Wireless phone use in childhood and adolescence and neuroepithelial brain tumours: Results from the international MOBI-Kids study

In recent decades, the possibility that use of mobile communicating devices, particularly wireless (mobile and cordless) phones, may increase brain tumour risk, has been a concern, particularly given the considerable increase in their use by young people. MOBI-Kids, a 14-country (Australia, Austria, Canada, France, Germany, Greece, India, Israel, Italy, Japan, Korea, the Netherlands, New Zealand, Spain) case-control study, was conducted to evaluate whether wireless phone use (and particularly resulting exposure to radiofrequency (RF) and extremely low frequency (ELF) electromagnetic fields (EMF)) increases risk of brain tumours in young people. Between 2010 and 2015, the study recruited 899 people with brain tumours aged 10 to 24 years old and 1,910 controls (operated for appendicitis) matched to the cases on date of diagnosis, study region and age. Participation rates were 72% for cases and 54% for controls. The mean ages of cases and controls were 16.5 and 16.6 years, respectively; 57% were males. The vast majority of study participants were wireless phones users, even in the youngest age group, and the study included substantial numbers of long-term (over 10 years) users: 22% overall, 51% in the 20-24-year-olds. Most tumours were of the neuroepithelial type (NBT; n = 671), mainly glioma. The odds ratios (OR) of NBT appeared to decrease with increasing time since start of use of wireless phones, cumulative number of calls and cumulative call time, particularly in the 15-19 years old age group. A decreasing trend in ORs was also observed with increasing estimated cumulative RF specific energy and ELF induced current density at the location of the tumour. Further analyses suggest that the large number of ORs below 1 in this study is unlikely to represent an unknown causal preventive effect of mobile phone exposure: they can be at least partially explained by differential recall by proxies and prodromal symptoms affecting phone use before diagnosis of the cases. We cannot rule out, however, residual confounding from sources we did not measure. Overall, our study provides no evidence of a causal association between wireless phone use and brain tumours in young people. However, the sources of bias summarised above prevent us from ruling out a small increased risk.

Pregnancy and perinatal conditions and atopic disease prevalence in childhood and adulthood

BACKGROUND

Previous studies showed controversial results for the influence of pregnancy-related and perinatal factors on subsequent respiratory and atopic diseases in children. The aim of this study was to assess the association between perinatal variables and the prevalence of asthma, bronchial hyperreactivity (BHR), flexural eczema (FE), allergic rhinitis, and sensitization in childhood and early adulthood.

METHODS

The studied population was first examined in Munich and Dresden in 1995/1996 at age 9-11 years. Participants were followed until age 19-24 years using questionnaires and clinical examinations. Associations between perinatal data and subsequent atopic diseases were examined using logistic regression analyses adjusting for potential confounders.

RESULTS

Cesarean section was statistically significantly associated with BHR in early adulthood (odds ratio 4.8 [95% confidence interval 1.5-15.2]), while assisted birth was associated with presence of asthma symptoms in childhood (2.2 [1.2-3.9]), FE symptoms (2.2 [1.2-4.3]) and doctor's diagnosis of atopic dermatitis (1.9 [1.0-3.4]) in childhood, and sensitization in early adulthood (2.2 [1.1-4.3]). Lower birth length (1.9 [1.1-3.2]), lower birthweight (0.5 [0.3-0.9]), and higher birthweight (0.6 [0.4-1.0]) were predictive of sensitization in early adulthood compared to average birth length and birthweight, respectively. None of the other perinatal factors showed statistically significant associations with the outcomes.

CONCLUSIONS

Our results indicate that children who are born by cesarean section and especially by assisted birth, might be at greater risk for developing asthma, FE, and sensitization and should hence be monitored. Prenatal maternal stress might partly explain these associations, which should be further investigated.

Snap-fits and upper limb functional limitations in German automotive workers

BACKGROUND

The use of snap-fit fasteners in automotive assembly has increased in the last 10 years. Their impact on musculoskeletal function of the upper limbs in assembly workers is not well described.

AIMS

To investigate the association between snap-fit assembly and upper limb functional limitations (ULFLs) in workers after a large-scale expansion of snap-fit assembly by a German automotive company.

METHODS

Cross-sectional data on blue-collar production workers' exposure to snap-fit assembly and ULFLs were collected from medical check-ups and company registers. The association between duration of snap-fit assembly and ULFLs, and the dose-response relationship between the two were analysed using logistic regression, adjusted for body mass index, gender and employment duration before snap-fit exposure.

RESULTS

The study group included 10722 workers. Within the company, 8.4, 6.9 and 10.3% were exposed to snap-fit 1-12, 13-24 and ≥25 months, respectively. After adjusting for confounders, snap-fit exposure for 1-12 months [odds ratio (OR) = 1.59, 95% confidence interval (CI) 0.88-2.88] and 13-24 months (OR = 1.48, 95% CI 0.76-2.88) was not statistically significantly associated with ULFLs compared with an unexposed group. However, exposure to ≥25 months of snap-fit assembly was statistically significant associated with ULFLs showing >2-fold risk (OR = 2.44, 95% CI 1.52-3.92). No clear dose-response relationship was found.

