Curtis G. Hames

HDL cholesterol and other lipids in coronary heart disease. The cooperative lipoprotein phenotyping study.

The relation between coronary heart disease (CHD) prevalence and fasting lipid levels was assessed by a case-control study in five populations with a total of 6859 men and women of black, Japanese and white ancestry drawn from subjects aged 40 years and older from populations in Albany, Framingham, Evans County, Honolulu and San Francisco. In each major study group mean levels of high density lipoprotein (HDL) cholesterol were lower in persons with CHD than in those without the disease. The average difference was small - typically 3–4 mg/dl - but statistically significant. It was found in most agerace-sex specific groups. The inverse HDL cholesterol-CHD association was not appreciably diminished when adjusted for levels of low density lipoprotein (LDL) cholesterol and triglyceride. LDL, total cholesterol and triglycerides were directly related to CHD prevalence; surprisingly, these findings were less uniformly present in the various study groups than the inverse HDL cholesterol-CHD association.

PREDIAGNOSTIC SERUM SELENIUM AND RISK OF CANCER

Selenium levels in serum samples collected in 1973 from 111 subjects in whom cancer developed during the subsequent 5 years were compared with those in serum samples from 210 cancer-free subjects matched for age, race, sex, and smoking history. The mean selenium level of cases (0.129 +/- SEM 0.002 micrograms/ml) was significantly lower than that of controls (0.136 +/- 0.002 micrograms/ml). The risk of cancer for subjects in the lowest quintile of serum selenium was twice that of subjects in the highest. Multivariate adjustment for geographical area and serum levels of lipids, vitamins A and E, and carotene, did not alter this relation. The association between low selenium level and cancer was strongest for gastrointestinal and prostatic cancers. Serum levels of vitamins A and E compounded the effect of low selenium; relative risks for the lowest tertile of selenium were 2.4 and 3.9 in the lowest tertiles of vitamins E and A, respectively.

Relation of Serum Vitamins a and E and Carotenoids to the Risk of Cancer

Epidemiologic studies suggest that low carotene intake and low levels of serum retinol may be associated with an increased risk of cancer. Likewise, in some animal studies vitamin E has been associated with a reduced rate of induced cancers. Therefore, we measured retinol, retinol-binding protein, vitamin E (alpha-tocopherol), and total carotenoids in serum collected in 1973 from 111 participants in the Hypertension Detection and Follow-up Program who were free of cancer at the time but were diagnosed as having cancer during the subsequent five years. These measurements were compared with those in 210 controls who were matched for age, sex, race, and time of blood collection, and who remained free of cancer. Mean values for retinol were similar for cases and controls (67.3 and 68.7 micrograms per deciliter, respectively [95 per cent confidence limits for case-control difference, -6.7 to 3.5]). Values were also similar for retinol-binding protein (6.01 and 5.94 mg per deciliter [-0.42 to 0.56]), and carotenoids (114.5 and 111.6 micrograms per deciliter [-9.1 to 15.9]). The mean base-line retinol level in the 18 subjects with subsequent lung cancer was higher than that in their matched controls (79.0 vs. 71.4 micrograms per deciliter, -4.9 to 19.7). Serum vitamin E levels were somewhat lower in subjects who later had cancer than in controls (1.16 and 1.26 mg per deciliter, -0.22 to 0.02), in part because of the confounding effect of serum cholesterol levels (when adjusted for lipid levels, the case-control difference was -0.05 mg per deciliter; -0.17 to 0.07). These data do not support hypotheses relating intake or serum levels of antioxidant vitamins to a reduced cancer risk.

Risk of stroke in asymptomatic persons with cervical arterial bruits: a population study in Evans County, Georgia.

A survey of the rural community in Evans County, Georgia, revealed cervical arterial bruits in 72 (4.4 per cent) of 1620 persons 45 years of age of older without previous stroke, transient ischemic attacks, or overt ischemic heart disease. The prevalence of such asymptomatic bruits increased with age and was greater in women and persons with hypertension. We estimated the risk of stroke associated with cervical bruits during a six-year follow-up period, taking age and blood pressure into account. The presence of asymptomatic bruits was associated with a significantly higher risk of stroke in men but not in women, with odds ratios of 7.5 and 1.6, respectively. Despite the high risk of stroke among men with bruits, the correlation between the location of the bruits and the type of subsequent stroke was poor. Moreover, cervical bruits in men were a risk factor for death from ischemic heart disease. We suggest that asymptomatic cervical bruits are an indication of systemic vascular disease and do not themselves justify invasive diagnostic procedures or surgical correction of underlying extracranial arterial lesions.

Racial differences in blood pressure in evans county, Georgia: Relationship to sodium and potassium intake and plasma renin activity☆☆☆

Abstract To investigate the hypothesis that the higher prevalence of hypertension in blacks may be related to a greater dietary intake of sodium, we studied the relationship between race, blood pressure, estimates of dietary sodium and potassium intake, and plasma renin activity (PRA), in two population samples from Evans County, Georgia. In the first random sample obtained in 1961, dietary electrolyte intake was estimated by duplicate dietary collections and simultaneous 24-hr urine collections. In the second sample obtained in 1968, a single-morning urine specimen was obtained and PRA was measured in each subject. The data demonstrate that blacks and whites ingested similar quantities of sodium, but that the dietary potassium intake of blacks was consistently less than that of whites. Blacks had higher blood pressures than whites and a greater prevalence of individuals with diastolic blood pressures >90 mmHg. PRA was inversely correlated with age, blood pressure and estimates of sodium intake. The higher blood pressures and higher prevalence of hypertension in blacks does not appear to be a function of a greater dietary sodium intake in blacks. However, an increased susceptibility to the hypertensinogenic effects of sodium in blacks remains a possibility.

