Study population and data collection
Epidemiological Study on the Risk of Asthma in Cleaning Workers 2 (EPIASLI2) was a
two-stage epidemiological study conducted to assess associations between cleaning work,
including specific worksites and exposures to cleaning products, and dermatological and
respiratory health symptoms (9). The study methods have been described previously (9).
Summarized briefly, between February and December 2008, 4 993 self-administered, paperand-
pencil-style questionnaires were distributed to employees of 37 cleaning companies
operating in the province of Barcelona, Spain. Nine hundred and fifty questionnaires were
returned by mail; of those, 132 (14%) were excluded because they were incomplete or
lacked responses to key questionnaire items and the remaining 818 respondents constituted