N H Nielsen

Videncenter for Allergi, København, Capital Region, Denmark

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Publications (85)382.47 Total impact

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    ABSTRACT: Background Blue-collar workers have a high risk of occupational contact dermatitis, but epidemiological studies are scarce.Objectives To investigate allergic contact dermatitis in blue-collar workers with dermatitis registered by the Danish Contact Dermatitis Group.MethodsA retrospective analysis of patch test data from 1471 blue-collar workers and 1471 matched controls tested between 2003 and 2012 was performed. A logistic regression was used to test for associations.ResultsThe blue-collar workers often had occupational hand dermatitis (p < 0.001). Atopic dermatitis was less commonly observed among blue-collar workers (19.6%) than among controls (23.9%) (p = 0.005). Allergens with a statistically significant association with the occupational group of blue-collar workers were epoxy resins, methyldibromo glutaronitrile, 2-bromo-2-nitro-1,3-propanediol, potassium dichromate, and methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI). The following occupations were additionally identified as risk factors for contact sensitization to MCI/MI and MI, epoxy resins, and potassium dichromate, respectively: painting, construction work, and tile setting/terrazzo work.Conclusion Contact allergy is a major problem among blue-collar workers. The data indicate a healthy worker effect among blue-collar workers diagnosed with dermatitis, as blue-collar workers were diagnosed significantly less often with atopic dermatitis than were controls.
    Contact Dermatitis 07/2014; · 2.93 Impact Factor
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    ABSTRACT: Occupational contact dermatitis among hairdressers is frequent, owing to daily exposure to irritants and allergens. To identify sensitization to the most common allergens associated with the occupation of hairdressing. Patch test results of 399 hairdressers and 1995 matched controls with contact dermatitis, registered by the Danish Contact Dermatitis Group between January 2002 and December 2011, were analysed. All patients were patch tested with the European baseline series, and hairdressers were additionally tested with the hairdressing series. Occupational contact dermatitis (p < 0.001) and hand eczema (p < 0.001) were observed significantly more often among hairdressers than among controls. Atopic dermatitis was less commonly observed among hairdressers (21.3%) than among controls (29.4%) (p < 0.01). Allergens from the European baseline series with a statistically significant association with the occupation of hairdressing were p-phenylenediamine, thiuram mix, and benzocaine. Frequent sensitizers from the hairdressing series were ammonium persulfate, toluene-2,5-diamine, 3-aminophenol, and 4-aminophenol. Cysteamine hydrochloride and chloroacetamide emerged as new sensitizers. These results indicate a healthy worker effect among hairdressers diagnosed with eczema. Ammonium persulfate and p-phenylenediamine remain frequent sensitizers in hairdressers with contact dermatitis. Cysteamine hydrochloride and chloroacetamide should be included in future surveillance studies.
    Contact Dermatitis 12/2013; · 2.93 Impact Factor
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    Contact Dermatitis 07/2012; 67(1):49-51. · 2.93 Impact Factor
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    ABSTRACT: Background. Painters are among the occupational groups that most commonly experience occupational contact dermatitis, but few investigations exist concerning this occupation. Objectives. To characterize painters with contact dermatitis and identify the most common allergens associated with the occupation. Materials and methods. All patch test results of 219 painters and 1095 matched controls registered by the Danish Contact Dermatitis Group between 2001 and 2010 were analysed. Results. Hand eczema (p < 0.0001) and occupational contact dermatitis (p < 0.0001) were observed significantly more often in the painters than in the group of controls. Sensitizations to the following allergens from the European baseline series were associated with the occupation and were statistically significant: methylchloroisothiazolinone/methylisothiazolinone, epoxy resin, formaldehyde, and quaternium-15. Three different isothiazolinones emerged as the most frequent sensitizers of the allergens tested in addition to the baseline series. Conclusions. The results indicate that painters have an increased risk of developing occupational hand eczema. Isothiazolinones and epoxy resin proved to be the two most frequent sensitizers in painters.
