Biological monitoring of occupational exposure to N,N -dimethylformamide – the effects of co-exposure to toluene or dermal exposure

Objectives: The objective of this study is to assess the exposure and intake dose of N,N-dimethylformamide (DMF) and the correlation between them, according to the type of exposure for the workers in the DMF industry. Methods: We monitored 345 workers occupationally exposed to DMF, from 15 workshops in the synthetic fiber, fiber coating, synthetic leather and paint manufacturing industries. Ambient monitoring was carried out with personal samplers to monitor the external exposure. Biological monitoring was done to determine the internal dose by analyzing N-methylformamide (NMF) in end-shift urine. Work procedure and exposure type of each DMF workshop was carefully surveyed, to classify workers by exposure type according to work details. Workers were classified into three groups (Group A: continuous and direct exposure through inhalation and skin; Group B: intermittent and short-term exposure through inhalation and skin; Group C: continuous and indirect exposure mostly through inhalation). Results: Geometric mean of DMF concentration in air was 2.62 (GSD 5.30) ppm and that of NMF in urine was 14.50 (GSD 3.89) mg/l. In the case of continuous absorption through inhalation and dermal exposure (Group A), the value of NMF in urine corresponding to 10 ppm of DMF was 45.3 mg/l (r=0.524, n=178), 39.1 mg/g creatinine (r=0.424), while it was 37.7 mg/l (r=0.788, n=37), 24.2 mg/g creatinine (r=0.743) in the case of absorption mostly through inhalation (Group C). Creatinine correction reduced the correlation between two parameters. Conclusion: The NMF in urine corresponding to 10 ppm DMF, of the dermal and inhalation exposure group was 39.1 mg/g creatinine (r=0.424, n=178), while that of the inhalation exposure-only group was 24.2 mg/g creatinine (r=0.743, n=37). Co-exposure with toluene reduced the NMF excretion in urine. Received: 4 October 1999 / Accepted: 25 April 2000     

Biomarkers of exposure and effect��interpretation in human risk assessment

The effect of exposure to carcinogenic polycyclic aromatic hydrocarbons adsorbed onto respirable air particles (PM2.5, diameter 相似文献   

Smoke-free policies and non-smokers’ reactions to SHS exposure in small and medium enterprises

Introduction

Non-smoker employees can significantly improve the existing smoke-free policies in the workplace by asserting their right for smoke-free air and confronting smoker colleagues. The aim of the study was to assess the psychological and social drivers of non-smokers’ readiness to assert their right for smoke-free air in the workplace.

Materials and Methods

Twenty-six small-and-medium enterprises (SME) with diverse background were randomly selected, and 284 employees agreed to participate in the study. Our study focused on the responses of 85 non-smokers (M age = 34 years, SD = 7.98, 84.2% worked in indoor offices). A cross-sectional design was used and participants completed a structured anonymous questionnaire assessing background and demographic characteristics, and psychosocial predictors of assertiveness intentions.

Results

Although more than half of non-smokers reported they were often/almost always bothered by exposure to SHS, roughly one third of them reported having asked their colleagues not to smoke at work. Regression analysis showed that the effects of distal predictors (i.e. annoyance due to SHS exposure) were mediated by past behaviour, attitudes (protection motivation beliefs), social norms, and self-efficacy.

Conclusions

Health beliefs related to SHS exposure, and concerns about workplace health and job performance, social norms and self-efficacy can increase the assertiveness of non-smokers in workplace settings. Related campaigns should focus on communicating normative messages and self-efficacy training to empower non-smoker employees to act assertively towards protecting their smoke-free rights.     

α-Tocopherol supplementation and the oxidative stress,homocysteine, and antioxidants in lead exposure

To investigate whether α-tocopherol supplementation in workers exposed to lead would reduce the oxidative stress intensity and decrease homocysteine level, the examined population was randomly divided into two groups. Workers in the first group (n = 49, reference group) were not administered any drugs. Workers in the second group (n = 34) were administered orally α-tocopherol, 200 mg per day for 12 weeks. The level of α-tocopherol significantly increased compared to the baseline and the reference group. The level of thiol groups significantly increased compared to the reference group. However, the levels of malondialdehyde and homocysteine did not significantly change. Animal studies suggest the ability of α-tocopherol administration to reverse adverse health effects of lead exposure, such as oxidative stress; however, the results of this study on humans do not confirm these protective effects.     

