SERPINF1 and Alzheimer disease: To evaluate the relevance of PEDF on AD, we first tested serum samples of 31 AD patients (50–91 years old; average = 70 years old) and 271 normal controls (the youth group: 25–45 years old, N = 121; the middle-aged group: 46–60 years old, N = 95; and the old-aged group: > 60 years old, N = 55).