Table 1. Characteristics of Prevalence, Incidence, and AA Populations.
| Category | Denominator | AA cohort (n = 5801) | |
|---|---|---|---|
| Prevalence (n = 5 569 768) | Incidence (n = 2 896 241) | ||
| Age, mean (SD), y | 7.0 (11.3) | 8.1 (6.6) | 9.0 (4.5) |
| Median (Q1-Q3) | 3.0 (0.3-10.1) | 6.6 (2.4-12.7) | 8.6 (5.3-12.6) |
| Follow-up, mean (SD), y | 4.7 (5.6) | 3.2 (3.2) | 5.3 (3.9) |
| Median (Q1-Q3) | 2.7 (0.2-7.8) | 2.2 (0.2-5.5) | 5.2 (1.4-8.7) |
| Sex, No. (%) | |||
| Male | 2 820 226 (50.6) | 1 410 294 (48.7) | 2542 (43.8) |
| Female | 2 748 501 (49.3) | 1 485 837 (51.3) | 3259 (56.2) |
| Unknown | 1041 | 110 | 0 |
| Race and ethnicity, No. (%) | |||
| Asian | 218 094 (3.9) | 104 103 (3.6) | 359 (6.2) |
| Black | 900 261 (16.2) | 563 554 (19.5) | 1094 (18.9) |
| Hispanic | 603 390 (10.8) | 319 579 (11.0) | 1348 (23.2) |
| White | 3 094 716 (55.6) | 1 598 707 (55.2) | 2362 (40.7) |
| Othera | 753 307 (13.5) | 310, 298 (10.7) | 638 (11.0) |
Abbreviations: AA, alopecia areata; Q, quarter
a
Participants self-identified as Other.