Xiaoming Liang

The Validation of Work-related Self-reported Asthma Exacerbation

Objective: To determine the validity of work-related self-reported exacerbation of asthma using the findings from serial peak expiratory flow (PEF) measurements as the standard. Methods: Adults with asthma treated in a health maintenance organisation were asked to conduct serial spirometry testing at home and at work for 3 weeks. Self-reported respiratory symptoms and medication use were recorded in two ways: a daily log completed concurrently with the serial PEF testing and a telephone questionnaire administered after the PEF testing. Three researchers evaluated the serial PEF records and judged whether a work relationship was evident. Results: 95 of 382 (25%) working adults with asthma provided adequate serial PEF data, and 13 of 95 (14%) were judged to have workplace exacerbation of asthma (WEA) based on these data. Self-reported concurrent medication use was the most valid single operational definition, with a sensitivity of 62% and a specificity of 65%. Conclusions: A work-related pattern of self-reported asthma symptoms or medication use was usually not corroborated by serial PEF testing and failed to identify many people who had evidence of WEA based on the serial PEF measurements.

Characterization of cleaning and disinfecting tasks and product use among hospital occupations

BACKGROUND Healthcare workers have an elevated prevalence of asthma and related symptoms associated with the use of cleaning/disinfecting products. The objective of this study was to identify and characterize cleaning/disinfecting tasks and products used among hospital occupations. METHODS Workers from 14 occupations at five hospitals were monitored for 216 shifts, and work tasks and products used were recorded at five-minute intervals. The major chemical constituents of each product were identified from safety data sheets. RESULTS Cleaning and disinfecting tasks were performed with a high frequency at least once per shift in many occupations. Medical equipment preparers, housekeepers, floor strippers/waxers, and endoscopy technicians spent on average 108-177 min/shift performing cleaning/disinfecting tasks. Many occupations used products containing amines and quaternary ammonium compounds for >100 min/shift. CONCLUSIONS This analysis demonstrates that many occupations besides housekeeping incur exposures to cleaning/disinfecting products, albeit for different durations and using products containing different chemicals.

A Comparison of Work-Exacerbated Asthma Cases from Clinical and Epidemiological Settings

BACKGROUND Clinical and epidemiological studies commonly use different case definitions in different settings when investigating work-exacerbated asthma (WEA). These differences are likely to impact characteristics of the resulting WEA cases. OBJECTIVES To investigate this issue by comparing two groups of WEA cases, one identified using an intensive clinical evaluation and another that fulfilled epidemiological criteria. METHODS A total of 53 clinical WEA cases had been referred for suspected work-related asthma to two tertiary clinics in Canada, where patients completed tests that confirmed asthma and ruled out asthma caused by work. Forty-seven epidemiological WEA cases were employed asthma patients treated at a health maintenance organization in the United States who completed a questionnaire and spirometry, and fulfilled criteria for WEA based on self-reported, work-related worsening of asthma and relevant workplace exposures as judged by an expert panel. RESULTS Using different case criteria in different settings resulted in case groups that had a mix of similarities and differences. The clinical WEA cases were more likely to have visited a doctors office ≥3 times for asthma in the past year (75% versus 11%; P<0.0001), but did not seek more asthma-related emergency or in-patient care, or have lower spirometry values. The two groups differed substantially according to the industries and occupations where the cases worked. CONCLUSIONS Findings from both types of studies should be considered when measuring the contribution of work to asthma exacerbations, identifying putative agents, and selecting industries and occupations in which to implement screening and surveillance programs.

Occupational Exposure to Vapor-Gas, Dust, and Fumes in a Cohort of Rural Adults in Iowa Compared with a Cohort of Urban Adults

