Table 2 Occupational case‐control studies that assessed TCE exposure and NHL.

Author(s) and year	Study population	Diagnostic period	Number of cases and controls	Number of exposed cases	Study description
Greenland et al, 199431	Deceased transformer assembly workers	1969–84	15 eligible lymphoma cases with job history information available 1202 controls	Specific number of TCE exposed cases was not available	Nested case control study that examined cancer mortality and occupational exposure to seven chemicals or chemical groups among transformer assembly workers. Agent specific job‐exposure matrices (JEM) were created based on chemical inventories and detailed work history information
Hardell et al, 199433	Swedish men admitted to the Dept of Oncology in Umea and population registered controls	1974–78	105 cases 335 controls	4 TCE exposed cases	Evaluated the relationship between exposure to phenoxyacetic acids, chlorophenols, or organic solvents and NHL. Exposure information was obtained by questionnaire and telephone interviews. Occupations were classified according to the Nordic Working Classification system
Persson et al, 198934	Swedish male and female hospital registered cases and population registered controls	1964–86	106 cases 275 controls	8 TCE exposed cases	Evaluated the relationship between occupational risk factors and malignant lymphomas in men and women A nine page questionnaire was used to ascertain occupational exposure information. Qualitative information regarding exposure to solvents was obtained directly from the questionnaires
Siemiatycki, 199132	Males aged 35–70 residing in the Montreal Metropolitan area	1979–85	215 cases 2357 “other” cancer patient controls 533 population controls	6 TCE exposed cases	Evaluated TCE as one of over 290 substances. Self‐reported information on occupational exposure was evaluated by industrial hygienists to determine whether there was potential for TCE exposure