CONCLUSIONS

Our study suggests a negative long-term impact from snap-fit assembly on workers' upper limb function. Company physicians should be vigilant for signs of upper limb musculoskeletal disorders among workers exposed to snap-fit assembly.

Attitude of medical students towards occupational safety and health: a multi-national study

BACKGROUND

Work-related diseases contribute immensely to the global burden of diseases. Better understanding of attitudes of health care workers towards occupational safety and health (OSH) is important for planning.

OBJECTIVE

To assess the attitude of medical students towards OSH around the globe.

METHODS

A questionnaire assessing the attitude towards OSH was administered to medical and paramedical students of 21 Medical Universities across the globe. In the current study 1895 students, aged 18-36 years, from 17 countries were included. After having performed a principal components analysis, the associations of interest between the identified components and other socio demographic characteristics were assessed by multivariate linear regression.

RESULTS

Principal component analysis revealed 3 components. Students from lower and lower-middle-income countries had a more positive attitude towards OSH, but the importance of OSH was still rated higher by students from upper-income countries. Although students from Asian and African continents showed high interest for OSH, European and South-Central American students comparatively rated importance of OSH to be higher. Paramedical students had more positive attitude towards OSH than medical students.

CONCLUSION

The attitude of students from lower-income and lower-middle-income towards importance of OSH is negative. This attitude could be changed by recommending modifications to OSH courses that reflect the importance of OSH. Since paramedical students showed more interest in OSH than medical students, modifications in existing health care system with major role of paramedics in OSH service delivery is recommended.

Are primary school students exposed to higher noise levels than secondary school students in Germany?

BACKGROUND

Noise, one of the major environmental nuisances, affects the learning ability of children negatively.

OBJECTIVE

With the assumption that in the existing German 4-type school system children are exposed to various noise levels in each type of school, we investigated the association between children's school type and environmental noise level.

METHODS

In this cross-sectional study, we included 550 children, primary and secondary school students, aged 8-12 years, and who lived in 4 Bavarian cities. The environmental noise level was assessed by personal 24-h dosimeter measurements. The associations of interest were assessed by linear regression.

RESULTS

The average day noise level of 80.0 dB(A) was relatively high, exceeding the threshold level of 60 dB(A). In the model adjusted for sex, socioeconomic status (SES), and place of residence, noise level was significantly higher for primary schools by almost 2.3 dB(A); however, after additional adjustments for age, this association was distorted. The mean night noise level of 43.7 dB(A) was not associated with the school level. We could not find any significant differences in the noise level between different types of secondary schools.

CONCLUSION

We found evidence that in Germany, children, especially of a younger age from primary school, are exposed to high noise levels during day in and outside the school environment. School administration and parents should work to make schools less noisy and more accomplished for learning to achieve a bright future for the children.

[Objective assessment of total noise exposure over 24 hours: a cross-sectional study in Bavaria]

INTRODUCTION

Noise can affect well-being and performance of individuals and might be associated with an increased risk of cardiovascular events. To date most epidemiological studies considered exposure from a single source of noise. The EU Environmental Noise Directive (2002/49/EC) requires a summative measurement of ambient noise. This study aimed to capture the participants' exposure to environmental noise by means of personal noise dosimetry.

METHODS

Children (n=628, participation=61%, age 8-12 years), adolescents (n=632, participation=58%, age 13-17 years) and adults (n=482, participation=40%, age 18-65 years) were selected randomly from the population registry of 4 Bavarian towns and were invited to participate in a 24-h measurement using noise dosimetry. Noise exposures during day and night were analyzed separately. In addition, predictors of noise exposure were assessed.

RESULTS

For daytime noise exposure mean±standard deviation were in children 80.0±5.8 dB(A), in adolescents 76.0±6.2 dB(A), in adults 72.1±6.1 dB(A) (p(ANOVA)<0.001). During the day personal noise exposure was statistically significantly higher for participants from smaller towns than for those living in Munich, while nighttime noise exposure was highest for participants from Munich [44.1±7.2 dB(A)].

CONCLUSION

The summative noise exposure in urban Bavaria is high, in particular among children at daytime. Increased exposure levels in children might be caused by themselves while, e.g., playing. Whether the higher daytime exposure in towns is due to high noise levels commuting between home and work has to be assessed in future studies.

The occupational contribution to severe exacerbation of asthma

The goal of this study was to identify occupational risk factors for severe exacerbation of asthma and estimate the extent to which occupation contributes to these events. The 966 participants were working adults with current asthma who participated in the follow-up phase of the European Community Respiratory Health Survey. Severe exacerbation of asthma was defined as self-reported unplanned care for asthma in the past 12 months. Occupations held in the same period were combined with a general population job-exposure matrix to assess occupational exposures. 74 participants reported having had at least one severe exacerbation event, for a 1-yr cumulative incidence of 7.7%. From regression models that controlled for confounders, the relative risk (RR) was statistically significant for low (RR 1.7, 95% CI 1.1-2.6) and high (RR 3.6, 95% CI 2.2-5.8) biological dust exposure, high mineral dust exposure (RR 1.8, 95% CI 1.02-3.2), and high gas and fumes exposure (RR 2.5, 95% CI 1.2-5.5). The summary category of high dust, gas, or fumes exposure had RR 3.1 (95% CI 1.9-5.1). Based on this RR, the population attributable risk was 14.7% among workers with current asthma. These results suggest occupation contributes to approximately one in seven cases of severe exacerbation of asthma in a working population, and various agents play a role.

