Genetic and environmental influences on self-reported diet: a reared-apart twin study

A sample of 66 monozyogtic twins reared apart (MZA) and 51 dizygotic twins reared apart (DZA), and 101 nontwin individuals (mostly spouses of the twins) who participated in the Minnesota Study of Twins Reared Apart (MISTRA) from 1979 to 1995 completed a self-report food frequency questionnaire. Intraclass-correlations and model-fitting analyses indicated that approximately 30% of the variance in the self-report of diet was attributable to genetic factors, with random environmental factors and measurement error responsible for the remaining variance. Spouse correlations were moderate. To investigate the effects of living together during marriage, the absolute differences between husband and wife on the dietary variables with years of marriage were correlated. None of the correlations were significant. Hierarchical multiple regression analyses also indicated that no convergence occurred during marriage. These results suggest that sharing a current family environment exerts minimal influence on individual differences in self-reported diet.