Abstract
Background
Cleaning workers are regularly exposed to cleaning products containing hazardous chemicals. This study investigated acute symptoms associated with chemical exposures among cleaning workers and their safe work practices.
Methods
This cross-sectional study included 183 cleaning workers employed in an academic medical center and affiliated health sciences campuses in Northern California. Data on respiratory, eye, skin, neurological, and gastrointestinal symptoms and occupational factors were collected by in-person interviews or self-administered questionnaires.
Results
Chemical-related symptoms (several times monthly or more often) were more common among workers who performed patient-area cleaning (44%) than hospital-custodians (36%) or campus-custodians (28%). After controlling for age, sex, and job title, symptoms were associated with exposure to carpet cleaners (OR=2.98, 95% CI 1.28–6.92), spray products (OR=2.82, 95% CI 1.16–6.82), solvents (OR=2.71, 95% CI 1.20–6.15), and multi-purpose cleaners (OR=2.58, 95% CI 1.13–6.92). Except for gloves, regular use of personal protective equipment was infrequent.
Conclusions
Study findings suggest a need for additional interventions such as use of less toxic products to reduce health risks among cleaning workers.
Keywords: cleaners, cleaning, chemical exposure, healthcare, safe work practice
INTRODUCTION
Cleaning workers are regularly exposed to chemical products used in cleaning tasks. Cleaning products contain various chemical ingredients such as detergents, disinfectants, surfactants, solvents, corrosion inhibitors, fragrances and preservatives. Some of these chemicals are classified as corrosives, irritants, sensitizers, carcinogens, or neurotoxic agents [Wolkoff, et al. 1998, Zock 2005]. Regular and frequent exposure to cleaning products without adequate protection puts cleaning workers at risk of acute and chronic adverse health effects from hazardous chemicals.
Cleaning workers rank among the top 20 occupations with the highest rates of occupational injuries and illnesses in the United States. Four percent of their injuries and illnesses are attributed to exposure to harmful substances or environments [Bureau of Labor Statistics 2010]. Irritation of the eyes, skin, and respiratory tract, allergy, and chemical burns have been identified as common acute health and safety problems among cleaning workers [Alamgir and Yu 2008, Arif, et al. 2008, Charles, et al. 2009, Lynde, et al. 2009, Nielsen and Bach 1999, Sarri, et al. 1991]. A Danish study of 1,011 female cleaning workers in nursing homes, schools, and offices reported that the annual symptom prevalence was 46% for nose or throat symptoms, 31% for eye symptoms, with an asthma prevalence of 8% [Nielsen and Bach 1999]. A Canadian study found that the prevalence of skin rash was significantly higher among male professional cleaning workers than other building workers (21% vs. 11%) [Lynde, et al. 2009]. Two other studies reported a prevalence of hand dermatitis of 12–15% among hospital cleaning workers [Gawkrodger, et al. 1986, Hansen 1983, Lynde, et al. 2009]. In addition, epidemiological studies have found elevated risks of asthma among cleaning workers and significant associations between asthma and exposure to cleaning products [Jaakkola and Jaakkola 2006, Karjalainen, et al. 2002, Reinisch, et al. 2001, Rosenman, et al. 2003, Vizcaya, et al. 2011, Zock, et al. 2001, Zock, et al. 2007, Zock, et al. 2010].
Among the types of cleaning products, disinfectants are recognized as among the most hazardous. Disinfectants include active ingredients such as chlorine-releasing compounds, alcohols, aldehydes, and quaternary ammonium compounds [Wolkoff, et al. 1998, Zock 2005]. Disinfectants used on environmental surfaces are regulated by the Environmental Protection Agency. In healthcare, disinfecting activities are essential for infection control in certain settings, and therefore cleaning workers in healthcare may have increased risk of disinfectant exposure than workers in other settings. Among various occupational groups in healthcare settings, cleaning workers have been identified as an occupation at higher risk of chemical-associated injuries or illnesses [Centers for Disease Control and Prevention (CDC) 2010, Weaver, et al. 1993].
Information is limited on the extent of chemical exposure and associated acute health problems among cleaning workers in healthcare. This study was conducted to investigate the prevalence of and risk factors for acute health symptoms associated with chemical exposures and safe work practices among cleaning workers in hospital and affiliated settings.
METHODS
Study Setting and Participants
This cross-sectional study recruited a convenience sample of cleaning workers employed at a university medical center and affiliated health sciences campuses in Northern California. Cleaning workers were defined as employees who perform janitorial, cleaning, or housekeeping services regardless of job title. The medical center (called “hospital” afterwards) has about 7,000 employees and 690 patient beds in two locations. As of December 2010, the Hospitality Service Department had 280 employees, which consisted of 122 (44%) patient support assistants (PSAs) who assist patient transport and perform cleaning of patient rooms and clinical areas (e.g., operating room), and 133 (48%) custodians who perform cleaning of other nonclinical or public areas (e.g., hallway, restroom, or waiting room). The remaining employees had supervisory or other job responsibilities (8%). The university health sciences campus (called “campus” afterwards) is affiliated with the hospital, but has a separate management system for cleaning services. A total of 128 custodians were employed by the campus. The study setting has adopted certified green products for most cleaning agents. A variety of cleaners, degreasers, finishers, sealers, and polishes were used and included chemicals such as ethanolamines, glycol ethers (2-butoxyethanol, ethylene glycol ethylhexyl ether, dipropylene glycol methyl ether), alcohols (benzyl alcohol, ethyl alcohol, isopropyl alcohol), and d-limonene.
The cleaning service departments’ managers helped the investigators’ access to the workers. The investigators attended monthly staff meetings and other events (e.g., staff stretching exercise time) to provide study information and recruit participants. As the majority of the workers spoke Chinese or Spanish as their first language, all study information was provided in three languages (English, Chinese, and Spanish). The study flyers were placed on cleaning department bulletin boards and in hospital employee lounges. Eligible participants were cleaning workers who were employed for at least one month and could speak, read, and understand English, Chinese, or Spanish. Supervisors who performed cleaning as a partial job responsibility were also included. A $25 gift card was given to each participant after completing the questionnaire. The study was approved by the Committee on Human Research of the University of California at San Francisco.
Data Collection and Instruments
This study collected data using a questionnaire in English, Chinese, or Spanish. The English questionnaire was developed initially and reviewed by two occupational health experts and one cleaning service manager. The questionnaire was pilot tested with four hospital cleaning workers and minor modifications were made to improve clarity in wording and format. Chinese and Spanish versions were developed through translation and back-translation processes by independent bilingual persons. The principal investigator compared the back-translated versions and the original English version. For a few discrepancies identified, translations were corrected and finalized with consultation with a third bilingual person. The initial data collection method was face-to-face interviews conducted by trained bilingual interviewers. A self-administration method was subsequently added to facilitate participant recruitment.
