FACULT Y OF HEALTH SCIENCES UNIVERSI TY OF COPENHAGE N PhD thesis Prevention of occupational hand eczema among Danish hairdressing apprentices Anne Bregnhøj, MD Research Centre for Hairdressers and Beauticians and National Allergy Research Centre Department of Dermato-Allergology Gentofte University Hospital Denmark Prevention of occupational hand eczema among Danish hairdressing apprentices PhD Thesis University of Copenhagen 2011 Anne Bregnhøj, MD Research Centre for Hairdressers and Beauticians and National Allergy Research Centre Department of Dermato-Allergology Gentofte Hospital, University of Copenhagen 1 This PhD thesis is based on the following manuscripts: Study part I: I. Bregnhøj A, Søsted H, Menné T, Johansen JD. Healthy worker effect in hairdressing apprentices. Contact Dermatitis. 2011 feb;64(2):80-4 II. Bregnhøj A, Søsted H, Menné T, Johansen JD. Exposures and reactions to allergens among hairdressing apprentices and matched controls. Contact Dermatitis 2011. feb;64(2):85-9 Study part II: III. Bregnhøj A, Søsted H, Menné T, Johansen JD. Validation of self-reported hand eczema among Danish hairdressing apprentices. Accepted for publication in Contact Dermatitis. IV. Bregnhøj A, Menné T, Johansen JD, Søsted H. Prevention of hand eczema among Danish hairdressing apprentices – an intervention study. Submitted for publication. Supervisors: Jeanne Duus Johansen, Professor, MD, DMSc National Allergy Research Centre Department of Dermato-Allergology Copenhagen University Hospital Gentofte Denmark Torkil Menné, Professor, MD, DMSc Department of Dermato-Allergology Copenhagen University Hospital Gentofte Denmark Heidi Søsted, Cand. Pharm., PhD Research Centre for Hairdressers and Beauticians Department of Dermato-Allergology Copenhagen University Hospital Gentofte Denmark 2 PREFACE Occupational hand eczema is one of the most frequent occupational diseases in Denmark, bringing with it a high impact on the affected individuals and society. Hairdressers and hairdressing apprentices are at a particularly high risk, which is why it seems relevant to illuminate preventive strategies in this group. The work of this thesis was conducted from October 2007 to February 2011 at the Research Centre for Hairdressers and Beauticians, Department of Dermato-Allergology, Copenhagen University Hospital Gentofte. I gratefully acknowledge my supervisors: Jeanne Duus Johansen for her excellent, and always patient, guidance and for creating a work environment that exceeds all expectations; Torkil Menné for his never-ending enthusiasm and invaluable scientific and clinical knowledge; and, lastly, Heidi Søsted for making this PhD thesis possible—it has been a close, joyful and very rewarding cooperation. Susanne Schweitz is acknowledged for her excellent secretarial assistance and many good conversations, and Søren Gade for his technical and statistical assistance. All my colleagues at the Research Centre for Hairdressers and Beauticians, the National Research Centre for Multiple Chemical Sensitivity and the National Allergy Research Centre are thanked for fruitful scientific discussions and good laughs. The Danish Hairdressers’ and Beauticians’ Union is acknowledged for providing financial and moral support. All participating vocational schools, teachers and apprentices are thanked for their excellent cooperation and commitment—it has been of great importance to the outcome of the study. This study received funding from the Danish Hairdressers’ and Beauticians’ Union, the Danish Hairdressers’ Association, the Danish Working Environment Research Fund and the Aage Bangs Foundation. All are gratefully acknowledged. Finally, my parents and parents-in-law are thanked for offering me shelter on my many journeys around the country, my sons for their joyful company on the road and my husband for endless support and for providing me with a GPS so I could find my way home. Gentofte, March 2011 Anne Bregnhøj, MD 3 ABBREVIATIONS AD Atopic Dermatitis CD Contact Dermatitis CI Confidence Interval HECSI Hand ECzema Severity Index HEROS Hand eczema score for occupational screenings NOSQ Nordic Occupational Skin Questionnaire NT Not Tested OR Odds Ratio OHSI Osnabrück hand eczema score PPD P-phenylenediamine PTD Toluene-2,5-diamine UK United Kingdom 4 TABLE OF CONTENTS 1 SUMMARY 8 1.1 Summary in English 8 1.2 Summary in Danish 9 2 BACKGROUND 11 2.1 Occupational skin disease 11 2.2 Hand eczema 11 2.3 Hairdressing apprentices 12 2.3.1 Exposures 12 2.3.2 Other occupational-related diseases 13 2.4 Intervention 13 2.5 Effect evaluation 14 3 AIMS