Objective: This study examined the relationship between the physical work environment and work functioning impairment while working from home in the context of rapid changes associated with the COVID-19 pandemic. Methods: This cross-sectional study of internet monitors was conducted between December 22 and 26, 2020. Of a total of 33,302 participants, 5,760 who worked from home at least 1 day a month, excluding those who met the exclusion criteria, were included in the analysis. A binary

more »

... ve assessment of the physical work environment while working from home was used as an exposure factor. We examined 9 items related to the physical work environment, including level of illuminance and use of suitable desks and chairs, traditionally recommended for health and safety management when working at a desk. The number of non-conformities to 7 items was also used as an exposure factor. The presence of severe work functioning impairment was measured using the Work Functioning impairment Scale (WFun), a self-reported outcome measure of the degree of work functioning impairment. Odds ratios of severe work functioning impairment were estimated using mixed-effects logistic regression analysis with the prefecture of residence as a random effect. Results: Multivariate analysis showed that the odds ratio of severe work functioning impairment was significantly higher among those who indicated "No" to all recommended items except for "I work at a desk/chair for office use." The highest odds ratio of work functioning impairment was associated with a "No" response to "There is enough light to do my work" (aOR: 2.02, 95%CI: 1.73-2.35, p<0.01). Our results also suggest the presence of a dose-response relationship between the number of non-conformities to recommendations for work environments while working from home and work functioning impairment. Conclusions: Our findings suggest that it is important for both companies and individual workers to create a work environment that prevents negative health outcomes and improves productivity while working from home.