Skip to main content

Table 1 Characteristics of the study population

From: Risk of epilepsy in opposite-sex and same-sex twins: a twin cohort study

 

Female twins

Male twins

Characteristics

OSa (n=11,078)

SSa (n=19,186)

OSa (n=11,080)

SSa (n=20,207)

N (%)

N (%)

N (%)

N (%)

Zygosity

 Monozygotic

.

3,425 (17.9)

.

3,436 (17.0)

 Dizygotic

11,078 (100)

5,719 (29.8)

11,080 (100)

6,030 (29.8)

 Unknown

.

10,042 (52.3)

.

10,741 (53.2)

Maternal age at birth (years)

 

 <25

976 (8.8)

2,662 (13.9)

985 (8.9)

2,727 (13.5)

 25-29

3,364 (30.4)

6,514 (34.0)

3,353 (30.3)

6,745 (33.4)

 30-35

4,421 (39.9)

6,828 (35.6)

4,421 (39.9)

7,357 (36.4)

 35-39

2,029 (18.3)

2,796 (14.6)

2,033 (18.3)

3,021 (15.0)

 40+

288 (2.6)

386 (2.0)

288 (2.6)

357 (1.8)

Paternal age at birth (years)

 <30

2,727 (24.6)

5,891 (30.7)

2,728 (24.6)

6,398 (31.7)

 30-39

6,883 (62.1)

11,088 (57.8)

6,880 (62.1)

11,468 (56.8)

 40+

1,374 (12.4)

2,032 (10.6)

1,375 (12.4)

2,091 (10.3)

 Missing

94 (0.8)

175 (0.9)

97 (0.9)

250 (1.2)

Maternal completed highest education

 Primary and lower secondary

1,902 (17.2)

3,600 (18.8)

1,914 (17.3)

3,763 (18.6)

 Upper and post-secondary

4,477 (40.4)

7,801 (40.7)

4,468 (40.3)

8,210 (40.6)

 Tertiary

4,560 (41.2)

7,476 (39.0)

4,558 (41.1)

7,979 (39.5)

 Missing

139 (1.3)

309 (1.6)

140 (1.3)

255 (1.3)

Paternal completed highest education

 Primary and lower secondary

2,038 (18.4)

3,612 (18.8)

2,029 (18.3)

3,909 (19.3)

 Upper and post-secondary

5,218 (47.1)

9,140 (47.6)

5,231 (47.2)

9,485 (46.9)

 Tertiary

3,561 (32.1)

5,867 (30.6)

3,557 (32.1)

6,190 (30.6)

 Missing

261 (2.4)

567 (3.0)

263 (2.4)

623 (3.1)

Calendar year of birth

 1977-1984

1,234 (11.1)

2,806 (14.6)

1,231 (11.1)

3,249 (16.1)

 1985-1994

2,451 (22.1)

4,994 (26.0)

2,463 (22.2)

4,953 (24.5)

 1995-1999

2,212 (20.0)

3,414 (17.8)

2,213 (20.0)

3,768 (18.6)

 2000-2004

2,553 (23.0)

3,913 (20.4)

2,550 (23.0)

4,114 (20.4)

 2005-2009

2,628 (23.7)

4,059 (21.2)

2,623 (23.7)

4,123 (20.4)

  1. aOS opposite-sex twins, i.e., twins with an opposite sex co-twin, SS same-sex twins, i.e., twins with a same sex co-twin