The ordinary work environment increases symptoms from eyes and airways in mild steel welders.

PURPOSE: We aimed to follow diary-registered symptoms from eyes and airways in mild steel welders and relate them to different exposure measures. Furthermore, we would clarify the influence of possible effect modifiers. METHODS: Non-smoking welders with (N = 74) and without (N = 32) work-related symptoms the last month were enroled. Symptoms and work tasks each day for three two-week periods during 1 year were obtained. Respirable dust (RD) was measured 1 day each period for each worker. The personal daily exposure was assessed as: (1) days at work, (2) welding time and (3) estimates of RD from welding and grinding, calculated from diary entries and measurements. RESULTS: Only 9.2 % of the particle measurements exceed the Swedish occupational exposure limit (OEL; 5 mg/m(3)). Days at work increased the risk of symptoms studied: eyes: 1.79 (1.46-2.19), nasal: 2.16 (1.81-2.58), dry cough: 1.50 (1.23-1.82) and wheezing and/or dyspnoea: 1.27 (1.03-1.56; odds ratio, 95 % confidence interval). No clear dose-response relationships were found for the other exposure estimates. Eye symptoms increased by number of years welding. Nasal symptoms and dry cough increased having forced expiratory volume in first second below median at baseline. Wheezing and/or dyspnoea increased in winter, by number of years welding, having a negative standard skin-prick test and having a vital capacity above median at baseline. CONCLUSION: The current Swedish OEL may not protect welders against eye and airway symptoms. The results add to the evidence that welders should be offered regular medical surveillance from early in the career.

Brain imaging and human nutrition: which measures to use in intervention studies?

The present review describes brain imaging technologies that can be used to assess the effects of nutritional interventions in human subjects. Specifically, we summarise the biological relevance of their outcome measures, practical use and feasibility, and recommended use in short- and long-term nutritional studies. The brain imaging technologies described consist of MRI, including diffusion tensor imaging, magnetic resonance spectroscopy and functional MRI, as well as electroencephalography/magnetoencephalography, near-IR spectroscopy, positron emission tomography and single-photon emission computerised tomography. In nutritional interventions and across the lifespan, brain imaging can detect macro- and microstructural, functional, electrophysiological and metabolic changes linked to broader functional outcomes, such as cognition. Imaging markers can be considered as specific for one or several brain processes and as surrogate instrumental endpoints that may provide sensitive measures of short- and long-term effects. For the majority of imaging measures, little information is available regarding their correlation with functional endpoints in healthy subjects; therefore, imaging markers generally cannot replace clinical endpoints that reflect the overall capacity of the brain to behaviourally respond to specific situations and stimuli. The principal added value of brain imaging measures for human nutritional intervention studies is their ability to provide unique in vivo information on the working mechanism of an intervention in hypothesis-driven research. Selection of brain imaging techniques and target markers within a given technique should mainly depend on the hypothesis regarding the mechanism of action of the intervention, level (structural, metabolic or functional) and anticipated timescale of the intervention's effects, target population, availability and costs of the techniques.

Is acculturation associated with physical activity among female immigrants in Sweden?

BACKGROUND: Immigrant women in Sweden have lower levels of leisure time physical activity (LTPA) than Swedish-born women. The reasons are unclear, although acculturation has been suggested to play a role. METHODS: We used a cross-sectional study design to investigate the association between LTPA and two indicators of acculturation: (i) language proficiency (ability to understand news reports on the radio and television) and (ii) age at the time of migration, and if there existed a modifying effect on these hypothesized associations. The study sample consisted of 1651 women, aged 18-65, living in Sweden and born in Finland, Chile or Iraq. A postal questionnaire (translated into the women's native language) was used to collect the variables. The International Physical Activity Questionnaire was used to assess LTPA. Data were collected in 2002-05 and analyzed in 2009-10. A partial-proportional odds model was used for the analysis. RESULTS: Increased language proficiency was associated with increased LTPA [odds ratio (OR) = 2.31, 95% confidence interval (CI) = 1.57-3.41]. Country of birth modified the association. Furthermore, younger age at migration was associated with increased LTPA (OR = 1.44, 95% CI = 1.01-2.03). CONCLUSIONS: Increased language proficiency has the potential to be an important health-promoting factor among immigrant women.

Dietary factors and low-grade inflammation in relation to overweight and obesity.