The study questionnaire included items about demographics (age, sex, race/ethnicity, country of birth, and education), health conditions (e.g., asthma, contact dermatitis, other comorbidities, and perceived general health), job information (job title, job tenure, full-time status, and shift), chemical exposure, safe work practices and health symptoms associated with chemical exposure.
Chemical exposure items were adapted from studies by Zock and colleagues [2001] and Nielsen and Bach [1999]. We asked how many days in the usual work week the worker performed the cleaning task (e.g., floor polishing, window or mirror cleaning, or discharge cleaning of in-patient rooms) and used the cleaning product (e.g., bleach, solvents, polishers, or glass cleaners). For those who had any frequency of exposure to the task or product, the duration of exposure per day was assessed on a 5-point scale (<0.5 hours, 0.5–1 hour, >1–2 hours, >2–4 hours, >4 hours).
Safe work practices were assessed by chemical safety behavior and use of personal protective equipment (PPE). Chemical safety behavior was asked by an 8-item measure developed by the investigators based on a reference by the California Division of Occupational Safety and Health (Cal/OSHA) [2005]. Respondents answered how often they engaged in the behavior on a 5-point scale (never, rarely, sometimes, most of the time, all the time). As for PPE use, respondents were asked to indicate how often in the past 30 days they wore gloves, long-sleeve clothing, rubber apron, safety glasses or goggles, face shield, and surgical mask while handling chemicals on a 5-point scale (never, rarely, sometimes, most of the time, all the time).
For chemical-related health symptoms (16 items), we asked how often in the past 12 months the respondent had symptoms involving the respiratory tract, eye, skin, nervous and gastrointestinal systems which were associated with the use of chemicals to perform cleaning tasks. Symptom items (see Table 2) were selected based on the Respiratory Sensitizers Surveillance Questionnaire developed by Cal/OSHA (http://www.dir.ca.gov/dosh/doshreg/5179Meetings.html) and related literature [Brevard et al. 2003]. The questions were asked using a 5-point scale (daily, several times weekly, several times monthly, several times yearly, never in the past 12 months). Those who reported symptoms were further asked about whether they sought medical care, missed work due to the symptoms, and reported the condition to the supervisor.
TABLE 2.
Symptom Experiences Related to Chemical Exposure among Cleaning Workers (N=183)
| Daily | Several times weekly | Several times monthly | Several times yearly | Never in the past 12 months | |
|---|---|---|---|---|---|
|
|
|||||
| Symptoms | N (%) | N (%) | N (%) | N (%) | N (%) |
| Respiratory | 15 (8.2) | 17 (9.3) | 24 (13.1) | 32 (17.5) | 95 (51.9) |
| Stuffy, itchy, or runny nose | 7 (3.8) | 13 (7.1) | 15 (8.2) | 31 (17.0) | 117 (63.9) |
| Burning in nose or throat | 5 (2.7) | 2 (1.1) | 7 (3.8) | 22 (12.0) | 147 (80.3) |
| Cough | 3 (1.7) | 7 (3.8) | 9 (4.9) | 32 (17.5) | 132 (72.1) |
| Phlegm from chest | 3 (1.6) | 1 (0.6) | 7 (3.8) | 15 (8.2) | 157 (85.8) |
| Chest tightness | 1 (0.6) | 2 (1.1) | 8 (4.4) | 11 (6.0) | 161 (88.0) |
| Shortness of breath | 3 (1.6) | 3 (1.6) | 6 (3.3) | 14 (7.7) | 157 (85.8) |
| Wheezing | 3 (1.6) | 2 (1.1) | 2 (1.1) | 7 (3.8) | 169 (92.4) |
| Ocular | 8 (4.4) | 4 (2.2) | 16 (8.7) | 31 (16.9) | 124 (67.8) |
| Watery, itchy, or burning eyes | 4 (2.2) | 5 (2.7) | 15 (8.2) | 25 (13.7) | 134 (73.2) |
| Red eyes | 5 (2.8) | 1 (0.6) | 5 (2.7) | 21 (11.5) | 150 (82.4) |
| Blurred or distorted vision | 1 (0.6) | 1 (0.6) | 1 (0.6) | 8 (4.4) | 172 (94.0) |
| Dermal | 5 (2.7) | 2 (1.1) | 4 (2.2) | 24 (13.1) | 148 (80.9) |
| Itchy or burning skin | 3 (1.6) | 1 (0.6) | 4 (2.2) | 22 (12.0) | 153 (83.6) |
| Rash | 4 (2.2) | 3 (1.6) | 0 (0) | 14 (7.7) | 162 (88.5) |
| Neurological | 5 (2.7) | 9 (4.9) | 8 (4.4) | 30 (16.4) | 131 (71.6) |
| Headache | 5 (2.7) | 9 (4.9) | 8 (4.4) | 26 (14.2) | 135 (73.8) |
| Dizziness or lightheadedness | 2 (1.1) | 4 (2.2) | 2 (1.1) | 13 (7.1) | 162 (88.5) |
| Gastrointestinal | 0 (0) | 2 (1.1) | 4 (2.2) | 10 (5.5) | 167 (91.3) |
| Nausea | 0 (0) | 2 (1.1) | 4 (2.2) | 10 (5.5) | 167 (91.3) |
| Vomiting | 0 (0) | 0 (0) | 0 (0) | 5 (2.7) | 178 (97.3) |
| Any symptom | 24 (13.1) | 15 (8.2) | 27 (14.8) | 37 (20.2) | 80 (43.7) |
Data Analysis
Data entry and analysis were performed using the statistical programs STATA version 11.2 (StataCorp, College Station, TX) and SAS version 9.2 (SAS Institute, Cary, NC). Data from pilot testing were excluded from the data analysis. All data were double entered by different individuals and the two datasets were compared to identify and correct entry errors. Descriptive statistics were used to summarize chemical-related symptoms and other study variables. To examine associations of symptoms with relevant study variables, symptom cases were defined as those who reported any chemical-related symptoms experienced “several times monthly or more often” (hereafter referred to as “at least monthly”). Demographic and job characteristics and health conditions were compared between symptom cases and non-cases using chi-square or Fisher’s exact tests. As for chemical exposure variables, we found that the numbers of workers who had no exposure were too small (<2–10%) to serve as the reference group for several items (e.g., mixing chemical solutions, dusting, mopping, disinfectants). Hence we categorized chemical exposure into no/low, medium, and high exposures by tertile split of the calculated product of exposure frequency (days/week) and duration category (hours/day). For some chemical exposure items (e.g., waxing floors, stripping floors, carpet cleaners), most respondents (66–84%) reported no exposure and the approach of using tertiles were considered to be inappropriate. Hence, these variables were dichotomized into no exposure and any exposure. Multiple logistic regressions were conducted to examine associations between chemical-related symptoms and job or chemical exposure variables. Odds ratios (ORs) and 95% Confidence Intervals (CIs) were calculated.
