Associations between tobacco smoking status and patch test results-A cross-sectional pilot study from the Information Network of Departments of Dermatology (IVDK).

BACKGROUND: Earlier studies suggested a potential association between tobacco smoking and nickel sensitization, but little is known about other contact allergens. OBJECTIVES: To investigate the association of smoking status and contact sensitizations as well as subtypes of dermatitis, and to analyse the sensitization profiles of tobacco smokers. PATIENTS AND METHODS: Within the Information Network of Departments of Dermatology (IVDK), we performed a cross-sectional multicentre pilot study comprising 1091 patch-tested patients from 9 departments, comparing 541 patients with a history of cigarette smoking (281 current and 260 former smokers) with 550 never-smokers. RESULTS: We could not confirm the previously reported association between nickel sensitization and tobacco smoking. Moreover, sensitizations to other allergens, including colophony, fragrance mix I, Myroxylon pereirae and formaldehyde, were not increased in cigarette smokers compared with never smokers. Hand dermatitis (50.6% vs. 33.6%) and occupational cause (36.2% vs. 22.5%) were significantly more frequent among cigarette smokers compared with never-smokers as shown by non-overlapping 95% confidence intervals. CONCLUSIONS: Although our study does not allow a firm conclusion on whether smoking status contributes to certain contact sensitizations, it confirms an association of smoking with hand dermatitis and occupational cause.

Patch testing in occupational dermatology: Practical aspects in relation to the conditions in Germany.

Allergic contact dermatitis is one of the most frequent occupational skin diseases. Targeted allergen avoidance can only be achieved by identification of the causative allergen. Therefore, patch testing is of utmost importance in occupational dermatology, not only in terms of assessing causal relationships but also regarding the implementation of prevention measures and evaluation of the legal criteria for an occupational skin disease in Germany (statutory occupational disease BK 5101). The lack of commercial patch test preparations poses a great diagnostic challenge. Patch testing of patient's own materials from their workplace is therefore very important to reduce diagnostic gaps. The performance and documentation of the patch test should be in line with current guidelines and recommendations to ensure the necessary test quality and comprehensibility of the test results.

[Prevention and health promotion in dermatology]. / Prävention und Gesundheitsförderung in der Dermatologie.

The term prevention includes measures that are used to avoid illnesses or damage to health as well as to reduce the risk of illness or to delay its occurrence. Preventive measures can be classified based on various criteria: temporal differentiation (primary, secondary, and tertiary prevention), context (behavioral and relational prevention), and recipient (general and individual prevention). Health promotion is used when appropriate measures are intended to strengthen and increase human health potential and resources. This includes, among other things, measures to develop health-promoting behavior (empowerment) and measures regarding the planning and implementation of health-promoting behavior (participation). One goal of these measures is generally to increase health literacy. This article describes examples of prevention and health promotion measures for occupational skin cancer (counseling approach for individual sun protection for outdoor workers; "individuelle Lichtschutzberatung" [ILB]) as well as occupational hand eczema within the meaning of German occupational disease number 5101 (outpatient and inpatient individual prevention measures). These are supplemented by the example of outpatient age-adapted small group trainings for patients with atopic dermatitis according to the multicenter evaluated concept of AGNES e. V. ("Arbeitsgemeinschaft Neurodermitisschulung") and ARNE ("Arbeitsgemeinschaft Neurodermitisschulung im Erwachsenenalter"). These examples also address aspects of sustainability and digitalization (eHealth, eLearning) in the areas of prevention and health promotion.

Prevalence and incidence of hand eczema in healthcare workers: A systematic review and meta-analysis.

Healthcare workers (HCWs) are considered a high-risk group for developing hand eczema (HE), mainly owing to wet work and contact with allergens at work. To meta-analyse the prevalence and incidence of HE in HCWs, as well as mapping the prevalence of atopic dermatitis (AD) and HE severity in HCWs. A systematic review and meta-analysis was performed following the Preferred Reporting Items for Systematic Reviews and Meta-analyses 2020 guidelines. Published literature from 2000 to 2022 was eligible based on predefined inclusion and exclusion criteria. A total of 18 studies were included. Pooled life-time, 1-year and point prevalence of self-reported HE in HCWs was 33.4% (95% confidence interval [CI]: 28.3-38.6), 27.4% (95% CI: 19.3-36.5) and 13.5% (95% CI: 9.3-18.4), respectively. AD prevalence was 15.4% (95% CI: 11.3-19.9). Overall, the majority of HCWs reported mild HE. One included study assessed HE incidence reporting 34 cases/1000 person years. Most studies scored low-moderate using the New Ottawa Scale and the pooled point prevalence data showed broad CIs. In conclusion, the high prevalence of HE in HCWs underlines the increased risk and need for preventive measures for this professional group. There is, however, a need of further standardized high-quality studies.

