Biomedical subjects

L S Webber

Publications and source records attributed to L S Webber.

At least 91 records · Page 5Linked to original sources

PubMed1987

The association between cardiovascular response tasks and future blood pressure levels in children: Bogalusa Heart Study.

Children were selected from a total community survey and categorized into three blood pressure (BP) groups (low less than 10 percentile, midrange 10 to 90 percentile, high greater than 90 percentile) based on resting diastolic pressure (DBP). To examine the relationship of cardiovascular reactivity with BP levels 4 years later, three cardiovascular response tasks (orthostatic, handgrip, and cold pressor) were administered. Partial correlations, adjusted for initial resting BP, showed that peak BP responses to the three tasks were related to future resting systolic and diastolic BP. Further analyses showed that DBP reactivity was related to future BP tracking in children with high DBP levels. In the high DBP group, while resting DBP levels did not differ for trackers vs nontrackers, peak DBP responses to each of the three tasks did (orthostatic, p less than 0.001; handgrip, p less than 0.05; cold pressor, p less than 0.01). The combination of resting and peak BP levels may provide more powerful predictions of future BP levels in children.

Adolescent↗

PubMed1987

Black-white differences in serum lipoproteins during sexual maturation: the Bogalusa Heart Study.

Serum lipid, lipoprotein cholesterol, and apolipoprotein (A-I and B) levels were compared between 940 black and 1710 white children who were between the ages of 5 and 17 years. Stratification, matching, and analysis of covariance were used to determine whether black-white differences in levels of serum triglycerides (TG), very low- (VLDL-C), and high- (HDL-C) density lipoprotein cholesterol, and apolipoprotein A-I (apoA-I) could be explained by differences in sexual maturation, obesity, cigarette smoking, alcohol intake, oral contraceptive use, insulin, and glucose. Independently of these covariates, blacks had elevated levels of HDL-C and apoA-I (males only), and whites had increased levels of TG and VLDL-C. All differences were statistically significant at the 0.001 level. In addition, racial contrasts tended to be greater in sexually mature, as compared with prepubertal, males; a similar divergence of levels with sexual maturation was not observed in females. HDL-C levels in white males were partially explained (R2 = 0.12) by sexual maturation, insulin, and obesity; apoA-I levels were associated with only sexual maturation and insulin. Racial differences in levels of serum lipids, lipoprotein cholesterol, and apoA-I in early life, therefore, exist independently of differences in several lipoprotein determinants. Since the initial stages of atherosclerosis begin in the young, these black-white lipoprotein contrasts may influence differences in adult coronary heart disease rates between the races.

Adolescent↗

PubMed1987

Sources of error in measurement of children's blood pressure in a large epidemiologic study: Bogalusa Heart Study.

Accurate and reliable measurement of blood pressure is essential in the determination of early hypertensive disease. Multiple blood pressure measures were determined by well trained field observers on a large number of children representing a total pediatric community. Changes in children's blood pressure levels with multiple measurements, as well as differences between field observers, were examined. A random effects analysis of variance model was used to determine specific contributors to blood pressure variability in an epidemiologic survey of children. Observer differences were found to be the largest preventable contributor to blood pressure variation. In addition, systolic blood pressure levels decreased approx. 2.5 mmHg from the first to the third blood pressure station. More than 86% of systolic blood pressure readings and 90% of diastolic blood pressure readings by two different observers on the same child were within 15 mmHg. These data emphasize the importance of both adequate training of field observers and the use of replicate blood pressure measurements by multiple observers to determine blood pressure levels accurately in an epidemiologic survey.

Adolescent↗

PubMed1987

Racial difference in hemoglobin concentration of young adults.

Hemoglobin concentration was measured in 1,001 young adults (34% black, 66% white), ages 17 to 24 years, in a community survey. Hemoglobin levels were 0.9 g/dl lower in blacks than in whites (P less than 0.001) and 2.0 g/dl lower in females than in males (P less than 0.001). Black females had the highest prevalence of anemia (16%) and the lowest prevalence of polycythemia 3%), while white females had the lowest prevalence of anemia (1%) and highest prevalence of polycythemia (9%). Mean hemoglobin levels in females did not increase after approximately age 12 1/2 years, while those in males continued to increase until age 17 years. Regular cigarette smoking was a potent risk factor for polycythemia in white males. Number of cigarettes smoked per week and number of years as a regular smoker increased hemoglobin concentration. New criteria, based on population distribution of hemoglobin levels, may be needed for defining anemia and polycythemia in black populations and cigarette smokers.