Influence of race, sex and weight on blood pressure behavior in young adults.

This study is concerned with blood pressure behavior in young adults (aged 15 to 29 years) in the biracial community of Evans County, Ga., on two occasions 7 years apart. On the basis of casual blood pressure recordings the prevalence of systolic pressure equal to or greater than 140 mm Hg or diastolic pressure equal to or greater than 90 mm Hg, or both, showed race/sex differences as follows: white males 19.0 percent, white females 12.7 percent. black males 34.0 percent, black females 31.6 percent. Similar differences were noted in the incidence during the 7 year interval. The problem presented by the variability of the casual blood pressure recording is apparent in this interval study. Of particular interest is the association of weight with blood pressure in this youthful group, particularly among white males and females and black females, in relation to both initial and subsequent pressure levels. The data suggest that in this population under 30 years, weight is a risk factor for hypertension, and that maintenance of ideal weight, instituted in youth, may be a preventive measure.

The relationship of serum cholesterol to the incidence of cancer in Evans County, Georgia

Abstract A total community sample of 3102 individuals from Evans County, Georgia, was followed for 12–14 yr. One hundred and twenty-nine documented new (incident) cases of cancer were ascertained during this period from medical records and death certificates. Cases were considered for inclusion only if documented at least 12 months after intake into the cohort study. Cases were classified as definite, probable and possible to strict criteria. Blood samples were drawn at intake in 1960–1962 and frozen. Serum cholesterol levels were determined at intake in the total population (including 127 of the 129 incident cases of cancer). The central finding of the study is that incident cancer cases had significantly lower mean serum cholesterol levels at intake than the non-cancer population. The association was in the same direction for all four race-sex groups (WM, WF, BM, BF), but tended to be stronger overall for males than females, and was quite consistent for the various cancer sites and cell types. Both matched and regression residual analyses were used to control for the confounding variables considered (age, race, sex, overweight, social class and smoking).

CORONARY HEART DISEASE AMONG NEGROES AND WHITES IN EVANS COUNTY, GEORGIA.

Abstract A study has been carried out on various segments of the population of Evans County, Georgia. Coronary heart disease (CHD), and serum cholesterol levels were found to vary significantly between Negro and white males, with whites having the higher values. Significant differences in CHD and cholesterol were also found between high and low social class white males, with higher levels among high social class. The differences in CHD and cholesterol between Negro and white males were attributed to social class because low social class white males and Negro males did not differ significantly in either CHD prevalence or cholesterol level. The social class differences could be accounted for by differences in occupation. The important aspect of occupation appeared to be physical activity, and this was supported by additional data on activity obtained for one occupation group. Neither dietary fat intake nor cigarette smoking could explain the differences in CHD prevalence between Negroes and whites or high and low social class. Despite significant associations of physical activity with CHD and serum cholesterol, the association of serum cholesterol and CHD could explain only part of the association of physical activity with CHD. It is concluded that differences in CHD and serum cholesterol observed between the various racial, social class, and occupational groups of males appear explainable by differences in physical activity. Thus, a low level of physical activity appears to be a major determinant of CHD prevalence.

Distribution of triglyceride and total, LDL and HDL cholesterol in several populations: a cooperative lipoprotein phenotyping study.

Abstract Data on the distribution of triglyceride and total, LDL and HDL cholesterol are presented for age groups 40 yr and older. The populations represented came from Framingham, Albany, Honolulu, San Francisco, Evans County and Puerto Rico. They include white, Japanese and black persons and both sexes. Blood samples and lipid measurements were obtained after overnight fast by a common protocol as part of a cooperative study of lipoprotein phenotyping. Means, medians, standard deviations and 95th percentiles are given as well as intercorrelations among the various lipids. Average cholesterol levels ranged from 200 mg/dl (Puerto Rican men) to over 240 mg/dl (Framingham women). Average triglyceride levels ranged from less than 100 mg/dl (Evans County) to an average of 175 mg/dl (Japanese men). For men aged 50–69 triglyceride levels were higher in Puerto Rico than in Albany or Framingham, despite much lower levels of serum cholesterol. The 95th percentile for LDL cholesterol in age groups with at least 100 persons ranged from 196 to 209 mg/dl for men and between 221 and 228 mg/dl for women. The 95th percentile for triglyceride, however, varied greatly by age and population from as low as 249 mg/dl to as high as 451 mg/dl.

Sex differences in coronary mortality among diabetics in Evans County, Georgia

Abstract Long-term epidemiological studies of diabetes mellitus and its sequelae are very few in number. More specifically, to our knowledge, only three prospective epidemiological studies have addressed themselves to the sex difference in coronary mortality among diabetics. The present report, in agreement with the three other long-term studies, demonstrates, in a 4.5-yr follow-up, an excess risk of CHD mortality among diabetics, of greater magnitude in women than in men. A multivariable risk function analysis was applied which included age, race, fasting triglycerides, cholesterol, body mass, blood pressure, smoking history and laboratory determination of the presence or absence of definite or probable diabetes. The accumulation of cardiovascular risk factors in diabetic women, though markedly stronger than among diabetic men, does not fully explain the higher CHD mortality among diabetic women.