Statistical analysis
Allocation-adjustment factors were age, sex, egg consumption, plasma free choline level, Cognitrax short version total and verbal memory scores, MMSE-J score, and GDS-S-J score. The reason why the verbal memory score was added to the adjustment factor is that the function was confirmed by previous research [The test results are presented as the mean ± standard error of the amount of change. The statistical significance level was set at 