RESULTS
Characteristics of Participants
A total of 183 cleaning workers (142 hospital workers and 41 campus workers) participated in this study (Table 1). This sample represented 45% of all cleaning workers in the study setting. The sample included 68 PSAs (37%), 64 hospital custodians (35%), 39 campus custodians (21%), and 12 supervisors (7%). The mean age of the participants was 48.0 years old (SD 9.9, range 20–73) and the mean job tenure was 8.1 years (median 6.3, range 0.3–33.4). The majority was female (56%), Asian (65%), foreign-born (86%), and had an educational level of high school or lower (72%). Most participants were full-time workers (96%) and worked on shifts other than days (57%). For hospital custodians and PSAs, the proportion of female and Asian workers were significantly higher among study participants than among nonparticipants (p<0.05) [data not shown]. The majority (54%) perceived their general health status as excellent or very good. A history of asthma or contact dermatitis was reported by 22 workers (12%); of these, 4 workers (18%) reported having both conditions.
TABLE 1.
Chemical-Related Symptom Experiences (Several Times Monthly or More Often) by Personal and Job Characteristics and Health Conditions
| Chemical-related symptoms |
||||
|---|---|---|---|---|
| Variable | Total, N=183 (100%) |
Yes n=66 (36%) |
No n=117 (64%) |
P-value |
| Demographic characteristics | ||||
| Sex | ||||
| Male | 81 (44.3) | 20 (24.7) | 61 (75.3) | 0.004 |
| Female | 102 (55.7) | 46 (45.1) | 56 (54.9) | |
| Age (year) | ||||
| <30 | 11 (6.0) | 7 (63.6) | 4 (36.4) | 0.211 |
| 30–39 | 22 (12.0) | 9 (40.9) | 13 (59.1) | |
| 40–49 | 57 (31.1) | 21 (36.8) | 36 (63.2) | |
| 50–59 | 76 (41.5) | 24 (31.6) | 52 (68.4) | |
| ≥60 | 17 (9.3) | 3 (21.4) | 11 (78.6) | |
| Race/ethnicity | ||||
| Hispanic | 37 (20.2) | 15 (40.5) | 22 (59.5) | 0.932 |
| Asian | 119 (65.0) | 42 (35.3) | 77 (64.7) | |
| African American | 21 (11.5) | 7 (33.3) | 14 (66.7) | |
| Other | 6 (3.3) | 9 (33.3) | 18 (66.7) | |
| Country of birth | ||||
| United States | 26 (14.3) | 10 (38.5) | 16 (61.5) | 0.752 |
| Other | 156 (85.7) | 55 (35.3) | 101 (64.7) | |
| Education | ||||
| Elementary | 13 (7.1) | 6 (46.2) | 7 (53.9) | 0.482 |
| High school | 118 (64.5) | 39 (33.1) | 79 (67.0) | |
| College (≥ 1year) | 52 (28.4) | 21 (40.4) | 31 (59.6) | |
| Job characteristics | ||||
| Job tenure (years) | ||||
| < 1 | 8 (4.4) | 3 (37.5) | 5 (62.5) | 0.886 |
| 1–4 | 47 (25.7) | 15 (31.9) | 32 (68.1) | |
| 5–9 | 67 (36.6) | 24 (35.8) | 43 (64.2) | |
| ≥10 | 61 (33.3) | 24 (39.3) | 37 (60.7) | |
| Work status | ||||
| Full-time | 176 (96.2) | 61 (34.7) | 115 (65.3) | 0.100 |
| Part-time or per-diem | 7 (3.8) | 5 (71.4) | 2 (28.6) | |
| Work shift | ||||
| Day | 78 (42.6) | 32 (41.0) | 46 (59.0) | 0.229 |
| Other | 105 (57.4) | 34 (32.4) | 71 (67.6) | |
| Health conditions | ||||
| Perceived general health | ||||
| Excellent or very good | 99 (54.1) | 35 (35.4) | 64 (64.7) | 0.826 |
| Good | 62 (33.9) | 24 (38.7) | 38 (61.3) | |
| Fair or poor | 22 (12.0) | 7 (31.8) | 15 (68.2) | |
| Asthma | ||||
| Yes | 17 (9.3) | 11 (64.7) | 6 (35.3) | 0.010 |
| No | 166 (90.7) | 55 (33.1) | 111 (66.9) | |
| Contact dermatitis | ||||
| Yes | 9 (4.9) | 7 (77.8) | 2 (22.2) | 0.012 |
| No | 174 (95.1) | 59 (33.9) | 115 (66.1) | |
| Allergy | ||||
| Yes | 52 (28.4) | 22 (42.3) | 30 (57.7) | 0.268 |
| No | 131 (71.6) | 44 (33.6) | 87 (66.4) | |
Chemical-related Symptoms
Table 1 shows chemical-related symptom experiences (at least monthly) by demographic and job characteristics and health conditions. Female workers were significantly more likely to experience symptoms than male workers (45% vs. 25%, p=0.004); significance remained after adjustment for age and job title (OR=2.13, 95% CIs 1.07–4.23). Age was not significantly associated with symptoms, but the proportion of workers with symptoms tended to decrease with increasing age. A history of asthma was reported by 17 workers (9%); nine workers were currently taking a medication for asthma and one out of 11 workers who were diagnosed with asthma at 18 ages or order reported that it was related to her previous job. Workers with a history of asthma or contact dermatitis were significantly more likely to experience chemical-related symptoms than workers without such conditions (asthma: 65% vs. 33%, p=0.010; contact dermatitis: 78% vs. 34%, p=.012). In further analyses, a significant association was found between respiratory symptoms and asthma history (59% with asthma history vs. 28% without asthma history; p=0.008), but not between skin symptoms and contact dermatitis (22% with the history vs. 5% without the history; p=0.094). A significant association was found between experiences of respiratory symptoms and skin symptoms with Fisher’s exact test (p=0.004) [data not shown].
Table 2 provides detailed data on symptom experiences related to chemical exposure. The 12-month prevalence of any chemical-related symptoms was 56% (13% daily, 8% several times weekly, 15% several times monthly, and 20% several times a year). Of the participants, 31% reported having experienced respiratory symptoms at least monthly: stuffy, itchy or runny nose (19%) was the most common respiratory symptom, with shortness of breath and wheezing reported by 7% and 4%, respectively. Symptoms occurring at least monthly were reported for ocular (15%), neurological (13%), dermal (6%), and gastrointestinal (3%) systems.
