Lars Ole Goffeng

Nerve conduction, visual evoked responses and electroretinography in tunnel workers previously exposed to acrylamide and N-methylolacrylamide containing grouting agents

The study examines possible persisting effects on the peripheral nervous system and visual system in tunnel workers previously exposed to acrylamide and N-methylolacrylamide during grouting work. We compared neurophysiological function in 44 tunnel workers previously exposed during grouting operations (2-10 years post exposure), with 49 tunnel workers with no history of exposure to acrylamide. Nerve conduction velocities (NCV), distal delay, F-response and amplitude in median and ulnar nerves of the right arm, peroneal, sural and tibial nerves of the right leg, visual evoked response (VER) and electroretinography (ERG) were measured. VER and ERG were also performed in 24 subjects more recently exposed to acrylamide grout (16 months post exposure). Exposure to acrylamide containing grouts was assessed by questionnaires. A statistically significant reduction in the mean sensory NCV of the sural nerve (p=0.005), as well as a non-significant reduction of sural amplitude was found in the previously exposed group compared to the control group. VER latencies to the onset of the occipital potential (N75) were prolonged in both exposed groups compared to the control group (p<0.05). ERG 30 Hz flicker amplitude was reduced in the recently exposed group compared to the referents (p<0.05). The results indicate slight subclinical, but persistent toxic effects in the sural nerve and the visual system in tunnel workers exposed to N-methylolacrylamide and acrylamide during grouting operations.

Self-reported symptoms and neuropsychological function among tunnel workers previously exposed to acrylamide and N-methylolacrylamide.

OBJECTIVE The aim of this study was to examine possible exposure-related symptoms and neuropsychological changes among tunnel workers previously exposed to grout containing acrylamide and N-methylolacrylamide. METHODS In a cross sectional study, 44 male tunnel workers previously exposed to acrylamide and N-methylolacrylamide during grouting operations were exam-in-ed with neuropsychological tests, 2-10 years after last exposure. The control group consisted of 49 male tunnel workers with no history of acrylamide exposure. Questionnaires were used to assess retrospectively recalled symptoms during work and current symptoms at the time of the examination. RESULTS The prevalence of paresthesia in hands and legs, and leg cramps during work peri-ods were higher in the exposed than control group. Self-reported prevalence of skin irritation, peeling of skin on the hands, white-finger attacks, headache, and breathlessness was also higher among the exposed workers. The Q-16 questionnaire on current symptoms indicated higher symptom prevalence among the exposed of impaired memory and concentration, emotional change, sleep disturbances, tiredness, headache, and sensory or motor changes. In contrast, no association was found between neuropsychological test results and acrylamide exposure, adjusting for relevant confounders. However, selected motor symptoms were associated with the corresponding results on tests for motor function. CONCLUSIONS Despite higher prevalences of self-reported current symptoms among the acrylamide-exposed compared to the control group, we did not find an association between occupational acrylamide exposure and health out-comes as measured by the chosen neuropsychological tests. Observed associations between chemical exposure and self-reported symptoms should be interpreted with great caution.

Fluctuations in heart rate variability of health care workers during four consecutive extended work shifts and recovery during rest and sleep

The aim of this study was to investigate fluctuations in heart rate variability (HRV), which reflect autonomic nervous system (ANS) function and potential psychological and physical strain, among 24 health care workers during work and sleep during four consecutive extended work shifts. Data included 24/36/12 h of HRV measurements, two logbooks, and a questionnaire. A cross-shift/cross-week design was applied. HRV was measured during work, leisure time, and sleep. The HRV data included time-domain [mean RR, SD of normal to normal R-R intervals (SDNN), and root mean square of the successive differences (RMSSD)] and frequency-domain [low frequency (LF)/high frequency (HF) ratio] parameters. HRV parameters revealed significant differences among work, leisure time, and sleep. Mean RR, RMSSD, and SDNN values were lower and the LF/HF ratio was higher on the first versus last day of the work period; however, the differences were most prominent in the morning hours. The results indicate higher levels of cardiovascular stress on the first versus fourth day of the working period, and measurements at night indicate a satisfactory recovery from the extended shifts.