Office Equipment and Supplies: A Modern Occupational Health Concern?

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1 American Journal of Epidemiology Copyright 1999 by The Johns Hopkins University School of Hygiene and PubBc Health All rights reserved vol. 0, No. 11 Printed In USA. Office Equipment and Supplies: A Modern Occupational Health Concern? Maritta S. Jaakkola 1JI and Jouni J. K. Jaakkola 13 The Helsinki Office Environment Study, a population-based cross-sectional study was carried out in Finland in 1991 among 2,68 workers in 41 randomly selected office buildings. The aim was to evaluate the relations between work with office equipment and supplies and the occurrence of eye, nasopharyngeal, skin, and general symptoms (often denoted as sick building syndrome (SBS)), chronic respiratory symptoms, and respiratory infections. Work with self-copying paper was significantly related to weekly work-related eye, nasopharyngeal, and skin symptoms, headache and lethargy, as well as to the occurrence of wheezing, cough, mucus production, sinusitis, and acute bronchitis. Photocopying was related to nasal irritation, and video display terminal work to eye symptoms, headache, and lethargy. Am J Epidemiol 1999; 0: copying processes; occupational health; respiratory disorders; sick building syndrome; video display terminals Modern office work with use of office equipment has raised concerns about possible adverse health effects. Since the 190s, reports have linked mucosal, skin, and general symptoms to work with self-copying paper (1-). Emission of various particulate and volatile substances has been suggested as specific causes (1,2, 16-18). Because of limitations of the earlier studies, the role of self-copying paper in causing ill-health in office workers has remained controversial (). Photocopying has also been linked to symptoms of sick building syndrome (SBS) (13, 19-22). None of the earlier studies addressed potential effects of selfcopying paper or photocopying on chronic respiratory symptoms or respiratory infections. Work with video display terminals (VDTs) has been associated with skin and eye problems, and headache (13, 14, 23-29), but potential effects of VDT work are still controversial (23, 30). The Helsinki Office Environment Study was initiated in 1990 to answer questions on health effects of Received for publication August 25, 1998, and accepted for publication March 23, Abbreviations: Cl, confidence interval; OR, odds ratio; SBS, sick building syndrome; VDT, video display terminal. 1 Department of Epidemiology, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD. 2 Department of Occupational Medicine, Finnish Institute of Occupational Health, Helsinki, Finland. 3 Environmental Epidemiology Unit Department of Public Hearth, University of Helsinki, Helsinki, Finland. Reprint requests to Dr. Maritta S. Jaakkola, Department of Epidemiology, Johns Hopkins University School of Hygiene and Public Health, 6 N. Wolfe Street, Rm. E6006, Baltimore, MD the office environment (31, 32). This report evaluates the relations between work with office equipment and supplies and the occurrence of symptoms of SBS, chronic respiratory symptoms, and respiratory infections. MATERIALS AND METHODS Study design and study population This is a population-based cross-sectional study of 2,68 workers in 41 randomly selected office buildings in the Helsinki metropolitan area. These office workers completed a self-administered questionnaire. Details of the framework for the study and of data collection procedures have been presented in previous reports (31,32). Outcomes SBS symptoms. Nine particular work-related symptoms of the SBS () experienced at least weekly during the previous 12 months were studied (table 3). The standardized questions used to define the SBS outcomes are described elsewhere (31). Chronic respiratory symptoms. Chronic respiratory symptoms during the previous year (table 3) were defined based on standardized questions as follows: wheezing of the chest with colds and/or apart from colds, cough on most days for >3 months, and mucus production on most days for 3 months. Chronic bronchitis was defined as chronic cough and mucus production for >2 years. Respiratory infections. Frequency of respiratory infections experienced during the previous year was 1223 Downloaded from