Among103 workers who experienced chemical-related symptoms, 35 (34%) saw a healthcare provider due to the symptom, 27 (26%) reported the symptom to their supervisors, and 15 (15%) missed work. Hispanic workers were significantly more likely to see healthcare providers than Asian or Black workers (54% vs. 26% or 13%, respectively; p=0.006). Symptom reporting to supervisors was significantly less common among female workers than among male workers (19% vs. 42%; p=0.013) and among Asian workers than among other workers (14% vs. 49%; p=0.0002).
Job Exposures and Chemical-related Symptoms
Table 3 shows chemical-related symptoms and respiratory symptoms by job location, job title and selected work areas. Chemical-related symptoms were more common among hospital workers (39%) than among campus workers (27%). PSAs had the highest symptom prevalence (44%). After adjustment for age and sex, hospital custodians and PSAs had 19–43% increased odds of experiencing chemical-related symptoms compared to campus custodians, although this finding was not statistically significant. Chemical-related symptoms were significantly associated with working on in-patient floors (OR=2.55, 95% CI 1.28–5.08) and intensive care units (OR=2.53, 95% CI 1.15–5.55). For respiratory symptoms, overall findings showed similar patterns with slightly weaker associations compared to the findings on chemical-related symptoms, and statistical significance was found only for working on in-patient floors (OR=2.37. 95% CI 1.18–4.75).
TABLE 3.
Age and Sex Adjusted Associations Between Chemical-related Symptoms (Several Times Monthly or More Often) and Job Location, Job Title, and Area of Work Assignment Among Cleaning Workers (N=183)
| Variable | Chemical-related Symptoms | Respiratory Symptoms Only | ||||
|---|---|---|---|---|---|---|
|
| ||||||
| Yes | No | OR (95% CIs) | Yes | No | OR (95% CIs) | |
| Job location | ||||||
| Campus | 11 (26.8) | 30 (73.2) | 1.00 | 11 (26.8) | 30 (73.2) | 1.00 |
| Hospital | 55 (38.7) | 87 (61.3) | 1.29 (0.57–2.91) | 45 (31.7) | 97 (68.3) | 0.96 (0.42–2.18) |
| Job title | ||||||
| Custodian, campus | 11 (28.2) | 28 (71.8) | 1.00 | 11 (28.2) | 28 (71.8) | 1.00 |
| Custodian, hospital | 23 (35.9) | 41 (64.1) | 1.19 (0.48–2.94) | 20 (31.3) | 44 (68.7) | 1.01 (0.40–2.50) |
| Patient support assistant, hospital | 30 (44.1) | 38 (55.9) | 1.43 (0.58–3.53) | 25 (36.8) | 43 (63.2) | 1.10 (0.44–2.75) |
| Supervisor, campus or hospital | 2 (16.7) | 10 (83.3) | 0.49 (0.09–2.72) | 0 (0) | 12 (100) | - |
| Select area of work assignment * | ||||||
| In-patient floor | 29 (51.8) | 27 (48.2) | 2.55 (1.28–5.08) | 25 (44.6) | 31 (55.4) | 2.37 (1.18–4.75) |
| Intensive care units | 20 (54.1) | 17 (46.0) | 2.53 (1.15–5.55) | 16 (43.2) | 21 (56.8) | 1.92 (0.87–4.22) |
| Out-patient clinics | 17 (44.7) | 21 (55.3) | 2.04 (0.94–4.41) | 13 (34.2) | 25 (65.8) | 1.55 (0.70–3.43) |
| Operating rooms | 13 (32.5) | 27 (67.5) | 0.71 (0.32–1.56) | 9 (22.5) | 31 (77.5) | 0.50 (0.21–1.21) |
| Non-surgical procedure rooms | 16 (50.0) | 16 (50.0) | 2.05 (0.93–4.55) | 13 (40.6) | 19 (59.4) | 1.76 (0.78–3.94) |
| Emergency department | 6 (33.3) | 12 (66.7) | 1.04 (0.36–3.04) | 5 (27.8) | 13 (72.2) | 0.98 (0.32–3.00) |
| Post-anesthesia care unit | 3 (50.0) | 3 (50.0) | 2.46 (0.46–13.0) | 3 (50.0) | 3 (50.0) | 3.07 (0.58–16.2) |
| Clinical or medical laboratories | 21 (39.6) | 32 (60.4) | 1.57 (0.78–3.16) | 18 (34.0) | 35 (66.0) | 1.56 (0.76–3.18) |
Categories are not mutually exclusive. More than one area can be assigned to workers. Those who do not work in the area were used as the reference group in the analysis.
Table 4 shows multivariable analyses on the associations of chemical-related symptoms and respiratory symptoms with job tasks and cleaning products. After adjustment for age, sex, and job title, chemical-related symptoms were significantly associated with tasks using spray products (OR=2.82, 95% CI 1.16–6.82 for medium exposure) and with high exposure to liquid multi-use cleaners (OR=2.58, 95% CI 1.13–5.89), solvents or stain removers (OR=2.71, 95% CI 1.20–6.15), carpet cleaners (OR=2.98, 95% CI 1.28–6.92) and products that smell like lemon or orange (OR=2.16, 95% CI 1.03–4.51). For respiratory symptoms, significant associations were found with medium exposure to tasks using spray products (OR=3.16, 95% CI 1.24–8.04) and high exposures to liquid multi-use cleaners (OR=2.35, 95% CI 1.02–5.43) and carpet cleaners (OR=2.33, 95% CI 1.00–5.43).
TABLE 4.
