Table 2.

Relative risk of ALS in full siblings and children of proband ALS cases, compared to risk of ALS in a reference population, Sweden, 1961-2005

	Cases	Person-years	RR*	95% CI†
Reference group	6,646	341,171,009	1.0
Exposed group	46	229,638	9.7	7.2-12.8
Age of proband at diagnosis of ALS
≤44 years	3	14,784	36.5	9.1-94.7
45-54 years	6	32,835	16.0	6.4-32.4
55-64 years	24	67,127	21.3	13.9-31.1
65-74 years	10	77,713	5.6	2.8-9.8
≥75 years	3	37,179	2.2	0.6-5.7
Kinship to the proband
Siblings	9	13,540	16.8	8.1-30.4
Children	37	216,098	8.8	6.2-12.0
Paternal proband	15	130,202	6.5	3.7-10.3
Maternal proband	22	85,896	11.7	7.4-17.3

^*Relative risk, derived from multivariable Poisson regression models, adjusted for age, sex, and calendar period.

^†Confidence interval.