2 1224 Jaakkola and Jaakkola asked (table 3). For the analyses, the outcome was dichotomized into no infections and at least one infection during the previous year (for common colds, the cut-off point was >2 infections per year). Exposures The exposures of interest were working with selfcopying paper, photocopiers, and VDTs. Exposure assessment was based on answers to structured questions: Do you use video display terminal/photocopiers/ self-copying paper in your work? For photocopiers and VDT work, use in hours per week was also asked. In the analyses, work with self-copying paper was a dichotomous variate. Work with photocopiers and VDTs were included as continuous variables (hours/week) or as ordinal scale variables divided into three categories, based on assumed biologic relevance and distributions of reported use (table 2). Statistical methods The odds ratio was used as the measure of effect of exposure on symptom or infection occurrence. Odds ratios were estimated in logistic regression analyses adjusting for potential confounders displayed in table 1 (-36). RESULTS The characteristics and exposures of the study population are presented in tables 1 and 2. In the multivariate analyses, a striking and consistent finding was substantially increased risks of upper airways symptoms TABLE 1. Characteristics of the study population: Helsinki Office Environment Study, Finland, 1991 Characteristic Men (n= 1,119) Women (n= 1,559) Total (n = 2,68) Age (years) ^ Education Nonprofessional Vocational school University or college Other Atopy* Smoking Nonsmoker Ex-smoker Current smoker Passive smoking in the office Shared officef Type of ventilation system in the office^ Natural ventilation Mechanical exhaust Simple mechanical ventilation Air conditioning without humidification Air conditioning with humidification Atmosphere at work Satisfied Neutral Unsatisfied Work stress Not at all, slight Moderate Much, very much Interest in work Almost always, often Sometimes Rarely, never Defined as any history of doctor-diagnosed atopic eczema, allergic rhinitis, conjunctivitis, or asthma. t Defined as office shared with one or more workers versus own office. i In the analyses, natural ventilation and mechanical exhaust were combined to form the reference category. Am J Epidemiol Vol. 0, No. 11, 1999 Downloaded from

3 Office Equipment and Occupational Health 1225 TABLE 2. Handling of sett-copying paper, photocopying, and work with vldeodisplay terminal (VDT): Helsinki Office Environment Study, Finland, 1991 Exposure Men (n= 1,119) Women (n= 1,559) Total (n = 2,68) Handling of self-copying paper 2 39 Photocopying (hours per week) None S VDT work (hours per week) None typical of SBS and of all chronic lower respiratory symptoms in relation to working with self-copying paper (table 3). The highest odds ratios were observed for pharyngeal symptoms and chronic bronchitis. Eye and skin symptoms, headache, and lethargy were also related to handling of self-copying paper, whereas difficulty in concentrating was not. Acute bronchitis and sinusitis showed significantly increased risks in relation to working with self-copying paper, and common colds were almost significantly associated with self-copying paper exposure. In the analyses including categorical exposure variables, photocopying and work with VDTs were not consistently related to SBS symptoms or to chronic respiratory symptoms. General symptoms were significantly related to working with VDTs for >11 hours per week (table 3). This was attributable to headache and lethargy, whereas the risk for difficulty in concentrating was not increased. Significant relations of photocopying or VDT work with respiratory infections were not observed. Additional multivariate analyses were carried out with continuous exposure variables (hours per week) in order to increase the power to detect any significant relations. These analyses were carried out separately among those working with photocopiers or VDTs, since subjects with these occupational exposures may differ from those not exposed. Among those working with photocopiers, significant relations were observed between nasal symptoms and the amount of photocopying, in particular for nasal irritation (odds ratio (OR) = 1.02 per one hour per week, 95 percent confidence interval (CI) 1.005,1.049). Significant relations between headache and lethargy and the amount of VDT work were confirmed in the analyses including a continuous exposure. Significant relations were also observed for eye symptoms (OR = per hour per week, 95 percent CI 1.005, 1.0) and for occurrence of common colds (OR = per hour per week, 95 percent CI 1.001, 1.019) and acute bronchitis (OR = per hour per week, 95 percent CI 1.002, 1.026). DISCUSSION Self-copying paper Handling of self-copying paper was related to increased risks of SBS symptoms, chronic respiratory symptoms, and acute bronchitis and sinusitis. At the time of our study (1991) most of self-copying paper used was carbonless paper. Handling of carbonless copy paper can result in exposure to different chemicals and particles with possible adverse health effects, including solvents and color-forming chemicals (1, 2, 6, 16-18, 23). The exposure route may be direct, through air and contact with skin, or indirect, through contact of fingers that have handled the chemical containing paper with the eyes, nasal mucosa, and skin. Relations with general symptoms suggest that substances may be adsorbed and dispersed via circulation. The pathophysiologic mechanisms are not known. Earlier findings do not support allergic reactions as the primary mechanism (23), and irritative and toxic mechanisms are more likely to be involved. Earlier studies have focused on symptoms of SBS, and relations of self-copying paper with chronic respiratory symptoms or respiratory infections have not, to our knowledge, been addressed before. Our results on SBS symptoms are consistent with some earlier studies from Denmark (13), Sweden (14), and the United States (21). The results suggest that reduction of exposure to carbonless copy paper would be beneficial for office workers. Photocopying It has been suggested (19, 23, 3) that photocopiers emit chemicals, such as volatile organic compounds, Am J Epidemiol Vol. 0, No. 11, 1999 Downloaded from