OF THE STUDIES 16 4 MATERIALS AND METHODS 17 4.1 Study design 17 4.1.1 The education of hairdressing apprentices 17 4.2 Study population 17 4.3 The intervention 18 4.4 The questionnaires 20 4.4.1 Baseline questionnaire 20 4.4.2 Validation of the baseline questionnaire 21 4.4.3 The follow-up questionnaire 21 4.4.4 Definitions 21 4.4.5 Validation of the follow-up questionnaire 21 4.5 Clinical examination 21 4.6 Data entering 22 4.7 Study Part I, Manuscripts I and II 22 4.7.1 Matched control group 22 4.7.2 Statistical analysis 22 5 4.8 Study Part II, Manuscript III 22 4.8.1 Statistical analysis 22 4.9 Study Part II, Manuscript IV 23 4.9.1 Exclusions 23 4.9.2 Dropouts 24 4.9.3 Statistical analysis 24 5 RESULTS 26 5.1 Study Part I, Manuscripts I and II 26 5.1.1 Descriptive statistics 26 5.1.2 Non-respondent analysis 26 5.1.3 Hand eczema at inclusion 27 5.1.4 Atopic dermatitis at inclusion 27 5.1.5 Personal exposure at inclusion 28 5.1.6 Skin reactions at inclusion 28 5.2 Study Part II, Manuscripts III and IV 30 5.2.1 Descriptive statistics 30 5.2.2 Dropout analysis 30 5.2.3 Validation of self-reported hand eczema 31 5.2.4 Work exposure 33 5.2.5 Glove use 33 5.2.6 Wet work 35 5.2.7 Incidence of hand eczema 35 5.2.8 Risk factors for hand eczema at the final follow-up 36 5.2.9 Clinical severity of hand eczema 38 5.2.10 Personal exposure at final follow-up 38 6 DISCUSSION 39 6.1 General discussion 39 6.1.1 Study Part I, Manuscripts I and II 39 6.1.1.1 Hand eczema 39 6.1.1.2 Atopic dermatitis 39 6.1.1.3 Personal exposure and skin reactions 40 6.1.2 Study Part II, Manuscripts III and IV 41 6.1.2.1 Validation of self-reported hand eczema 41 6.1.2.2 Change of behaviour due to intervention 41 6.1.2.3 Incidence of hand eczema 42 6.1.2.4 Risk factors for hand eczema 43 6.2 Methodological considerations, manuscripts I - IV 43 6.2.1 Study design 43 6.2.2 Study population 44 6.2.3 Validity of questions 45 6.2.4 Bias in connection to questionnaires 46 6.2.5 Definitions 46 6.2.6 Clinical examinations 47 7 CONCLUSION 48 6 8 PERSPECTIVES AND FUTURE STUDIES 49 9 REFERENCES 50 10 MANUSCRIPT I - IV 58 7 1 SUMMARY 1.1 Summary in English This PhD thesis deals with prevention of occupational hand eczema among Danish hairdressing apprentices. Hairdressers and hairdressing apprentices have a high incidence of occupational hand eczema. This is mainly because they are exposed to many potentially sensitizing products and have an extensive exposure to wet work due to the nature of their work. Hairdressing apprentices seem to be at a particularly high risk of developing the disease, probably because they often carry out the shampooing and hair dying procedures in the salons. The main aims of this thesis were to contribute to a better characterisation of hairdressing apprentices and to develop, implement and evaluate an evidence-based educational programme with focus on reducing the incidence of hand eczema among Danish hairdressing apprentices. The study was a clinically controlled, prospective intervention study. A cohort was established of first-year hairdressing apprentices from all 10 Danish vocational schools in the period August 2008–March 2009. In total, 502 apprentices were included at the time they started their education. All apprentices were examined at three clinical controls: within the first two weeks of their education, after approximately 8 months and after approximately 18 months. At each visit they were examined for hand eczema using the HECSI scoring system, and on all three occasions they completed a questionnaire concerning topics such as previous skin diseases, personal exposures and skin reactions, working habits, use of gloves and development of hand eczema during their education. Half the schools (the intervention schools) underwent a specially developed educational programme, and the teachers were trained in prevention of hand eczema. The remaining schools were control schools. The thesis consists of two study parts. Study Part I deals with the characteristics of the cohort and is based on a questionnaire study comprising 502 new hairdressing apprentices. The same questionnaire was sent to a reference group of 1870 young people, matched with the hairdressing apprentices on sex, age and postcode. The characteristics primarily concern skin diseases among the hairdressing apprentices prior to the start of their education, with focus on atopic dermatitis and previous hand eczema, and covering, for example, personal exposures to hair dye products and eventual skin reactions. Study Part II deals with the results of the