Table 2.

Pairwise concordance for infectious mononucleosis

	All twin pairs
	Concordant*	Discordant†	% Pairwise concordance (s.e.)
Infectious mononucleosis
Monozygotic twins	35	255	12·1 (2)
Dizygotic twins	23	356	6·1 (1)
Same-sex dizygotic twins‡	12	220	5·1 (2)
By gender
Monozygotic twins
Female-female	27	190	12·4 (2)
Male-male	8	65	11·0 (4)
Dizygotic twins
Female-female	9	168	5·1 (2)
Male-male	3	52	5·5 (3)
Male-female	11	136	7·5 (2)
By education
Monozygotic twins
< 16 years of school	20	134	13·0 (3)
≥ 16 years of school	15	121	11·0 (3)
Dizygotic twins
< 16 years of school	13	204	6·0 (2)
≥ 16 years of school	10	152	6·2 (2)
Same-sex dizygotic twins‡
< 16 years of school	9	129	6·5 (2)
≥ 16 years of school	3	91	3·2 (2)

^*Both members of the pair were diagnosed with infectious mononucleosis.

^†One member of the pair was diagnosed with infectious mononucleosis.

^‡Subset of dizygotic twins who are male-male or female-female pairs.