Maria C. Mirabelli

Exposure to substances in the workplace and new-onset asthma: an international prospective population-based study (ECRHS-II)

BACKGROUNDnThe role of exposure to substances in the workplace in new-onset asthma is not well characterised in population-based studies. We therefore aimed to estimate the relative and attributable risks of new-onset asthma in relation to occupations, work-related exposures, and inhalation accidents.nnnMETHODSnWe studied prospectively 6837 participants from 13 countries who previously took part in the European Community Respiratory Health Survey (1990-95) and did not report respiratory symptoms or a history of asthma at the time of the first study. Asthma was assessed by methacholine challenge test and by questionnaire data on asthma symptoms. Exposures were defined by high-risk occupations, an asthma-specific job exposure matrix with additional expert judgment, and through self-report of acute inhalation events. Relative risks for new onset asthma were calculated with log-binomial models adjusted for age, sex, smoking, and study centre.nnnFINDINGSnA significant excess asthma risk was seen after exposure to substances known to cause occupational asthma (Relative risk=1.6, 95% CI 1.1-2.3, p=0.017). Risks were highest for asthma defined by bronchial hyper-reactivity in addition to symptoms (2.4, 1.3-4.6, p=0.008). Of common occupations, a significant excess risk of asthma was seen for nursing (2.2, 1.3-4.0, p=0.007). Asthma risk was also increased in participants who reported an acute symptomatic inhalation event such as fire, mixing cleaning products, or chemical spills (RR=3.3, 95% CI 1.0-11.1, p=0.051). The population-attributable risk for adult asthma due to occupational exposures ranged from 10% to 25%, equivalent to an incidence of new-onset occupational asthma of 250-300 cases per million people per year.nnnINTERPRETATIONnOccupational exposures account for a substantial proportion of adult asthma incidence. The increased risk of asthma after inhalation accidents suggests that workers who have such accidents should be monitored closely.

Occupational risk factors for asthma among nurses and related healthcare professionals in an international study

Objective: The authors examined the relations between self-reported work tasks, use of cleaning products and latex glove use with new-onset asthma among nurses and other healthcare workers in the European Community Respiratory Health Survey (ECRHS II). Methods: In a random population sample of adults from 22 European sites, 332 participants reported working in nursing and other related healthcare jobs during the nine-year ECRHS II follow-up period and responded to a supplemental questionnaire about their principal work settings, occupational tasks, products used at work and respiratory symptoms. Poisson regression models with robust error variances were used to compare the risk of new-onset asthma among healthcare workers with each exposure to that of respondents who reported professional or administrative occupations during the entire follow-up period (nu200a=u200a2481). Results: Twenty (6%) healthcare workers and 131 (5%) members of the referent population reported new-onset asthma. Compared to the referent group, the authors observed increased risks among hospital technicians (RR 4.63; 95% CI 1.87 to 11.5) and among those using ammonia and/or bleach at work (RR 2.16; 95% CI 1.03 to 4.53). Conclusions: In the ECRHS II cohort, hospital technicians and other healthcare workers experience increased risks of new-onset current asthma, possibly due to specific products used at work.

A workforce-based study of occupational exposures and asthma symptoms in cleaning workers

Objectives To study associations between use of cleaning products and asthma symptoms in cleaning workers. Methods Information on respiratory symptoms, history of asthma, workplaces, use of cleaning products and acute inhalation incidents were obtained through a self-administered questionnaire. 917 employees of 37 cleaning companies in Barcelona were studied. 761 (83%) were current cleaners, 86 (9%) former cleaners and 70 (8%) had never worked as cleaners. Multivariable logistic regression analyses were used to evaluate the associations between specific exposures among current cleaners and wheeze without having a cold, chronic cough and current asthma. Associations with an asthma symptom score were also studied using negative binomial regression analyses to report mean ratios. Results After adjusting for sex, age, nationality and smoking status, the prevalence of current asthma was non-significantly higher among current (OR 1.9; 95% CI 0.5 to 7.8) and former cleaners (OR 1.9; CI 0.6 to 5.5) than in never cleaners. Cleaners working in hospitals during the last year had a significantly increased prevalence of wheeze, current asthma and a 1.8 (95% CI 1.2 to 2.8) times higher mean asthma score. Use of hydrochloric acid was strongly associated with asthma score (mean ratio 1.7; 95% CI 1.1 to 2.6). Use of ammonia, degreasers, multiple purpose products and waxes was also associated with asthma score. Conclusions Cleaning work in places with high demand for disinfection, high cleaning standards and use of cleaning products containing respiratory irritants is associated with higher risk of asthma symptoms. This suggests irritants have an important role in cleaning-related asthma.