Quality of patch testing patient's own material in patients with suspected occupational skin diseases throughout Germany: Interim results of the German Social Accident Insurance (DGUV) research project FB 317b.

BACKGROUND: Due to limited availability of commercial test preparations, patch testing patient's own material (POM) is of great importance to diagnose occupational allergic contact dermatitis. OBJECTIVES: To assess the quality of performance and documentation of patch testing with POM in patients with suspected occupational skin diseases (OSD) in Germany. METHODS: Retrospective-prospective analysis of protocols of patch tests with POM was conducted between 2013 and 2021 in patients with suspected OSD and submitted to statutory accident insurance institutions. Assessments were done by predefined criteria. RESULTS: Three thousand and four patch tests with POM from 460 patients were included. A full description of the POM was provided in 73.3% of all tests. The test concentration, test vehicle and pH value were documented in 74.3%, 70.5% and 42.2% of tests, for which the respective parameters were considered relevant. One hundred and sixty-one positive reactions to POM were documented. In 72%, sufficient patch testing with commercial test substances was conducted to investigate the positive reaction. In 30.4%, consecutive patch testing of all ingredients of the POM was done. CONCLUSIONS: The results not only show considerable shortcomings mainly in documentation but also to some extent performance of patch tests with POM in patients with suspected OSD in Germany.

Diagnosis and treatment of Hymenoptera venom allergy: S2k Guideline of the German Society of Allergology and Clinical Immunology (DGAKI) in collaboration with the Arbeitsgemeinschaft für Berufs- und Umweltdermatologie e.V. (ABD), the Medical Association of German Allergologists (AeDA), the German Society of Dermatology (DDG), the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery (DGHNOKC), the German Society of Pediatrics and Adolescent Medicine (DGKJ), the Society for Pediatric Allergy and Environmental Medicine (GPA), German Respiratory Society (DGP), and the Austrian Society for Allergy and Immunology (ÖGAI).