    Contact Dermatitis 05/2012; 67(5):293-297. · 2.93 Impact Factor
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    ABSTRACT: Epoxy resin monomers are strong skin sensitizers that are widely used in industrial sectors. In Denmark, the law stipulates that workers must undergo a course on safe handling of epoxy resins prior to occupational exposure, but the effectiveness of this initiative is largely unknown. To evaluate the prevalence of contact allergy to epoxy resin monomer (diglycidyl ether of bisphenol A; MW 340) among patients with suspected contact dermatitis and relate this to occupation and work-related consequences. The dataset comprised 20 808 consecutive dermatitis patients patch tested during 2005-2009. All patients with an epoxy resin-positive patch test were sent a questionnaire. A positive patch test reaction to epoxy resin was found in 275 patients (1.3%), with a higher proportion in men (1.9%) than in women (1.0%). The prevalence of sensitization to epoxy resin remained stable over the study period. Of the patients with an epoxy resin-positive patch test, 71% returned a questionnaire; 95 patients had worked with epoxy resin in the occupational setting, and, of these, one-third did not use protective gloves and only 50.5% (48) had participated in an educational programme. The 1% prevalence of epoxy resin contact allergy is equivalent to reports from other countries. The high occurrence of epoxy resin exposure at work, and the limited use of protective measures, indicate that reinforcement of the law is required.
    Contact Dermatitis 04/2012; 67(2):73-7. · 2.93 Impact Factor
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    ABSTRACT: Filaggrin metabolites act as osmolytes and are important for skin hydration. Carriers of filaggrin loss-of-function mutations have a higher prevalence of atopic dermatitis and dry skin. There is also evidence to suggest that filaggrin mutations increase the risk of hand eczema in atopic individuals. In our clinic, we have observed a distinct phenotype of hand eczema in patients with filaggrin mutation carrier status, characterized by fissured dermatitis on the dorsal aspect of the hands and with only sparse involvement of the palms including fine scaling. To investigate whether filaggrin loss-of-function mutations are associated with skin fissures on the hands and/or fingers in the general population. Participants in a population-based study were questioned about skin symptoms, genotyped for filaggrin mutation, patch tested for nickel allergy and skin prick tested. In an adjusted logistic regression analysis, filaggrin mutation status was significantly associated with fissured skin on the hands and/or fingers in adults (odds ratio 1·93, 95% confidence interval 1·05-3·55) and showed a nearly significant negative interaction with atopic dermatitis (P=0·055), suggesting that the effect was predominantly in subjects without atopic dermatitis. Filaggrin loss-of-function mutations seem not only to increase the risk of atopic dermatitis and dry skin but also the risk of fissures on the hands and/or fingers in subjects without atopic dermatitis. Prophylactic emollient therapy should be particularly encouraged in filaggrin loss-of-function mutation carriers.
    British Journal of Dermatology 07/2011; 166(1):46-53. · 3.76 Impact Factor
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    ABSTRACT: Fragrances frequently cause contact allergy, and cosmetic products are the main causes of fragrance contact allergy. As the various products have distinctive forms of application and composition of ingredients, some product groups are potentially more likely to play a part in allergic reactions than others. To determine which cosmetic product groups cause fragrance allergy among Danish eczema patients. This was a retrospective study based on data collected by members of the Danish Contact Dermatitis Group. Participants (N = 17,716) were consecutively patch tested with fragrance markers from the European baseline series (2005-2009). Of the participants, 10.1% had fragrance allergy, of which 42.1% was caused by a cosmetic product: deodorants accounted for 25%, and scented lotions 24.4%. A sex difference was apparent, as deodorants were significantly more likely to be listed as the cause of fragrance allergy in men (odds ratio 2.2) than in women. Correlation was observed between deodorants listed as the cause of allergy and allergy detected with fragrance mix II (FM II) and hydroxyisohexyl 3-cyclohexene carboxaldehyde. Deodorants were the leading causes of fragrance allergy, especially among men. Seemingly, deodorants have an 'unhealthy' composition of the fragrance chemicals present in FM II.