follow-up study. Self-reported hand eczema was validated by using the clinical examination as the golden standard. Lastly, there is an evaluation of a possible effect of the prevention programme in terms of reducing the incidence of hand eczema in the intervention group compared with the control group. The results from Study Part I showed that fewer hairdressing apprentices had had hand eczema compared with the reference group. In addition, fewer apprentices were classified with atopic dermatitis compared with the reference group. A ‘healthy worker effect’ was found in connection with this education, when based on eczematous diseases. Study Part I also showed that the hairdressing apprentices were highly exposed to potent sensitizing allergens and that they reported a high frequency of skin reactions. These exposures and reactions were reported significantly more frequently than in the reference group. The exposures were primarily hair dyes, henna tattoos, eyebrow dyes, and piercings. 8 The results from Study Part II showed good agreement between self-reported hand eczema and the clinical examination, with high predictive values. Study Part II also showed significantly more use of gloves in the intervention group, especially when shampooing and when handling bleaching products. The apprentices in the intervention group used gloves for longer each day and fewer had wet hands for two hours or more during their work day. Additionally, Study Part II showed that significantly fewer apprentices who underwent the focused educational programme experienced hand eczema compared with those who underwent the standard programme. Approximately 20% of apprentices from the intervention group experienced hand eczema compared with approximately 30% of those from the control group (P=0.04). This study provides important characteristics of hairdressing apprentices’ personal exposures, work routines and development of hand eczema. Additionally, we succeeded in reducing the incidence of hand eczema among those apprentices in this study design. 1.2 Summary in Danish Denne ph.d.-afhandling omhandler forebyggelse af arbejdsbetinget håndeksem blandt danske frisørelever. Frisører og frisørelever har en høj forekomst af arbejdsbetinget håndeksem. Dette grunder i, at de via deres arbejde udsættes for mange allergifremkaldende produkter samt vådt arbejde. Frisørelever synes at være i en særlig høj risiko, sandsynligvis fordi de ofte håndterer hårvask og hårfarvning på kunderne. Studiets overordnede formål var at give en karakteristik af frisørelever samt at udarbejde, implementere og evaluere et evidensbaseret undervisningsprogram med fokus på nedbringelse af hyppigheden af håndeksem blandt danske frisørelever. Studiet var et klinisk, kontrolleret, prospektivt interventions studie. Der blev opbygget en kohorte af nystartede frisørelever fra samtlige 10 danske frisørskoler i perioden august 2008 – marts 2009. Der blev i alt inkluderet 502 elever i forbindelse med deres opstart på skolerne. Alle elever blev set til tre kliniske kontroller; indenfor de første to uger af deres uddannelse, efter ca. 8 måneder og efter ca. 18 måneder. Til hver kontrol blev de undersøgt for håndeksem ved hjælp af HECSI score og ved alle tre lejligheder svarede de på et spørgeskema med spørgsmål om bl.a. tidligere hudsygdomme, personlige eksponeringer og hudreaktioner herpå, arbejdsrutiner, brug af handsker og udviklingen af håndeksem under deres uddannelse. Halvdelen af skolerne (interventionsskolerne) modtog et særligt tilrettelagt undervisningsprogram, og lærerne blev specielt uddannet i forebyggelse af håndeksem, den anden halvdel fungerede som kontrolskoler. Afhandlingen består af to delstudier. Delstudie I omhandler karakteristik af kohorten ved inklusionen, og er baseret på spørgeskemaundersøgelse af 502 nye frisørelever. Et tilsvarende spørgeskema blev sendt til en referencegruppe på 1870 unge mennesker, som var matchet frisøreleverne på køn, alder og geografisk fordeling i landet. Denne karakteristik omhandler primært frisørelevernes hudsygdomme før deres opstart på uddannelsen, med fokus på atopisk dermatitis og tidligere håndeksem, samt deres personlige eksponeringer af bl.a. hårfarveprodukter og eventuelle hudreaktioner herpå. Delstudie II omhandler resultaterne fra follow-up studiet. Ved hjælp af den kliniske undersøgelse valideres selvrapporteret håndeksem i kohorten. Derudover evalueres det om der er opnået en effekt af forebyggelsesprogrammet i form af en reduktion af forekomsten af håndeksem i interventionsgruppen sammenlignet med kontrolgruppen. 9