Fig 1.
Flowchart of study population selection.
Table 1.
Demographic characteristics and descriptive statistics of study variables.
Table 2.
Narrow sense heritability of TSH and fT4.
Fig 2.
Heritability estimates for TSH and fT4 levels shown in literature and in our study.
Overall and sex specific heritability estimates for TSH and fT4 levels from our study and literature[4–9] were plotted. Rhombic markers (M) are male, triangular markers (F) are female, and circle markers (M+F) are male and female. Size of markers represents the number of participants. Ellipse consisting of dotted line indicates a study of the same subject group, or a single study. Region marked “Korean” refers to estimates from this study. Heritability of TSH and fT4 levels shows sex differences (double arrow), as well as proportional tendency (dotted line).
Table 3.
Genotype by sex interaction on variance of TSH and fT4 levels.
Table 4.
Genetic, environmental, and phenotypic correlations between TSH and fT4 levels.