. Author manuscript; available in PMC: 2019 May 27.

Published in final edited form as: J Expo Sci Environ Epidemiol. 2018 Nov 27;29(5):663–673. doi: 10.1038/s41370-018-0095-0

Table 2.

Toenail metal measurements among NAS participants, 1992 to 2014

	People	# of samples	Mean # of samples per subject	Mean Years Btw samples	S.D	Median Years btw. Samples	Mean years btw. 1st and last sample	S.D	Median years btw. 1st and last sample
Lead	790	1818	2.03	4.81	2.45	3.48	10.08	4.82	10.41
Arsenic	804	1866	2.04	4.79	2.57	3.34	9.96	4.81	10.43
Cadmium	789	1812	2.03	4.82	2.46	3.49	10.06	4.79	10.41
Manganese	766	1757	2.02	4.73	2.44	3.35	9.82	4.63	10.46
Mercury	711	1266	1.63	5.35	2.69	4.20	8.21	4.15	8.46