Healthy hire effect, job selection and inhalation exposure among young adults with asthma

The aim of the present study was to assess whether asthma onset prior to entering the workforce influences whether a person holds a subsequent job with asthma-related inhalation exposures. The data of 19,784 adults from the European Community Respiratory Health Survey were analysed. For each respondent, a current or previously held job was linked to a job exposure matrix assigning high, low or no exposure to dust, gases or fumes. Jobs were also categorised according to the risk of exposures related to occupational asthma. Associations between asthma and subsequent occupational exposures were assessed using logistic regression models, with a random intercept for study centre and fixed adjustment for age, sex, type of study sample and smoking status. Of the respondents, 8% (n = 1,619) reported asthma with onset before completion of full-time education. This population was at decreased risk of having a job with high (odds ratio 0.79; 95% confidence interval 0.68-0.92) or low (0.91; 0.80-1.03) exposure to dust, gases or fumes. The associations were consistent across exposure types (dusts, gases or fumes) and for jobs with a high risk of occupational asthma. Adults with asthma onset prior to entering the workforce may be less likely to hold jobs involving inhalation exposures.

GA2LEN (Global Allergy and Asthma European Network) addresses the allergy and asthma 'epidemic'

Allergic diseases represent a major health problem in Europe. They are increasing in prevalence, severity and costs. The Global Allergy and Asthma European Network (GA(2)LEN), a Sixth EU Framework Program for Research and Technological Development (FP6) Network of Excellence, was created in 2005 as a vehicle to ensure excellence in research bringing together research and clinical institutions to combat fragmentation in the European research area and to tackle allergy in its globality. The Global Allergy and Asthma European Network has benefited greatly from the voluntary efforts of researchers who are strongly committed to this model of pan-European collaboration. The network was organized in order to increase networking for scientific projects in allergy and asthma around Europe and to make GA(2)LEN the world leader in the field. Besides these activities, research has also been carried out and the first papers are being published. Achievements of the Global Allergy and Asthma European Network can be grouped as follows: (i) those for a durable infrastructure built up during the project phase, (ii) those which are project-related and based on these novel infrastructures, and (iii) the development and implementation of guidelines. The major achievements of GA(2)LEN are reported in this paper.

An international prospective general population-based study of respiratory work disability

BACKGROUND

Previous cross-sectional studies have shown that job change due to breathing problems at the workplace (respiratory work disability) is common among adults of working age. That research indicated that occupational exposure to gases, dust and fumes was associated with job change due to breathing problems, although causal inferences have been tempered by the cross-sectional nature of previously available data. There is a need for general population-based prospective studies to assess the incidence of respiratory work disability and to delineate better the roles of potential predictors of respiratory work disability.

METHODS

A prospective general population cohort study was performed in 25 centres in 11 European countries and one centre in the USA. A longitudinal analysis was undertaken of the European Community Respiratory Health Survey including all participants employed at any point since the baseline survey, 6659 subjects randomly sampled and 779 subjects comprising all subjects reporting physician-diagnosed asthma. The main outcome measure was new-onset respiratory work disability, defined as a reported job change during follow-up attributed to breathing problems. Exposure to dusts (biological or mineral), gases or fumes during follow-up was recorded using a job-exposure matrix. Cox proportional hazard regression modelling was used to analyse such exposure as a predictor of time until job change due to breathing problems.

RESULTS

The incidence rate of respiratory work disability was 1.2/1000 person-years of observation in the random sample (95% CI 1.0 to 1.5) and 5.7/1000 person-years in the asthma cohort (95% CI 4.1 to 7.8). In the random population sample, as well as in the asthma cohort, high occupational exposure to biological dust, mineral dust or gases or fumes predicted increased risk of respiratory work disability. In the random sample, sex was not associated with increased risk of work disability while, in the asthma cohort, female sex was associated with an increased disability risk (hazard ratio 2.8, 95% CI 1.3 to 5.9).

CONCLUSIONS

Respiratory work disability is common overall. It is associated with workplace exposures that could be controlled through preventive measures.

Serum leptin and adiponectin levels and their association with allergic sensitization

BACKGROUND

Obesity and respiratory allergies have increased in parallel in industrialized countries. We have recently shown an association between obesity and allergic sensitization whereby obesity diminished the protective effect of childhood farm contact.

OBJECTIVE

To assess whether taking obesity into account allergic sensitization is associated with adipokine levels in blood and whether this effect is modified by childhood farm contact.

METHODS

Serum samples of 231 adult participants (age 18-45 years) of the Lower Saxony Lung Study were analysed for leptin and adiponectin by ELISA. Subjects were elected to represent equal-sized groups with respect to obesity (<30 vs> or =30 kg/m(2)), childhood farm contact, specific IgE to ubiquitous allergens and sex. Multiple logistic regression models were adjusted for potential confounders.

