Table 3.

ALS risk associated with categorized nail Hg levels.

Nail mercury level	μg/g	Controls n=210 (%)	ALS patients n=70 (%)	Univariate Odds Ratio	(95% CI)	Multivariable* Odds Ratio	(95% CI)	p-value
<25th percentile	< 0.042	41 (19.5)	30 (42.9)	1.0 (ref)		1.0 (ref)
25th–90th percentile	0.042–0.38	154 (73.3)	27 (38.6)	0.24	(0.13–0.45)	0.21	(0.11–0.41)	4.18E–06
< 90th percentile	< 0.38	195 (92.9)	57 (81.4)	1.0 (ref)		1.0 (ref)
≥ 90th percentile	≥ 0.38	15 (7.1)	13 (18.6)	2.96	(1.32–6.61)	2.64	(1.12–6.18)	0.024

^*Adjusted for age, smoking status.