Data analysis
The chi-square test was used to analyze the differences in paternal perinatal depression and independent variables, including the stages of COVID-19 epidemic, family function, demographic variables (age, ethnicity, education, Hukou, family income, insurance, and first-time father), and health behaviour factors (sleep quality, smoking, drinking, and exercise). Multiple logistic regression analyses were used to evaluate the effects of the independent variables on paternal perinatal depression. Model 1 only included the periods of COVID-19 epidemic and family function. Model 2 included demographic variables on the basis of model 1. Model 3 included health behaviour factors on the bases of model 2. The results of multiple logistic regression analyses are reported as adjusted odds ratios (OR) and 95% confidence intervals (CI). All tests were two-sided and p-values less than 0.05 were considered statistically significant. Statistical analyses were performed using SAS 9.4 for Windows.