Bengt Sjögren

Neuropsychiatric symptoms among welders exposed to neurotoxic metals.

Neuropsychiatric symptoms in 65 welders exposed to aluminium and 217 railroad track welders were studied with the aid of a previously validated questionnaire. Semiquantitative data on exposure to the metals aluminium, chromium, lead, manganese, and nickel were also recorded by questionnaire. Logistic regression was employed to study the relation between exposure and the prevalence of symptoms. Welders exposed to aluminium, lead, or manganese for a long period had significantly more neuropsychiatric symptoms than welders not exposed to these metals. The results indicate that detailed psychometric studies should be performed on welders exposed long term to specific metals as such exposures might affect their nervous system.

Occupational exposure to dust: inflammation and ischaemic heart disease.

OBJECTIVES: To review the possible association between occupational exposure to dust and ischaemic heart disease (IHD). METHODS: A literature search was performed of relevant studies regarding IHD in specific exposures to dust. The chosen exposures were arsenic, asbestos, beryllium, lead, polycyclic aromatic hydrocarbons, and quartz. The chosen occupations were farmers, paper and paper pulp workers, sawyers, and welders. DISCUSSION: A theory was launched in 1995 that urban particulate air pollution may provoke alveolar inflammation, with release of mediators capable of increasing blood coagulability in susceptible people and cause cardiovascular deaths. The present review expands this hypothesis and links occupational exposure to inhaled particles with the occurrence of ischaemic heart disease. CONCLUSION: This hypothesis should be tested by comparing the concentrations of fibrinogen in workers exposed and nonexposed to particles with control for other possible confounders such as smoking habits.

Rapid effects of air pollution on ventricular arrhythmias

AIMS Air pollution has been associated with ventricular arrhythmias in patients with implantable cardioverter defibrillators (ICDs) for exposure periods of 24-48 h. Only two studies have investigated exposure periods <24 h. We aimed to explore such effects during the 2 and 24 preceding hours as well as in relation to distance from the place of the event to the air pollution monitor. METHODS AND RESULTS We used a case-crossover design to investigate the effects of particulate matter <10 microm in diameter (PM10) and nitrogen dioxide (NO2) in 211 patients with ICD devices in Gothenburg and Stockholm, Sweden. Events interpreted as ventricular arrhythmias were downloaded from the ICDs, and air pollution data were collected from urban background monitors. We found an association between 2 h moving averages of PM10 and ventricular arrhythmia [odds ratio (OR) 1.31, 95% confidence interval (CI) 1.00-1.72], whereas the OR for 24 h moving averages was 1.24 (95% CI 0.87-1.76). Corresponding ORs for events occurring closest to the air pollution monitor were 1.76 (95% CI 1.18-2.61) and 1.74 (95% CI 1.07-2.84), respectively. Events occurring in Gothenburg showed stronger associations than in Stockholm. CONCLUSION Moderate increases in air pollution appear to be associated with ventricular arrhythmias in ICD patients already after 2 h, although future studies including larger numbers of events are required to confirm these findings. Representative geographical exposure classification seems important in studies of these effects.

Uptake and urinary excretion of aluminum among welders

SummaryThe urinary excretion of aluminum was measured in 23 welders before and after an exposure-free interval of 16 to 37 days. In addition, the concentration of aluminum in the air was measured at the work site of 16 aluminum welders on the same work-day as the first urine sample was taken. The concentration of aluminum in the urine depended on both the level and duration of exposure. The postshift urinary concentration of aluminum prior to an exposure-free interval was mainly related to the current air concentration, whereas the urinary concentration of aluminum determined after the exposure-free interval was related to total exposure duration (years). Among welders exposed for less than 1 year, the halftime for urinary concentration was about 9 days whereas welders exposed for more than 10 years had half-times calculated to be 6 months or longer. The results indicate that aluminum is retained and stored in at least two functional compartments of the body and is eliminated from these compartments at different rates.

