BACKGROUND:

Methodologically, statistical methods in genetics and epidemiology have developed largely independently; and as a result, there seemed to be little communication between the two fields. Some of the most important hypotheses regarding familial aggregation of chronic diseases related to gene-environment interactions which drew on both fields. The method of analysis used in this study dealt simultaneously with survival time nature of the outcome variable, multiple and continuous environmental risk factors, and correlation in outcomes between related individuals.

The study was supported by the Small Grants Program established by the National Heart, Lung, and Blood Institute in January 1990 to extend analyses of research data generated by clinical trials, population research, and demonstration and education studies.

DESIGN NARRATIVE:

Data available from two epidemiologic questionnaires administered ten years apart were used to determine the extent to which an increased familial risk in cardiovascular disease mortality among twins was mediated by similarities in behavioral risk factors such as smoking, diet, weight changes, physical activity, and socioeconomic variables. The contributions of genetic and environmental factors to twin similarities in health behavior were also examined.