    Contact Dermatitis 05/2011; 64(5):258-64. · 2.93 Impact Factor
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    ABSTRACT: The phenotypic traits of people with the filaggrin mutation (FLG) genotype and atopic dermatitis (AD) are still under elucidation, and the association with concomitant AD and contact allergy (CA) has not previously been examined. To assess FLG status in a subset of patients with AD and a minimum of one positive patch-test reaction. In total, 430 people from a hospital population and 3335 people from the general population were tested for FLG mutations by DNA hybridization to paramagnetic polystyrene beads and analysis on a multiplex analysis system. All of the individuals in the hospital population had a minimum of one CA. AD was diagnosed according to the UK Working Party Criteria, (questions-only version). Individuals from the hospital population who had both AD and CA were considered as cases, and comparison of mutation carrier frequency was estimated (χ(2) test) against individuals without AD but with CA from the hospital population, individuals from the general population, and individuals with AD from the general population. The mutation frequency in patients with AD and CA in the hospital population was significantly less than that of people with AD from the general population (OR = 0.54; 95% CI 0.30-0.98). No difference in mutation frequency was found between individuals with and without AD in the hospital population (OR = 1.40; 95% CI 0.70-2.79), or between individuals with AD and CA in the hospital population and in the overall general population (OR = 1.29; 95% CI 0.76-2.20). The spectrum of observable traits characteristic for the FLG mutation genotype in patients with AD is at present not defined. Our results indicate that the subset of patients with both AD and CA represent a phenotype of AD that is not associated with FLG mutations.
    Clinical and Experimental Dermatology 03/2011; 36(5):467-72. · 1.33 Impact Factor
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    ABSTRACT: It was recently shown that filaggrin null mutation carrier status was associated with nickel allergy and self-reported intolerance to costume jewellery. Because of the biochemical characteristics of filaggrin, it may show nickel barrier properties in the stratum corneum. To investigate whether subjects with filaggrin null mutations report nickel dermatitis at an earlier age than wild-type individuals, and to analyse whether null mutation carriers have stronger patch test reactivity to nickel sulfate than do wild-type individuals. A total of 3471 Danes (18-69 years of age) answered a questionnaire about general health, and underwent patch testing and filaggrin genotyping. The mean number of years at risk of developing nickel dermatitis was significantly lower for the filaggrin null genotype than for the wild-type genotype when ear piercing status was considered. In positive patch test readings, the proportion of null mutants increased with increasing reaction strength. Filaggrin null mutations may lower the age of onset of nickel dermatitis. The hypothesis that ear piercings obscure the effect of filaggrin null mutations on the development of nickel allergy in statistical analyses was supported. An association between the null genotype and increased nickel sensitivity was indicated by patch test reading and questionnaire data.
    Contact Dermatitis 01/2011; 64(1):24-31. · 2.93 Impact Factor
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    ABSTRACT: Fragrance mix II (FM II) is a relatively new screening marker for fragrance contact allergy. It was introduced in the patch test baseline series in Denmark in 2005 and contains six different fragrance chemicals commonly present in cosmetic products and which are known allergens. To investigate the diagnostic contribution of including FM II in the baseline series by comparing it with other screening markers of fragrance allergy: fragrance mix I (FM I), Myroxylon pereirae and hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC). Retrospective study of 12 302 patients consecutively patch tested with FM II by members of the Danish Contact Dermatitis Group 2005-2008. FM II gave a positive patch test in 553 patients (4.5%), and in 72.2% of these patients the reaction was judged to be clinically relevant. FM II ranked second in detecting fragrance allergy, after FM I. If FM II had not been included as a screening marker in the baseline series, 15.6% (n = 202) of individuals with fragrance allergy would not have been identified by the other fragrance screening markers (FM I, M. pereirae or HICC). FM II contributes substantially to detecting fragrance allergy. It ranked second among the fragrance screening markers tested in the baseline series and detects individuals with an allergy who otherwise would not have been identified.
