Association between years with incidence of communicable diseases focused on COVID-19 and hand hygiene among adults in South Korea: a cross-sectional study

Background: Handwashing is important considering the impact of communicable diseases on the public. We aimed to identify the association between years with incidence of communicable diseases during the coronavirus disease 2019 (COVID-19) pandemic and hand hygiene in South Korea. Methods: This cross-sectional study evaluated 5 years (2013, 2015, 2017, 2019, and 2020) of data from the Korea Community Health Survey and included 1,034,422 adults. Multinomial logistic regression analysis was performed to assess handwashing frequency by year. Receiver operating characteristic analysis was used to determine the cut-off point for handwashing frequency. Results: The always/frequently handwashing rate was 44.7%. This tendency was stronger in adults with each ascending year, with reference to 2013 (2015, odds ratio [OR] = 1.10, 95% confidence interval [CI] = 1.08, 1.13; 2017, OR = 1.10, 95% CI = 1.08, 1.13; 2019, OR = 1.17, 95% CI = 1.14, 1.20; 2020, OR = 3.21, 95% CI = 3.14, 3.29). Among women, the OR of frequently/always handwashing was 3.55 times higher (95% CI = 3.45, 3.66) in 2020 than in 2013. This OR was 2.95 among men (95% CI = 2.86, 3.04). In influenza-vaccinated participants, the OR of frequent/always handwashing was 3.25 times higher in 2020 than in 2013 (95% CI = 3.15, 3.36), while in non-vaccinated participants it was 3.17 (95% CI = 3.08, 3.27). Among adults who practiced physical distancing during the COVID-19 pandemic, the OR was 1.36 times higher (95% CI = 1.29, 1.42) with frequent handwashing, 1.64 times higher (95% CI = 1.57, 1.70) than those who did not practice it. Conclusions: There was a strong tendency toward frequent handwashing over the years; the trend was even greater in 2020 during the COVID-19 pandemic. Given that communicable diseases and handwashing are closely related, it is necessary to promote hand hygiene for prevention.