Cognitive symptoms and welding fume exposure.

BACKGROUND: Prevalence of moderate to severe cognitive symptoms is markedly higher in UK professional divers who have also worked as a welder (28%) than in either divers who have not welded (18%) or offshore workers who have worked neither as a diver nor as a welder (6%).

OBJECTIVES: To determine whether cognitive symptoms are related to welding fume exposure or diving.

METHODS: Three age-matched groups of male workers were studied using postal questionnaire: professional divers who had worked as a welder (PDW, n = 361), professional welders who had not dived (NDW, n = 352), and offshore oil field workers who had neither dived nor welded (NDNW, n =503). Health-related quality of life was assessed by the Short Form 12 questionnaire (SF12). Cognitive symptomatology was assessed using the Cognitive Failures Questionnaire (CFQ). A single variable for welding fume exposure (mg m(-3) days) was calculated, incorporating welding experience in different environments and using different welding techniques and respiratory protective equipment. The level of fume exposure during hyperbaric welding operations was measured during such work as ambient PM(10) (particles of 10 µm or less). Diving exposure was assessed as the number of dives performed plus the number of days spent working during saturation diving.

RESULTS: Questionnaires were returned by 153 PDW, 108 NDW, and 252 NDNW. SF12 scores were the same in all groups and fell within normative values. Mean (95% CI) CFQ scores were higher in PDW [40.3 (37.7-42.9)] than in both NDW [34.6 (31.6-37.7)] and NDNW [32.1 (30.4-33.9)], but the scores in no groups fell outside the normative range. The mean PM(10) exposure during hyperbaric welding operations was 2.58 mg m(-3). The geometric mean mg m(-3) days (95% CI) for welding fume exposure in NDW [33 128 (24 625-44 567) n = 85] was higher than for that in PDW [10 904 (8103-14 673) n = 112]. For PDW the geometric mean (95% CI) diving exposure was 1491 [(1192-1866) n = 94] dives and days in saturation. In the general linear model regression analyses adjusted for age, alcohol consumption, and somatization, there was no signification association of CFQ score with either welding fume exposure (F = 0.072, P = 0.79, n = 152) or diving exposure (F = 0.042, P = 0.84, n = 74).

CONCLUSIONS: In conclusion, cognitive sympomatology was not related to retrospectively assessed measures of welding fume exposure or diving experience. In addition, the levels of cognitive symptomatology, even in PDW, did not exceed normative values.