Antonie W. Voors

Relation of serum lipoprotein levels and systolic blood pressure to early atherosclerosis. The Bogalusa Heart Study.

Abstract We assessed the relation of risk factors for cardiovascular disease to early atherosclerotic lesions in the aorta and coronary arteries in 35 persons (mean age at death, 18 years). Aortic involvement with fatty streaks was greater in blacks than in whites (37 vs. 17 percent, P<0.01). However, aortic fatty streaks were strongly related to antemortem levels of both total and low-density lipoprotein cholesterol (r = 0.67, P<0.0001 for each association), independently of race, sex, and age, and were inversely correlated with the ratio of high-density lipoprotein cholesterol to low-density plus very-low-density lipoprotein cholesterol (r = -0.35, P = 0.06). Coronary Artery fatty streaks were correlated with very-low-density lipoprotein cholesterol (r=0.41, P = 0.04). Mean systolic blood-pressure levels also tended to be higher in the four subjects with coronary-artery fibrous plaques than in those without them: 112 mm Hg as compared with 104 (P = 0.09). These results document the importance of risk-fa...

Tracking of cardiovascular disease risk factor variables in school-age children☆

Persistence in ranks (tracking) for cardiovascular disease risk factor variables was examined in 2236 children who were screened three times over a 5-yr period. As expected, the greatest persistence was noted for height (r = 0.47-0.99) and weight (r = 0.70-0.96). Correlation coefficients for systolic blood pressure and diastolic blood pressure ranged from 0.38 to 0.66 and 0.22 to 0.49 respectively. Among lipids, the correlations were highest for serum beta-lipoprotein cholesterol ranging from 0.62 to 0.78. For those children who were at or above the 90th percentile on a risk factor variable during the first examination, a tendency to retain their ranks in the second and third examinations was noted. For systolic blood pressure, 35% of those initially high remained high in the second examination and 30% in the third examination. Correspondingly, for those initially high for beta-lipoprotein cholesterol, 47 and 41% remained high. A linear discriminant model was used to distinguish characteristics of children who persisted at high rankings and those who did not. The model was effective for total and beta-lipoprotein cholesterol, but only moderately so for systolic blood pressure.

Racial differences of parameters associated with blood pressure levels in children—The Bogalusa Heart Study

Racial differences in prevalence of essential hypertension are well known. In order to explore these differences at an early age in terms of etiology, we investigated schoolchildren in an entire, biracial community. A sample of 278 children, stratified by diastolic (fourth-phase) blood pressure and specific for age, race, and sex, was reexamined 1--2 yr after initial observation for the following: (1) a physical examination and urinalysis to exclude secondary hypertension; (2) 24-hr urine sodium, potassium, plasma renin activity, and serum dopamine beta-hydroxylase; (3) 1-hr oral glucose tolerance test; and (4) heart rate and blood pressure at rest and under standarized physical stress. We found that 24-hr urine sodium was positively associated with blood pressure level as measured on the same day for the high blood pressure strata of black children. Urine potassium excretion was lower in blacks than in whites, although their intakes seemed equal. In the high blood pressure strata especially, black boys had lower renin activity than whites, and the resting-supine and stressed systolic blood pressures were higher in black boys than in any other group. In these black boys, resting and stressed systolic pressures were negatively related to plasma renin activity. On the other hand, dopamine beta-hydroxylase levels in white children were higher than in blacks for all blood pressure strata, and in the high blood pressure strata white children had higher 1-hr glucose levels and faster resting heart rates than black children. Different mechanisms may play a role in and contribute to the early stage of essential hypertension.

Occurrence in children of multiple risk factors for coronary artery disease: the Bogalusa heart study.

The aggregation at high levels of risk factor variables for coronary artery disease (CAD) was studied in 4064 children of a biracial population in Bogalusa, Louisiana. Above the age-, race-, and sex-specific 75th percentiles for serum cholesterol, blood pressure, and a weight-height index were 144 (3.33%) schoolchildren. This was greater than expected (P <0.001) under a null hypothesis of no association. The relationship was stronger in white males (3.8%) and black females (4.0%) than in white females (2.8%) and black males (2.7%). This aggregation tended to increase with age. For preschool children we found no more aggregation than expected. Data from these and future observations may enable us to identify a cohort of children who persistently exhibit multiple risk factor variables at high levels. This identification would be essential should prevention efforts for CAD be initiated.

Cardiovascular disease risk factor variables in children at two successive years--the Bogalusa heart study.

Abstract As part of a community study of cardiovascular disease risk factor variables, 1101 children in four age-cohorts (5, 8, 11, 14 years) were examined during two successive years. The bivariate correlations within each of the four cohorts between one year and the next were highest for height, weight and triceps skinfold, intermediate for systolic blood pressure, total cholesterol, and β-lipoprotein, and lowest for diastolic blood pressure, triglycerides, pre-β-lipoprotein, and α-lipoprotein. Employing multiple linear regression, we observed that once the level of a specified risk factor variable at the time of the initial examination was known, the inclusion of six additional independent variables did not substantially increase our ability to predict the level of that specific risk factor variable one year later. In a further analysis of the extremes, we observed that of those children who had triceps skinfold thicknesses above the 90th percentile at the first examination, over 70% remained in the top decile one year later. Comparable findings for blood pressure were 41% for systolic and 23% for diastolic, while for the lipids and lipoproteins, between 45 and 32% of those with initially elevated levels remained above the 90th percentile. These results suggest that tracking of obesity, blood pressure, and serum lipids and lipoproteins which is known to occur during adulthood is apparent, on an annual basis, in 5-to 15-year-old pediatric age groups.

Racial contrasts in cardiovascular response tests for children from a total community.

