. Author manuscript; available in PMC: 2018 Nov 1.

Published in final edited form as: Crit Rev Toxicol. 2017 Jul 18;47(10):811–844. doi: 10.1080/10408444.2017.1342598

Table 2.

Studies included in review: Descriptive characteristics, summary of exposure metrics, neurological testing and tier ratings

Studies^*		Type of Work	Number of Workers^†	Age of exposed ^‡		Study Design^¶	Exposure Category^§	Exposure Metrics^‖				Testing & Tiers^#
Author Year	Country		Exposed/Controls study groups	Mean	(range) or SD			U_Hg	B_Hg	Air_Hg	DUR	PE	NB	EPS
Albers 1982	US	Chloralkali	138/0	NR	(NR)	XS	High	√				2	2	2

Angotzi 1981	Italy	Hg distillation	55/29	39^‡	(NR)	XS	Low	√	√	√	√	2	2	2

Bidstrup 1951	England	a) DC meter	161/0 (a)=103; (b)=58	NR	(19–65)	XS/D	(a)=High; (b)=Medium	24-hr_s		√x	√	3	–	–
Bidstrup 1951	England	b) AC meter	161/0 (a)=103; (b)=58	NR	(19–65)	XS/D	(a)=High; (b)=Medium	24-hr_s		√x	√	3	–	–

Bunn 1986 ^*	US	Chloralkali	(1): 115/0	NR	(NR)	Longitudinal: 1: (1976–79)	Cohort 1: High	√		√	√	2	–	–
Bunn 1986 ^*	US	Chloralkali	(2): 101/0 (a)=51; (b)=50	NR	(NR)	2: (1957–78)	Cohort 2: (a)=Medium; (b)=Low	√		√	√	2	–	–

Camerino 2002	Italy	Chloralkali	38/34	39	(23–57)	XS	≤BEI	√_s			√	–	1	–

Cavalleri 1995	Italy	Thermometer	33/33	27	± 9	XS; F/U: 1-yr	Medium	√_s			√	2	2	–

Chang 1995	China	Chloralkali	26/52	43	(33–54)	XS	Low	24-hr_s	√		√	3	–	2

Chapman 1990	US	Hg-Zn battery	18/27	33	(20–57)	XS	≤BEI	24-hr_s			√	3	1	–

Ehrenberg 1991	US	Thermometer	83/79	35	(18–68)	XS	Medium	√_s		√	√	2	–	–

Ellingsen 2001	Norway	Chloralkali	47/47	42	(24–67)	XS	≤BEI	√	√		√	–	1	–

El Sadik 1970 ^*	Egypt	Chloralkali	39/10	NR	(20–49)	XS	High	√_s		√x	√	2	–	–

Fawer 1983	Switzerland	Chloralkali/Hg-lamps/Acetaldehyde	26/25	44	± 2	XS	≤BEI	√_s	√	√	√	–	2	–

Gambini 1978	Italy	Chloralkali	(1): 131/130	34	(NR)	1: XS	Cohort 1: Low	√		√	√	2	–	–
Gambini 1978	Italy	Chloralkali	(2): 129/0 (a)=61; (b)=68	NR	(NR)	2: 2-yr P	2: (a)=Low; (b)= ≤BEI	√		√	√	2	–	–

Gilioli 1976	Italy	Chloralkali	86/0	43	± 10	XS/D	High	√		√x		3	–	3

Gonzalez-Fernandez 1984	Spain	Hg-glass relays	5/0	NR	(NR)	XS; F/U: 2-month, post-chelation	High	√	√	√	√	3	–	–

			71/43
Gunther 1996 ^*	Germany	Chloralkali	(a)=14(14–21); (b)=33(34–50)	44	(NR)	Longitudinal: (1979–87)	(a)=Medium; (b)= ≤BEI	√		√	√	2_NR	2	–
Gunther 1996 ^*	Germany	Chloralkali	(a)=14(14–21); (b)=33(34–50)	43	(NR)			√		√	√	2_NR	2	–

Iwata 2007	China	Hg mine/smelter	27/52	41	± 10	XS	High	√_s		√		–	1	–

Langolf 1978	US	Chloralkali	79/51	37	± 11	XS ^‡ F/U: 1-yr	High	√		√	√	1	1	1

Langworth 1992	Sweden	Chloralkali	89/75	42	(22–64)	XS	≤BEI	√_s	√		√	1	1	–

Levine 1982	US	Chloralkali	18/138	31	(19–56)	XS ^‡	High	√				3	–	2

Li 2007	China	Hg smelter	22/40	42	(30–63)	XS	High	√_s		√		2	–	–

Liang 1993	China	Hg lamps	88/70	34	± 7	XS	≤BEI	24-hr_s		√	√	–	2	–

McCullough 2001	US	Hg recycling	16/0	33	(18–47)	XS/D	High	√			√	3	2	–

Miller 1975	US	Chloralkali	77/65	36	± 10	XS F/U: 4–6 mo.	High	√_s	√		√	3	2	2

Piikivi 1984	Finland	Chloralkali	36/36	40	± 10	XS	Low	√	√		√	2_NR	1	–

Piikivi 1989	Finland	Chloralkali	60/60	38	(26–56)	XS	≤BEI	√_s	√		√	1_NR	2	1

Pranjic 2003	Bosnia	Chloralkali	45/32	35	(23–58)	XS	High	√		√x	√	1_NR	1	–

Rentos 1968	US	Hg mill/mine	13/9	NR	(NR)	XS	High	√_s		√		2	–	–

Roels 1982	Belgium	Chloralkali/Hg-Zn battery	43/47	38	(23–57)	XS	Medium	√_s	√		√	2	2	–