Low-grade inflammation is a characteristic of the obese state, and adipose tissue releases many inflammatory mediators. The source of these mediators within adipose tissue is not clear, but infiltrating macrophages seem to be especially important, although adipocytes themselves play a role. Obese people have higher circulating concentrations of many inflammatory markers than lean people do, and these are believed to play a role in causing insulin resistance and other metabolic disturbances. Blood concentrations of inflammatory markers are lowered following weight loss. In the hours following the consumption of a meal, there is an elevation in the concentrations of inflammatory mediators in the bloodstream, which is exaggerated in obese subjects and in type 2 diabetics. Both high-glucose and high-fat meals may induce postprandial inflammation, and this is exaggerated by a high meal content of advanced glycation end products (AGE) and partly ablated by inclusion of certain antioxidants or antioxidant-containing foods within the meal. Healthy eating patterns are associated with lower circulating concentrations of inflammatory markers. Among the components of a healthy diet, whole grains, vegetables and fruits, and fish are all associated with lower inflammation. AGE are associated with enhanced oxidative stress and inflammation. SFA and trans-MUFA are pro-inflammatory, while PUFA, especially long-chain n-3 PUFA, are anti-inflammatory. Hyperglycaemia induces both postprandial and chronic low-grade inflammation. Vitamin C, vitamin E and carotenoids decrease the circulating concentrations of inflammatory markers. Potential mechanisms are described and research gaps, which limit our understanding of the interaction between diet and postprandial and chronic low-grade inflammation, are identified.

Gene expression analysis in induced sputum from welders with and without airway-related symptoms.

PURPOSE: To identify changes in gene expression in the airways among welders, with and without lower airway symptoms, working in black steel. METHODS: Included were 25 male, non-smoking welders. Each welder was sampled twice; before exposure (after vacation), and after 1 month of exposure. From the welders (14 symptomatic, of whom 7 had asthma-like symptoms), RNA from induced sputum was obtained for gene expression analysis. Messenger RNA from a subset of the samples (n = 7) was analysed with microarray technology to identify genes of interest. These genes were further analysed using quantitative PCR (qPCR; n = 22). RESULTS: By comparing samples before and after exposure, the microarray analysis resulted in several functional annotation clusters: the one with the highest enrichment score contained "response to wounding", "inflammatory response" and "defence response". Seven genes were analysed by qPCR: granulocyte colony-stimulating factor 3 receptor (CSF3R), superoxide dismutase 2, interleukin 8, glutathione S-transferase pi 1, tumour necrosis factor alpha-induced protein 6 (TNFAIP6), interleukin 1 receptor type II and matrix metallopeptidase 25 (MMP25). Increased levels of CSF3R, TNFAIP6 and MMP25 were indicated among asthmatic subjects compared to non-symptomatic subjects, although the differences did not reach significance. CONCLUSIONS: Workers' exposure to welding fumes changed gene expression in the lower airways in genes involved in inflammatory and defence response. Thus, microarray and qPCR technique can demonstrate markers of exposure to welding fumes and possible disease-related markers. However, further studies are needed to verify genes involved and to further characterise the mechanism for welding fumes-associated lower airway symptoms.

N-nitrosamines in the southern Swedish rubber industries - exposure, health effects, and immunologic markers.

OBJECTIVES: The aim of this study was twofold: (i) to evaluate the air levels of N-nitrosamines in the Swedish rubber industry and (ii) to estimate the risk of symptoms and changed levels of immunologic markers in relation to these levels. METHODS: Using adsorption tubes, we collected samples of N-nitrosamines in the breathing zone of 96 rubber workers and analyzed them with liquid chromatography tandem mass spectrometry. Of these 96 workers, 66 were included in a medical examination and blood analysis together with an additional 106 rubber workers and 118 unexposed subjects. Medical and occupational histories were obtained in structured interviews, symptoms were recorded and immunologic markers analyzed in blood. RESULTS: The sum of N-nitrosamines ranged from less than the limit of detection to 36 microg/m (3)and differed with the vulcanization (ie, curing process) method used. Workers vulcanizing with a salt bath had the highest levels (median 4.2 microg/m (3)). Compared to the unexposed subjects, the rubber workers had an increased risk of nosebleeds, eye and throat symptoms, hoarseness, cough, nausea, headache, and changed levels of eosinophils and total immunoglobulin G (IgG). However, we found no clear exposure-response relationship with the symptoms or the immunologic markers studied. CONCLUSIONS: High levels of N-nitrosamines were found and must be lowered considerably in order to decrease the risk of cancer. There is a need for an occupational exposure limit for N-nitrosamines in Sweden. The lack of exposure-response relationships with the subacute symptoms examined in this study may be due to a healthy-worker selection or to the possibility that the symptoms are caused by an exposure not co-varying with N-nitrosamines.

Gene expression in nasal lavage from hairdressers exposed to persulphate.

