Wearing face masks in public during the influenza season may reflect other positive hygiene practices in Japan

Background: Although the wearing of face masks in public has not been recommended for preventing influenza, these devices are often worn in many Asian countries during the influenza season. In Japan, it is thought that such behavior may be an indicator of other positive hygiene practices. The aim of this study, therefore, was to determine if wearing a face mask in public is associated with other positive hygiene practices and health behaviors among Japanese adults. Methods: We initially recruited around 3,000 Japanese individuals ranging from 20 to 69 years of age who were registered with a web survey company. Participants were asked to recall their personal hygiene practices during the influenza season of the previous year. Logistic regression analysis was then used to examine the associations between wearing a face mask in public and personal hygiene practices and health behaviors. Results: A total of 3,129 persons responded to the survey, among whom 38% reported that they had worn a face mask in public during the previous influenza season. Wearing a face mask in public was associated with various self-reported hygiene practices including: frequent hand washing (adjusted Odds Ratio [OR]: 1.67; 95% Confidence Interval [95% CI]: 1.34-1.96), occasional hand washing (OR: 1.43; 95% CI: 1.10-1.75), frequently avoiding crowds (OR: 1.85; 95% CI: 1.70-1.98), occasionally avoiding crowds (OR: 1.65; 95% CI: 1.53-1.76), frequent gargling (OR: 1.68; 95% CI: 1.51-1.84), occasional gargling (OR: 1.46; 95% CI: 1.29-1.62), regularly avoiding close contact with an infected person (OR: 1.50; 95% CI: 1.33-1.67), occasionally avoiding close contact with an infected person (OR: 1.31; 95% CI: 1.16-1.46), and being vaccinated of influenza in the last season (OR: 1.31; 95% CI: 1.17-1.45). Conclusions: Overall, this study suggests that wearing a face mask in public may be associated with other personal hygiene practices and health behaviors among Japanese adults. Rather than preventing influenza itself, face mask use might instead be a marker of additional, positive hygiene practices and other favorable health behaviors in the same individuals.