Occurrence of cognitive symptoms in dental assistants with previous occupational exposure to metallic mercury.

Previous investigations have presented evidence for an increased prevalence of late cognitive effects in dental personnel exposed to metallic mercury. We wanted to examine if there was a correlation between mercury exposure and cognitive effects in a Norwegian population of dental workers, and if so, to quantify the occurrence. The study group consisted of 608 female dental assistants from central Norway and 425 female controls from the general population, all under the age of 70. They had responded to a standardized postal questionnaire (Euroquest) inquiring about seven symptoms in regard to neurology, psychosomatics, memory, concentration, mood, sleep disturbances, and fatigue. A score was calculated for each symptom based on 4-15 single questions graded on a scale from 1 (seldom or never) to 4 (very often). Dental assistants and controls had a participation rate of 56.4% and 42.9% respectively. Dental assistants reported more cognitive symptoms than the controls, but on average they reported having each of the symptoms "now and then" or less frequently. There were 4.4% of the dental assistants and 2.8% of the controls who reported having three or more of the seven symptoms "often" or more frequently. The corresponding figures for five or more of the seven symptoms were 1.0% and 0.5% respectively. The occurrence of cognitive malfunction may be moderately increased in dental assistants. For dental assistants there was a relative risk of 1.6 of having three or more symptoms "often" or more frequently, and a relative risk of 2.0 of having five or more symptoms as frequently. It can be assumed from our results that the prevalence of possibly work-related cognitive malfunction in dental assistants is between 0.4% and 2.8%, dependent on the applied severity.

Short term changes in lung function, leukocytosis in blood, and lachrymal fluid among bacterial single cell protein workers after an episode with high exposure to endotoxins.

AIMS: To study possible effects of endotoxin exposure among bacterial single cell protein workers on pulmonary function, blood parameters, and lachrymal fluid before and after a work shift. METHODS: The study included 23 men and five women who were examined at the start and at the end of a work shift. Most workers performed a task with unusually high exposure levels. Twelve of the workers were re-examined the day after. The workers were divided into three exposure groups: production workers with the highest assumed exposure levels (n = 18), engineers (n = 5), and clerks (n = 2). The median endotoxin level during a work shift was 34000 EU/m3 in the high exposure group (range 3300-89000 EU/m3 ), 11000 EU/m3 (range 350-27000 EU/m3) among the engineers, and 180 EU/m3 (range 60-300 EU/m3) for the clerks. The workers answered a questionnaire about work related symptoms. Assessment of lung function included dynamic lung volumes and flows. The blood analysis included cell count of leukocytes and mediators of inflammation, fibrinogen, interleukin-6 (IL-6), D-dimer, and C-reactive protein (CRP). Cells in lachrymal fluid were counted with a microscope. RESULTS: The forced vital capacity (FVC) changed significantly (p<0.05) from 5.34 l (SD 0.9) to 5.25 l (SD 0.9) and forced expired volume in one second (FEV1) from 4.15 l (SD 0.7) to 4.07 l (SD 0.7) during the work shift. The leukocytes increased significantly (p<0.05) from 6.9 10(9)/l (SD 1.2) to 7.7 10(9)/l (SD 1.5) and IL-6 from 1.5 ng/l (SD 0.6) to 3.31 ng/l (SD 2.7). Except for fibrinogen, which had a borderline increase and PEF that decreased, the parameters were normalised the day after. Four of the workers had an increase of neutrofile granulocytes in the lachrymal fluid during the shift. There was a significant association between the endotoxin concentration and decrease of FEV1 despite the use of powered respirators. CONCLUSIONS: During a work shift with unusual high levels of endotoxins at a plant manufacturing bacterial single cell protein the results show that FVC and FEV1 were reduced. Mediators of inflammation increased along with leucocytosis in blood and lachrymal fluid among the workers.

Increase in interleukin-6 and fibrinogen after exposure to dust in tunnel construction workers.

OBJECTIVES: To see if there is any change in blood concentrations of interleukin-6 (IL-6) and fibrinogen during a working shift in tunnel construction workers. METHODS: 12 Tunnel construction workers were followed up during a 24 hours period after returning from a 9 day work free period. The first blood sample was taken on Monday afternoon before starting the shift. Another was taken around midnight after 8 hours of work, and another the next afternoon after about 12 hours of rest. Exposure to respirable dust was measured by personal samplers. RESULTS: The exposure of the workers to respirable dust, in terms of an 8 hour time weighted average, varied between 0.3 and 1.9 mg/m(3). For IL-6, there was an increase in the median serum concentration from 1.14 ng/l before starting the shift to 4.86 ng/l after 8 hours of work (p=0.002). For fibrinogen, there was an increase in the median concentration from 3.40 g/l before entering the shift to 3.70 g/l 24 hours later (p=0.044). There was a positive correlation between values of IL-6 at the end of the working shift and the fibrinogen concentrations the next afternoon (Pearson's R=0.73, p=0.007). The observed increase in IL-6 was significant for both smokers and non-smokers. CONCLUSION: The study shows an increase in both IL-6 and fibrinogen concentrations during a working shift for both smoking and non-smoking tunnel construction workers.

[Pulmonary function in Norwegian farmers keeping domestic animals]. / Lungefunksjon blant norske husdyrbønder.

In a group of farmers keeping domestic animals, all pulmonary function tests, except for PEF, showed lower values than in a Norwegian reference population. Spirometric values for FVC, FEV1, and PEF were higher among pig farmers than among other farmers. Poultry farmers had lower values of PEF compared to other farmers. One third of all farmers had values of FEF25-75% that were depressed more than 20%, possibly indicating that the smaller, more peripheral airways more frequently are affected than the central airways. No single causal factor for the reduced lung function was found, but farmers that worked in newer cow-stables had a lower lung function than other farmers, especially if the houses were built in the interval 1975-84.

[Respiratory tract symptoms among farmers keeping animals in Midt-Norge]. / Luftveissymptomer blant husdyrbønder i Midt-Norge.

In this survey from central Norway, the prevalence of respiratory symptoms in a representative sample of 1,580 farmers who kept domestic animals was compared with the prevalence of such symptoms among 655 controls, both sexes included. The farmer group experienced more symptoms that were exacerbated by work than the controls did (mucous membrane irritation 19% versus 10%, tightness in the chest 7% versus 4%, dyspnoea 4% versus 1% and cough with phlegm 25% versus 22%). No difference could be found between the groups as regards the prevalence of organic dust toxic syndrome or chronic bronchitis. The occurrence of symptoms was correlated to the number of working hours per day, and to the number of years the person had worked with animals. Farmers who kept cattle, pigs or poultry all showed raised prevalence of respiratory symptoms. The results indicate that the working environment of farmers who kept domestic animals may cause respiratory disorders.