol ratios. It is concluded that 2.5 mg of indapamide per day effectively lowers blood pressure with no significant adverse metabolic effects.

Adult↗
PubMed1990

Passive smoking and 20-year cardiovascular disease mortality among nonsmoking wives, Evans County, Georgia.

The association of passive smoking and cardiovascular disease (CVD) mortality was assessed in a cohort of 513 rural, married Black and White women who were disease-free and self-described as never-smokers at baseline in 1960. Over a 20-year period, 76 of 147 total deaths were attributed to CVD. Relative risk estimates adjusted for age, cholesterol, blood pressure, and body mass from proportional hazards models were 1.59 for CVD (95% CI = 0.99, 2.57) and 1.39 (CI = 0.99, 1.94) for all cause mortality among women with husbands who smoked cigarettes.

Adolescent↗
PubMed1988

Race and sex differences in the correlates of blood pressure change.

Potential predictors of systolic and diastolic blood pressure change between 1960 and 1967 in the biracial population of Evans County, Georgia, were investigated. An all possible regressions multiple linear regression analysis was used. For systolic blood pressure change, the level of systolic blood pressure, age, and change in Quetelet index were significant (p less than 0.05) correlates in white men. The level of systolic blood pressure, the level and change of socioeconomic status, change in Quetelet index, and change in cholesterol were significant correlates for white women. The level of Quetelet index was of borderline significance (p less than 0.055) when the other significant variables were included in the model for white women. The change in Quetelet index was the only significant correlate of systolic blood pressure change in blacks. For diastolic blood pressure change, age, change in hematocrit, and change in Quetelet index were significant correlates for white men. Age, level and change of socioeconomic status, level and change of Quetelet index, and change in hematocrit were the significant correlates in white women. In black men, change in Quetelet index and age were significant. In black women, only age was a significant correlate of diastolic blood pressure change. These results indicate that there may be important differences in these correlates between race-sex groups and thus in the mechanism of blood pressure change for different race-sex groups. groups.

Adult↗
PubMed1988

Status of patients seven years after completion of the hypertension detection and follow-up program in Evans County, Georgia.

The Evans County, Georgia, cohort of the Hypertension Detection and Follow-up Program (HDFP) was reexamined seven years after termination of the trial in 1979. Of the 510 survivors, 91 percent of the black and 91 percent of the white hypertensive subjects were evaluated by blood pressure (BP) levels, electrocardiograms (ECG), height-weight measurements, and questionnaire. The HDFP had treated a randomly selected half of the patients in an intensive stepped care (SC) program and the other half was referred to usual care (RC). At the beginning of the five-year trial, diastolic blood pressure (DBP) levels were higher in blacks in both SC and RC. At the completion of the trial in 1979, black women had mean DBP levels comparable to whites in both SC and RC, but black men displayed higher levels. During the five years of the trial there were no cases of left ventricular hypertrophy (LVH) in SC in either race. In RC the incidence of LVH was slightly higher in blacks than in whites. During the seven-year post-trial period, the incidence of LVH in blacks rose to 13 percent, more than double that of whites. Medication compliance was reduced in black men during this time, most likely because of removal of the supporting elements of HDFP (frequent medical contacts, free medication).In both races, hypertensive subjects underwent weight changes during the seven years of the post-trial period. Weight loss of 15 lb was associated with normotension. Weight gain of 9 to 10 lb over seven years was associated with hypertensive BP levels.The supportive or detrimental effect of weight loss or weight gain on BP levels was thus reconfirmed in this biracial cohort.

Adult↗
PubMed1987

Genetic analysis of serum lipid levels and blood pressure in a large kindred.

A 267-member Caucasian kindred with a high incidence of cardiovascular disease, originally from Evans County, Georgia, was chosen for genetic analysis of serum lipid levels and blood pressure. Total serum cholesterol, triglycerides, high density lipoprotein cholesterol (HDL), and systolic and diastolic blood pressures were natural logarithm transformed and then adjusted for significant age, sex, and behavioral trait effects. Major gene pedigree analysis was used to estimate genetic parameters and to test hypotheses about the mode of transmission of each trait. Multivariate methods were also used to estimate linear combinations of the variables that best fit genetic models. The data were consistent with a major gene segregating for high levels of triglycerides in this kindred. However, dominant and recessive hypotheses could not be distinguished. Although diastolic blood pressure fit a mixture of two distributions significantly better than a single normal, major gene hypotheses could be rejected while the no-transmission hypothesis could not. There was no evidence of a major gene effect on cholesterol, HDL, systolic blood pressure, or any of the hypothetical traits represented by linear functions of the physical-lipid traits.

Adult↗
PubMed1987

Electrocardiographic abnormalities and mortality among middle-aged black men and white men of Evans County, Georgia.

The distribution of electrocardiographic (ECG) abnormalities and the relationship between ECG abnormalities and mortality after 20 years of follow-up were examined among 40-64-year-old black men and white men enrolled in the Evans County Heart Study. Major or minor ECG abnormalities, as defined in the Pooling Project, were present at entry for 53% of blacks (164 of 308) and 31% of whites (159 of 511). For both races, the presence of ECG abnormalities was directly related to age, blood pressure, and Quetelet's index at baseline. After adjustment for these and other risk factors, major ECG abnormalities were similarly predictive of all-cause mortality for blacks [rate ratio (RR) = 1.7 (1.1.2.8)] and whites [RR = 2.2 (1.4, 3.4)]. Associations of similar magnitude were observed in relationship to deaths from all cardiovascular diseases and deaths from coronary heart disease. These results are consistent with the hypothesis that ECG abnormalities convey risk for blacks as well as whites.

Adult↗
PubMed1986

Cardiovascular disease risk factors and mortality among black women and white women aged 40-64 years in Evans County, Georgia.

There have been few prospective studies of the epidemiology of cardiovascular disease in women, especially black women. The authors report the 20-year mortality experience of 391 black and 549 white women aged 40-64 years recruited in 1960-1961 into the Evans County Cardiovascular Study. The vital status of 98.9% of the white women and 96.2% of the black women had been determined as of May 1, 1980. Using Cox' proportional hazards model, the authors estimated that black women had a 70% excess risk of cardiovascular disease mortality compared with white women, unadjusted for any risk factors. At entry, black women had higher systolic blood pressure, higher Quetelet index, lower serum cholesterol, lower social status, and similar age distribution and prevalence of cigarette smoking compared with white women. Cardiovascular disease mortality was significantly associated with systolic pressure in all women, serum cholesterol in white women, and Quetelet index in low social status white women. Adjustment for cardiovascular disease risk factors and social status explained most of the difference in cardiovascular disease mortality between blacks and whites.

Adult↗
PubMed1985

Is serum selenium a risk factor for cancer?

A narrow band of counties extending along the southeastern Atlantic coast from Jacksonville, Florida to Charleston, South Carolina were found to have excessively high incidence rates for esophageal cancer in non-white males. White males in the same areas have a 30% higher incidence rate for lung cancer but only average incidence rates were found for non-white males. Selenium is considered to decrease cancer risk in the animal model. In this coastal region, a study of 130 cancer patients who developed a malignancy 2-12 years after baseline examination showed no dose response relationship between baseline serum selenium levels and risk of subsequent cancer.

Black People↗