    Contact Dermatitis 11/2010; 63(5):270-6. · 2.93 Impact Factor
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    ABSTRACT: Hand eczema is prevalent in the general population. It remains unclear whether or not filaggrin gene (FLG) null mutations increase the overall risk of hand eczema or only increase the risk of hand eczema in subjects with atopic dermatitis. To investigate the association between FLG null mutations and hand eczema. A random sample of 3335 adults from the general population in Denmark was patch tested, FLG genotyped for R501X and 2282del4 null mutations and questioned about hand eczema. Participants with combined presence of atopic dermatitis and FLG null mutation status had a significantly higher prevalence of hand eczema, an earlier onset of hand eczema and a higher persistence of hand eczema compared with subjects with normal FLG status and absence of atopic dermatitis. Logistic regression analyses revealed positive associations between hand eczema within the past 12 months and FLG null mutation status in participants with a history of atopic dermatitis [odds ratio (OR) 2.98; 95% confidence interval (CI) 1.27-7.01], but not in subjects without atopic dermatitis (OR 0.82; 95% CI 0.41-1.67). FLG null mutations were significantly associated with hand eczema (< 12 months) in subjects with atopic dermatitis. Combined atopic dermatitis and filaggrin null mutation status was strongly associated with early onset of hand eczema and hand eczema persistence.
    British Journal of Dermatology 07/2010; 163(1):115-20. · 3.76 Impact Factor
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    ABSTRACT: It was recently shown that filaggrin gene (FLG) null mutations are positively associated with nickel sensitization. We have hypothesized that histidine-rich filaggrin proteins in the epidermis chelate nickel ions and prevent their skin penetration and exposure to Langerhans cells. Furthermore, we have proposed that the low degree of genetic predisposition to nickel sensitization found by a Danish twin study was explained by a high prevalence of ear piercing among participants resulting in 'bypassing' of the filaggrin proteins. To investigate the association between FLG null mutations and (nickel) contact sensitization. A random sample of 3335 adults from the general population in Denmark was patch tested and genotyped for R501X and 2282del4 in the FLG gene. The combined carrier frequency of FLG null mutations was 8·1%. Nickel, fragrance and contact sensitization to at least one allergen were not associated with FLG null mutations. A crude analysis on women who did not have ear piercings revealed a positive association between FLG null mutations and nickel sensitization [8·3% vs. 2·4%; odds ratio (OR) 3·71, 95% confidence interval (CI) 0·73-18·96] as well as between FLG null mutations and allergic nickel dermatitis (8·3% vs. 1·3%; OR 6·75, 95% CI 1·17-38·91). FLG mutation status and atopic dermatitis were positively associated with neomycin or ethylenediamine sensitization. This study suggests that FLG null mutations may be a risk factor for the development of nickel sensitization. However, ear piercing was a much stronger risk factor in our general population and we could therefore identify a positive association only in women without ear piercings. Contact sensitization to specific chemicals is related to treatment exposure.
    British Journal of Dermatology 03/2010; 162(6):1278-85. · 3.76 Impact Factor
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    ABSTRACT: There is evidence that stimulants such as alcohol and tobacco have an effect on the immune system, but little is known about how these lifestyle factors affect the prevalence of contact sensitization. This study investigated whether smoking and alcohol consumption were associated with contact sensitization and nickel sensitization. A random sample of adults (n=3460) from the general population of Copenhagen was invited to participate in a general health examination including patch-testing. Alcohol consumption was not associated with nickel sensitization, whereas a significant trend (p<0.05) was identified between smoking status and nickel sensitization in an adjusted model; i.e. nickel sensitization was higher among both previous smokers (odds ratio (OR) = 1.19; confidence interval (CI) = 0.81-1.76), current light smokers (OR=1.50; CI=0.94-2.37) and current heavy smokers (OR=1.56; CI = 0.87-2.80) compared with never smokers. This study confirmed that smoking is associated with nickel sensitization, but rejected an association with alcohol consumption.
    Acta Dermato-Venereologica 01/2010; 90(1):27-33.
