Table 1.
Demographic information for California twin pairs born in 1957–1982
| Infectious mononucleosis |
||||
|---|---|---|---|---|
| All twins*n (%) | Concordant pairs† n (%) | Discordant pairs‡ n (%) | P value§ | |
| Race/ethnicity | ||||
| White | 5265 (76) | 56 (96) | 554 (91) | |
| Latino | 857 (12) | 1 (2) | 22 (4) | |
| Black | 186 (3) | 0 (0) | 8 (1) | |
| Native American | 91 (1) | 0 (0) | 2 (0) | |
| Asian | 235 (4) | 0 (0) | 6 (1) | |
| Other | 88 (1) | 0 (0) | 7 (1) | |
| Unknown¶ | 204 (3) | 1 (2) | 12 (2) | 0·82 |
| Gender | ||||
| Female-female | 3686 (53) | 36 (62) | 358 (59) | |
| Male-male | 1733 (25) | 11 (19) | 117 (19) | |
| Male-female | 1507 (22) | 11 (19) | 136 (22) | 0·84 |
| Zygosity | ||||
| Monozygotic | 2957 (43) | 35 (60) | 255 (42) | |
| Dizygotic | 3969 (57) | 23 (40) | 356 (58) | 0·006 |
| Zygosity – gender | ||||
| Monozygotic | ||||
| Female-female | 1994 (29) | 27 (46) | 190 (31) | |
| Male-male | 963 (14) | 8 (14) | 65 (11) | |
| Dizygotic | ||||
| Female-female | 1692 (24) | 9 (16) | 168 (27) | |
| Male-male | 770 (11) | 3 (5) | 52 (9) | |
| Male-female | 1507 (22) | 11 (19) | 136 (22) | 0·08 |
| Age (yr)∥ | 30·8 ± 6·9 | 32·3 ± 5·7 | 31·9 ± 6·4 | 0·65 |
| Total | 6926 | 58 | 611 | |
*
All twin pairs in whom both members completed the screening questionnaire.
†
Both members of the pair were diagnosed.
‡
One member of the pair was diagnosed.
§
P values are based on χ2 test for the categorical variables and based on two-sample t test for the continuous variables.
¶
Twin pairs in which members’ responses did not agree with each other.
∥
Mean age at completion of the questionnaire ± standard deviation.