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

Table 3 Age specific hazard ratios (HR) for epilepsy in OS twins compared with SS twins

Age group and exposure status	Female					Males
Age group and exposure status	Population	Epilepsy cases	IR^a	Crude HR	Adjusted HR [95% CI]^b	Population	Epilepsy cases	IR^a	Crude HR	Adjusted HR [95% CI]^b
<1 year
SS	19,186	47	26.66	Ref	Ref	20,207	63	33.99	Ref	Ref
OS	11,078	19	18.65	0.70	0.74[0.42-1.30]	11,080	34	33.40	0.98	0.98[0.63-1.51]
1-9 years
SS	19,039	130	9.04	Ref	Ref	19,990	176	11.60	Ref	Ref
OS	11,004	86	10.55	1.16	1.17[0.89-1.55]	10,992	87	10.69	0.92	0.95[0.73-1.23]
10-18 years
SS	12,379	73	8.81	Ref	Ref	13,150	70	8.01	Ref	Ref
OS	6,722	35	8.38	0.95	0.95[0.63-1.44]	6,713	34	8.16	1.01	0.98[0.65-1.48]
19-35 years
SS	6,282	32	7.06	Ref	Ref	6,533	26	5.19	Ref	Ref
OS	2,805	12	6.05	0.86	0.87[0.45-1.69]	2,789	7	3.58	0.69	0.72[0.31-1.66]

^aIncidence rate (/10,000 person-years)
^bHazard ratios, adjusted for maternal age at time of birth (<25, 25-29, 30-34, 35-39, 40+ years), paternal age at time of birth (<30, 30-39, 40+ years, missing), maternal and paternal highest completed education (primary and lower secondary, upper and post-secondary, tertiary, and missing), and calendar year (1977-1984, 1985-1994, 1995-1999, 2000-2004, 2005-2009)

ISSN: 2042-6410