Associations between Chemical-related Symptoms (Several Times Monthly or More Often) and Job Exposurea Among Cleaning Workers (N=183): Odds Ratios (95% CIs) Adjusted for Age, Sex, and Job Title (Reference=No/Low Exposure)
| Variable | Chemical-related Symptoms | Respiratory Symptoms Only | ||
|---|---|---|---|---|
|
| ||||
| Medium exposure | High exposure | Medium exposure | High exposure | |
| Work Task | ||||
| Mixing or diluting cleaning solutions | 0.85 (0.35–2.06) | 1.04 (0.40–2.72) | 0.78 (0.31–1.92) | 0.92 (0.34–2.52) |
| Cleaning equipment after use | 1.87 (0.72–4.88) | 0.88 (0.31–2.47) | 1.79 (0.65–4.92) | 0.86 (0.28–2.61) |
| Dusting, sweeping, vacuuming | 0.50 (0.17–1.43) | 1.59 (0.69–3.67) | 0.62 (0.20–1.91) | 2.05 (0.84–5.05) |
| Mopping, wet cleaning, damp wiping | 1.36 (0.52–3.61) | 1.62 (0.58–4.55) | 2.30 (0.74–7.17) | 3.11 (0.94–10.3) |
| Buffing, polishing, waxing floorsb | - | 1.54 (0.67–3.52) | - | 1.72 (0.73–4.06) |
| Stripping floorsb | - | 2.02 (0.81–5.01) | - | 2.48 (0.96–6.45) |
| Cleaning windows or mirrors | 1.13 (0.47–2.69) | 1.17 (0.47–2.86) | 1.51 (0.59–3.89) | 1.57 (0.60–4.12) |
| Cleaning toilet bowls or sinks | 1.37 (0.60–3.14) | 1.56 (0.68–3.59) | 1.71 (0.72–4.01) | 1.96 (0.82–4.69) |
| Cleaning furniture | 1.38 (0.59–3.20) | 0.98 (0.42–2.27) | 1.07 (0.44–2.61) | 1.03 (0.43–2.44) |
| Cleaning tasks using sprays | 2.82 (1.16–6.82) | 1.79 (0.81–3.96) | 3.16 (1.24–8.04) | 1.98 (0.87–4.51) |
| Regular cleaning of patient rooms in useb | - | 1.62 (0.68–3.83) | - | 1.49 (0.60–3.71) |
| Discharge cleaning of patient roomsb | - | 1.77 (0.74–4.25) | - | 1.98 (0.77–5.11) |
| Cleaning isolation roomsb | - | 1.10 (0.49–2.46) | - | 1.19 (0.51–2.79) |
| Cleaning Product | ||||
| Liquid multi-use cleaning products | 1.09 (0.49–2.43) | 2.58 (1.13–5.89) | 0.83 (0.35–1.95) | 2.35 (1.02–5.43) |
| Polishes, waxesb | - | 1.23 (0.57–2.65) | - | 1.26 (0.57–2.79) |
| Disinfectants | 1.00 (0.43–2.32) | 0.80 (0.33–1.90) | 0.67 (0.28–1.62) | 0.72 (0.30–1.74) |
| Bleach | 1.24 (0.55–2.80) | 1.62 (0.71–3.72) | 1.29 (0.55–3.04) | 1.68 (0.70–4.01) |
| Solvents, stain removers | 1.92 (0.84–4.39) | 2.71 (1.20–6.15) | 1.38 (0.59–3.23) | 2.29 (0.99–5.26) |
| Glass cleaning products | 1.77 (0.76–4.15) | 2.01 (0.89–4.53) | 1.34 (0.55–3.27) | 1.96 (0.85–4.54) |
| Products for mopping the floor | 0.94 (0.41–2.15) | 1.45 (0.60–3.50) | 0.75 (0.32–1.76) | 1.06 (0.43–2.59) |
| Products for cleaning carpetsb | - | 2.98 (1.28–6.92) | - | 2.33 (1.00–5.43) |
| Furniture spraysb | - | 1.78 (0.78–4.07) | - | 1.50 (0.63–3.56) |
| Products that smell like lemon or orangeb | - | 2.16 (1.03–4.51) | - | 2.04 (0.96–4.33) |
| Products combined immediately before useb | - | 1.29 (0.53–3.11) | - | 0.59–3.69) |
No/Low, medium, or high exposures were categorized by tertile split of the frequency of exposure (days per week X hours per day)
As most cases (66% to 84%) had no exposure to the task or product, the variables were dichotomized. High exposure indicates having any exposure.
Safe Work Practices and Chemical-related Symptoms
Table 5 shows safe work practices among cleaning workers by job location and symptoms. More than 80% of participants reported that they complied with all chemical safety practices all the time or most of the time. Almost all participants (98%) reported wearing gloves all the time or most of the time whereas regular use of other PPE was uncommon (e.g., safety glass/goggle 28% and face shield 16%). Hospital workers were significantly more likely to wear a safety glass/goggle (X2=14.39, p=0.0001), face shield (X2=9.95, p=0.0016), and surgical mask (X2=11.48, p=0.0007) than campus workers. No symptoms were significantly associated with regular wearing of safety glass/goggle, long-sleeve clothing, or surgical mask and ventilating the cleaning space (Table 6).
TABLE 5.
Safe Work Practices Among Cleaning Workers
| % Compliance: All the time or most of the timea |
|||||
|---|---|---|---|---|---|
| All (N=183) | Job location |
Chemical-related symptoms |
|||
| Variable | Hospital (n=142) |
Campus (n=41) |
Yes (n=66) |
No (n=117) |
|
| Chemical safety behavior | |||||
| I follow safety rules at work | 97.8 | 97.9 | 97.6 | 96.9 | 98.3 |
| When I use a new cleaning product, I read the label of the product | 91.2 | 90.7 | 92.7 | 87.9 | 93.0 |
| I follow the directions of cleaning products | 96.2 | 96.5 | 95.1 | 93.9 | 97.4 |
| I do not mix cleaning products to make them strongerb | 87.6 | 86.0 | 92.7 | 87.9 | 87.4 |
| I do not use concentrated products without diluting them to make them strongerb | 90.5 | 88.4 | 97.6 | 93.9 | 88.5 |
| I wash my hands before eating, drinking or smoking | 99.5 | 99.3 | 100 | 100 | 99.2 |
| When I get chemicals on my skin, I wash my skin immediately | 98.9 | 98.6 | 100 | 100 | 98.3 |
| When I use chemicals to clean an area, I ventilate the space with any available methods | 80.8 | 80.2 | 82.9 | 80.0 | 81.3 |
| Use of PPE while handling chemicals | |||||
| Gloves | 98.4 | 98.6 | 97.6 | 100 | 97.4 |
| Surgical Mask | 37.2 | 43.7 | 14.6 | 39.4 | 35.9 |
| Safety goggle or glass | 28.4 | 35.2 | 4.9 | 31.8 | 26.5 |
| Long sleeve clothing | 26.2 | 27.5 | 22.0 | 30.3 | 23.9 |
| Face shield | 15.9 | 20.4 | 0 | 16.7 | 15.4 |
| Rubber apron | 3.3 | 3.5 | 2.4 | 4.6 | 2.6 |
Answer categories also included never, rarely, and sometimes.
The original wording in the questionnaire was in a reverse direction.
TABLE 6.