RESULTS

Leptin levels were positively related to the prevalence of sensitization (highest vs lowest quartile odds ratio 6.7, 95% confidence interval 2.0-22.4). For adiponectin levels, a weak, not statistically significant inverse association with sensitization was shown (highest vs lowest quartile 0.4, 0.2-1.1). The association between leptin and sensitization appeared to be more pronounced in subjects with farm contact; however, the effect modification was not statistically significant.

CONCLUSION

These findings suggest that adipokines might be involved in the causal pathway between obesity and allergic sensitization.

Occupation and adult onset of rhinitis in the general population

OBJECTIVES

Occupational exposures have been associated with an increased risk of new-onset rhinitis in apprentices. However, population-based prospective data are scarce and do not cover new onset of rhinitis later in life. The authors studied the association between occupational exposure and adult onset of rhinitis prospectively.

METHODS

The data of 4994 participants (age at follow-up 28-57 years) from 27 centres of the European Community Respiratory Health Survey II who were symptom-free at baseline were analysed. As outcome at follow-up self-reported (a) nasal allergies ("allergic rhinitis") and (b) runny, blocked nose for 12 months a year ("perennial rhinitis") were used. Occupational exposures at any time during follow-up were defined by job title.

RESULTS

The cumulative incidence of allergic rhinitis, perennial rhinitis and both conditions was 12%, 11% and 3%, respectively. Compared to office workers, male medical professionals were at increased risk of new onset of allergic rhinitis (OR 3.0; 95% CI 1.4 to 6.4). Odds ratios were reduced in metal workers not involved in metal making or treating (0.3; 95% CI 0.1 to 0.7). For perennial rhinitis ORs were significantly increased in cleaners (1.4; 95% CI 1.0 to 2.1).

CONCLUSIONS

Cleaners and medical professionals may be at increased risk for adult-onset rhinitis.

Leisure time activity and new onset of wheezing during adolescence

Asthma prevalence is increasing in adult and paediatric patients. In the present study, the association between different leisure time activities and new onset of wheezing was analysed in adolescents aged 16-18 yrs taking part in a questionnaire-based follow-up of the International Study on Asthma and Allergies in Childhood in Munich and Dresden, Germany. Of the 3,785 adolescents who took part in the follow-up (76% response), 2,910 adolescents without earlier episodes of wheezing in childhood were included in the analyses. Of these, 330 (11.3%) reported new onset of wheeze during the previous 12 months. In the bivariate analyses, exercising more than once per week or performing computer work >1 h.day(-1) were inversely related to new onset of wheeze. In contrast, visiting discotheques on a regular basis increased the risk of new onset of wheeze (12.9 versus 9.9%). The observed inverse relationship between physical activity and new onset of wheeze was not an independent effect but mediated by differences in active smoking. The association between physical activity and new onset of wheeze disappeared when active smoking was taken into account. However, the present data do not allow for determining whether smoking operated as a confounder or as an intermediate factor, i.e. whether physical activities prevented active smoking.

First months of employment and new onset of rhinitis in adolescents

The aim of the present study was to investigate the incidence of rhinitis in adolescents, taking into account the duration and type of employment in holiday and vocational jobs, and to study latency until development of symptoms. Participants of the International Study of Asthma and Allergies in Childhood (ISAAC)-II study in Munich and Dresden (Germany), who were enrolled in 1995, were re-contacted by a postal questionnaire in 2002 (aged 16-18 yrs). The questionnaire focused on allergic rhinitis, type and duration of all jobs, and potential confounders. All jobs held for >/=8 h.week(-1) and >/=1 month were coded and occupational exposure was assigned by a job-exposure matrix. Out of the 3,785 participants, 964 reported an employment history. The median (25th-75th percentile) duration of employment was 10 (1-16) months. After adjusting for potential confounders, those working in high-risk occupations (odds ratio (OR) 1.4, 95% confidence interval (CI) 1.0-2.1) had an increased risk for new onset of rhinitis, especially those exposed to low molecular weight agents (OR 1.8, 95% CI 1.1-2.8). The incidence of rhinitis was highest among those currently employed in a high-risk job for <10 months. Teenagers who start working in high-risk occupations have a higher incidence of rhinitis compared with those not working. This increased risk might occur early on during employment.

Characterisation of asthma among adults with and without childhood farm contact

Childhood farm contact is associated with a lower prevalence of sensitisation and allergic rhinitis. Findings have been contradictory for asthma. The aim of the present study was to investigate the differences between farm and nonfarm subjects using objective measurements. A cross-sectional questionnaire study was performed among rural adults aged 18-44 yrs, of which 37% lived on a farm during the first 3 yrs of life and were thus referred to as "farm subjects". Lung function, bronchial hyperresponsiveness (BHR) to methacholine and sensitisation were measured in a random sample. A total of 1,595 subjects were included in the analyses. Among farm subjects, sensitisation against inhalant allergens (odds ratio (OR) 0.7; 95% confidence interval 0.6-0.9), allergic rhinitis (0.5 (0.4-0.8)) and asthma diagnosis (0.7(0.4-1.1)) were less common than among nonfarm subjects. For BHR and lung function, no statistically significant differences were found between the two groups. Stratifying for sensitisation, farm subjects had a lower OR of asthma diagnosis (0.5 (0.3-1.0)) and a nonsignificantly reduced OR of BHR with sensitisation (0.8 (0.5-1.1)). The present study confirmed, using objective measurements, that farm subjects have a lower prevalence of symptoms and asthma diagnosis, while the prevalence of bronchial hyperresponsiveness does not differ.

