Table 1 Baseline characteristics of the AREDS and AREDS2 cohorts
AREDSAREDS2P Valuea
Subject-level variables
 Number of subjectsN = 2721N = 1700
 Age
  Mean (SD)68.7 (4.9)71.5 (7.7)8.0 × 10−43
  Median (range)68.5 (55.3–81.2)73 (50–86)
 Sex (n, %)
  Female1527 (56)997 (59)0.11
  Male1194 (44)703 (41)
 Education
  ≤High school906 (33)485 (29)3.0 × 10−3
  >High school1814 (67)1189 (70)
  Missing1 (0)28 (2)
 Smoking (n, %)
  Never smoked1272 (47)739 (43)0.08
  Former smoker1288 (47)863 (51)
  Current smoker161 (6)98 (6)
TreatmentPlacebo: 842 (31)Placebo: 409 (24)
Antioxidants alone: 850 (31)L+Z: 418 (25)
Zinc: 507 (19)LCPUFA: 451 (27)
Antioxidants+Zinc: 522 (19)L+Z plus LCPUFA: 422 (25)
Genetic risk score (GRS)
 Mean (SD)1.00 (0.14)1.08 (0.13)8.1 × 10−67
 Median (range)1.01 (0.61–1.45)1.08 (0.58–1.42)
Follow-up time
 Mean (SD)10.3 (1.7)4.8 (0.5)
 Median (range)10.9 (1.8–12.6)4.9 (2.1–5.9)
Eye-level variables
 Number of eyesN = 5017N = 2830
 Baseline AREDS AMD severity score
  Mean (SD)3.0 (2.3)6.3 (1.3)<1.0 × 10−300
  Median (range)2 (1–8)7 (1–8)<1.0 × 10−300
   1–3 (n, %)3125 (62)119 (4)<1.0 × 10−300
   4–6 (n, %)1293 (26)1211 (43)
   7–8 (n, %)599 (12)1500 (53)
  • a P-values were from two-sided t-test for continuous variables, and were from chi-square test for categorical variables. Wilcoxon rank-sum test was applied to test the median of the eye-level baseline severity score.