OBJECTIVES: Many hairdressers experience work-related symptoms from the airways caused by bleaching powder. This contains persulphates, which could be irritating to the mucous membrane and also may evoke an allergic reaction. However, specific IgE antibodies are difficult to detect. We found earlier that hairdressers with work-related bleaching powder-associated nasal symptoms reacted to persulphate, but that atopics also did and that the mechanism appeared to be similar in the two groups. In this study, we analysed gene expression of cytokines in the nose in order to further investigate the mechanism for work-related bleaching powder-associated nasal symptoms. METHODS: The study subjects belonged to either hairdressers with work-related bleaching powder-associated nasal symptoms (S; n = 6), hairdressers without work-related bleaching powder-associated symptoms (WS; n = 7) or atopics (A; n = 6). Nasal lavage was performed before and during (up to 4 h after the last challenge) provocation with potassium persulphate. Expression of two genes involved in allergic inflammation [interleukin 5 (IL5) and IL13] and one involved in cell-mediated immunity (interferon-gamma; IFNG) were analysed in nasal lavage with quantitative PCR. RESULTS: The change of IL5 in the S group differed when compared to the WS group (P = 0.0051), in the A group when compared to the WS group (P = 0.014), but not in the S group when compared to the A group (P = 0.82). The change of IL13 in the A group differed when compared to the S (P = 0.041) and WS (P = 0.014) groups, but no difference was noticed between the S and WS groups (P = 0.30). The relative level of IFNG increased from before challenge to during challenge in the S group (P = 0.031). CONCLUSIONS: Symptomatic hairdressers showed increased expression of IL5 and IFNG, but not IL13, during challenge. Hairdressers without work-related bleaching powder-associated nasal symptoms showed no markedly changed reaction. Atopics showed increased expression of IL5 and IL13. Thus, this may indicate a difference in the mechanism of symptoms between symptomatic hairdressers and atopics. However, due to the low number of participants, further studies are needed to elucidate the mechanism for persulphate-associated nasal symptoms.

Symptoms and immunologic markers among vulcanization workers in rubber industries in southern Sweden.

OBJECTIVES: The aim of this study was to estimate the risk of symptoms and the possible derangement of levels of immunologic markers for contemporary Swedish rubber workers. Furthermore, the relation between exposure and these biomarkers of response was examined using urinary levels of 2-thiothiazolidine-4-carboxylic acid (TTCA), which reflect the exposure. METHODS: Included in the study were 166 exposed workers and 117 controls. Medical and occupational histories were obtained in structured interviews. Symptoms were recorded, and immunologic markers were analyzed in blood. Urinary levels of TTCA were determined by liquid chromatography tandem mass spectrometry. RESULTS: Compared with the controls, the exposed workers had increased risks of eye symptoms [odds ratio (OR) 3.0], nose bleeds (OR 4.0), burning and dry throat (OR 3.0), hoarseness (OR 2.4), severe dry cough (OR 3.8), nausea (OR 4.3), and headache (OR 2.5). When the exposed workers were divided into three groups according to the TTCA levels, the highest risks were observed among the exposed workers with intermediate TTCA levels. Furthermore, the exposed workers in all of the TTCA subgroups had elevated concentrations of total immunoglobulin G when compared with the controls. Elevated concentrations of leukocytes, neutrophils, and eosinophils were observed in the group with high TTCA levels. CONCLUSIONS: This work shows an increased risk of several symptoms and elevated levels of some immunologic markers among exposed workers in Swedish rubber industries. In addition, relationships between urinary levels of TTCA and some biomarkers of response were reported.

Lung function in relation to 2-thiothiazolidine-4-carboxylic acid and genetic effect modification among rubber workers in Sweden.

OBJECTIVE: What is the risk of impaired lung function in contemporary Swedish rubber workers and are there modifying effects of genetic variants? METHODS: Included in the study were 159 rubber exposed and 118 not-rubber exposed workers. Lung function was analyzed as forced vital capacity percent of predicted and forced expiratory volume in 1 second percent of predicted. Levels of 2-thiothiazolidine-4-carboxylic acid (a marker of carbon disulfide and vulcanization fumes) was assessed with liquid chromatography tandem mass spectrometry. Polymorphisms in glutathione-related genes were analyzed by Taqman-based allelic discrimination and ordinary polymerase chain reaction. RESULTS: There was an association between increasing levels of 2-thiothiazolidine-4-carboxylic acid and impaired lung function among exposed workers. The association was modified by glutathione S-transferase alpha 1 (GSTA1)-52 and GSTP1-114. GSTM1 had an influence on lung function among unexposed workers. CONCLUSIONS: There may be a risk of impaired lung function in contemporary rubber workers. Gene-modifying effects may be considered in risk assessments.

Levels of 1-hydroxypyrene, symptoms and immunologic markers in vulcanization workers in the southern Sweden rubber industries.