European dissemination of a web- and case-based learning system for occupational medicine: NetWoRM Europe

OBJECTIVE

Occupation has a large impact on health in Europe. In order to prevent and recognize occupational diseases, medical students and physicians should know about the potentially causal relationship between profession and diseases as well as the basic legal aspects of occupational medicine (OM). However, the opportunity of bedside teaching, the students' most favoured way of teaching, is limited.

METHODS

One possibility to complete and improve traditional training in OM is computer-oriented case-based learning. Using the authoring system "CASUS" (INSTRUCT AG) cases can be created and handled without knowledge in computer sciences.

RESULTS

So far, 19 cases have been created and evaluated by students of German universities. Due to the great efforts arising from the creation of such multimedia cases it is desirable and cost-effective to use the existing cases at several medical universities. Therefore, the Net-based Training in Work-Related Medicine (NetWoRM) project shares cases on an international base. In February and April 2005, 13 case-authors from 12 centres were trained in the basics of case creation during a 3 week programme in Munich. The overall evaluation of the participants indicated that this way of teaching case creation is very efficient. Up to now, nine cases were translated into English and five into Spanish. First implementation of the cases in Spain and Finland showed a good acceptance by the students but more evaluation has still to be done.

CONCLUSION

Based on these results we conclude that exchange of case-based e-learning in OM is feasible and rewarding on an international base.

Do respiratory symptoms predict job choices in teenagers?

Existing guidelines advise adolescents with asthma and allergies against high-risk occupations. The aim of the current authors' analyses was to investigate the resulting self-selection in a prospective cohort study. The participants of Phase II of the International Study of Asthma and Allergies in Childhood in Germany (aged 9-11 yrs at baseline) were re-contacted after 7 yrs (response rate was 77%) and were asked to complete a questionnaire, which included items on atopic diseases. The subjects were also asked about the type of job they would like to have in the future (preferred job choice). Exposure to agents with potential asthma risk was evaluated using a job exposure matrix. The analyses were restricted to those in school-based vocational training programmes without occupational exposures. A total of 33% of subjects chose jobs with high asthma risk, 23% selected low asthma risk jobs and the remaining adolescents indicated jobs without known asthma risk (reference category). There were no statistically significant associations between asthma, allergic rhinitis or atopic dermatitis and selecting jobs with asthma risk. Participants with allergic rhinitis tended to select high risk jobs less frequently. In conclusion, self-selection into low risk jobs seems to play a minor role in teenagers with asthma or allergies.

[Acute effects on the health of children after accidental exposure to epichlorohydrine]

PURPOSE

In September 2002, two freight trains collided at Bad Muender, Germany. The inhabitants were potentially exposed to combustion products and to the human carcinogen epichlorohydrine (ECH). We aimed to describe the geographical distribution of and potential risk factors for acute symptoms among children residing in Bad Muender.

METHODS

The parents of a random sample of children were invited to answer a mail-in questionnaire (response rate 63%). The main outcome measures were self-reported acute symptoms potentially associated with combustion products (e. g., irritation of the eyes, nose, or throat) and stress-related unspecific symptoms (e. g., gastrointestinal complaints, sleep problems, headaches). The main location during the first 26 hours after the train accident served as exposure proxy measure. In addition, potential predictors for the symptoms under study were assessed.

RESULTS

The prevalence of symptoms associated with combustion products was 5.9%. Unspecific symptoms were reported for 6.3% of the children. Main location and prevalence of symptoms were not significantly associated. Physician-diagnosed asthma and nasal allergies were the main predictors of symptoms.

CONCLUSION

The prevalence of acute symptoms was relatively high in a random sample of children living close to the incident. However, associations between exposure to the accident and symptoms could not be established conclusively.

Needlestick injuries during medical training

Medical students are at risk of acquiring infections caused by needlestick injuries, although it is unknown when needlestick injuries are most likely to occur during medical training. The aim of this study was to define high-risk periods over the course of medical training. A cross-sectional study was conducted among medical students in the first, third, fourth and fifth years of training at two medical schools in Munich. Overall, 1317 (85%) students returned a questionnaire on demographic data, vaccination status against hepatitis B, lifetime prevalence of needlestick injuries, level of knowledge about measures after such accidents, and transmission risks. Lifetime prevalence of needlestick injuries was 23%, ranging from 12% in first year students to 41% in fourth year students. These accidents happened most commonly during medical internships, especially during blood-taking practices; an activity that usually starts during the third year of training. The frequency of respondents not vaccinated against hepatitis B also varied between first (21%) and fourth (6.6%) year students. Needlestick injuries occur frequently and early on in medical training. In order to decrease the risk of preventable infections, complete coverage of vaccination against hepatitis B should be achieved early in medical training.