Associations Between Safe Work Practice and Chemical-related Symptoms (Several Times Monthly or More Often) Among Cleaning Workers (N=183)
| Chemical-related symptoms | OR (95% CIs) adjusted for age, sex, and job title | ||
|---|---|---|---|
| Variable | Yes | No | |
| Safety glass or goggle | Ocular | ||
| All the time/most of the time | 12 (23.1) | 40 (76.9) | 1.41 (0.52–3.80) |
| Never/rarely/sometimes | 16 (12.2) | 115 (87.8) | |
| Long sleeve clothing | Dermal | ||
| All the time/most of the time | 3 (6.3) | 45 (93.8) | 1.10 (0.27–4.53) |
| Never/rarely/sometimes | 8 (5.9) | 127 (94.1) | |
| Surgical mask | Respiratory or neurological | ||
| All the time/most of the time | 24 (35.3) | 44 (64.7) | 1.08 (0.53–2.20) |
| Never/rarely/sometimes | 37 (32.2) | 78 (63.9) | |
| Ventilate the space when using chemicals | Respiratory or neurological | ||
| All the time/most of the time | 48 (33.6) | 95 (66.4) | 0.77 (0.33–1.76) |
| Never/rarely/sometimes | 12 (35.3) | 22 (64.7) | |
DISCUSSION
Hospital cleaning workers perform cleaning tasks in settings where infection control is crucial, but may be at risk of adverse health effects from frequent exposure to cleaning and disinfecting products. This study investigated acute symptoms associated with chemical exposure among cleaning workers in an academic medical center and affiliated health sciences campuses. Our study showed that chemical-related symptoms, particularly respiratory symptoms, were relatively common among cleaning workers while regular use of PPE, except for gloves, was infrequent. Symptoms were more common among hospital cleaning workers than among campus custodians.
The annual prevalence of any chemical symptoms was 56% among cleaning workers, most commonly nasal irritation and cough. The prevalence of respiratory symptoms (48%) was similar to the prevalence (46%) from a Danish study of female cleaning workers in nursing homes, schools and offices [Nielsen and Bach 1999]. Our study also found that reported symptoms were relatively frequent among cleaning workers, with about one-third of workers experiencing respiratory symptoms at least monthly. Cleaning products contain volatile chemicals, and acute and chronic inhalation exposures pose respiratory health risks including asthma [Bello, et al. 2009, Jaakkola and Jaakkola 2006, Vizcaya, et al. 2011, Zock, et al. 2010]. In our study, most workers (81%) reported ventilating the cleaning space always or most of the time and about one third reported regularly wearing a surgical mask. No associations were found between regular ventilation and surgical mask use and respiratory symptoms.
Symptoms of eye irritation were the second most commonly reported among cleaning workers in this study, and the annual prevalence (32%) was similar to the report (31%) by Nielsen and Bach [1999]. A surveillance report by CDC [2010] showed that ocular symptoms were the most common disinfectant-related injury or illness in healthcare workers, often due to splashes without eye protection. Our study found that only 28% of participants reported regular use of safety glasses or goggles. Although we did not find a significant association, workers reporting frequent eye symptoms tended to wear eye protection more often than workers reporting infrequent or no symptoms. Lombardi et al. [2009] reported that use of protective eyewear among workers was influenced by perceptions of hazards and risks, enforcement and reinforcement, and barriers such as lack of comfort and fogging/scratching of the eyewear.
Our study identified that working on in-patient floors and intensive care units were significantly associated with increased symptoms. We found no association between using disinfectants and reported symptoms, but bleach showed non-significantly increased ORs (1.24 and 1.62) with medium and high exposures. Symptoms were significantly associated with spray products, multi-use cleaners, solvents, carpet cleaners, and products with smell like lemon or orange (these products potentially contain limonene). Spray products and solvents can increase the risk of inhalation exposure [Bello, et al. 2009], and these products were found to be associated with increased risks of asthma in other studies [Zock, et al. 2001, Zock, et al. 2007]. A study of domestic and professional cleaners [Arif, et al. 2008] showed that more than 70% of products used by the workers were identified as respiratory irritants and sensitizers.
In controlling chemical hazards, elimination or substitution with less toxic products is the most effective, first-line approach. It should be noted that the study setting has replaced most cleaning products with green products, which contain less hazardous chemicals for human health and environmental impacts. For example, carcinogens, mutagens, reproductive toxins, asthmagens, skin sensitizers, and chemicals causing skin corrosion or serious eye damage may not be included in any product that obtains certification under certain criteria [Green Seal Inc., 2012]. Although mostly green certified products were used in the study setting, symptoms of acute irritation were nevertheless common among workers in our study.
Symptom perception and reporting can be influenced by sex and cultural factors [Barsky, et al. 2001, Callister, et al. 2003, Rahim-Williams, et al. 2012]. Our study observed interesting findings for sex. While female workers were more likely to experience symptoms than male workers, male workers were more likely to report the symptoms to their supervisors than female workers. We further analyzed for sex by controlling for significant variables of work area, task, or products as well as age and job title, and sex was still significant in all of the analyses [data not shown]. Higher incidence or prevalence of work-related injuries, illnesses, or symptoms in female workers was reported by other studies of various occupational groups [Alterman, et al. 2008; Barbosa, et al. 2013; Buchanan, et al. 2010; Kasner, et al. 2012]. Alamgir and Yu [2008] also reported a significantly higher incidence rate of work-related injuries among female cleaners in healthcare, but no significant difference was found for irritation or allergy. With regard to our findings of less symptom reporting to supervisors among female workers, little information is available in the literature. Some gender associated sociocultural aspects may play a role in communication or relationships with supervisors, but further research is needed to validate and better understand this finding.
In our study, participants were predominantly non-white, foreign-born workers (65% Asian). Symptom prevalence was not significantly different by either race/ethnicity or immigration status, but we found that symptom reporting to supervisors was significantly less among Asian workers than among non-Asian workers. As Asian workers are usually a small racial group in US studies, it is difficult to find a study to compare our findings. In a study of hotel room cleaners, Premji and Krause [2010] compared the prevalence of work-related pain and reporting to management by ethnicity and immigration status and found a significantly higher prevalence among Hispanic workers but no differences in pain reporting to management. Ethnic disparities in work-related injuries or pain have also been reported by other studies [Alterman, et al. 2008; Buchanan, et al. 2009, Friedman and Forst 2008, Tak, et al. 2010].
Our study has the following methodological strengths. We were able to increase the participation of immigrant workers by conducting the survey and interviews in three different languages. Also, two-thirds of the data were collected by in-person interview, and trained interviewers provided additional explanation as needed and improved data completeness. We, however, found a significant difference in symptom reporting between the two methods in further analysis [data not shown]: symptom cases were significantly more among interviewed subjects than among those who self-administered the questionnaire. This finding is different from other studies [Rhodes et al. 1995; Steketee et al. 1996], which observed greater reporting of urinary symptoms or obsessive compulsive symptoms in self-administered methods than in interviews. In another study of binge eating, the two methods showed the opposite direction in reporting depending on the subjects’ diagnosis [Birgegard et al. 2014]. Further evaluation is needed identify the impact of the methods on our study findings.