Adolescent↗

PubMed1987

Relation of body fat distribution to hyperinsulinemia in children and adolescents: the Bogalusa Heart Study.

The relation of body fat distribution to plasma levels of glucose and insulin during an oral glucose tolerance test was examined in 355 Black and White school-age children. Both central and peripheral fat were similarly related to fasting, 30-min, and 1-h glucose. Unlike peripheral fat, central body fat was more strongly related to the 1-h insulin response (r = 0.35 vs 0.26); this association remained significant for central fat independent of peripheral fat (r = 0.18). The strong relation of central fat to insulin response was noted in both races and sexes but not in either sexually immature or relatively thin children. These findings indicate that, even in early life, a central body fat pattern relates positively to insulin response to glucose load. Thus, knowledge of body fat localization may help identify persons most susceptible to hyperinsulinemia in early life.

Adipose Tissue↗

PubMed1987

Adverse influences of alcohol, tobacco, and oral contraceptive use on cardiovascular risk factors during transition to adulthood.

Risk factors for cardiovascular disease were measured in 990 young adults, aged 17-24 years, in a 1982-1983 survey of the biracial (black-white) community of Bogalusa, Louisiana. Even after controlling for age and obesity, several lifestyle factors (cigarette smoking, alcohol consumption, and oral contraceptive use) were independently related (p less than 0.05) to levels of serum lipids, lipoprotein cholesterol fractions, and blood pressure. Oral contraceptive use was associated with increased levels of both serum triglycerides (20 mg/dl, blacks; 25 mg/dl, whites) and low density lipoprotein (LDL) cholesterol (19 mg/dl, whites), and decreased levels of high density lipoprotein (HDL) cholesterol (-6 mg/dl, whites). Linear regression analyses also showed that cigarette smoking was associated with elevated levels of serum triglycerides (ranging from 15 to 26 mg/dl) and decreased levels of HDL cholesterol (ranging from -9 to -11 mg/dl) in white males and females. Although persons who smoked cigarettes were also likely to consume alcohol, alcohol intake in nonsmokers was positively associated with levels of serum triglycerides, LDL cholesterol, and very low density lipoprotein cholesterol in white males, and with blood pressure levels in black males. A statistically significant association between alcohol intake and HDL cholesterol levels (r = 0.24) was observed only in white females who did not smoke. These adverse influences of lifestyle factors on cardiovascular disease risk may provide a rational basis for intervention during adolescence and early adulthood.

Adolescent↗

PubMed1987

Designation of children with high blood pressure--considerations on percentile cut points and subsequent high blood pressure: the Bogalusa Heart Study.

The effects of changing the percentile cut points of prior blood pressure measurements (both single and serial examinations) on prediction of subsequent high blood pressure, and of the definition of subsequent high blood pressure were assessed in 1,501 children from Bogalusa, Louisiana. Subjects were 2-14 years old at initial examination (year 1, 1973-1974) and were reexamined three, five, and eight years after the initial examination. Increasing the stringency of the prior measurement cut point resulted in increased specificity and positive predictive value, but decreased sensitivity and negative predictive value. For prediction of subsequent systolic blood pressure at the 90th percentile from year 1 levels, increasing the year 1 cut point from the 80th to the 95th percentile resulted in decreased sensitivity from 42.8 to 13.0%, and increased specificity from 83.0 to 97.3%. For systolic pressure, requiring all prior serial measurements to be above specified cut points resulted in further increases in specificity (maximizing at 100%) and decreases in sensitivity (minimizing at 2.1%). Using a year 1 cut point at the 90th percentile, increases in the definition of subsequent high blood pressure (from the 80th percentile to 140/90 mmHg or on treatment, respectively) resulted in increased sensitivity (from 20.5 to 33.3%) and negative predictive value, with decreasing specificity (from 93.9 to 91.3%) and positive predictive value. The results indicate that use of stringent criteria (serially at the 95th percentile) to identify children at risk for future essential hypertension will result in a substantial portion of the childhood population who will escape early identification but who will develop adult hypertension. Less stringent criteria will increase sensitivity and thereby provide the opportunity for primary prevention to a larger portion of the general childhood population who are at high risk for adult hypertension.