Heart rate variability, hemostatic and acute inflammatory blood parameters in healthy adults after short-term exposure to welding fume

The present study aimed to investigate, whether short-term experimental exposure to high levels of welding fumes would be capable of exerting acute effects in healthy subjects. Specifically, we assessed cardiovascular function in terms of heart rate variability (HRV) as well as the concentrations of inflammatory mediators and hemostatic proteins in blood as outcome measures. Twenty subjects without a history of airway and cardiovascular diseases were exposed to either control air or welding fume for 1 h on 2 separate days under standardized conditions. The median concentration of the alveolar particle fraction during welding was 3.5 mg/m(3 )(quartiles: 1.4-6.3 mg/m(3); range 1.0-25.3 mg/m(3)). Five hours later a panel of clinical assessments was performed, including HRV measurement and drawing of blood samples. There were no changes in symptom ratings or lung function after welding fume exposure. Exposures did also not differ regarding effects on time- and frequency-domain parameters of HRV. Similarly, blood leukocyte numbers, cell differentials and the blood levels of fibrinogen, C-reactive protein, antithrombin III, factor VIII, von Willebrand factor, ristocetin cofactor, sICAM-1, tumor necrosis factor alpha, interleukin 6, interleukin 8 and epithelial neutrophil activating peptide 78 were not altered by welding fume inhalation. However, there was a significant fall in the level of endothelin-1 (P < 0.01). In conclusion, the data did not indicate effects of clinical significance of a short-term high-level exposure to welding fumes on HRV or a set of blood hemostatic and acute inflammatory parameters in healthy subjects. The small but statistically significant effect on endothelin levels demonstrated that measurable effects could be elicited even in these individuals. Overall, welding fumes are not likely to exert acute cardiovascular effects in healthy individuals.

Inverse association between farm animal contact and respiratory allergies in adulthood: protection, underreporting or selection?

BACKGROUND

It has been argued that the inverse association between exposure to farm animals and nasal allergies observed in children and adults might be because of self-selection.

AIMS

We aimed to assess the health-based selection out of farming in adults.

MATERIAL AND METHODS

A cross-sectional study was carried out in a rural region. Overall, 4053 inhabitants (63%) aged 18-44 years responded to a questionnaire on respiratory diseases, life-time exposure to farming environments and potential confounders. For 2678 of these, specific immunoglobulin E to common allergens was available. The outcome was: (i) sensitization and symptoms of nasal allergies (symptomatic sensitization); (ii) sensitization without symptoms of nasal allergies (asymptomatic sensitization).

RESULTS

Farm animal contact in childhood was associated with a decreased risk of symptomatic and asymptomatic sensitization. Continued exposure to farm animals in adulthood further decreased the odds ratio of symptomatic (odds ratio 0.2; 95% confidence interval 0.1, 0.4) but not asymptomatic sensitization (0.7; 0.4, 1.1). Starting farm animal contact in adulthood even increased the odds ratio of asymptomatic sensitization (2.4; 1.1, 5.2).

CONCLUSIONS

The preventive effect of childhood contact to farm animals against sensitization continues into adulthood. However, in adulthood self-selection based on symptoms and underreporting of symptoms might also play a role.

Smoking and the incidence of asthma during adolescence: results of a large cohort study in Germany

BACKGROUND

The association between smoking and asthma or wheeze has been extensively studied in cross sectional studies, but evidence from large prospective cohort studies on the incidence of asthma during adolescence is scarce.

METHODS

We report data from a cohort study in two German cities, Dresden and Munich. The study population (n = 2936) was first studied in 1995/6 at age 9-11 years as part of phase II of the International Study of Asthma and Allergies in Childhood (ISAAC II) and followed up in 2002/3. At baseline the parents completed a questionnaire and children underwent clinical examination and blood sampling. At follow up the young adults completed questionnaires on respiratory health, living, and exposure conditions. Incidence risk ratios (IRR) were calculated and adjusted for potential confounders using a modified Poisson regression approach.

RESULTS

The adjusted IRR for incident wheeze for active smokers compared with non-smokers was 2.30 (95% confidence interval (CI) 1.88 to 2.82). The adjusted IRR was slightly higher for incident wheeze without a cold (2.76, 95% CI 1.99 to 3.84) and the incidence of diagnosed asthma (2.56, 95% CI 1.55 to 4.21). Analysis of duration and intensity of active smoking indicated dose dependent associations. Stratified analyses showed that the risk of incident wheeze without a cold in atopic smokers increased with decreasing plasma alpha(1)-antitrypsin levels at baseline (1.64, 95% CI 1.22 to 2.20 per interquartile range).

CONCLUSIONS

Active smoking is an important risk factor for the incidence of asthma during adolescence. Relatively lower plasma levels of alpha(1)-antitrypsin, although well above currently accepted thresholds, may increase susceptibility to respiratory disease among atopic smokers.

Atemwegsgesundheit und Allergiestatus bei jungen Erwachsenen in ländlichen Regionen Niedersachsens

BACKGROUND

Up to now potential health effects of environmental exposure to intensive livestock production facilities have not been thoroughly studied. The aim of the Lower Saxony Lung Study (NiLS) was to assess the prevalence of respiratory symptoms and disease in an area with intensive animal production facilities taking into account environmental exposure to emissions from these large-scale farms.