Our study has several limitations. First, causality cannot be established in the associations observed in this study due to the cross-sectional design. Second, our findings might have been affected by selection bias due to a low response rate (about 46%) and healthy worker survivor effect. The participants are not likely to be representative of all cleaning workers in the study setting. Female and Asian workers were overrepresented in the sample of hospital workers. Workers who experienced more severe symptoms or had low tolerance to chemical exposures might have left their job. Lower symptom prevalence rates among older workers may suggest healthy worker survivor bias, which leads to the underestimation of the true prevalence. Third, this study relied on self-reported data, which are subject to reporting bias from social desirability or recall bias. As for exposure to cleaning products, some researchers have reported underestimation by self-reports or differences between self-reports and job exposure matrix among general hospital workers [Delclos, et al. 2009, Donnay, et al. 2011]. Compared to general hospital workers, cleaning workers might be more knowledgeable about cleaning products as they currently use them for their main job activities. Therefore, recall bias in answering job activities and chemical exposure in usual work week may be of less concern in this study. For safe work practices and reported symptoms, we cannot exclude potential misclassification due to reporting bias. Our approach of defining cases as those who had symptoms at least monthly, however, may provide more conservative estimations in the examined associations. Fourth, the small sample size in this study limited the statistical power to detect true associations. Finally, our findings from the small convenience sample cannot be generalized to the cleaning worker population.
CONCLUSIONS
Work-related health symptoms can affect the well-being, work performance, and quality of work life of workers. Acute health problems associated with chemical exposure among cleaning workers have not been well described. This study identified that chemical-related symptoms of irritation were frequent among cleaning workers, especially hospital workers who clean patient areas. Use of PPE except for gloves was not part of regular safety practices among cleaning workers. The study findings suggest the need for interventions to reduce hazardous chemical exposure and indicate areas needed to be targeted for injury and illness prevention programs for cleaning workers. The US Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health [2013] recommend that occupational exposures and health risks from cleaning products should be reduced by selecting the least hazardous products, utilizing modern cleaning equipment that minimizes chemical use, maintaining and operating proper ventilation systems, complying with safe work practices and using adequate PPE. Future research studies employing longitudinal design, a larger sample size, objective exposure assessment and diaries of work activities and symptoms are suggested to better quantify the extent of chemical exposure and associated health effects. Furthermore, effective intervention programs should be developed and implemented to improve safe work practices and reduce adverse health outcomes for cleaning workers.
ACKNOWLEDGEMENT
This research was supported by the grants from the National Institute of Nursing Research (1P30NR011934–01). The authors thank Dr. M. Abbas Virji for inputs in the survey questionnaire development and managers of the hospital and campus cleaning service departments and data collectors for assistance and support.
Contract grant sponsor: National Institute of Nursing Research (1P30NR011934–01)
Footnotes
Disclosure Statement: The authors report no conflicts of interests.
REFERENCES
- Alamgir H, Yu S. 2008. Epidemiology of occupational injury among cleaners in the healthcare sector. Occup Med (Lond) 58: 393–399. [DOI] [PubMed] [Google Scholar]
- Alterman T, Steege AL, Li J, Petersen MR, Muntaner C. 2008. Ethnic, racial, and gender variations in health among farm operators in the United States. Ann Epidemiol 18:179–186. [DOI] [PubMed] [Google Scholar]
- Arif AA, Hughes PC, Delclos GL. 2008. Occupational exposures among domestic and industrial professional cleaners. Occup Med (Lond) 58: 458–463. [DOI] [PubMed] [Google Scholar]
- Barbosa RE, Assuncao AA, de Araujo TM. 2013. Musculoskeletal pain among healthcare workers: An exploratory study on gender differences. Am J Ind Med. doi: 10.1002/ajim.22215. [Epub ahead of print] [DOI] [PubMed]
- Barsky AJ, Peekna HM, Borus JF. 2001. Somatic symptom reporting in women and men. J Gen Intern Med 16: 266–275. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bello A, Quinn MM, Perry MJ, Milton DK. 2009. Characterization of occupational exposures to cleaning products used for common cleaning tasks--a pilot study of hospital cleaners. Environ Health 8: 11. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Birgegård A, Norring C, Clinton D. 2014. Binge eating in interview versus self-report: different diagnoses show different divergences. Eur Eat Disord Rev 22:170–175. [DOI] [PubMed] [Google Scholar]
- Brevard TA, Calvert GM, Blondell JM, Mehler LN. 2003. Acute occupational disinfectant-related illness among youth, 1993–1998. Environ Health Perspect 111:1654–1659. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Buchanan S, Vossenas P, Krause N, Moriarty J, Frumin E, Shimek JA, Mirer F, Orris P, Punnett L. 2009. Occupational injury disparities in the US hotel industry. Am J Ind Med 53: 116–125. [DOI] [PubMed] [Google Scholar]
- Bureau of Labor Statistics. 2010. Nonfatal occupational injrues and illnesses requiring days away from work, 2009. In: Department of Labor editor. Available: http://www.bls.gov/news.release/archives/osh2_11092010.pdf [accessed August 30 2013]. [Google Scholar]
- Callister LC, Khalaf I, Semenic S, Kartchner R, Vehvilainen-Julkunen K. 2003. The pain of childbirth: perceptions of culturally diverse women. Pain Manag Nurs 4: 145–154. [DOI] [PubMed] [Google Scholar]
- Cal/OSHA Consultation Service, California Department of Industrial Relations. 2005. Working safer and easier for janitors, custodians, and housekeepers. Available: https://www.dir.ca.gov/dosh/dosh_publications/Janitors.pdf [accessed August 30 2013].