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    ABSTRACT: In theory, all pigmented make-up products may contain metal allergens including nickel. Eyelid dermatitis has previously been observed among nickel allergic dermatitis patients following exposure to nickel containing mascara and eye shadow. However, an association between nickel eyelid dermatitis and nickel in make-up products remains controversial. This cross-sectional patch test study investigated whether the frequency of self-reported cosmetic dermatitis from mascara or eye shadow use was higher among nickel allergic Danish women than women without nickel allergy. In 2006, a total of 1843 18-69 year old women completed a postal questionnaire including questions on cosmetic dermatitis and were patch tested with nickel sulphate. Data were analysed by logistic regression analyses and associations were expressed as odds ratios (ORs) with 95% confidence intervals (CIs). The prevalence of nickel allergy was similar among women who reported cosmetic dermatitis from eye shadow or mascara and among women who did not report such symptoms. Cosmetic dermatitis was positively associated with self-reported atopic dermatitis and age. Overall, no association between having nickel allergy and reporting cosmetic dermatitis from mascara or eye shadow use was found in the general population. This does not exclude a causal relationship in selected cases.
    Journal of the European Academy of Dermatology and Venereology 11/2009; 24(6):722-5. · 2.69 Impact Factor
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    ABSTRACT: The prevalence of contact allergy in the general population is nearly 20%. This study aimed to monitor the development of contact allergy to allergens from the TRUE-test (panels 1 and 2) between 1990 and 2006. Two random samples of adults from the general population in Copenhagen, Denmark, were invited to participate in a general health examination including patch testing. In 1990 and 2006, we patch tested and questioned 543 and 3460 adult Danes. Patch test readings were performed on day 2 only. The overall prevalence decreased significantly from 15.5% in 1990 to 10.0% in 2006, mainly as a result of a decrease in thimerosal allergy from 3.4% to 0.8%. Furthermore, the prevalence of cobalt allergy and rubber-related allergens decreased from 1.1% to 0.2% and from 1.5% to 0.2%, respectively. Stratification by sex and age group revealed decreasing prevalences of contact allergy in all male age groups and in young and middle-aged female age groups (18-55 years) whereas increasing prevalences were observed among older women (56-69 years). The diverging trend observed in women was probably explained by a cohort effect due to a change in the prevalence of nickel allergy following the Danish regulation on nickel exposure. Although the overall prevalence of contact allergy decreased in the general population, frequent contact allergens such as fragrance mix II and methyldibromo glutaronitrile were not tested. Thus, contact allergy remains prevalent in the general population.
    British Journal of Dermatology 11/2009; 161(5):1124-9. · 3.76 Impact Factor
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    ABSTRACT: An association between nickel contact allergy and hand eczema has previously been demonstrated. In 1990, Denmark regulated the extent of nickel release in the ear-piercing process as well as nickel release from consumer products. This study aimed to evaluate the effect of the Danish nickel regulation by comparing the prevalence of concomitant nickel allergy and hand eczema observed in two repeated cross-sectional studies performed in the same general population in Copenhagen. In 1990 and 2006, 3881 18-69 year olds completed a postal questionnaire and were patch tested with nickel. Data were analysed by logistic regression analyses and associations were expressed as odds ratios (ORs) with 95% confidence intervals (CIs). The prevalence of concomitant nickel contact allergy and a history of hand eczema decreased among 18-35-year-old women from 9.0% in 1990 to 2.1% in 2006 (P < 0.01). The association between nickel contact allergy and a history of hand eczema decreased in this age group between 1990 (OR = 3.63; CI = 1.33-9.96) and 2006 (OR = 0.65; CI = 0.29-1.46). Among older women, no significant changes were observed in the association between nickel contact allergy and hand eczema. Conclusions: Regulatory control of nickel exposure may have reduced the effect of nickel on hand eczema in the young female population.