METHODS

All 10 864 inhabitants (age 18 to 44 years) of four towns with a large number of intensive animal production facilities in the area were invited to answer a mail-in questionnaire. Of these, 6416 subjects were randomly selected for the clinical part of the study (specific IgE, lung function measurements, bronchial provocation with methacholine). Overall, 6937 subjects answered the questionnaire (68 %), 60 % took part in the clinical tests.

RESULTS

The prevalence of allergic disease in the study population was lower than in urban citizens. Subjects with more than 12 animal houses within 500 m of their home had an increased odds ratio for wheezing without a cold (odds ratio 2.7; 95 % confidence interval 1.4 - 5.4). They also showed a significantly decreased FEV (1) (mean 0.26 l; 0.04 l - 0.48 l) as well as a trend for a lower Tiffeneau-Index.

CONCLUSIONS

In result, a large number of intensive animal production facilities might be associated with decreased lung function results in the immediate neighbours. Further studies are necessary to confirm our findings.

Farming exposure in childhood, exposure to markers of infections and the development of atopy in rural subjects

BACKGROUND

Within the context of the hygiene hypothesis, we aimed to study the potential association between farming-related risk factors and Toxoplasma gondii (T. gondii) as well as Helicobacter pylori (H. pylori) seropositivity.

METHODS

The study included questionnaire data and serum samples of 321 young adults living in a rural environment. Serum samples were analysed for specific IgE to a common panel of aeroallergens (SX1) as well as IgG against T. gondii and H. pylori.

RESULTS

Regular contact with animal stables before the age of 3 years (odds ratio (OR) (95% confidence interval): 2.0 [1.0; 4.0]) and unpasteurized milk consumption at age 6 years (1.8 [1.0; 3.3]) were the strongest risk factors for T. gondii infection. None of the farming-related factors were significantly associated with H. pylori infection. Current consumption of raw farm milk was not significantly associated with H. pylori infection (2.1 [0.8; 5.3]). Regular contact with animal houses before the age of 7 years was the strongest predictor for atopy (0.49 [0.26-0.96]). The reduction in risk could not be further decreased by any other factor under consideration. After adjustment for animal house contact, the OR for atopy was decreased by raw milk consumption and H. pylori infection in an additive manner.

CONCLUSION

Exposure to farming environments in childhood might predict T. gondii seropositivity in rural subjects. Nevertheless, the strongest predictor for atopy in rural subjects seems to be regular contact with farm animals. Whether T. gondii infection is an intermediate factor in the association between farm contact and atopy needs to be confirmed in larger studies.

Biomonitoring results and cytogenetic markers among harbour workers with potential exposure to river silt aerosols

BACKGROUND

Workers on dredgers and lighters on rivers are potentially exposed to a variety of substances.

AIMS

To determine the internal load of heavy metals and arsenic as well as levels of cytogenetic markers in workers exposed to river silt aerosols.

METHODS

One hundred exposed workers were examined up to eight times within three years. Additionally, 100 control workers were studied once. Blood samples were analysed for lead, mercury, and cadmium. Additionally, micronuclei frequency and sister chromatid exchange (SCE) rates were determined. Urinary samples were analysed for cadmium, mercury, nickel, chromium, and arsenic. Information on potential confounders, such as smoking habits and consumption of fish were assessed.

RESULTS

Apart from some increased concentrations of mercury in blood (maximum 14.6 microg/l) and arsenic in urine (maximum 356.5 microg/l) all measurements were within reference values. None of the exposure and effect markers were found to be significantly increased in exposed workers compared to non-exposed controls. In multiple linear regression models, mercury levels in blood as well as the concentration of arsenic in urine were strongly related to fish consumption. Cadmium levels in blood as well as urinary cadmium concentrations were strongly related to smoking habits. After adjusting for smoking habits, SCE rates were associated with cadmium levels in blood.

CONCLUSION

Increased exposure levels or enhanced levels of cytogenetic markers were not found in workers exposed to river silt aerosols. However, cadmium exposure in blood was related to SCE frequency.

[Electromagnetic pollution (electrosmog)--potential hazards of our electromagnetic future]

The term electromagnetic environment encompasses the totality of all electric, magnetic and electromagnetic fields generated by natural and technical sources. A differentiation is made between low- and high-frequency electromagnetic fields. Typical sources of the former are domestic electricity Exposure to the latter is, for example, associated with the sue of mobile telephones. Studies on the health-related effects of electromagnetic fields are available in particular for the low-frequency range, based on an appropriate estimation of exposure. A number of these studies reveal an association between exposure to this type of electromagnetic fields and the occurrence of infantile leukemia in the highest exposure category. For high-frequency electromagnetic fields the number of epidemiological studies is limited. An increased risk of an accident occurring through the use of a cellular phone while driving has consistently been shown. Against the background of our limited knowledge about possible adverse effects of exposure to mobile phone transmitters, and the inability of the public to influence such exposure, transparency in the communication of the risks involved is of great importance.

