Table 2.
Incidence and prevalence rates for eating disorders in a sample of 496 adolescent females followed over an 8-year period
| Annual prevalence | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Eating Disorder | Lifetime prevalence by Age 20 n (%, CI) |
Cumulative incidence over 8-year follow-up n (%, CI) |
Yr 1 |
Yr 2 |
Yr 3 |
Yr 4 |
Yr 5 |
Yr 6 |
Yr 7 |
Yr 8 |
| Subthreshold AN | 3 (0.6 ±0.7) |
3 (0.6 ±0.7) |
0 | 0 | 2 | 1 | 0 | 0 | 0 | 0 |
| Threshold AN | 3 (0.6 ±0.7) |
3 (0.6 ±0.7) |
0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 |
| Subthreshold BN | 30 (6.1 ±2.1) |
26 (5.2 ±1.9) |
3 | 2 | 5 | 5 | 8 | 10 | 9 | 5 |
| Threshold BN | 8 (1.6 ±1.1) |
6 (1.2 ±1.0) |
2 | 1 | 0 | 0 | 1 | 4 | 2 | 0 |
| Subthreshold BED | 23 (4.6 ±1.8) |
21 (4.2 ±1.8) |
2 | 4 | 1 | 1 | 4 | 5 | 7 | 8 |
| Threshold BED | 5 (1.0 ±0.9) |
5 (1.0 ±0.9) |
0 | 0 | 0 | 0 | 1 | 2 | 3 | 2 |
| PD | 22 (4.4 ±1.8) |
22 (4.4 ±1.8) |
0 | 5 | 1 | 0 | 4 | 4 | 6 | 7 |
Note: AN = anorexia nervosa, BN = bulimia nervosa, BED = binge eating disorder, PD = purging disorder. Eating disorder classifications are not mutually exclusive across disorders or between subthreshold and threshold cases (e.g., a participant can be classified as being subthreshold BN at one time point, then threshold at another time point). Lifetime prevalence reflects the number of participants who met criteria at baseline and those who showed onset of these eating disorders during the 8-year follow-up. Cumulative 8-year incidence reflects the number of participants who showed onset during the 8-year follow-up, excluding participants who met criteria at baseline. Annual prevalence reflects the number of participants who met criteria for a disorder at any point during each annual assessment period.