Adolescent↗

PubMed1987

Relation of obesity to clustering of cardiovascular disease risk factors in children and young adults. The Bogalusa Heart Study.

The relation of obesity to clustering of systolic blood pressure, fasting insulin, and ratio of low and very low density lipoprotein cholesterol to high density lipoprotein cholesterol [LDL-C + VLDL-C)/HDL-C) was investigated in 3,503 subjects aged 5-24 years in Bogalusa, Louisiana, from September 1981 to September 1983. Risk ratios (RR) were calculated as the number of subjects with risk factor variables in the upper tertile divided by the expected number. The variables showed strong clustering (RR = 3.1); however, after adjusting for obesity, clustering of systolic pressure, (LDL-C + VLDL-C)/HDL-C, and insulin was reduced (RR = 1.3). Lean subjects (lower tertile of obesity) showed less clustering than expected (RR = 0.4), while more obese subjects (upper tertile of obesity) had greater clustering than expected (RR = 3.1). Furthermore, trunk fat deposition (subscapular skinfold) had a greater impact on clustering at high levels than limb fat deposition (triceps skinfold). Since obesity is related to clustering of risk factor variables in children and young adults, the prevention of the onset of obesity in early life may be important to reducing the risk of coronary heart disease in later life.

Adolescent↗

PubMed1987

Implementation of "Heart Smart:" a cardiovascular school health promotion program.

The Bogalusa Heart Study, an investigation of 8,000 children, has compiled a large data bank on cardiovascular (CV) risk factors in children during the past 12 years. Precursors of heart disease begin at a young age, with many children already possessing one or more known clinical risk factors--hypertension, obesity, and adverse lipoprotein changes. Having obtained data examining the determinants, distributions, interrelationships and trends over time for CV risk factors, a foundation was provided to address additional questions directed toward intervention strategies. "Heart Smart" is a comprehensive, research-based CV health promotion program testing differential effects of a population (public health) strategy versus a high-risk approach within four elementary schools. The major goal of "Heart Smart" is to reduce CV risk factors in children with an intervention to facilitate the adoption of healthful lifestyles. Objectives, intervention modalities, and design and evaluation procedures for children and adults in a total school environment (K-6) are described.

Cardiovascular Diseases↗

PubMed1987

Blood pressure and echocardiographic measures in children: the Bogalusa Heart Study.

M mode echocardiograms were obtained from 654 healthy subjects, 7 to 22 years of age, whose diastolic blood pressure levels remained in the same height-, race-, and sex-specific decile during two biannual examinations. Echocardiographic measures of heart size, obtained according to the recommendations of the American Society for Echocardiography, were compared across the entire systolic and diastolic blood pressure distributions. Echocardiographic indexes of left heart size varied as a function of both blood pressure levels and body size. Significant positive correlations were present between systolic blood pressure and different measures of left ventricular size. Left ventricular wall thickness in systole correlated with systolic blood pressure (r = .42, p less than .0001), and persistence of this relationship was noted after adjustment for body size. Left ventricular wall thickness in diastole correlated with blood pressure before adjustment (r = .31, p less than .0001), but the relationship was not significant after adjustment for body size. The ratio of left ventricular thickness to chamber size (systole) correlated with systolic blood pressure levels both before and after adjustment for body size (r = .20 and r = .22, p less than .001). Male subjects of both races demonstrated significantly higher adjusted left ventricular mass, left ventricular wall thickness, and left ventricular chamber size. Adjusted left ventricular wall stress was significantly related to both systolic (r = .14) and diastolic blood pressure levels (r = .14, p less than .001). Measures of left ventricular wall thickness increased throughout the entire blood pressure distribution, indicating a consistent trend rather than a threshold effect seen only in the highest blood pressure groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1987

Black-white differences in cholesterol levels of serum high-density lipoprotein subclasses among children: the Bogalusa Heart Study.