[Passive smoking--current position of science]

Among all indoor pollutants, environmental tobacco smoke (ETS) might be the most important. In population-based studies 30 to 60 % of the participants reported regular exposure to ETS. ETS has been classified as carcinogenic by several national and international agencies. In 2002, a paragraph on restriction of smoking at the workplace has been added to the German Workplaces Ordinance. International meta-analyses have been published on the potential health effects of ETS exposure. In these studies, the pooled relative risk (RR) for lung cancer has been estimated between 1.1 and 1.3. The pooled risk estimate for coronary heart disease (CHD) was slightly higher (1.25 - 1.35). The RR in the group with the highest exposure might be as high as 2. An increased risk has also be shown consistently for respiratory symptoms, asthma, and COPD. Because of the high incidence of CHD the public health impact of ETS exposure on CHD might be higher than the impact due to additional lung cancer cases.

[Respiratory diseases in European farmers-II. Part of the European farmers' project]

BACKGROUND

The aim of the European Farmers' Project was to estimate the prevalence of respiratory diseases in farmers across Europe. Furthermore, risk factors for respiratory symptoms in different parts of agricultural production should be assessed.

METHODS

In the first part of the study, 7496 farmers from four European countries answered a written questionaire. Of these, 229 were visited at their farms in the second part of the survey. On site, spirometry, allergy tests, as well exposure measurements were performed.

RESULTS

Farmers with animal production had a significantly lower prevalence of allergic diseases than the general population. In contrast, the prevalence of chronic phlegm was higher in animal farmers. Organic dust toxic syndrome (ODTS) was a major predictor of chronic bronchitis. It was indicated that allergens found in the working environment could be transfered to the living environment of the farmer. Poor ventilation as well as high temperatures inside the animal buildings were shown to have a negative impact on respiratory symptoms and lung function parameters.

CONCLUSION

Animal farmers are at high risk of chronic bronchitis. Intervention studies on the efficacy of different types of ventilation are now warranted. Furthermore, prospective studies on the associaton between ODTS and COPD should be done.

Prevalence of respiratory symptoms in sheep breeders

BACKGROUND

The European Farmers' Study has indicated that sheep farmers might be at risk for the development of respiratory symptoms.

AIMS

To assess the prevalence of respiratory symptoms in sheep breeders and potential work related risk factors.

METHODS

All sheep breeders listed in two regions of South Germany were asked to answer a mailed questionnaire on respiratory symptoms, work related respiratory symptoms (WRS), and details of farming. Overall, 325 sheep breeders keeping at least 10 sheep could be included in the survey (response rate 81.9%). The prevalences were compared to the results of the European Farmers' Study.

RESULTS

Sheep breeders showed a significantly higher prevalence of asthma related symptoms (prevalence odds ratio (POR) 2.1, 95% CI 1.5 to 3.0), chronic phlegm (POR 4.0, 95% CI 2.8 to 5.9), and WRS (POR 1.7, 95% CI 1.3 to 2.2) after adjusting for age, gender, smoking habits, full time farming, and study centre. In the multiple logistic regression model the risk for asthma related symptoms was doubled in full time farmers (POR 2.3, 95% CI 1.2 to 4.3). The major predictor of WRS was full time farming (POR 1.6, 95% CI 0.93 to 2.7) and the use of chemical footbaths (POR 2.1, 95% CI 1.2 to 3.7).

CONCLUSIONS

Sheep breeders might be at high risk for the development of respiratory symptoms. These symptoms may be associated with work intensity and chemical exposure during work. Studies including objective measurements should be performed.

[Respiratory diseases in European farmers. Part 1: Literature review]

Farming is still one of the most important economic sectors in the world. At the same time, a high prevalence of respiratory diseases in farmers is well known. Among these, allergic and non-allergic asthma, chronic bronchitis, hypersensitivity pneumonitis and organic dust toxic syndrome (ODTS) are of uppermost importance. Because of the large variety of agriculture across Europe exposure conditions and risk factors for airway diseases may vary largely. While exposure to organic dusts and irritants are most important in grain and animal production, workers in greenhouses are mainly exposed to pollen, fungi, as well as pesticides. Up to now, the knowledge about the prevalence of respiratory diseases in European farmers working in different agricultural sectors was limited. Furthermore, reliable data on farming characteristics as well as exposure patterns that might prone risk factors for respiratory diseases were missing. Therefore, the European Farmers' Project was initiated. The results of this study are given in the second part of this paper.

Region-related risk factors for respiratory symptoms in European and Californian farmers

The aim of this study was to determine the prevalences and regional risk factors for respiratory symptoms in European and Californian farmers. Farmers participating in the 1993-1997 surveys performed in Europe (n = 7,188) and California (n = 1,839) were included in this cross-sectional study. Respiratory symptoms and farming characteristics were assessed by questionnaire and risk factors associated with symptoms using logistic regression. The prevalences of rhinitis and asthma were lower in European (12.7% and 2.8%) than in Californian farmers (23.9% and 4.7%), but chronic bronchitis and toxic pneumonitis were more prevalent in Europe (10.7% and 12.2%) than in California (4.41% and 2.7%). Respiratory symptoms were associated with poultry and rabbit farming, flower growing and the cultivation of grain and oil plants. Working in Europe was a statistically significant risk factor for chronic bronchitis and toxic pneumonitis. Chronic bronchitis was related to toxic pneumonitis, work inside confinement buildings and greenhouses. Chronic bronchitis and toxic pneumonitis are highly prevalent among European farmers and are mainly attributable to indoor work.