Domestic use of hypochlorite bleach, atopic sensitization, and respiratory symptoms in adults

BACKGROUNDnProfessional use of hypochlorite (bleach) has been associated with respiratory symptoms. Bleach is capable of inactivating allergens, and there are indications that its domestic use may reduce the risk of allergies in children.nnnOBJECTIVEnTo study the associations between household use of bleach and atopic sensitization, allergic diseases, and respiratory health status in adults.nnnMETHODSnWe identified 3626 participants of the European Community Respiratory Health Survey II in 10 countries who did the cleaning in their homes and for whom data on specific serum IgE to 4 environmental allergens were available. Frequency of bleach use and information on respiratory symptoms were obtained in face-to-face interviews. House dust mite and cat allergens in mattress dust were measured in a subsample. Associations between the frequency of bleach use and health outcomes were evaluated by using multivariable mixed logistic regression analyses.nnnRESULTSnThe use of bleach was associated with less atopic sensitization (odds ratio [OR], 0.75; 95% CI, 0.63-0.89). This association was apparent for specific IgE to both indoor (cat) and outdoor (grass) allergens, and was consistent in various subgroups, including those without any history of respiratory problems (OR, 0.85). Dose-response relationships (P < .05) were apparent for the frequency of bleach use and sensitization rates. Lower respiratory tract symptoms, but not allergic symptoms, were more prevalent among those using bleach 4 or more days per week (OR, 1.24-1.49). The use of bleach was not associated with indoor allergen concentrations.nnnCONCLUSIONnPeople who clean their homes with hypochlorite bleach are less likely to be atopic but more likely to have respiratory symptoms.

The occupational contribution to severe exacerbation of asthma.

The goal of this study was to identify occupational risk factors for severe exacerbation of asthma and estimate the extent to which occupation contributes to these events. The 966 participants were working adults with current asthma who participated in the follow-up phase of the European Community Respiratory Health Survey. Severe exacerbation of asthma was defined as self-reported unplanned care for asthma in the past 12 months. Occupations held in the same period were combined with a general population job-exposure matrix to assess occupational exposures. 74 participants reported having had at least one severe exacerbation event, for a 1-yr cumulative incidence of 7.7%. From regression models that controlled for confounders, the relative risk (RR) was statistically significant for low (RR 1.7, 95% CI 1.1–2.6) and high (RR 3.6, 95% CI 2.2–5.8) biological dust exposure, high mineral dust exposure (RR 1.8, 95% CI 1.02–3.2), and high gas and fumes exposure (RR 2.5, 95% CI 1.2–5.5). The summary category of high dust, gas, or fumes exposure had RR 3.1 (95% CI 1.9–5.1). Based on this RR, the population attributable risk was 14.7% among workers with current asthma. These results suggest occupation contributes to approximately one in seven cases of severe exacerbation of asthma in a working population, and various agents play a role.

Occupational exposure to chlorophenol and the risk of nasal and nasopharyngeal cancers among U.S. men aged 30 to 60

BACKGROUNDnElevated rates of nasal and nasopharyngeal cancers have been associated with wood-related occupational exposures, including chlorophenols, formaldehyde, and wood dust.nnnMETHODSnOccupational information was obtained from 43 nasal carcinoma cases, 92 nasopharyngeal carcinoma cases, and 1909 controls, by interview. Exact conditional logistic regression was used to evaluate the association of these cancers with chlorophenol exposure, estimated from a review of verbatim responses.nnnRESULTSnBoth nasal and nasopharyngeal cancers were significantly associated with estimated duration of chlorophenol exposure. For nasopharyngeal cancer, elevated risk was observed among those who held jobs assigned medium or high intensity chlorophenol exposure (n(exposed)=18, OR=1.94, 95% CI=1.03-3.50) and among those with 10+ years in jobs assigned high intensity with high certainty (n(exposed)=3, OR=9.07, 95% CI=1.41-42. 9). Controlling for estimated formaldehyde and wood dust exposure did not alter these findings, as much of the estimated chlorophenol exposure was among machinists.nnnCONCLUSIONSnThese findings support the hypothesis that occupational exposure to chlorophenol is a risk factor for nasal and nasopharyngeal cancer, although the role of machining-related exposures warrants further assessment.

Occupational exposures and uncontrolled adult-onset asthma in the European Community Respiratory Health Survey II

Occupational exposure is a well-recognised modifiable risk factor for asthma, but the relationship between occupational exposure and asthma control has not been studied. We aimed to study this association among working-age adults from the European Community Respiratory Health Survey (ECRHS). Data were available for 7077 participants (mean age 43 years, 45% never-smokers, 5867 without asthma and 1210 with current asthma). Associations between occupational exposure to specific asthmagens and asthma control status (33% with uncontrolled asthma, based on the Global Initiative for Asthma guidelines) were evaluated using logistic and multinomial regressions, adjusted for age, sex and smoking status, with study areas included as a random effect. Statistically significant positive associations were observed between uncontrolled adult-onset asthma and both past 12-month and 10-year exposure to any occupational asthmagens (OR (95% CI) 1.6 (1.0–2.40) and 1.7 (1.2–2.5), respectively); high (1.7 (1.0–2.8) and 1.9 (1.3–2.9), respectively) and low (1.6 (1.0–2.7) and 1.8 (1.2–2.7), respectively) molecular weight agents; and cleaning agents (2.0 (1.1–3.6) and 2.3 (1.4–3.6), respectively), with stronger associations for long-term exposures. These associations were mainly explained by the exacerbation domain of asthma control and no associations were observed between asthmagens and partly controlled asthma. These findings suggest that occupational exposure to asthmagens is associated with uncontrolled adult-onset asthma. Occupational risk factors should be quickly identified to prevent uncontrolled asthma. Occupational exposure to asthmagens is associated with uncontrolled adult-onset asthma in ECRHS II http://ow.ly/reN8g