- Centers for Disease Control and Prevention. 2010. Acute antimicrobial pesticide-related illnesses among workers in health-care facilities - California, Louisiana, Michigan, and Texas, 2002–2007. Morb Mortal Wkly Rep 59: 551–556. [PubMed] [Google Scholar]
- Charles LE, Loomis D, Demissie Z. 2009. Occupational hazards experienced by cleaning workers and janitors: A review of the epidemiologic literature. Work 34: 105–116. [DOI] [PubMed] [Google Scholar]
- Delclos GL, Gimeno D, Arif AA, Benavides FG, Zock JP. 2009. Occupational exposures and asthma in health-care workers: comparison of self-reports with a workplace-specific job exposure matrix. Am J Epidemiol 169: 581–587. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Donnay C, Denis MA, Magis R, Fevotte J, Massin N, Dumas O, Pin I, Choudat D, Kauffmann F, Le Moual N. 2011. Under-estimation of self-reported occupational exposure by questionnaire in hospital workers. Occup Environ Med 68: 611–617. [DOI] [PubMed] [Google Scholar]
- Friedman LS, Forst L. 2008. Ethnic disparities in traumatic occupational injury. J Occup Environ Med 50: 350–358. [DOI] [PubMed] [Google Scholar]
- Gawkrodger DJ, Lloyd MH, Hunter JA. 1986. Occupational skin disease in hospital cleaning and kitchen workers. Contact Dermatitis 15: 132–135. [DOI] [PubMed] [Google Scholar]
- Green Seal, Inc. 2012. GS-37 Green Seal™ standard for cleaning products for industrial and institutional use (6th ed.) Available: http://www.greenseal.org/Portals/0/Documents/Standards/GS-37/GS-37_Cleaning_Products_for_Industrial_and_Institutional_Use_Standard_Seventh_Edition.pdf [accessed August 30 2013]. [Google Scholar]
- Hansen KS. 1983. Occupational dermatoses in hospital cleaning women. Contact Dermatitis 9: 343–351. [DOI] [PubMed] [Google Scholar]
- Jaakkola JJ, Jaakkola MS. 2006. Professional cleaning and asthma. Curr Opin Allergy Clin Immunol 6: 85–90. [DOI] [PubMed] [Google Scholar]
- Karjalainen A, Martikainen R, Karjalainen J, Klaukka T, Kurppa K. 2002. Excess incidence of asthma among Finnish cleaners employed in different industries. Eur Respir J 19: 90–95. [DOI] [PubMed] [Google Scholar]
- Kasner EJ, Keralis JM, Mehler L, Beckman J, Bonnar-Prado J, Lee SJ, Diebolt-Brown B, Mulay P, Lackovic M, Waltz J, Schwartz A, Mitchell Y, Moraga-McHaley S, Roisman R, Gergely R, Calvert GM. 2012. Gender differences in acute pesticide-related illnesses and injuries among farmworkers in the United States, 1998–2007. Am J Ind Med 55:571–583. [DOI] [PubMed] [Google Scholar]
- Lombardi DA, Verma SK, Brennan MJ, Perry MJ. 2009. Factors influencing worker use of personal protective eyewear. Accid Anal Prev 41: 755–762. [DOI] [PubMed] [Google Scholar]
- Lynde CB, Obadia M, Liss GM, Ribeiro M, Holness DL, Tarlo SM. 2009. Cutaneous and respiratory symptoms among professional cleaners. Occup Med (Lond) 59: 249–254. [DOI] [PubMed] [Google Scholar]
- Nielsen J, Bach E. 1999. Work-related eye symptoms and respiratory symptoms in female cleaners. Occup Med (Lond) 49: 291–297. [DOI] [PubMed] [Google Scholar]
- Occupational Safety and Health Administration, National Institute for Occupational Safety and Health. 2013. Protecting workers who use cleaning chemicals. Available: http://www.cdc.gov/niosh/docs/2012-126/pdfs/2012-126.pdf [accessed August 30 2013].
- Premji S, Krause N. 2010. Disparities by ethnicity, language, and immigrant status in occupational health experiences among Las Vegas hotel room cleaners. Am J Ind Med 53: 960–975. [DOI] [PubMed] [Google Scholar]
- Rahim-Williams B, Riley JL, 3rd, Williams AK, Fillingim RB. 2012. A quantitative review of ethnic group differences in experimental pain response: do biology, psychology, and culture matter? Pain Med 13: 522–540. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Reinisch F, Harrison RJ, Cussler S, Athanasoulis M, Balmes J, Blanc P, Cone J. 2001. Physician reports of work-related asthma in California, 1993–1996. Am J Ind Med 39: 72–83. [DOI] [PubMed] [Google Scholar]
- Rhodes T, Girman CJ, Jacobsen SJ, Guess HA, Hanson KA, Oesterling JE, Lieber MM. 1995. Does the mode of questionnaire administration affect the reporting of urinary symptoms? Urology 46:341–345. [DOI] [PubMed] [Google Scholar]
- Rosenman KD, Reilly MJ, Schill DP, Valiante D, Flattery J, Harrison R, Reinisch F, Pechter E, Davis L, Tumpowsky CM, Filios M. 2003. Cleaning products and work-related asthma. J Occup Environ Med 45: 556–563. [DOI] [PubMed] [Google Scholar]
- Sarri C, Eng E, Runyan C. 1991. Injuries among medical laboratory housekeeping staff: incidence and worker perceptions. J Occup Med 33: 52–56. [DOI] [PubMed] [Google Scholar]
- Steketee G, Frost R, Bogart K. 1996. The Yale-Brown Obsessive Compulsive Scale: interview versus self-report. Behav Res Ther 34:675–684. [DOI] [PubMed] [Google Scholar]
- Tak S, Alterman T, Baron S, Calvert GM. 2010. Racial and ethnic disparities in work-related injuries and socio-economic resources among nursing assistants employed in US nursing homes. Am J Ind Med 53: 951–959. [DOI] [PubMed] [Google Scholar]
- Vizcaya D, Mirabelli MC, Anto JM, Orriols R, Burgos F, Arjona L, Zock JP. 2011. A workforce-based study of occupational exposures and asthma symptoms in cleaning workers. Occup Environ Med 68: 914–919. [DOI] [PubMed] [Google Scholar]
- Weaver VM, McDiarmid MA, Guidera JA, Humphrey FE, Schaefer JA. 1993. Occupational chemical exposures in an academic medical center. J Occup Med 35: 701–706. [DOI] [PubMed] [Google Scholar]
- Wolkoff P, Schneider T, Kildeso J, Degerth R, Jaroszewski M, Schunk H. 1998. Risk in cleaning: chemical and physical exposure. Sci Total Environ 215: 135–156. [DOI] [PubMed] [Google Scholar]
- Zock JP. 2005. World at work: cleaners. Occup Environ Med 62: 581–584. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zock JP, Kogevinas M, Sunyer J, Almar E, Muniozguren N, Payo F, Sanchez JL, Anto JM. 2001. Asthma risk, cleaning activities and use of specific cleaning products among Spanish indoor cleaners. Scand J Work Environ Health 27: 76–81. [DOI] [PubMed] [Google Scholar]
- Zock JP, Plana E, Jarvis D, Anto JM, Kromhout H, Kennedy SM, Kunzli N, Villani S, Olivieri M, Toren K, Radon K, Sunyer J, Dahlman-Hoglund A, Norback D, Kogevinas M. 2007. The use of household cleaning sprays and adult asthma: an international longitudinal study. Am J Respir Crit Care Med 176: 735–741. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zock JP, Vizcaya D, Le Moual N. 2010. Update on asthma and cleaners. Curr Opin Allergy Clin Immunol 10: 114–120. [DOI] [PMC free article] [PubMed] [Google Scholar]