Otitis,rhinitis, and atopy in relation to domestic endotoxin and β-glucan exposure among children in Singapore

Background  

Exposure to microbial cell wall agents (MCWAs) has been related to the risk for atopy, otitis, and rhinitis.     

Asbestos exposure and malignant lymphoma: a multicenter case–control study in Germany and Italy

Aims

To analyze the relationship between asbestos exposure and malignant lymphoma in a multicenter case–control study conducted in Germany and Italy according to a common core protocol.

Methods

Male and female patients with malignant lymphoma (n = 1,034) between 18 and 80 years of age were prospectively recruited in six study areas in Germany (Ludwigshafen/Upper Palatinate, Heidelberg/Rhine-Neckar-County, Würzburg/Lower Frankonia, Hamburg, Bielefeld/East Westphalia, and Munich) and in two study areas in Sardinia, Italy (Cagliari and Nuoro provinces). A total of 1,173 population control subjects were drawn from population registers. In a structured personal interview, we elicited a complete occupational history, including every occupational period that lasted at least 1 year. On the basis of job task-specific supplementary questionnaires, trained experts assessed the exposure to asbestos. As a measure of cumulative asbestos exposure on a time by intensity scale, fiber-years were calculated. 12 cases (1.2%) and 12 control subjects (1.0%) had a cumulative asbestos exposure of more than 2.6 fiber-years (highest exposure category according to the 90th percentile of exposed control subjects). Odds ratios (OR) and 95% confidence intervals (CI) were calculated using unconditional logistic regression analysis adjusted for age, sex and study region. Patients with specific lymphoma sub-entities were additionally compared with the entire control group.

Results

We observed no statistically significant association between cumulative asbestos exposure and the risk of any lymphoma subtype. An elevated risk was found for the association between exposure to more than 2.6 fiber-years and multiple myeloma (OR = 6.0; 95% CI 1.4–25.1); however, numbers were small (n = 3 cases, all of them from Italy; n = 12 control subjects).

Conclusions

Our study does not support an association between asbestos exposure and risk of malignant lymphoma.     

Chronic bronchitis and pesticide exposure: a case–control study in Lebanon

Objective Pesticides are widely used toxics. The objective of the study is to evaluate the odds of exposure to pesticides in chronic bronchitis patients.Methods Using the American Thoracic Society standardized questionnaire confirmed by medical diagnosis of chronic bronchitis, a case–control study was␣performed in Lebanon. Pesticide exposure was estimated and between groups comparison was made.Results The study involved 262 controls and 110 chronic bronchitis outpatient subjects from 10 medical centers. Any exposure to pesticides was associated to chronic bronchitis (OR = 2.46 [1.53–3.94]; p < 10⁻⁴). Occupational use presented the highest association (15.92 [3.50–72.41]; p < 10⁻⁴), followed by regional exposure (3.70 [2.05–6.70]; p < 10⁻⁴). Results were confirmed by multivariate and subgroup analysis.Conclusion Pesticide exposure was associated with chronic bronchitis in Lebanese adults. Pesticides toxicological effects may explain chronic respiratory effects associations found with all exposure types.     

Are there sex and gender differences in acute exposure to chemicals in the same setting?

We have little understanding of the influence that sex and gender may have on exposure to and measurement of occupational chemicals. If men and women are in the same physical environment, whether that be an occupational or an environmental setting, researchers need to question whether their acute exposure, as measured by administered and/or biologically effective dose, is the same. Not doing so may result in incorrect inferences being made about the risks associated with that exposure. Three critical questions arise specifically, do men and women differ in (1) their personal environments (immediate physical environments and personal attributes), (2) their absorption of the substance across the various biological barriers, and (3) the amount of active substance that reaches the target sites? Both contextual (e.g., smoking habits, diet, use of personal care products and jewellery, hobbies, stress, and use of medications) and biological (e.g., endocrine status) factors should be considered in answering these questions. Examples from the literature are provided to show that, depending on the chemical compound, there may be sex and gender differences in exposure to chemicals which can be manifested in sex differences in absorption, distribution, metabolism, storage, and excretion. An argument is developed to support the need to make information available, such as pharmacokinetic modeling studies in both men and women including appropriate age groups representing the spectrum of life stages and reproductive status.     