Hymenoptera venom (HV) is injected into the skin during a sting by Hymenoptera such as bees or wasps. Some components of HV are potential allergens and can cause large local and/or systemic allergic reactions (SAR) in sensitized individuals. During their lifetime, ~ 3% of the general population will develop SAR following a Hymenoptera sting. This guideline presents the diagnostic and therapeutic approach to SAR following Hymenoptera stings. Symptomatic therapy is usually required after a severe local reaction, but specific diagnosis or allergen immunotherapy (AIT) with HV (VIT) is not necessary. When taking a patient's medical history after SAR, clinicians should discuss possible risk factors for more frequent stings and more severe anaphylactic reactions. The most important risk factors for more severe SAR are mast cell disease and, especially in children, uncontrolled asthma. Therefore, if the SAR extends beyond the skin (according to the Ring and Messmer classification: grade > I), the baseline serum tryptase concentration shall be measured and the skin shall be examined for possible mastocytosis. The medical history should also include questions specific to asthma symptoms. To demonstrate sensitization to HV, allergists shall determine concentrations of specific IgE antibodies (sIgE) to bee and/or vespid venoms, their constituents and other venoms as appropriate. If the results are negative less than 2 weeks after the sting, the tests shall be repeated (at least 4 - 6 weeks after the sting). If only sIgE to the total venom extracts have been determined, if there is double sensitization, or if the results are implausible, allergists shall determine sIgE to the different venom components. Skin testing may be omitted if in-vitro methods have provided a definitive diagnosis. If neither laboratory diagnosis nor skin testing has led to conclusive results, additional cellular testing can be performed. Therapy for HV allergy includes prophylaxis of reexposure, patient self treatment measures (including use of rescue medication) in the event of re-stings, and VIT. Following a grade I SAR and in the absence of other risk factors for repeated sting exposure or more severe anaphylaxis, it is not necessary to prescribe an adrenaline auto-injector (AAI) or to administer VIT. Under certain conditions, VIT can be administered even in the presence of previous grade I anaphylaxis, e.g., if there are additional risk factors or if quality of life would be reduced without VIT. Physicians should be aware of the contraindications to VIT, although they can be overridden in justified individual cases after weighing benefits and risks. The use of ß-blockers and ACE inhibitors is not a contraindication to VIT. Patients should be informed about possible interactions. For VIT, the venom extract shall be used that, according to the patient's history and the results of the allergy diagnostics, was the trigger of the disease. If, in the case of double sensitization and an unclear history regarding the trigger, it is not possible to determine the culprit venom even with additional diagnostic procedures, VIT shall be performed with both venom extracts. The standard maintenance dose of VIT is 100 µg HV. In adult patients with bee venom allergy and an increased risk of sting exposure or particularly severe anaphylaxis, a maintenance dose of 200 µg can be considered from the start of VIT. Administration of a non-sedating H1-blocking antihistamine can be considered to reduce side effects. The maintenance dose should be given at 4-weekly intervals during the first year and, following the manufacturer's instructions, every 5 - 6 weeks from the second year, depending on the preparation used; if a depot preparation is used, the interval can be extended to 8 weeks from the third year onwards. If significant recurrent systemic reactions occur during VIT, clinicians shall identify and as possible eliminate co-factors that promote these reactions. If this is not possible or if there are no such co-factors, if prophylactic administration of an H1-blocking antihistamine is not effective, and if a higher dose of VIT has not led to tolerability of VIT, physicians should should consider additional treatment with an anti IgE antibody such as omalizumab as off lable use. For practical reasons, only a small number of patients are able to undergo sting challenge tests to check the success of the therapy, which requires in-hospital monitoring and emergency standby. To perform such a provocation test, patients must have tolerated VIT at the planned maintenance dose. In the event of treatment failure while on treatment with an ACE inhibitor, physicians should consider discontinuing the ACE inhibitor. In the absence of tolerance induction, physicians shall increase the maintenance dose (200 µg to a maximum of 400 µg in adults, maximum of 200 µg HV in children). If increasing the maintenance dose does not provide adequate protection and there are risk factors for a severe anaphylactic reaction, physicians should consider a co-medication based on an anti-IgE antibody (omalizumab; off-label use) during the insect flight season. In patients without specific risk factors, VIT can be discontinued after 3 - 5 years if maintenance therapy has been tolerated without recurrent anaphylactic events. Prolonged or permanent VIT can be considered in patients with mastocytosis, a history of cardiovascular or respiratory arrest due to Hymenoptera sting (severity grade IV), or other specific constellations associated with an increased individual risk of recurrent and/or severe SAR (e.g., hereditary α-tryptasemia). In cases of strongly increased, unavoidable insect exposure, adults may receive VIT until the end of intense contact. The prescription of an AAI can be omitted in patients with a history of SAR grade I and II when the maintenance dose of VIT has been reached and tolerated, provided that there are no additional risk factors. The same holds true once the VIT has been terminated after the regular treatment period. Patients with a history of SAR grade ≥ III reaction, or grade II reaction combined with additional factors that increase the risk of non response or repeated severe sting reactions, should carry an emergency kit, including an AAI, during VIT and after regular termination of the VIT.

S2k guideline diagnosis, prevention, and therapy of hand eczema.

The consensus-based guideline "Diagnosis, prevention, and treatment of hand eczema (HE)" provides concrete instructions and recommendations for diagnosis, prevention, and therapy of HE based on an evidence- and consensus-based approach. The guideline was created based on the German guideline "Management von Handekzemen" from 2009 and the current guideline of the European Society of Contact Dermatitis (ESCD) "Guidelines for diagnosis, prevention, and treatment of hand eczema" from 2022. The general goal of the guideline is to provide dermatologists and allergologists in practice and clinics with an accepted, evidence-based decision-making tool for selecting and conducting suitable and sufficient therapy for patients with hand eczema. The guideline is based on two Cochrane reviews of therapeutic and preventive interventions for HE. The remaining chapters were mainly developed and consented based on non-systematic literature research by the expert group. The expert group consisted of members of allergological and occupational dermatological professional associations and working groups, a patient representative, and methodologists. The proposals for recommendations and key statements were consented by using a nominal group process during a consensus conference on September 15, 2022. The structured consensus-building process was professionally moderated. This guideline is valid until February 22, 2028.