OBJECTIVES: The aim of this study was to determine urinary 1-hydroxypyrene (1-HP) levels in contemporary Swedish vulcanization workers and in controls. These levels were used as an index substance for vulcanization fumes, as well as a biomarker for polycyclic aromatic hydrocarbons (PAHs). The risk of symptoms and changed levels of immunologic markers were investigated in relation to the 1-HP levels. METHODS: Included in the study were 163 exposed workers and 106 controls. Medical and occupational histories were obtained by structured interviews. Symptoms were recorded and immunologic markers analysed in blood by routine analysis methods. Levels of 1-HP were determined by liquid chromatography and fluorescence detection. RESULTS: The highest levels of 1-HP were found among exposed workers using injection and compression vulcanization and lower levels were found among exposed workers vulcanizing with salt bath, hot air, microwaves or fluid-bed. Compared to controls, exposed workers had increased risks of eye symptoms, nosebleeds, burning and dry throat, hoarseness, severe dry cough, nausea and headache. Furthermore, exposed workers had elevated levels of neutrophils and total IgG (immunoglobulin subclass G). However, only for severe dry cough an evident exposure-response relationship with urinary 1-HP levels was found. CONCLUSIONS: This work clearly shows increased levels of urinary 1-HP in Swedish vulcanization workers. Furthermore, it demonstrates an increased risk of several symptoms and elevated levels of some immunologic markers in these workers. However, no obvious exposure-response relationships were found.

Influence of glutathione-related genes on symptoms and immunologic markers among vulcanization workers in the southern Sweden rubber industries.

OBJECTIVE: The aim was to elucidate the role of genetic variants on symptoms of the eyes and airways, headache and nausea, as well as on immunologic markers, among vulcanization workers in the contemporary Swedish rubber industry. Polymorphisms in genes, which are involved in the defense against reactive oxygen species and metabolism of toxic substances present in the vulcanization fumes, were analyzed. METHODS: One hundred and forty-five exposed and 117 unexposed workers were included in the study. Medical and occupational histories were obtained in structured interviews. Symptoms were recorded and immunologic markers analyzed in blood. Polymorphisms in glutathione-related genes (glutamate cysteine ligase catalytic subunit (GCLC)-129, glutamate cysteine ligase modifier subunit (GCLM)-588, glutathione S-transferase alpha 1 (GSTA1)-52, GSTM1*O, GSTP1-105, GSTP1-114, and GSTT1*O) were analyzed by Taqman-based allelic discrimination and ordinary PCR. RESULTS: A protective effect of GSTA1-52 (G/A + A/A) genotype on symptoms and immunologic cells, in particular among exposed workers, was suggested. Exposed workers with GSTT1*O had increased risk of nosebleed compared to exposed workers with GSTT1*1. Exposed workers with GSTP1-105 (ile/val + val/val) had decreased levels of total immunoglobulin E (IgE) compared to exposed workers with GSTP1-105 ile/ile. GCLC-129 variant genotype demonstrated increased levels of immunologic cells among exposed workers, although statistical significance was not reached. CONCLUSION: Our data indicate that hereditary factors influence the susceptibility to symptoms and the immunologic response of workers in the rubber industry.

Levels of 2-thiothiazolidine-4-carboxylic acid (TTCA) and effect modification of polymorphisms of glutathione-related genes in vulcanization workers in the southern Sweden rubber industries.

OBJECTIVES: Workers in the rubber industry are exposed to a complex mixture of hazardous substances and have increased risk of developing several diseases. However, there is no up to date survey examining the exposure in the Swedish rubber industry. One of the toxic compounds in the industry is carbon disulfide (CS(2)), which is biotransformed to 2-thiothiazolidine-4-carboxylic acid (TTCA). TTCA is used as a biomarker of CS(2) exposure, but there seem to exist inter- and intraindividual variability; which could partly be due to genetic variation. The aim of the study was to determine TTCA levels and the modifying effects of glutathione-related genes in a group of Swedish rubber workers. METHODS: Urine was collected from both exposed workers and controls during the last 4 h of the work shift. The level of TTCA in urine was analyzed by liquid chromatograpy tandem mass spectrometry. Genotyping of the single nucleotide polymorphisms GCLC-129, GCLM-588, GSTA1-52, GSTP1-105 and GSTP1-114 and deletions of GSTM1 and GSTT1 were performed with real-time PCR or ordinary PCR and subsequent agarose electrophoresis. RESULTS: The highest levels of TTCA were found among workers curing with salt bath, hot air, microwaves or fluid-bed, and lower levels were found among workers curing with injection and compression molding. Furthermore, with respect to GSTM1 and GSTT1 there were statistically significant differences in TTCA-levels between genotypes among exposed workers but not among controls. The other five polymorphisms had no impact on the TTCA levels. CONCLUSIONS: The present study demonstrates relatively high levels of TTCA in urine from Swedish rubber workers. Polymorphisms in GSTM1 and GSTT1 modify the levels.