Lead and cadmium exposure in children living around a coal-mining area in Yatağan, Turkey

The study was designed to determine asymptomatic lead poisoning prevalence and cadmium exposure of preschool children living in a coal-mining area in Yata?an, Mugla, Turkey. The research was conducted between May and June 2002. The study included 236 children (53.4% female and 46.6% male) who were identified among the healthy children between the ages of 6 months and 6 years, using a systematic sampling method, from the records of the local medical centre of Yata?an. Assessments of the levels of blood lead and cadmium were performed by an atomic absorption spectrophotometer, in the Department of Biophysics, Cerrahpa?a Medical Faculty. The mean age of females and males were 49+/-18 and 43+/-19 months, respectively. The mean blood lead level was 33.8+/-15.6 microg/dL in females and 38.8+/-16.0 microg/dL in males. The mean blood lead level of the males was significantly higher than the females (P<0.05). Correlation analysis showed a statistically significant negative correlation between blood lead level and age in both sex groups (r= -0.367, P<0.001). The blood lead level was found to be > 10 microg/dL in 95.7% and >20 microg/dL in 87.6% of all children. The mean blood cadmium level of all children was 1.31+/-0.72 microg/dL. The blood cadmium level was found to be >0.5 microg/dL, which is considered to be toxic, in 85% of all children. The difference in blood cadmium levels between sexes was not significant. A statistically significant negative correlation was found between blood cadmium level and age of all children (r= -0.382, P<0.001). Although it is not possible to understand from this study what proportion of the biological lead and cadmium burden results from mining waste and what proportion comes from other sources, such as paint and gasoline residue deposited in soil and air, these results do indicate that asymptomatic lead poisoning and cadmium exposure are significant problems in children living in the Yata?an area. In conclusion, environmental lead measurements (house dust, soil, drinking water and air) must be performed, the results must be compared with the normal limits, and precautions must be taken if necessary in the Yata?an area. Future public health research efforts should focus on reducing the excessive levels of lead and cadmium in the environment.     

Apolipoprotein D and α1-microglobulin in human urine: effect of cadmium exposure

Summary Apolipoprotein D is a previously unrecognized urinary protein of unknown function which we have tested as a potential marker for kidney malfunction. This protein and ₁-microglobulin have been quantified by zone immunoelectrophoresis assay in urine samples from a group of eight men occupationally exposed to cadmium-containing welding fumes for many years. All these workers had highly elevated concentrations of urinary cadmium and indications of tubular proteinuria, as compared to a group of 50 apparently healthy normal men analyzed in parallel. The cadmium-exposed workers demonstrated three- and 15-fold average increases in apolipoprotein D and ₁-microglobulin, respectively, over normal values in urine, estimated both as excretion rates and as milligrams of protein per mmol of creatinine. All these increments were highly significantly different (P < 0.001) from the corresponding values of the reference group. Essentially the same results were obtained for each of the proteins from two independent consecutive samplings of the workers' urine. There were good linear (R = 0.70, 0.80) and logarithmic (R = 0.84, 0.81) correlations between the urinary concentrations of ₁-microglobulin and apolipoprotein D for both the reference and the study group. Although not as sensitive an indicator for tubular proteinuria as ₁-microglobulin, apolipoprotein D, being a storage-stable urinary protein, seems a valuable complement for the diagnosis of tubular malfunction.     