Cholesterol levels of serum high-density lipoprotein (HDL) subclasses, HDL2 and HDL3, were examined in a random subsample (n = 561) of children (7 to 17 years of age) from a total biracial community. Overall, black children in younger (7 to 10 years) and older (11 to 17 years) age groups alike had significantly higher HDL2 cholesterol (HDL2-C) and HDL3-C than their white counterparts. In addition, black children had a relatively higher frequency of joint occurrence of high levels of both HDL2-C and HDL3-C. A significant sex-related difference, with girls showing higher values than boys, was noted among younger age groups for HDL2-C. A male-female crossover trend in HDL2-C levels was apparent only among white children, with girls showing higher values after age 11. Both age and sexual maturation were inversely associated with HDL3-C levels in white children, irrespective of sex (p less than .001). Serum triglycerides were inversely related to both HDL2-C and HDL3-C only in white children (p less than .001). A black-white difference in HDL2-C persisted only among boys and girls in the older age group after adjusting for the covariates (sexual maturation, age, adiposity, oral contraceptive use, cigarette smoking, alcohol use, and serum triglycerides). With respect to HDL3-C, the covariate-adjusted difference remained significant only among boys in the older age group. Metabolic variations between the races in response to both physiologic and environmental factors likely account for the divergence in antiatherogenic HDL pattern.

Adolescent↗

PubMed1987

Racial contrasts in hemoglobin levels and dietary patterns related to hematopoiesis in children: the Bogalusa Heart Study.

Racial differences in hemoglobin (Hgb) levels were explored in two groups of children at different maturational stages, the pre-adolescent (10-year-olds: Whites n = 160, Blacks n = 56,) and the adolescent (15-year-olds; Whites n = 60, Blacks n = 44). Mean Hgb levels were higher for Whites than Blacks in both age groups. When all the dietary components (i.e., iron, zinc, copper, folacin, ascorbic acid and vitamins B12, E and B6) were considered as a group, they accounted for 8.4 per cent of the Hgb variance in 10-year-olds and 10.1 per cent of variance in 15-year-olds. However, even after controlling for the variations in dietary patterns of the adolescents and pre-adolescents, race still accounted for a notable proportion of Hgb variance in both age groups (9.1 per cent in 10-year-olds and 7.0 per cent in 15-year-olds). Within each race, gender accounted for a greater percentage of the Hgb variance in the adolescents than in the pre-adolescents. Our results indicate that in all likelihood racial differences in Hgb levels during childhood exist independent of racial differences in intake of specific "blood building" nutrients and maturational changes.

Adolescent↗

PubMed1987

Persistence of juvenile-onset obesity over eight years: the Bogalusa Heart Study.

The persistence of obesity and overweight over eight years was assessed in a biracial (Black-White) cohort of 1,490 two-to 14-year-olds. Initial levels of triceps skinfold thickness (TRSF) and Rohrer index (weight/height3) were moderately predictive of subsequent levels: r = 0.54 and 0.67, respectively. However, TRSF and Rohrer index tended to track most strongly in Black females (r = 0.64 and 0.72) and less well in both White females (r = 0.45 and 0.57) and preschool children (r = 0.45 and 0.54). Based on elevated levels of TRSF or Rohrer index, children were classified as obese or overweight, respectively. Of the 222 children who were initially above the 85th percentile for TRSF, 43 per cent remained obese after eight years. Persistence of overweight was slightly greater at follow-up, with 50 per cent of initially overweight children staying above the 85th percentile for Rohrer index. Severe, initial obesity/overweight (greater than 95th percentile) and consecutively elevated levels increased the probability of remaining obese/overweight. Results indicate that moderate, juvenile-onset obesity is malleable, but that the child who is extremely obese over consecutive examinations is likely to become an obese adult.

Adolescent↗

PubMed1987

Cardiovascular risk factors from birth to 7 years of age: the Bogalusa Heart Study. Serum lipids and lipoproteins.

Serum lipids and lipoprotein cholesterol fractions were examined in a newborn cohort that was followed from birth to 7 years of age. Although white and female infants had higher cord blood levels of high-density lipoprotein cholesterol (HDL-C) than did black and male infants, respectively, these differences did not persist throughout early childhood. Mean levels of all serum lipids and lipoproteins increased greatly in the first 6 months of life, and by 2 years of age, levels approached those seen in adolescents. Infants consuming cow's milk had higher 6-month levels of serum total cholesterol and low-density lipoprotein cholesterol than did formula-fed infants. However, milk source in infancy did not significantly influence total cholesterol or low-density lipoprotein cholesterol levels at age 7 years. Serum lipid and lipoprotein levels at age 7 years were associated with previously measured levels as early as 6 months of age, and infants with unfavorable levels were likely to have similar adverse levels at 7 years of age. In addition, increases in obesity between 6 months and 7 years of age were positively associated with increases in levels of serum triglycerides. These results suggest that certain persons at increased risk for cardiovascular disease can be identified in infancy.