4 ro O) 01 0) TABLE 3. Adjusted* odds ratios (OR) and 95% confidence intervals (Cl) estimated for weekly, work-related sick building syndrome (SBS) symptoms, chronic respiratory symptoms, and occurrence of respiratory Infections during the previous 12 months by handling of self-copying paper, photocopying, and video display terminal (VDT) work (from analyses with categorical exposure variables with no exposure as the reference category): Helsinki Office Environment Study, Finland,! 991 Outcome Handling of self-copying paper (yes) OR 95% Cl OR Photocopying (houra/week) 95% Cl OR 95% Cl OR 510 VDT work (hours/week) 95% Cl OR 95% Cl CD 01 Q. CO 0) E Symptoms/signs of SBS Eye symptoms 6 1.1,2.08 Nasal symptoms ,1.88 Irritation ,2.14 Congestion ,2.21 Discharge ,2.00 Pharyngeal symptoms , 2.62 Skin symptoms ,2.39 General symptoms 1.24, 1.55 Headache ,2.40 Lethargy ,1.8 Difficulty concentrating , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , 1.43 Chronic respiratory symptoms Wheezing ,1.56 Cough ,1.8 Mucus ,1.5 Chronic bronchitis , , , , , , , , , , , , , , , , , 1.45 cf Respiratory infectionst Common cold 1.20, 1.45 Tonsillitis ,1.16 Sinusitis ,1.8 Otitis ,1.3 Acute bronchitis ,1.9 Pneumonia , , , , , , , , , , , , , , , , , , , , , , , , , 3.3 Adjusted In logistic regression analysis for sex, age, atopy, education, smoking, exposure to environmental tobacco smoke at work, number of workers sharing the office, psychological and social factors, and building ventilation type. t Prevalence of 1 infections during the preceding 12 months, except for common cold: prevalence of i2 infections during the preceding 12 months. o co CO co Downloaded from

5 Office Equipment and Occupational Health 122 ozone, particles, and resin. These chemicals include several potential allergens and irritants (38). The results of earlier studies on health effects of photocopying (13, 20-22, 29) have been contradictory. In our study, photocopying was significantly related to nasal irritation, but not to other SBS symptoms or to chronic respiratory symptoms. VDT work Work with VDTs has been connected with exposure to electrostatic and electromagnetic fields (23). In our study, significant relations were found between VDT work and headache and lethargy. A significant relation was observed also with eye symptoms, but not with other mucosal SBS or chronic respiratory symptoms. Musculoskeletal burden and ocular distress are likely explanations for our findings rather than electromagnetic fields (25, 39, 40). Adverse effects of glare, poor contrast, constant focus on the eye, and impairment of the visual nervous system are possible explanations for the eye symptoms (25, 39). The clinical significance of weak relations found with the occurrence of common colds and acute bronchitis needs further research. Our results are consistent with four previous studies (25, 2-29). Validity of results We chose a population-based approach to avoid selection that might bias results if study subjects had been recruited because of health concerns. A random sample was selected from all office buildings in the Helsinki metropolitan area, so the results are generalizable to office workers in at least that area. The response rate to the questionnaire (81 percent) was relatively high. Office workers were informed about the general objective to study determinants of health in office buildings, but not about special attention paid to the office equipment. Blinding to the specific study questions reduces the likelihood of information bias in reporting exposure. Thus, recall bias in symptomatic individuals is not a likely explanation for our findings. Further support for information bias being unlikely comes from the fact that strong relations were observed mainly with self-copying paper rather than photocopying or VDT work, although the latter two received much more public attention at the time of the study. We controlled for most of the known confounders, including personal characteristics, smoking, socioeconomic status, other environmental factors in the office environment, and psychological and social factors at work. Any unknown confounder would have to be a strong determinant of the outcomes and have a considerably uneven distribution over exposure categories to be able to explain the observed findings. Conclusion Our results provide new evidence that handling selfcopying paper increases the risk of chronic respiratory symptoms as well as respiratory infections, such as sinusitis and acute bronchitis. They strengthen evidence on effects of self-copying paper on eye, mucosal, skin, and neurologic symptoms. The results also show evidence of effects of photocopying on nasal irritation and of VDT work on eye symptoms among office workers. In addition, VDT work is related to general neurologic symptoms, such as headache and lethargy. These findings emphasize that occupational hazards of the modem office environment should not be overlooked. REFERENCES 1. Marks JG Jr. Allergic contact dermatitis from carbonless copy paper. JAMA 1981;245: Shehade SA, Beck MH, Chalmers RJG. Allergic contact dermatitis to crystal violet in carbonless copy paper. Contact Dermatitis 198;1:310-ll. 3. Magnusson B. Irritation of the skin and mucous membranes by NCR paper. 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