Biomonitoring of 4,4′-methylene dianiline by measurement in hydrolysed urine and plasma after epicutaneous exposure in humans

Five healthy volunteers were dermally exposed for 1 h to 0.75–2.25 mol 4,4-methylene dianiline (MDA) dissolved in isopropanol, by use of a patchtest technique. Determination of MDA remaining in the patch units after exposure showed that a median of 28% (range 25–29%) was absorbed. By analysis of hydrolysed plasma, an initial accumulation of MDA could be shown, and then a decline. MDA was also detected in hydrolysed urine. The maximum rate of MDA excretion in urine was found 6–11 h after the onset of exposure. Within two subjects studied at three doses, the urinary excretion was proportional to the exposure. The elimination half-lives (elim-t _1/2) in plasma and urine had medians of 13 and 7 h, respectively. In eight out of nine exposures, the elim-t _1/2 was longer in plasma than in urine. Slow acetylation seemed to be associated with short elim-t _1/2 in urine. The median of total MDA amount excreted in urine during 48 h, was 33 nmol for the five subjects exposed to 0.75 mol, which corresponded to roughly 16% (range 2%–26%) of the absorbed dose while only a limited number of individuals were studied, the data still indicated that MDA in hydrolysed plasma or urine can be used for biological monitoring of occupational dermal exposure. However, the individual variation must be taken into account. Sampling should preferably be made several hours post shift. Urine is preferred before plasma at low exposures, because of its higher concentrations of MDA.     

Impairment in workers with isocyanate-induced occupational asthma and removed from exposure in the province of Québec between 1985 and 2002

OBJECTIVE: The objective of this project was to assess both the outcome for patients diagnosed with proven isocyanate-induced occupational asthma (IIOA) by specific inhalation challenge (SIC) and the functional impairment, 2 years after cessation of exposure to isocyanates, using the compensation insurance scale proposed in the province of Quebec. METHODS: We used a retrospective cohort of 233 patients diagnosed in the province of Quebec between 1985 and 2002 and randomly chose 105 of those patients. We kept 89 subjects with complete data at T0 (the time of diagnosis) and 79 were reevaluated at T2, approximately 2 years after their removal from exposure, for final impairment-disability assessment. At each evaluation (T0 and T2), a clinical examination and lung function tests, including spirometry and methacholine challenge, were performed. RESULTS: At T2, 79 of 89 patients were reassessed (89%). The remaining patients were lost to follow up (8) or too unstable to be reassessed for final impairment-disability settlement (2). No statistical difference was observed for spirometry data and antiasthmatic medication use between T0 and T2 (P = 0.11). At T2, 73% of patients were still using short-acting beta2 agonists and 39% inhaled glucocorticoids. A forced expiratory volume in 1 second variation of +/-10% from T0 to T2 occurred in 31 subjects (40%). Forced expiratory volume in 1 second worsened in 14 (18%), remained significantly unchanged in 51 (64%), and improved in 14 (18%). Nonspecific bronchial hyperresponsiveness (BHR) improved in significantly in 19 (24%); the others remained unchanged. Both were not associated with smoking status (P > 0.05). Nonspecific BHR was normalized in nine of 79 (11%) patients. Clinical remission occurred in only four (5%) subjects. The mean impairment-disability score was 21% +/- 13% at 2 years according to the scale used by the Workers' Compensation Board. CONCLUSIONS: These results show the generally poor medical outcome of IIOA and suggest the importance of early detection and withdrawal of the workers from exposure to isocyanates. They also emphasize the need for medical surveillance program and adequate treatment of patients with IIOA.     

Urinary parabens and triclosan concentrations and associated exposure characteristics in a Korean population—A comparison between night-time and first-morning urine