Age Factors↗

PubMed1987

Cardiovascular risk factors from birth to 7 years of age: the Bogalusa Heart Study. Design and participation.

Cardiovascular risk factor variables were examined in a cohort of 440 infants from birth through 7 years of age. Anthropometric measures, BP, serum lipid and lipoprotein values, and dietary intake data were obtained according to detailed protocols. Various quality controls to ensure the collection of valid and reliable data were instituted. Participation remained high throughout the study with 80% of the children examined at 6 months and 60% at 7 years of age. Rates were slightly higher for black than for white children. Children born in the private hospital were more likely to continue in the study than children born in the charity hospital. Children of parents examined when the child was 2 years of age were more likely to be examined during the preschool phases, but parental examination was not related to child examination when the child was 7 years of age. As in studies of school-aged children, measurement errors were lowest for height, weight, and serum total cholesterol. Measurement errors for BP were highest at the younger ages, particularly for diastolic BP. Examination of a newborn cohort throughout time affords the opportunity to study early development of relationships and tracking of cardiovascular risk factors.

Absenteeism↗

PubMed1987

Cardiovascular risk factors from birth to 7 years of age: the Bogalusa Heart Study. Tracking of body composition variables.

Height, weight, and skinfold measurements were obtained on a cohort of 447 children from birth (weight) or 6 months of age (height and skinfold) and monitored yearly thereafter until 7 years of age. At age 7 years, 250 remained for follow-up screening. A significant degree of tracking was found for all variables from age 1 to age 7 years. Height and weight tracked most strongly (age 1- to 7-year correlations = .42 and .44, respectively), whereas skinfold tracked somewhat lower (.28). Earlier levels of each anthropometric variable were the best predictor of later levels of that parameter. Implications for early detection and treatment of growth abnormalities are discussed.

Age Factors↗

PubMed1987

Cardiovascular risk factors from birth to 7 years of age: the Bogalusa Heart Study. Blood pressure.

BP was measured in 440 children followed longitudinally from birth to 7 years of age in Bogalusa, LA. Levels, trends, and determinants of BP were evaluated in this newborn cohort. Both systolic and diastolic BP levels remained relatively constant between the ages of 6 months and 7 years. BP levels varied between the different instruments, and differences were also noted between measures obtained using the same instrument before and after venipuncture. White children were noted to have slightly higher levels of systolic and diastolic BP pressure at 6 months and 1 year of age, even after adjustment for body size. Significant prediction of year 7 BP rank occurred as early as 6 months of age for systolic and at 1 year of age for diastolic BP levels. Body size was inconsistently related to BP levels from ages 6 months through 4 years, but the relationship was stronger and more consistent with changes in body size. Of interest is the relatively constant levels of indirect BP during this period of rapid growth, as measured by currently available instruments. These data emphasize the importance of cardiovascular risk factor measurement during early life and of the need to improve methods of indirect BP measurement in infancy.

Age Factors↗

PubMed1987

Cardiovascular risk factors from birth to 7 years of age: the Bogalusa Heart Study. Dietary intakes.

Dietary patterns and racial differences in nutrient intake were observed in children 6 months to 4 years of age in the Bogalusa Heart Study. Even in this sample of young children, the composition of the intakes of the majority of children was not compatible with prudent recommendations of less than 35% and 10% of energy from total and saturated fat, respectively. Mean cholesterol intake of the 4-year-old children (390 mg) was approximately one half of the average daily adult levels. The polyunsaturated to saturated fatty acid ratio ranged from 0.41 to 0.53 and sucrose to starch ratio from 1.32 to 1.57, reflecting a high saturated fat and sucrose intake. White children had greater intakes of sucrose than black children; however, total fat and cholesterol intakes were greater in black children. Gender differences were noted among the 2, 3, and 4-year-old children: energy, sugar, and starch intakes were greater in boys, and cholesterol intake per 1,000 kcal was greater in girls. Mean intakes per 1,000 kcal in Bogalusa were higher for fat and carbohydrate and lower for protein than reported in the Second Health and Nutrition Examination Survey. However, when the National Research Council recommended dietary allowances for protein and energy are used for comparison, a more than adequate intake was noted in these children. The data found in this newborn-infant cohort contribute information regarding the early development of dietary habits that likely influence eating behavior in later childhood and adolescence.

Age Factors↗