Persistence of levels for risk factor variables during the first year of life: The Bogalusa Heart Study

Abstract

The changes in cardiovascular disease risk factor variables during the first year of life were studied in a cohort of 440 children in Bogalusa, Louisiana. Statistically significant correlations were most evident for risk factor variable levels between 6 months and 1 yr of age with correlation coefficients of 0.81 for length, 0.87 for weight, 0.28 for systolic blood pressure, 0.42 for serum total cholesterol and 0.53 for β-lipoprotein cholesterol (all p < 0.0001). In a multiple-regression analysis in which the value of the risk factor variable at 1 yr of age is the dependent variable, only the value of that variable at 6 months of age yielded regression coefficients that were consistently statistically significant. For those children who were in the upper or lower deciles for a risk factor variable at 6 months of age, the distributions at 1 yr of age indicated a persistence in ranks. Some 32% of those in the top decile at 6 months for systolic blood pressure were also in the top decile at 1 yr of age. Similarly 30% of those in the top decile for serum total cholesterol, and 40% for β-lipoprotein cholesterol, remained at 1 yr in the top decile for total and β-lipoprotein cholesterol, respectively. Tracking can be detected in infants even with the dramatic changes occurring during the first year of life. These considerations are important for the study of the early natural history of coronary artery disease and hypertension and may help us to determine the earliest age for prediction of those children who will be prone to have heart disease as adults.