Parabens and triclosan have been widely used in many personal care products and cosmetics. The endocrine disrupting potential of these compounds is of increasing public health concern. The aim of this study is to understand the current exposure profile of these chemicals in last void before bedtime (night-time) and first-morning void (first-morning) urines among a Korean population and to characterize their exposure sources and pathways.A total of 261 people, including infants (0–2 years), toddlers (3–6 years), children (7–12 years), adolescents (13–18 years), and adults (≥19 years), were recruited, and sampled for night-time urine and first-morning urine of the following day. Methyl (MeP), ethyl (EtP), propyl (PrP) and butyl paraben (BuP), and triclosan were measured in urine. The demographic characteristics, use of personal care products, and food consumption were obtained through a questionnaire.Among the target compounds, EtP and MeP were most frequently detected at the highest concentrations. The median concentration of EtP in night-time urine was 32.4?μg/L (interquartile range: 8.37–82.8?μg/L), which is higher than previously reported worldwide. Unlike other test compounds, compared to those measured from first-morning urine, the EtP concentrations were significantly higher in night-time urine, suggesting the presence of different exposure sources. Among adults, the MeP and PrP concentrations in night-time urine were associated with frequent use of skin care products, colored cosmetics, bath products, toothpaste, vinyl food packaging, or consumption of canned food. The MeP and PrP concentrations were higher in females than in males, especially in night-time urine. The results of this study also show that multiple urine samples are necessary to capture the diurnal variation of non-occupational exposure to environmental chemicals, such as parabens.     

Phthalate exposure in pregnant women and newborns – The urinary metabolite excretion pattern differs distinctly

Some phthalates are endocrine disruptors and reproductive and developmental toxicants. Data on newborn phthalate exposure and elimination characteristics are scarce. We determined 21 urinary phthalate metabolites (indicating exposure to 11 parent phthalates) in two study approaches: in the first approach we collected the urine of 20 healthy newborns at days 2–5 post partum together with 47 urine samples of 7 women during pregnancy. In the second fine tuned approach we collected first urine samples of 9 healthy newborns together with their mother's urine shortly before birth. To ensure full and contamination free collection of the newborns first urines we used special adhesive urine bags for children. All urine samples revealed ubiquitous exposures to phthalates comparable to other populations. Metabolite levels in the newborns first day urine samples were generally lower than in all other samples. However, the newborns urines (both first and day 2–5 urines) showed a metabolite pattern distinctly different from the maternal and general population samples: in the newborns urines the carboxy-metabolites of the long chain phthalates (DEHP, DiNP, DiDP) were the by far dominant metabolites with a relative share in the metabolite spectrum up to 6 times higher than in maternal urine. Oppositely, for the short chain phthalates (DBP, DiBP) oxidized metabolites seemed to be less favored than the simple monoesters in the newborns urines. The skewed metabolite distribution in the newborns urine warrants further investigation in terms of early phthalate metabolism, the quantity of internal phthalate exposure of the fetus/newborn and its possible health effects.     

Are changes in mechanical exposure and musculoskeletal health good performance indicators for primary interventions?

OBJECTIVES: The purpose of this review is to present more insight into the effects of primary interventions on both mechanical exposure and musculoskeletal health and to determine whether these outcomes are good performance indicators of such interventions. METHODS: The literature was scrutinised for relevant references. Primary prevention was defined as any activity aimed at preventing the occurrence of musculoskeletal disorders in occupational populations. Primary outcome measures were mechanical exposure, musculoskeletal health, and sick leave due to musculoskeletal disorders. The impact of interventions was assessed by calculating the reduction in mechanical exposure and the preventable fraction (PF) of the musculoskeletal complaints. After selection, 40 studies were included for further analysis. RESULTS: In general, of the 40 included studies, 29 (73%) found a reduction in musculoskeletal symptoms (PF range 0.10-0.95). Eighteen out of 29 studies (62%) reported a statistically significant reduction in musculoskeletal disorders. In 12 of the 40 studies (30%) changes in both mechanical exposure and musculoskeletal health were used as performance indicators for the intervention. Of these studies nine (67%) showed a reduction in both mechanical exposure (range 14%-87% reduction) and musculoskeletal disorders or sick leave due to musculoskeletal disorders (PF range 0.15-0.92). From these nine it was seen that a reduction of at least 14% in mechanical exposure resulted in a concomitant reduction in musculoskeletal health. CONCLUSIONS: More quantitative information is needed to describe the relationship between mechanical exposure and musculoskeletal health as presented in the model. In this case it is recommended that in primary intervention studies not only changes in health outcomes be measured but also changes in mechanical exposure along the pathway of the intervention. In this way a better insight will be gained about the dose-response relationships between exposure to physical-load risk factors and work-related musculoskeletal disorders (WRMSD). More insight into these relationships will eventually lead to more efficient implementations of primary intervention strategies.     