Teledermatological Follow-Up Consultations in Individual Prevention of Occupational Dermatoses: A Monocentric Feasibility Study on Quality and Satisfaction by Patients and Physicians.

Teledermatology has become very popular, and not only due to the SARS-CoV-2 pandemic. Patients with occupational skin diseases (OSDs) could also benefit from teledermatology services as part of their follow-up care, but the opportunities and challenges for patients and dermatologists, especially regarding quality and satisfaction, need exploration. In this single-center feasibility study, 215 patients taking part in a tertiary prevention program for OSD were invited to participate. After obtaining consent, a follow-up video consultation appointment with the center's dermatologists was made. Quality and satisfaction with the consultations were evaluated by fully standardized online questionnaires filled in by the patients and dermatologists. A total of 68 teledermatological follow-up consultations were conducted by 10 dermatologists on 42 patients. Half of the dermatologists (50.0%) and 87.6% of the patients were satisfied with the video consultations. However, the lack of physical examination seems to be a problem, especially from the physicians' point of view (75.8%). A total of 66.1% of the dermatologists and 87.5% of the patients saw video consultations as useful supplements to face-to-face consultations. The results of our feasibility study indicate general satisfaction of patients and physicians with teledermatological sessions in occupational dermatology, especially as a useful supplement to face-to-face consultation.

[Hand eczema or psoriasis: update on the FB 323 study occupational dermatology cohort]. / Handekzem oder Psoriasis: Aktuelles aus der berufsdermatologischen Kohorte der FB323-Studie.

In daily dermatological practice, the distinction between eczema and psoriasis in dermatoses of the hands can be difficult. However, a clear diagnosis is necessary to initiate optimal therapy and management. In recent years, the so-called molecular classifier has been developed for optimized differentiation of eczema and psoriasis. An occupational dermatological cohort has been established at Heidelberg University Hospital since 2020. It is funded by the German Statutory Accident Insurance. The aim is to follow-up patients over 3 years where this new diagnostic method is used and to compare the results with a retrospective occupational dermatological cohort. Recruitment ended in December 2022. The current analysis reports participants' occupational activity, insurance status, disease progression, and number of sick days. A total of 287 patients were included; mean age was 50.4 years and 63.5% (n = 181) were undergoing treatment at the expense of the liable statutory accident insurance at the start of the study. About 50% of the patients worked in health professions, metal industry, or construction. The average duration of occupational dermatosis was 6.5 years. In 38.9% of the patients, the clinical diagnosis had been classified as unclear by the treating dermatologist. By using the molecular classifier, the diagnosis could be clarified in 98% of the cases (eczema vs. psoriasis). The first analyses demonstrate that the molecular classifier contributes to improving therapy by optimizing the diagnosis.

[Hand eczema and statutory accident insurance-what you should know for your practice]. / Handekzem und Unfallversicherung ­ was man für die Praxis wissen sollte.

Since January 1, 2021, recognition of occupational hand eczema as an occupational disease (OD) No. 5101 has been made significantly easier by eliminating the obligation to cease and desist work in the eczema-eliciting job. As a result of this change in OD law, an occupational disease can now also be recognized if the patient continues the (eczema-eliciting) work. This results in a significantly higher liability for accident insurance companies to enable high-quality care for affected patients by the dermatologist-and this, if necessary, in the long term until retirement. The number of recognized OD No. 5101 cases has already increased tenfold (around 4000 cases per year). Work-related hand eczema must be treated as quickly as possible in order to avoid a protracted course of the disease and job loss. Accordingly, those affected should be reported quickly to the accident insurance (dermatologist's report and/or OD notification). After the notification, in addition to the granting of outpatient treatment, the reporting dermatologist has an extensive range of preventive measures available (including skin protection seminars and inpatient treatment). In addition, there are no prescription fees and even basic skin care can be prescribed ("basic therapy"). The extra-budgetary care of hand eczema as a recognized occupational disease is associated with many advantages for the dermatologist's practice and the patient.

Bleaching powders, bleaching creams and other hair lightening preparations as sources for (airborne) allergic contact dermatitis and other health effects in hairdressers: Results of an empirical study.