Problem/Condition Many rural residents work in the field of agriculture; however, employment in nonagricultural jobs also is common. Because previous studies in rural communities often have focused on agricultural workers, much less is known about the occupational exposures in other types of jobs in rural settings. Characterizing airborne occupational exposures that can contribute to respiratory diseases is important so that differences between rural and urban working populations can be assessed. Reporting Period 1994–2011. Description of System This investigation used data from the baseline questionnaire completed by adult rural residents participating in the Keokuk County Rural Health Study (KCRHS). The distribution of jobs and occupational exposures to vapor-gas, dust, and fumes (VGDF) among all participants was analyzed and stratified by farming status (current, former, and never) then compared with a cohort of urban workers from the Multi-Ethnic Study of Atherosclerosis (MESA). Occupational exposure in the last job was assessed with a job-exposure matrix (JEM) developed for chronic obstructive pulmonary disease (COPD). The COPD JEM assesses VGDF exposure at levels of none or low, medium, and high. Results The 1,699 KCRHS (rural) participants were more likely to have medium or high occupational VGDF exposure (43.2%) at their last job than their urban MESA counterparts (15.0% of 3,667 participants). One fifth (20.8%) of the rural participants currently farmed, 43.1% were former farmers, and approximately one third (36.1%) had never farmed. These three farming groups differed in VGDF exposure at the last job, with the prevalence of medium or high exposure at 80.2% for current farmers, 38.7% for former farmers, and 27.4% for never farmers, and all three percentages were higher than the 15.0% medium or high level of VGDF exposure for urban workers. Interpretation Rural workers, including those who had never farmed, were more likely to experience occupational VGDF exposure than urban workers. Public Health Action The occupational exposures of rural adults assessed using the COPD JEM will be used to investigate their potential association with obstructive respiratory health problems (e.g., airflow limitation and chronic bronchitis). This assessment might highlight occupations in need of preventive interventions.

Occupation and task as risk factors for asthma-related outcomes among healthcare workers in New York City

BACKGROUND Previous studies have suggested an association of asthma onset and exacerbation with cleaning and disinfecting activities in a number of industries, including healthcare. The objective of the current study was to investigate the association of asthma and related outcomes with occupations and tasks in urban healthcare workers in the United States. METHODS A questionnaire was implemented in a sample of workers from nine healthcare occupations in New York City. We used regression models to examine the association of post-hire asthma, current asthma, exacerbation of asthma, a symptom algorithm for bronchial hyper-responsiveness (BHR-related symptoms), a symptom-based asthma score, and the symptom wheeze with occupation and four healthcare tasks, while adjusting for other risk factors and potential confounders. RESULTS A total of 2030 participants completed the questionnaire. The task of cleaning fixed surfaces was significantly associated with most outcome variables, including current asthma (odds ratio (OR) = 1.84, 95% confidence interval (CI) 1.26-2.68), moderate exacerbation (OR = 3.10, 95% CI 1.25-7.67), and BHR-related symptoms (OR = 1.38, 95% CI 1.08-1.77). In comparison to nursing assistants, the occupations environmental service workers and registered nurses were at higher risk for current asthma, and licensed practical nurses were at higher risk for moderate exacerbation. Other tasks associated with outcomes were administering aerosolized medications with current asthma and moderate exacerbation, and sterilizing medical equipment with BHR-related symptoms. CONCLUSIONS These findings add to the growing body of evidence for the association of asthma with cleaning and other activities in healthcare. Further research is especially needed to investigate the association of asthma-related outcomes with exposure metrics based on tasks, products, and chemical exposures in healthcare.

0108 Characterisation of Wet Work and Glove Use in Healthcare Occupations

Objectives Wet work (contact and/or use of liquids) could lead to skin exposures to chemical irritants and sensitizers among healthcare workers. The objective of this study was to characterise the frequency and duration of glove use when wet work was performed by healthcare workers. Method Direct observational studies were conducted from 2009 to 2011 at five hospitals on selected healthcare occupations. Information on tasks, chemical product use, and glove use was collected at five-minute intervals by trained research technicians using a standardised data collection form. Results Between five and 51 person-days were observed for each occupation. Any glove use during wet work ranged from 62% to 100% of person-days for occupations with more than 10 person-days observed. Endoscopy technicians had the highest proportion of time of glove use when wet work was observed (1845/2055 min = 90%), followed by medical equipment preparers, dental assistants, and housekeepers (1645/1950 min = 84%, 315/395 min = 80%, and 6090/7720 min = 79% respectively). Floor strippers/waxers (585/1225 min = 48%), respiratory therapists (65/160 min = 41%), and clinical laboratory technicians (10/60 min = 17%) had lower proportions of time of glove use. When a sensitizer was used during wet work, the proportion of time of glove use increased among all healthcare occupations with adequate data. Conclusions This analysis demonstrates that the duration of wet work and glove use vary by healthcare occupation. This assessment will be valuable for developing health and safety training programs and identifying possible avenues for intervention.