Offspring’s blood pressure and metabolic phenotype after exposure to gestational hypertension in utero

The aim of the study was to investigate the impact of de novo hypertension in pregnancy, i.e. gestational (non-proteinuric) hypertension (GH) and preeclampsia (PE), on the long-term metabolic outcome of the offspring. Data was obtained from the Northern Finland Birth Cohort 1986 (NFBC 1986), including 9,362 pregnancies and subsequent births between 1985 and 1986. Pregnancies were categorised into three groups: (1) GH with blood pressure (BP) ≥ 140/90 mmHg, (2) PE with BP ≥ 140/90 mmHg and proteinuria, and (3) reference group with normal BP. The final study population included 331 offspring of mothers with GH, 197 with PE and 5,045 offspring of normotensive mothers. The main outcome measures were systolic and diastolic blood pressure (SBP, DBP), mean arterial pressure (MAP), body mass index (BMI), and serum lipid, glucose and insulin levels of the 16 year-old offspring. The children of mothers with GH had higher BP compared to the reference group (SBP percentage difference 2.7 (95 % CI 1.6, 3.8); DBP 3.4 (2.1, 4.6); MAP 3.1 (2.0, 4.1), P < 0.001 for all) and a tendency towards higher cholesterol and apolipoprotein B values. The offspring of mothers with PE had higher DBP and MAP, however after the adjustments this difference disappeared. Maternal de novo hypertension during pregnancy is associated with offspring’s elevated blood pressure level already in adolescence. GH may also be associated with unfavourable lipid profile of the offspring.     

Exposure–response relationship between endotoxin exposure and lung function impairment in cotton textile workers

OBJECTIVES: Preventive workplace regulations are so far not based on an ubiquitously accepted threshold for airborne endotoxin in the bioaerosol. METHODS: In a cross-sectional study, 150 employees of a cotton spinning mill underwent lung function testing. Furthermore, in a random subset of 75 textile workers cross-shift lung function test and methacholine challenges were performed. Airborne current endotoxin exposure was classified as "low", "medium", and "high" (100-450 Endotoxin Units (EU)/m(3), respectively) based on endotoxin activity. RESULTS: The exposure-response relationship between current endotoxin exposure and prevalence of an obstructive ventilation pattern was significant (test for linear trend: P = 0.019); the adjusted odds ratio for high endotoxin exposure was 11.22 (95% confidence interval 1.03-121.17). Within individuals, FEV(1)/FVC% was significantly reduced after the shift (paired t test: P = 0.009) but not related to current endotoxin exposure. Twelve workers showed bronchial hyperresponsiveness (8.1% before and 12.2% after the work shift; Fisher's exact test: P = 0.021). CONCLUSION: The study among German cotton textile workers suggests an exposure-dependent effect of current endotoxin exposure on lung function impairment with significant effects above 450 EU/m(3).     

Indoor allergen exposure in west and East Germany: a cause for different prevalences of asthma and atopy?

West and East Germans have been living in two different political systems for 40 years. These two populations have become a classic epidemiological example for the hypothesis that lifestyle changes accompanying the industrial and economic development of modern societies are responsible for an increase in the prevalence of atopic diseases. A higher prevalence of atopic sensitization, asthma, and hay fever was found in young West Germans after the unification. It has been hypothesized that this phenomenon was at least partially due to the installation of insulating windows and central heating systems in Western homes, favoring the growth of microorganisms like mites and moulds and increasing indoor allergen exposure. This review summarizes studies that have investigated reservoir concentrations of indoor allergens in public buildings and private homes in East and West Germany. Whereas a higher prevalence of atopic sensitization in West Germans was found for nearly all tested allergens (cat, mite, pollen), allergen exposure was higher only for cat allergens, but probably not for mite and cockroach allergens or moulds. The published data do not support the view that the differences in specific sensitization are caused by differences in the exposure to specific allergens.