Welding and Ischemic Heart Disease

Abstract Metal welding and cutting are associated with inhalation of gases and respirable particles. The purpose of this study was to compare the mortality of male welders with that of all gainfully employed men in Sweden regarding ischemic heart disease (IHD). Male welders and gas cutters were identified in the Swedish National Censuses of 1970 and 1990. Two cohorts were established and followed until the end of 1995. The IHD mortality among the welders was compared with that of all gainfully employed men. An increased mortality due to IHD was observed among welders identified in the 1990 Census, SMR = 1.35, 95% confidence limits 1.1–1.6. The observed increased mortality due to IHD was unlikely to be explained by different smoking habits. A general hypothesis linking inhalation of particles to the occurrence of IHD via an inflammatory process is discussed.

Aluminium in the blood and urine of industrially exposed workers.

Blood and urine aluminium concentrations were studied in industrially exposed workers using electrothermal atomic absorption spectrometry. Welders and workers making aluminium powder and aluminium sulphate had higher concentrations in blood and urine than non-exposed referents. Workers in the electrolytic production of aluminium had higher urine but not blood concentrations than the referents. Thus aluminium was found to be absorbed by all industrially exposed workers. Blood concentrations were lower than those presumably associated with aluminium induced encephalopathy in patients receiving dialysis.

Evidence of aluminium accumulation in aluminium welders

Using atomic absorption spectrometry the aluminium concentrations in blood and urine and in two iliac bone biopsies obtained from welders with long term exposure to fumes containing aluminium were measured. The urinary excretion of two workers who had welded for 20 and 21 years varied between 107 and 351 micrograms Al/l, more than 10 times the concentration found in persons without occupational exposure. Urinary aluminium excretion remained high many years after stopping exposure. Blood and bone aluminium concentrations (4-53 micrograms Al/l and 18-29 micrograms Al/g respectively) were also raised but not to the same extent as urine excretion. It is concluded that long term exposure to aluminium by inhalation gives rise to accumulation of aluminium in the body and skeleton of health persons, and that the elimination of retained aluminium is very slow, in the order of several years.

Acute Effects of Exposure to Hexanal Vapors in Humans

Objective: n-Hexanal is a major component in emissions from stored wood pellets. The production and use of wood pellets has increased dramatically. Our aim was to evaluate acute health effects of n-hexanal vapors. Methods: Twelve healthy volunteers were exposed to 0, 2, and 10 ppm n-hexanal for 2 hours at rest in a balanced order. Results: Ratings of discomfort in the eyes and nose, solvent smell, and headache increased significantly with the level of exposure. Frequency of blinking was significantly increased at 10 ppm. No effects on pulmonary function and nasal swelling were detected, except a not-significant tendency to increased nasal obstruction at 10 ppm. No clear effects on plasma inflammatory markers (C-reactive protein and interleukin-6) were observed. Conclusions: Two hours of exposure to n-hexanal results in mild irritation at 10 ppm, with no apparent adversity at 2 ppm.

Urine chromium as an estimator of air exposure to stainless steel welding fumes

SummaryWelding stainless steel with covered electrodes, also called manual metal arc welding, generates hexavalent airborne chromium. Chromium concentrations in air and post-shift urine samples, collected the same arbitrarily chosen working day, showed a linear relationship. Since post-shift urine samples reflect chromium concentrations of both current and previous stainless steel welding fume exposure, individual urine measurements are suggested as approximate although not exact estimators of current exposure. This study evaluates the practical importance of such measurements by means of confidence limits and tests of validity.

The neurobehavioral impact of manganese: Results and challenges obtained by a meta-analysis of individual participant data

Results from a meta-analysis of aggregated data provoked a new analysis using individual data on the neuropsychological performance of occupationally exposed workers. Data from eight studies examining 579 exposed and 433 reference participants were included, 28 performance variables analyzed. The performance scores were adjusted for well-known individual-level covariates; the influence of possible, but unknown study-level covariates was attenuated by means of a z-normalization. Associations between performance and exposure were estimated by ANOVAs and ANCOVAs, the latter representing multi-level models. Four cognitive and motor performance variables each indicated significantly lower performances of exposed individuals when confounding was considered; slowed motor performances and deficits in attention and short-term memory were found. Performance on a single test was significantly related to the biomarker manganese in blood. The outcomes on susceptibility were weak. The slowing of responses was the most distinct feature of performances of exposed workers. It remains unclear, whether this result is related to the employed tests or provides important information about early stages of the neurotoxic impairment. More specific cognitive tests need to be employed to answer this question. The lack of dose-response relationships was related to features of the biomarker: it does not reflect the Mn in brain responsible for changes in performances.