Bogalusa Heart Study - Bogalusa

Description:

Longitudinal study of cardiovascular risk factors n children and young adults.

Hypothesis:

Demonstration of cardiovascular disease in early life.

Study Design

Study Design:

Patients Screened: Not given
Patients Enrolled: > 14,000
Mean Patient Age: Birth to 38

Patient Populations:

Children residing in Ward 4 of Washington Parish, Louisiana, including the community of Bogalusa.

Primary Endpoints:

Anatomic atherosclerotic lesions

Drug/Procedures Used:

Longitudinal surveys.

Principal Findings:

The Bogalusa Heart Study is a long-term epidemiologic study of cardiovascular risk factors from birth through the age of 38 years in a biracial population (65 percent white and 35 percent black). To date, data have been collected on approximately 14,000 people. Numerous publications from this series have described the relationship between cardiovascular risk factors in youth and atherosclerotic disease.

These studies have established that the major adult cardiovascular diseases (coronary-artery disease and essential hypertension), begin in childhood. Cardiovascular risk factors change during periods of growth and development, and there are distinct ethnic (black-white) and male-female differences that relate to adult heart disease. These risk factors have been shown to "track" over a 15-year period and are predictive of adult levels. Secular trends show increasing adiposity in the general population of children; an overall weight gain of 2 kg occurred during the decade from the 1970s to the 1980s, and approximately 5 kg during the decade from the 1980s to the 1990s. Increasing obesity is likely related to a more sedentary lifestyle. Cardiovascular risk factors also tend to cluster, for example, obesity correlates with higher blood pressure and with adverse serum lipoprotein changes. The development of lesions lags in young women at an equivalent age and with similar levels of risk factors. In addition, ethnic differences are noted in the development of changes related to atherosclerosis and hypertension.

Autopsies were performed on 204 young persons 2 to 39 years of age, who had died from various causes, principally trauma. Data on antemortem risk factors were available for 93 of these persons. Risk factors were correlated with the extent of atherosclerosis in the aorta and coronary arteries. The extent of fatty streaks and fibrous plaques in the aorta and coronary arteries increased with age. The association between fatty streaks and fibrous plaques was much stronger in the coronary arteries (r=0.60, P<0.001) than in the aorta (r=0.23, P=0.03).

Body-mass index, systolic and diastolic blood pressure, and serum concentrations of total cholesterol, triglycerides, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol, were strongly associated with the extent of lesions in the aorta and coronary arteries (canonical correlation [a measure of the association between groups of variables]: r=0.70; P<0.001).

Cigarette smoking increased the percentage of the intimal surface involved with fibrous plaques in the aorta (1.22 percent in smokers vs. 0.12 percent in nonsmokers, P=0.02) and fatty streaks in the coronary vessels (8.27 percent vs. 2.89 percent, P=0.04).

As the number of cardiovascular risk factors increased, so did the severity of asymptomatic coronary and aortic atherosclerosis. Subjects with 0, 1, 2, and 3 or 4 risk factors had, respectively, 19.1 percent, 30.3 percent, 37.9 percent, and 35.0 percent of the intimal surface covered with fatty streaks in the aorta (P for trend=0.01). The comparable figures for the coronary arteries were 1.3 percent, 2.5 percent, 7.9 percent, and 11.0 percent, respectively, for fatty streaks (P for trend=0.01) and 0.6 percent, 0.7 percent, 2.4 percent, and 7.2 percent for collagenous fibrous plaques (P for trend=0.003).

A substudy examined the reproducibility of K4 and K5 diastolic blood pressure measurements and the ability to predict adulthood values. Analyses included blood pressure measurements taken on 12,139 subjects during multiple cross-sectional screenings from 1973 to 1994; 20% (N = 2530) had measurements taken as a child, ages 4 to 18 years, and during adulthood, ages 19 to 32 years. Six resting blood pressure measurements were taken by trained observers with mercury sphygmomanometers at each screening with K1, K4, and K5 recorded. Variance components analysis was used to evaluate the reliability of K4 and K5. The total variance was larger for K5 (253 mm Hg2) than for K4 (109 mm Hg2) at age 5 years. Variance for both K4 and K5 decreased with age. The interobserver variability was larger for K5. Childhood K4 (vs childhood K5) was better correlated with adult K1 and K5 (0.28 vs 0.11 for K1; 0.33 vs 0.25 for K5 at age 11 to 13 years). K4 was also shown to have a higher odds ratio for predicting adult hypertension than K5 (1.57 vs 1.14 at age 11 to 13 years). During childhood K4 is a more reliable measure of diastolic blood pressure than K5. K4 diastolic blood pressure measured in childhood is a better predictor of adult hypertension.

Interpretation:

The Bogalusa Heart Study now establishes that precursors of adult cardiovascular diseases begin in childhood. The clearest evidence comes from autopsy studies that show coronary atherosclerotic lesions occur in early life and are strongly associated with very-low-density lipoprotein cholesterol, systolic and diastolic blood pressure, and obesity, and have an inverse relationship with high-density lipoprotein cholesterol. The demonstration of cardiovascular disease in early life gives credibility to risk-factor examination of children and the need for beginning of prevention in early life.

References:

1. N Engl J Med 1998;338:1650-6 Autopsy data 2. J Pediatr 1998;132:687-92 Predictive value of Korotkoff sounds 3. Ann New York Acad Sci.1997;817:189-98 Precursors of risk in young adults

Clinical Topics: Diabetes and Cardiometabolic Disease, Dyslipidemia, Prevention, Lipid Metabolism, Nonstatins, Hypertension, Smoking

Keywords: Odds Ratio, Atherosclerosis, Cross-Sectional Studies, Lipoproteins, Risk Factors, Blood Pressure, Observer Variation, Weight Gain, Autopsy, Smoking, Reproducibility of Results, Cholesterol, Sphygmomanometers, Adiposity, Obesity, Sedentary Lifestyle, Triglycerides, Hypertension


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