The Medical College of Virginia Twin Study

Background. In subjects of all ages, those who weigh the most often have the highest blood pressure. Thus, in epidemiological studies, weight is the most important correlate of blood pressure. Using the data from the Medical College of Virginia Twin Study, we asked these questions: 1) Do the same genetic paths that regulate body size also regulate systolic and diastolic blood pressure? 2) Are there distinct genetic pathways that regulate each of these variables? 3) Does environment play a major regulatory role? 4) Are the correlations among these variables mainly due to genetic or environmental effects? 5) Do genetic paths that regulate body size mediate the correlation between systolic blood pressure and diastolic blood pressure? Methods and Results. We ascertained 253 Caucasian twin pairs living in the Commonwealth of Virginia. The average age was 11.2±0.2 years. We used multivariate path analyses to investigate the genetic relations among systolic blood pressure, diastolic blood pressure, and body size. We found that there was