Roels 1985	Belgium	Chloralkali/Hg-Zn battery	Male Cohort:131/114	31	(19–57)	XS	(♂, ♀) = Low	√_s	√		√	–	1	–
Roels 1985	Belgium	Chloralkali/Hg-Zn battery	Female Cohort: 54/48	29	(19–51)	XS	(♂, ♀) = Low	√_s	√		√	–	1	–

Roels 1989	Belgium	Chloralkali/Hg-Zn battery	54/48	35	(20–57)	XS	Medium	√	√		√	1_NR	1	–

Schuckmann 1979	Germany	Chloralkali	39/39	NR	(NR)	XS	Medium	√	√	√	√	–	2	–

			567/382
Smith 1970	US	Chloralkali	(a)=27; (b)=61; (c)=145; (d)=334	NR	(19–69)	XS	(a)=High; (b)=High; c)=Medium; (d)=Low	√	√	√x	√	2	–	–

Soleo 1990	Italy	Hg Lamps	28/22 (a)=8; (b)=20	40	(NR)	XS	(a,b) = ≤BEI	24-hr		√	√	–	2	–

Suwa 1969	Japan	Hg mine	77/0	NR	(NR)	XS/D	High	√_s				3	–	–

Tang 2006	China	Thermometer	34/109 (a)=9; (b)=25	29	(18–55)	XS	(a)=Low; (b)= ≤BEI	√_s		√	√	2	–	–

Triebig 1982	Germany	Thermometer	18/18	20^‡	(18–66)	XS	Medium	√	√	√	√	3	–	2

Urban 1996	Slovakia	Hg smelter:	Cohort 1: 77/(0 PE; 46 EPS)	39	(21–58)	XS	Cohort 1: High	24-hr_s		√	√	3	–	2
Urban 1996	Slovakia	Chloralkali:	Cohort 2: 36/(0 PE; 46 EPS)	39	(21–61)	XS	Cohort 2: Medium	24-hr		√	√	3	–	2

Urban 2003	Slovakia	Chloralkali	24/24	42	(26–59)	XS	≤BEI	24-hr_s		√	√	–	2	–

Verberk 1986	Netherlands	Hg Lamps	21/0	51	(28–61)	XS/D	Low	√			√	3_NR	3	–

Vroom 1972	US	Thermometer	9/(0 PE; 9 EMG; 40 NCV)	51	(33–71)	XS	High	24-hr_s				3	3	2

Wastensson 2006	Sweden	Chloralkali	43/22	41	(25–65)	XS	≤BEI	√			√	1	1	–

West 1968 ^*	US	Hg Mill	14/9	38	(21–63)	XS	High	√_s		√	√	2	–	–

Zampollo 1987	Italy	Thermometer	17/0	42	(21–63)	XS/D	High	√_s	√		√	3	–	2

Zedda 1980	Italy	Hg Lamps	7/0	31	(22–49)	XS/D	Low	√		√	√	3	–	3

= Study has an explanatory note; explanatory notes are available in Supplemental notes for Table 2.

^†

= For studies that described neurological results separately for more than one study group: identifies the number of exposed workers in individual cohorts (enumerated as (1) or (2)), and/or the number of exposed workers within the same cohort, but stratified by exposure into two or more groups (indicated by lowercase letters (a)(b)(c)(d) and listed right to left in the order of highest to lowest exposure).

^‡

= Angotzi et al: mean age was calculated from the weighted average of the mean ages reported for two or more study groups; Triebig: median age.

^¶

= Study design identified as Cross-sectional (XS), Descriptive (D), Prospective (P), or Longitudinal; also notes if workers were followed-up (F/U).

^§

= Identifies the exposure category into which each study, cohort, or study group was stratified (High, Medium, Low, or ≤BEI).

^‖

= Exposure metrics used by each study: urine (U_Hg), blood (B_Hg), air (Air_Hg), or duration of exposure (DUR) measurements. U_Hg measurements are spot samples unless otherwise indicated; determinations based on single sample are noted as √s, exposure metric used to determine Exposure Category, if other than Current U_Hg is noted as √x.

= Type of evaluation (i.e. Physical Exam (PE), Neurobehavioral (NB), Electrophysiological Studies (EPS)) used in each study to evaluate neurological effects, and methodological adequacy of the evaluation (Tier 1=highest, Tier 3=lowest; see Method section in text for details).

Dash symbol "–" indicates study did not perform testing, and subscript NR indicates study performed testing but did not report results.