The threat of age discrimination against American workers seems to peak about age 50 and then again when workers near retirement age, according to a new study of validated discrimination claims.

The first spike of age discrimination claims seems to hit just when workers are entering their prime earning years and their salaries are increasing the most, said Vincent Roscigno, co-author of the study and professor of sociology at Ohio State University. The other spike comes when workers are just about ready to retire and may be eligible for pensions.