Large, unique registry of twin data used to examine genetic and environmental influences on blood pressure and body mass index

A 2020 article in the journal Hypertension analyzed data from the National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry), 1958-2013 [RESTRICTED] (ICPSR 36234), which authors Wang et al. accessed via the National Archive of Computerized Data on Aging (NACDA). The nearly 16,000 White male participants in the NAS-NRC Twin Registry were twin pairs born between 1917 and 1927, in which both members had served in the military. Data were collected from service records, a mailed questionnaire assessing zygosity, and repeating health surveys, including information on education, employment history, and earnings. Wang et al. performed their analysis on this large population-based twin registry because “it offered ample power to estimate heritabilities, genetic correlations, and interactions.” Specifically, they found it useful because it contains measures (rather than self-reports) of participants’ weight, blood pressure (BP), and height–information collected during the physical exams given when they entered the military. Wang et al. compared these measures from both identical and non-identical twins and “estimated the relative influence of genetic and environmental factors on height, weight, BMI, systolic blood pressure (SB), and diastolic blood pressure (DB), as well as the genetic and environmental correlations among BMI, SB, and DB.” They also tested the moderating effects of BMI on blood pressure heritabilities to explore potential gene-obesity interactions on blood pressure. Their findings “may prove valuable for gene-finding studies attempting to identify shared genetic pathways” relevant for treating hypertension. For decades, the NAS-NRC Twin Registry, a longitudinal panel study, collected a rich variety of data from and about the twin pairs. For more information about why and how the Registry was created, how often each follow-up was given to the participants, and what measures were taken, see its cohort profile in the International Journal of Epidemiology.