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Objectives: In 1978, a cross-sectional study of 279 lumberjacks exposed to hand-arm vibration and 178 unexposed referents was conducted. The aim of the present study was to provide a seven-year follow-up on (i) the changes in the white-finger symptoms among the lumberjacks and the referents, (ii) the effect of white-finger symptoms on the professional prognosis of the lumberjacks, and (iii) the relationship between hand-arm vibration and changes in wrist bones., Methods: The methods consisted of a questionnaire, a routine clinical examination, and radiographs of the wrists and hands. The examinations were conducted as a field study using a mobile unit., Results: The prevalence of white-finger symptoms was 18% among the lumberjacks and 3% among the referents in the original study. Seven years later 213 lumberjacks and 140 referents participated in the follow-up. The prevalence of white-finger symptoms was 24.9 among the lumberjacks and 5.7 among the referents, and the seven-year cumulative incidence was 14.7% among the lumberjacks and 2.3% among the referents. After allowance for age, there was no difference in the incidence of white-finger symptoms between the lumberjacks with fewer than 15 years of exposure and the referents, but the risk increased with increasing duration of exposure (risk ratio 8.9, 95% confidence interval 2.5-28.9 for those exposed at least 25 years). There was no difference between the two groups in the prevalence of radiographically detectable translucencies or osteoarthrotic changes in the wrists and hands., Conclusion: According to the results, white-finger symptoms are still a problem among lumberjacks who started chain-saw work before 1970.

A group of 98 male workers occupationally exposed to styrene was interviewed for information on the amount and frequency of alcohol consumption and changes in consumption frequency and tolerance. Alcohol consumption and changes in consumption were not compared to any reference data, but the changes in tolerance were. The styrene-exposed workers revealed a lowered tolerance somewhat more often than the unexposed group. Neither the duration nor the intensity of styrene exposure was related to any of the alcohol "behavior" variables. The amount of over-time work in exposure had a slight relationship to high alcohol consumption, but the interpretation of this relationship remains undecided. Subjective symptoms, like hand tremor and difficulties in staying asleep, were associated with the alcohol "behavior" variables, but these two symptoms were unrelated to intensity of styrene exposure. Of the psychological functions studied, lowered visuomotor speed showed a slight relationship to high alcohol consumption. Visuomotor inaccuracy, which had proved to be related to a high intensity of styrene exposure, revealed no connection with the alcohol "behavior" variables. It was concluded that alcohol consumption among styrene-exposed workers is not related to the same psychological symptoms and signs as styrene exposure.

To evaluate the possible embryotoxic effects of styrene, 67 female lamination workers occupationally exposed to styrene and 67 age-matched female industrial workers with no obvious chemical exposure were interviewed. The women, all under 40 a of age, did not differ significantly with respect to number of births, pregnancies, or spontaneous and induced abortions prior to the exposure period. During the styrene exposure the number of births was significantly lower among the exposed group, a result partly explained by a higher number of induced abortions. No differences were found in this material with regard to the number of spontaneous abortions.

Spray finishing operations often involve cleaning with solvents. White spirit is widely used as a solvent in car washes in Finland. The purpose of the present study was to determine the levels of solvent exposure of car washers and to evaluate the effectiveness of ventilation systems in car washing facilities. The study covered 11 car washes. Airborne solvent concentrations were measured both in workers' breathing zones and at stationary sampling sites. The solvent concentration in the breathing zones ranged from 5 to 465 mg/m3 during the washing of automobiles and from 45 to 685 mg/m3 during the washing of heavy vehicles. Brief concentration peaks up to 4,500 mg/m3 were detected. The flow rate of ventilation air ranged from 0.3 to 3.9 m3/s. The greatest reduction in solvent concentration in the workers' breathing zones was attained with a ventilation design where the supply air jets blew directly into the work zone.

The liver functions, as reflected by the serum enzyme activities of aspartate aminotranferase, alanine aminotransferase, and gamma glutamyl transferase and by the concentrations of cholic acid and deoxycholic acid, of 34 styrene-exposed and 34 reference female workers were followed prospectively for a year. The mean age of exposed workers was 34.2 years, mean duration of past exposure 5.1 years. The mean age of the referents was 30.7 years. During the follow-up period blood samples were collected three times for the determinations. The history of possible liver disease and alcohol consumption was ascertained by questionnaire. Altogether 87 samples of both groups were analyzed. The styrene-exposed group did not have higher values for any measurement when compared with those of the referents. Two persons in both groups had one sample with transaminase activities exceeding laboratory reference values. The abnormal values were associated with the use of drugs or alcohol. Cholic acid and chenodeoxycholic acid concentrations were of the same magnitude in both groups.