BACKGROUND: Various products are available for lightening hair. There are no data on which applications are actually used in hairdressing, impeding proper estimation of actual exposure and necessary preventive measures. OBJECTIVES: To assess information about availability, usage and formulation of lightening preparations in the German hairdressing trade. METHODS: A market survey was conducted and hairdressers were surveyed by online questionnaires. RESULTS: Of 783 hairdressers clicking the link, 565 hairdressers (91.2% female, mean age of 40.2 ± 11.7 years) from all German states responded (response rate: 72.2%). The questionnaire survey has shown that available hair-lightening preparations in the German hairdressing trade are (multiple selection possible): dust-free (88.5%) and non-dust-free bleaching powders (22.1%), bleaching creams (41.9%), high-lifting hair colour creams (88.8%) and normal hair colour creams (58.4%). Five hundred eighteen (91.7%) hairdressers favour lightening hair with powder. The market survey revealed that bleaching powders and creams contain potassium persulfate, ammonium persulfate and sodium persulfate or combinations of these persulfate salts. CONCLUSIONS: Hairdressers are exposed to various hair-lightening applications containing different chemicals. Preventive measures need to address adverse skin and respiratory effects. Implementation of targeted health education already in early career stages (i.e., apprenticeship) seems advisable and can be maintained by refresher trainings.

Contact sensitizations in massage therapists with occupational contact dermatitis: Patch test data of the Information Network of Departments of Dermatology, 2008-2020.

BACKGROUND: Massage therapists are particularly exposed to constituents of massage preparations, wet work and mechanical strain and therefore, at high risk to develop occupational dermatitis (OD). OBJECTIVES: To describe the sensitization spectrum of massage therapists with OD. PATIENTS AND METHODS: In a retrospective study, patch test data of patients with OD (128 massage therapists and 24 374 patients working in other professions) collected by the Network of Departments of Dermatology (IVDK, 2008-2020) were analysed. RESULTS: Hand dermatitis (91.4%) and allergic contact dermatitis (34.4%) were common in massage therapists with OD. Most frequent were sensitizations to fragrances/essential oils which were found in 54 (42.2%) massage therapists and thus, more often than in other patients with OD. Concomitant positivity to several fragrances/essential oils was frequent. In 8 (14.8%) of the 54 massage therapists, sensitizations to fragrances/essential oils were not detected with the baseline series, but only with special fragrance series. CONCLUSIONS: Allergic contact dermatitis is common in massage therapists with OD and is mainly caused by fragrances and essential oils. Hence, massage therapists should be aware of this risk. When OD is suspected, not only the baseline series, but also special fragrance series should be patch tested in this occupational group.

Prevalence and incidence of hand eczema in healthcare workers: protocol for a systematic review and meta-analysis.

INTRODUCTION: Healthcare workers (HCWs) constitute a high-risk group for developing occupational hand eczema (HE). The present systematic review and meta-analysis will compile and appraise evidence regarding prevalence and incidence of HE in HCWs. METHODS AND ANALYSIS: Systematic searches will be performed in three electronic literature databases (PubMed/Medline, Web of Science-Core Collection and Embase). Further references will be retrieved by a manual search of included studies' reference lists using snowballing techniques. We will include experimental studies, observational studies, survey-based studies and clinical studies (publications in English, French and German from 2000 onwards) reporting on certified and apprentice HCWs, who actively work in the job. We will look at the following outcomes: Prevalence and incidence of clinically assessed as well as self-reported HE in the style of the Nordic Occupational Skin Questionnaire-2002; HE severity (measured by eg, Hand Eczema Severity Index, Osnabrück Hand Eczema Severity Index, Physician Global Assessment or other validated instruments as well as self-reported or by using undefined categories such as 'mild', 'moderate' or 'severe'); clinically assessed (eg, clinical diagnosis, UK Working Party's diagnostic criteria, Hanifin and Rajka diagnostic criteria for atopic dermatitis (AD)) and self-reported AD. We will assess the risk of bias within studies using detailed criteria according to the Newcastle-Ottawa Scale. As we expect heterogeneity in methods and outcomes, we will conduct sensitivity analyses. A narrative synthesis of results instead of a meta-analysis will be done in case that quantitative pooling is not feasible. ETHICS AND DISSEMINATION: Ethical approval and patient consent are not required as this work is based on published studies. The results will be published in an international, peer-reviewed journal. PROSPERO REGISTRATION NUMBER: CRD42022303044.

