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.

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.

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.

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.

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.

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.

Dietary factors relate to cardiovascular risk factors in early life. Bogalusa Heart Study.

Relationships between diet and cardiovascular disease risk factors were studied in a cohort of infants in Bogalusa, Louisiana. The 24-hour dietary recalls and cardiovascular measurements were obtained on each child at age 6 months, yearly through age 4, and again at age 7 (cardiovascular measurements only). At ages 4 and 7, children with persistently high intakes of dietary cholesterol (three or more measurements in the upper tertile) had levels of serum total cholesterol approximately 14 mg/dl higher than children whose intakes of cholesterol were not persistently high. Children in the upper tertile for dietary cholesterol had levels of low density lipoprotein cholesterol (15 mg/dl at age 4 and 18 mg/dl at age 7) higher than children in the lower tertile for dietary cholesterol. Children with high intakes of animal fat were 2 to 6 kg heavier (p less than 0.05) than those with lower intakes. Changes in dietary cholesterol correlated significantly with changes in serum total cholesterol (r = 0.42) and low density lipoprotein cholesterol (r = 0.50) from 6 months to 4 years of age. Changes in subscapular skinfold measurements correlated significantly with changes in intake of total protein (r = 0.31), total fat (r = 0.25), starch (r = 0.31), and energy (r = 0.39) from ages 6 months to 4 years. Results indicate that tracking of dietary components and their relationships with cardiovascular disease risk factors can be detected at an early age. These findings may well be the groundwork for later studies of obesity and the early onset of hyperlipoproteinemia.

Quality control of dietary data collection in the CARDIA study.

The Coronary Artery Risk Development in (Young) Adults (CARDIA) Study developed and implemented quality control (QC) measures to minimize misclassification associated with dietary data. Manual and automated data inspection were used to monitor quality. Of the 5111 participants who completed a dietary history, 717 (14%) had dietary forms reviewed and 153 (3%) had the interview audiotaped. Results show that for the 717 forms reviewed, the overall form completion error rate was 0.22% and the "critical" error rate (i.e., those errors impacting on nutrient computations) was 0.12%. The proportion of forms free of any type of error increased over time (p less than 0.0001). The discrepancy rate in recording and interviewing methods as estimated from the 153 audiotaped interviews was 0.7%. Inter-interviewer differences were small as indicated by the audiotaped interviews and the proportion of error-free forms completed by interviewers. The results indicate that the dietary data collected in CARDIA were completely and accurately recorded for use in analysis.

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.