Genetic and environmental contributions to the association between body height and educational attainment: A study of adult Finnish twins

The nature of the association between body height and educational attainmen t found in previous studies remains to be clarified. The aim of this study was to examine factors contributing to this association by using a large Fi nnish twin data set (8798 adult twin pairs) gathered by questionnaire in 19 81. A bivariate twin analysis was used to determine whether the genetic and environmental factors behind body height and educational attainment correl ate with each other. A high heritability was found for body height (h(2) = 0.78 in men and h(2) = 0.75 in women), and a moderate heritability for educ ation (h(2) = 0.47 and h(2) = 0.43, respectively). Shared environmental eff ects were also important in body height (c(2) = 0.12 in men and c(2) = 0.11 in women) and education (c(2) = 0.36 and c(2) = 0.43, respectively). A hig h correlation (r(c) = 0.77 in men, r(c) = 0.58 in women) of shared environm ental factors education and body height, and weaker correlations (r = 0.11 and r = 0.08, respectively) of unshared environmental factors were found. T he correlation of genetic factors between these two characteristics was not statistically significant. The results suggest that the association betwee n body height and education is due mainly to nongenetic family factors.