Respiratory symptoms following wildfire smoke exposure: airway size as a susceptibility factor.

Background: Associations between exposure to smoke during wildfire events and respiratory symptoms are well documented, but the role of airway size remains unclear. We conducted this analysis to assess whether small airway size modifies these relationships. Methods: We analyzed data from 465 nonasthmatic 16- to 19-year-old participants in the Childrens Health Study. Following an outbreak of wildfires in 2003, each student completed a questionnaire about smoke exposure, dry and wet cough, wheezing, and eye symptoms. We used log-binomial regression to evaluate associations between smoke exposure and fire-related health symptoms, and to assess modification of the associations by airway size. As a marker of airway size, we used the ratio of maximum midexpiratory flow to forced vital capacity. Results: Forty percent (186 of 465) of this population (including students from 11 of 12 surveyed communities) reported the odor of wildfire smoke at home. We observed increased respiratory and eye symptoms with increasing frequency of wildfire smoke exposure. Associations between smoke exposure and having any of 4 respiratory symptoms were stronger in the lowest quartile of the lung function ratio (eg, fire smoke 6+ days: prevalence ratio: 3.8; 95% confidence interval (CI = 2.0–7.2), compared with the remaining quartiles (fire smoke 6+ days: prevalence ratio = 2.0; 1.2–3.2). Analysis of individual symptoms suggests that this interaction may be strongest for effects on wheezing. Conclusions: Small airways may serve as a marker of susceptibility to effects of wildfire smoke. Future studies should investigate the role of airway size for more common exposures and should include persons with asthma.

Healthy hire effect, job selection and inhalation exposure among young adults with asthma

The aim of the present study was to assess whether asthma onset prior to entering the workforce influences whether a person holds a subsequent job with asthma-related inhalation exposures. The data of 19,784 adults from the European Community Respiratory Health Survey were analysed. For each respondent, a current or previously held job was linked to a job exposure matrix assigning high, low or no exposure to dust, gases or fumes. Jobs were also categorised according to the risk of exposures related to occupational asthma. Associations between asthma and subsequent occupational exposures were assessed using logistic regression models, with a random intercept for study centre and fixed adjustment for age, sex, type of study sample and smoking status. Of the respondents, 8% (n = 1,619) reported asthma with onset before completion of full-time education. This population was at decreased risk of having a job with high (odds ratio 0.79; 95% confidence interval 0.68–0.92) or low (0.91; 0.80–1.03) exposure to dust, gases or fumes. The associations were consistent across exposure types (dusts, gases or fumes) and for jobs with a high risk of occupational asthma. Adults with asthma onset prior to entering the workforce may be less likely to hold jobs involving inhalation exposures.

Cleaning products and short-term respiratory effects among female cleaners with asthma.

Objective We evaluated the short-term effects of exposure to cleaning products on lung function and respiratory symptoms among professional cleaning women. Methods Twenty-one women with current asthma and employed as professional cleaners participated in a 15-day panel study. During 312 person-days of data collection, participants self-reported their use of cleaning products and respiratory symptoms in daily diaries and recorded their forced expiratory volume in 1u2005s (FEV1) and peak expiratory flow (PEF) three times per day using a handheld spirometer. We evaluated associations of cleaning product use with upper and lower respiratory tract symptoms using Poisson mixed regression models and with changes in FEV1 and PEF using linear mixed regression analyses. Results Participants reported using an average of 2.4 cleaning products per day, with exposure to at least one strong irritant (eg, ammonia, bleach, hydrochloric acid) on 56% of person-days. Among participants without atopy, lower respiratory tract symptoms were associated with the use of hydrochloric acid and detergents. Measurements of FEV1 and PEF taken in the evening were 174u2005mL (95% CI 34 to 314) and 37u2005L/min (CI 4 to 70), respectively, lower on days when three or more sprays were used. Evening and next morning FEV1 were both lower following the use of hydrochloric acid (−616 and −526u2005mL, respectively) and solvents (−751 and −1059u2005mL, respectively). Diurnal variation in FEV1 and PEF increased on days when ammonia and lime-scale removers were used. Conclusions The use of specific cleaning products at work, mainly irritants and sprays, may exacerbate asthma.