Excretion of mandelic acid from workers in the reinforced polyester plastic industry was studied with the determination of urinary mandelic acid concentrations. The styrene exposure level at the workplaces was evaluated with measurements of the styrene concentration in the ambient air. Three different groups (I, II and III) were studied. In group I [n=9, median of the time-weighted average (TWA) of exposure = 23 ppmof styrene, postexposure observation period = 64 h] two excretion slopes were observed, the first with a median half-time of 9.4 h (postexposure period 0--18 h) and a second with a median half-time of 16.6 h (postexposure period 19--64 h). For group II (n=9, median TWA exposure = 248 ppm, postexposure observation period = 15 h) a half-time of 6.4 h was found. These results suggest that the excretion rate of mandelic acid is dependent on the styrene exposure level. In addition the mandelic acid concentrations of 29 workers (group III) before and after the work shift were analyzed. The urinary mandelic acid concentrations of groups I, II and III, sampled immediately after the 8-h work shift, correlated with the 8-h TWA of styrene exposure (n=47, r=0.93). Accordingly about 2,300 mg of mandelic acid per gram of creatinine corresponded to 100 ppm of styrene.

The relationship between long-term occupational styrene exposure and disturbances in psychological functions was studied. The exposed group consisted of 98 male workers exposed to styrene in the manufacture of polyester plastic products, and the comparison group comprised 43 concrete reinforcement workers. The duration of exposure in years and the mean mandelic acid concentration in urine (five determinations during 5 weeks before the clinical examination) and the cumulative dose of exposure were used as the indicators of exposure. The psychological functions studied were intelligence, visuomotor speed, visuomotor accuracy, memory, vigilance, and psychomotor performance. Some personality test variables were also included. In a group comparison two variables (visuomotor inaccuracy and poor psychomotor performance) out of 20 showed statistically significant differences and characterized the styrene exposed group. These findings were confirmed when workers with low and high styrene exposure were compared. One variable measuring visuomotor speed and another measuring visual memory were related to the duration of exposure (R = 0.28, p less than 0.05). In a multiple regression analysis disturbances in visuomotor accuracy, poor psychomotor performance, and lowered vigilance proved to have some connection with a high mandelic acid concentration (R = 0.49, p less than 0.01). In addition workers with disturbances in visuomotor accuracy and slight disturbances in virumotor speed had higher mandelic acid concentrations when compared with those workers without any deterioration. The results indicate that disturbances in visuomotor accuracy and, to a lesser degree, in psychomotor performance are the main findings measured by test methods used in this study and related to one indicator of styrene exposure, mandelic acid concentration. The psychological methods used revealed subclinical symptoms related to exposure, and they should aid in making group diagnoses, e.g., when additional information is needed for the determination of the threshold limit value. The deterioration found in visuomotor accuracy could be related to lowered safety in work and traffic.

For the study of the relationship between styrene exposure and symptoms and signs of central nervous dysfunctions, 98 male workers occupationally exposed to styrene were given clinical, neurophysiological and psychological examinations; also a symptom survey was made. Urinary mandelic acid concentrations, measured once a week during five consecutive weeks, were used to express the exposure intensity. Different unexposed groups were used for reference. No exposure-response relationship was observed between symptoms of ill health and the urinary mandelic acid concentration, although the exposed group as a whole expressed significantly more symptoms than the reference group. The occurrence of abnormal electroencephalograms was about 10% in the group of workers with mandelic acid concentrations below 700 mg/l, but it was 30% among those whose mandelic acid concentration exceeded 700 mg/l, a level corresponding to the 8-h time-weighted average (TWA) of styrene exposure of about 30 ppm. With regard to psychological functions, the first change in visuomotor accuracy became discernible when the urinary mandelic acid concentration exceeded 800 mg/l. A more pronounced decrement appeared in both visuomotor accuracy and psychomotor performance when the mandelic acid concentration exceeded 1,200 mg/l, which corresponds to an 8-h TWA of styrene exposure of about 55 ppm.

Ninety-six male workers occupationally exposured to styrene in 24 plants producing reinforced polyester plastic products were studied neurophysiologically. The mean age of the subjects was 29.6 +/- 7.4 years, and the duration of the exposure varied from 6 months to 14 years (mean 5.0 years). Mandelic acid concentration in the urine (mean of five values determined during five consecutive weeks) was used as the measure of exposure. The individual means of the mandelic acid concentrations varied from 7 to 4,715 mg/dm3 (median 808 mg/dm3). Neurotoxic effects of styrene exposure upon the central nervous system were revealed by abnormalities in the EEG. The overall prevalence of abnormal EEGs was 24% (23 out of 96), which is higher than that found among a normal population (p less than 0.05). Abnormal EEGs were found in one-third of the subjects with relevant styrene exposure (mandelic acid concentration over 700 mg/dm3), while low-level styrene exposure did not increase the prevalence of normal EEGs above that found in a normal population. Nerve conduction velocity measurements performed on 40 subjects did not reveal any definite relationship between neuropathy and styrene exposure. The EEG examination is useful in the investigation of the neurotoxic effects of styrene. Whenever a possibility exists of excessive styrene exposure or beginning poisoning, the workers should be submitted to an EEG examination.