Prevention of occupational hand eczema in healthcare workers during the COVID-19 pandemic: A controlled intervention study.

BACKGROUND: Occupational hand eczema (HE) is common among healthcare workers (HCWs) and has-in some regions of the world-increased during the COVID-19 pandemic due to related hygiene measures. OBJECTIVES: To evaluate the efficacy of an intervention for HE prevention in HCWs during the pandemic. METHODS: A prospective, controlled, unblinded interventional trial was conducted in 302 HCWs. The intervention group (IG) (n = 135) received online-based health education and free access to hand cleansing and hand care products. The control group (CG) (n = 167) did not receive any intervention within the study. At baseline (T0), after 3 (T1) and 6 (T2) months, participants completed standardized questionnaires. The Osnabrueck Hand Eczema Severity Index (OHSI) was assessed at T0 and T2. RESULTS: During the observation period, there were no new HE cases in the IG (n = 115) and 12 cases (8.8%) in the CG (n = 136). OHSI values at T2 were lower in the IG (b = -1.44, p < 0.001). Daily use of emollients was higher at work (b = 1.73, p < 0.001) and at home (b = 1.62, p < 0.001) in the IG at T2. CONCLUSIONS: The intervention was effective in HE prevention and improving skin care behaviour during the COVID-19 pandemic.

Contact sensitization to essential oils: IVDK data of the years 2010-2019.

BACKGROUND: Essential oils (EOs) are widely used in cosmetics, perfumes, massage fluids, aroma therapy and natural medicine. Some EOs contain contact sensitizers. OBJECTIVES: To describe the frequency of sensitization to EOs in dermatitis patients presenting in skin clinics including concomitant reactions, to evaluate the EO patch test preparations and to identify patient groups with an increased risk of EO sensitization. PATIENTS AND METHODS: Retrospective analysis of data from the Information Network of Departments of Dermatology (IVDK), 2010-2019. RESULTS: Twelve EOs were patch tested in an aimed manner in 10 930 patients, of whom 908 (8.3%) reacted to at least 1 EO. Only 6 EOs elicited more than 1% positive patch test reactions: ylang ylang (I + II) oil (3.9%), lemongrass oil (2.6%), jasmine absolute (1.8%), sandalwood oil (1.8%), clove oil (1.6%) and neroli oil (1.1%). Concomitant reactions among EOs or to EOs and fragrances were frequent. Among EO-positive patients, women, leg dermatitis patients, patients aged 40 years or more, masseurs and cosmeticians were over-represented. CONCLUSIONS: Sensitization to EOs occurs, albeit infrequently in most cases. Masseurs and cosmeticians have an increased risk of sensitization to EOs.

Nickel and cobalt: Underestimated contact allergens in hairdressers?

INTRODUCTION: Nickel and cobalt were not regarded as pertinent contact allergens in the hairdressing trade for the last decades. It was even stated that the relevance of nickel allergy in the hairdressing trade has been overestimated for several years. Recently, nickel and cobalt release from a multitude of metal tools in the German hairdressing trade was documented in two field studies. METHODS: Review of two field studies. RESULTS: In 2019, nickel release from 9.2% of 229 tested metallic hairdressing tools was evidenced, and in 2021, nickel release from 27.6% as well as cobalt release from 2.1% of 475 tested tools was detected in overall 30 North German hairdressing salons. Tweezers, sectioning clips, hair clips, and straight razors were identified as nickel as well as cobalt releasing tools. Crochet hooks and tail combs were identified as only nickel releasing tools. DISCUSSION: A variety of metallic tools - which are used daily by hairdressers - release nickel and/or cobalt in allergologically relevant amounts. This circumstance has to be considered problematic with regard to the development of work-related allergic contact dermatitis. Thus, nickel and cobalt should possibly receive greater attention as potential contact allergens in the hairdressing trade. CONCLUSION: The proven nickel and cobalt release from metallic hairdressing tools might entail legal ramifications in terms of insurance law. In case of nickel and cobalt allergies within the occupational group of hairdressers, metal tools might be considered as feasible sources for nickel and cobalt exposure.