    Contact Dermatitis 10/2009; 61(6):342-8. · 2.93 Impact Factor
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    ABSTRACT: An inverse association between contact allergy and autoimmune diseases has been suggested. Psoriasis is an autoimmune disease and it has been debated whether contact allergy is less prevalent among patients with psoriasis. Previous studies have shown conflicting results. To examine a possible association between contact allergy and psoriasis in two conceptually different epidemiological studies. Two study populations were included: (i) a clinic-based register linkage study population, achieved by record linking information from the Danish National Hospital Registry identifying patients with psoriasis with information on contact allergy from a comprehensive patch test database of 15,641 patients; and (ii) a population-based cross-sectional study population organized in 1990, 1998 and 2006 and obtained by random samples from the Danish Central Personal Register. Information was obtained by questionnaire and patch testing of 4989 subjects. An inverse association was found between a psoriasis diagnosis and a positive patch test in both studies. The odds ratio for a person with a psoriasis diagnosis of having a positive patch test was, adjusted for sex and age, 0.58 [95% confidence interval (CI) 0.49-0.68] and 0.64 (95% CI 0.42-0.98), respectively, in the two studies. The finding of an inverse association between psoriasis and contact allergy may express opposite immunological mechanisms and calls for additional research in this field.
    British Journal of Dermatology 08/2009; 161(5):1119-23. · 3.76 Impact Factor
  • New England Journal of Medicine 06/2009; 360(21):2259-60. · 54.42 Impact Factor
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    ABSTRACT: Hand eczema is a prevalent disorder that leads to high health care costs as well as a decreased quality of life. Important risk factors include atopic dermatitis, contact allergy and wet work whereas the role of null mutations in the filaggrin gene complex remains to be clarified. It has been debated whether life-style factors such as tobacco smoking and alcohol consumption are associated with hand eczema. The current study aimed to investigate whether self-reported hand eczema was associated with smoking and alcohol consumption in the general population. Between June 2006 and May 2008, a cross-sectional study was performed in the general population in Copenhagen, the capital of Denmark. A random sample of 7931 subjects aged 18-69 years old was invited to participate in a general health examination including a questionnaire; 3471 (44%) participated. Data were analysed with logistic regression analyses and associations were expressed as odds ratios (ORs) with 95% confidence intervals (CI). The prevalence of hand eczema was higher among previous smokers (OR = 1.13; CI = 0.90-1.40), current light smokers (OR = 1.51; CI = 1.14-2.02) and current heavy smokers (OR = 1.38; CI = 0.99-1.92) compared with never-smokers. Tobacco smoking was positively associated with hand eczema among adults from the general population in Denmark. Apparently, current light smokers (< 15 g daily) had a higher prevalence of hand eczema than current heavy smokers (> 15 g daily) but this needs to be reconfirmed. Alcohol consumption was not associated with hand eczema.
    British Journal of Dermatology 06/2009; 162(3):619-26. · 3.76 Impact Factor
  • H Søsted, N H Nielsen, T Menné
    Contact Dermatitis 05/2009; 60(4):236-7. · 2.93 Impact Factor

Publication Stats

2k Citations
382.47 Total Impact Points

Institutions

  • 2007–2012
    • Videncenter for Allergi
      København, Capital Region, Denmark
  • 1999–2012
    • Copenhagen University Hospital Gentofte
      • Department of Dermato-Allergology
      Hellebæk, Capital Region, Denmark
  • 2009
    • Region Hovedstaden
      Hillerød, Capital Region, Denmark
  • 1999–2009
    • IT University of Copenhagen
      København, Capital Region, Denmark
  • 1993–2003
    • Glostrup Hospital
      • • Centre for Preventive Medicine
      • • Medical Department C
      København, Capital Region, Denmark
  • 2002
    • Roskilde University
      Roskilde, Zealand, Denmark
  • 1989–1996
    • Bispebjerg Hospital, Copenhagen University
      • Department of Pulmonary Medicine
      København, Capital Region, Denmark
  • 1987–1989
    • The Ohio State University
      • Division of Hospital Medicine
      Columbus, OH, United States
  • 1986–1989
    • Copenhagen University Hospital
      København, Capital Region, Denmark