Table 2 Occurrence of epilepsy in people admitted with multiple sclerosis, and of multiple sclerosis in people admitted with epilepsy: observed (O) and expected number (E) of cases in each cohort, relative risk (RR) ^a in the exposure cohort compared with the control cohort ^b , with its 95% confidence intervals (95% CI), and p values, by time intervals between the two conditions

Multiple sclerosis

<1 year

Epilepsy

13

3.6

3.6 (1.92–6.23)

<0.001

574

370.0

1.6 (1.44–1.70)

<0.001

1–4 years

16

4.3

3.7 (2.12–6.08)

<0.001

1194

251.0

4.9 (4.66–5.24)

<0.001

5–9 years

14

3.2

4.4 (2.41–7.48)

<0.001

726

166.0

4.5 (4.20–4.88)

<0.001

10+ years

19

4.1

4.7 (2.80–7.34)

<0.001

86

22.8

3.9 (3.11–4.85)

<0.001

Total

62

15.3

4.1 (3.14–5.27)

<0.001

2580

809.7

3.3 (3.14–3.40)

<0.001

Epilepsy

<1 year

Multiple sclerosis

9

3.3

2.9 (1.29–5.67)

0.003

206

196.1

1.1 (0.91–1.21)

0.48

1–4 years

9

3.4

2.7 (1.21–5.23)

0.006

394

154.0

2.8 (2.52–3.13)

<0.001

5–9 years

6

2.7

2.3 (0.82–5.09)

0.083

206

90.5

2.4 (2.10–2.83)

<0.001

10+ years

9

4.2

2.2 (0.99–4.24)

0.034

19

9.9

2.0 (1.19–3.27)

<0.005

Total

33

13.6

2.5 (1.71–3.54)

0.001

825

450.4

1.9 (1.79–2.07)

<0.001