SUMMARY Cardiovascular risk factors In childhood were assessed by re-examining a random sample of 278 children stratified by diastolic blood pressure (BP), obtained from 3524 children aged 7-15 years in an entire geographic biraclal community (Bogalusa). Re-examination included plasma renin and serum electrolytes, 24-hour urine electrolytes, heart rates, and BP at rest and in response to standardized physical stresses (orthostatic, isometric handgrip, and cold pressor tests). The BP responses in these tests were not increased in the high BP strata, which argues against a prevailing labile phase In early essential hypertension. Black children tended toward larger BP responses than whites. In black boys of the high BP stratum (n = 25), systolic supine or stressed BP were higher than for other race-sex groups; these pressures were associated negatively with plasma renin activity, which was low. White children in the high BP strata had increased heart rates, possibly indicating hyperkinetic circulation. These findings indicate that multiple mechanisms operate to control BP at different intensities for black and white children.

A model of intervention for prevention of early essential hypertension in the 1980s.

The onset of essential hypertension early in life is indicated by the high tracking of blood pressure during adolescence; intervention in adults with mild hypertension has been found successful. How, then, can high blood pressure levels in children be modified to prevent early hypertensive cardiovascular disease in adulthood? In an entire biracial town (population 9000) we surveyed 1604 (89%) of all children aged 8--18 years for blood pressure and reexamined those in the upper decile of mean blood pressure (for each race, sex, and height) on three additional occasions. On each examination nine blood pressures were taken by trained observers. All children consistently in the top decile were randomly allocated into either a treatment (n = 50) or comparison (n = 50) group. These two groups and an additional midrange blood pressure comparison group (n = 50) were followed regularly using school facilities including community and school programs. Treatment consisted of 1) dietary guidance; 2) modifications of school lunches and snacks with healthy substitutes; 3) parental involvement; 4) a low dose diuretic and beta-antagonist given by usual standards. All study groups were monitored for blood pressure in a blind manner. In 6 months of observation, blood pressure in the treatment group remained 5 and 3 mm Hg (systolic and diastolic) less than controls (p less than 0.001 and p less than 0.01). An orchestrated community-wide attack on early-stage hypertension is feasible and seems to offer exciting potential for prevention of early hypertensive disease.

Measurement error of risk factor variables in an epidemiologic study of children-the Bogalusa heart study.

Estimates of measurement error (precision) and of reliability (reproducibility) were obtained from two cross-sectional epidemiologic surveys of cardiovascular risk factor variables. Anthropometric, blood pressure and serum lipid measurements were obtained on children (ages 5–14 yr, N = 3524, first survey; ages 5–17 yr, N = 4074, second survey) in the biracial community of Bogalusa, Louisiana. The measurement error decreased by one half for the serum total cholesterol (from 9.50 to 4.04 mg%) and triglycerides (from 10.34 to 5.05 mg%,) between the two surveys. Although the measurement error remained stable for the automatic height and weight instruments, it decreased for the manual instruments. A decrease in the measurement error between the two surveys was also noted for the triceps skinfold thickness, the upper-arm length and the upper-arm circumference. Concurrent with the decrease in measurement error, there was an increase in reliability. The anthropometric variables were the most reliable, followed by the laboratory and then the blood pressure variables. The reliability during the second survey ranged from 0.99 to 0.9999 for the anthropometric variables, from 0.87 to 0.98 for the laboratory variables and from 0.75 to 0.89 for the blood pressure variables. The increasing reliability may indicate a reduction in the phenomenon of regression to the mean, the effect of training on the examiners, the increased proficiency in the use of the Technicon AAII and an increased capability of tracking variables over time.

Epidemiology of Essential Hypertension in Youth—Implications for Clinical Practice

Essential hypertension, a highly prevalent and devastating disease, likely begins in childhood, and presumably might respond at this stage to general preventive measures. The problems encountered in the recording of reproducible blood pressure levels are largely of a quantitative nature, and involve instrument validity, observer (examiner) training, and the interaction between the child and the physicians office environment. The problems of early diagnosis of hypertension are related to the lack of long-term observations of children. Population percentiles of normal blood pressure values could aid in the early diagnosis of hypertension. For this purpose the method of blood pressure measurement in the physicians office has to be strictly comparable to methods employed in accumulating the percentile or reference observations. Repeated measurements under basal-like conditions are advised, and the weight or height of the child is more important for standardization than is age.

Combined low-Dose Medication and Primary Intervention over a 30-Month Period for Sustained High Blood Pressure in Childhood

Studies of the pathobiologic consequences of high blood pressure in childhood, as well as those following blood pressure levels into young adulthood, indicate that early intervention in the natural history of essential hypertension is warranted. In an exploratory study of the concept, 95 children out of 1604 (aged 8 to 18 years), who persistently scored higher than the 90th percentile for blood pressure over a 4-month period, considering the race, sex, and height of the children, were studied. Five series of replicate measurements with 30 total observations were obtained. Children with evidence of secondary hypertension were excluded. The study children were randomly divided into treatment (n = 48) and high-comparison (n = 47) groups. Treatment consisted of low-dose combined drug therapy (propranolol and chlorthalidone) with an educational program directed towards hypertension and dietary and exercise modification. Monthly follow-up was continued for 30 months. Significant systolic (-3.59 mm Hg) and diastolic (-1.73 mm Hg) changes were noted up to 30 months (p less than 0.05) with minimal side effects. Furthermore, analyses suggested that the blood pressure change, at least in the first month, was mostly attributable to drug therapy. Moreover, the mechanism of blood pressure change appeared to be race-specific, with whites having pulse rate changes and blacks having significant weight changes, which were associated with blood pressure change. This trial shows further research is warranted to determine optimum approaches for early treatment of essential hypertension to prevent future hypertensive disease.