Non-specific building-related symptoms (NBRSs) describe various symptoms in those affected. Questionnaires are the first step in investigating suspected NBRSs in office environments and have been used for over two decades. However, changes in reporting of symptoms among office workers over time are currently unknown. The overall aim was thus to investigate if reported symptoms and perceived causality to the office environment have changed during 25 years of using the MM 040 NA Office questionnaire. A cross-sectional study of 26,477 questionnaires from 1995-2020 was conducted, where 12 symptoms and perceived causality to office environment were examined using logistic regression analyses of 5-year groups adjusted for sex and atopy. Reporting trends in the year groups varied slightly among symptoms, but eight symptoms were statistically significant in the 2015-2020 group compared to the 1995-1999 group. Seven symptoms had increased: fatigue, heavy-feeling head, headache, difficulties concentrating, itchy/irritated eyes, congested/runny nose, and dry/red hands. One symptom decreased: hoarseness/dry throat. Perceived causality of symptoms to the office environment decreased to a statistically significant degree in 2015-2020 for 11 symptoms, and there was an overall trend of decreasing perceived causality throughout the year groups for most symptoms. The observed time trends suggest a need for up-to-date reference data, to keep up with changes in symptom reporting in office environments over time.
Keywords: indoor work environment; non-specific building-related symptoms; occupational medicine; office worker; sick building syndrome.