Table 4.
Participant Characteristics Associated With Light-Adapted 3.0 Flicker Electroretinography (ERG) Amplitude
| N | LA 3.0 Flicker ERG Amplitude (µV) Median (Q1, Q3) | Unmeasurable % | Univariable Analysis P Valuea | Multivariable Analysis P valuea | |
| All | 126 | 2.0 (0.0, 7.7) | 29% | ||
| Clinical diagnosis | 0.004 | 0.004 | |||
| USH2 | 79 | 1.5 (0.0, 5.5) | 32% | ||
| ARRP | 47 | 3.1 (0.0, 20.0) | 26% | ||
| Age at enrollment, y | 0.69b | NAc | |||
| <30 y | 30 | 3.1 (0.2, 6.8) | 23% | ||
| 30 to < 40 y | 34 | 2.4 (0.0, 6.7) | 32% | ||
| 40 to < 50 y | 36 | 1.9 (0.0, 12.9) | 31% | ||
| ≥50 y | 26 | 1.8 (0.0, 7.2) | 31% | ||
| Gender | 0.49 | NAc | |||
| Female | 68 | 2.0 (0.0, 6.6) | 34% | ||
| Male | 58 | 2.2 (0.1, 11.7) | 24% | ||
| Duration of disease, yd | 0.06b | NAc | |||
| <10 | 37 | 5.9 (1.8, 12.8) | 16% | ||
| 10 to < 20 | 46 | 1.7 (0.0, 6.2) | 33% | ||
| ≥20 | 42 | 0.8 (0.0, 4.5) | 38% | ||
| Race/ethnicity | 0.28 | NAc | |||
| Non-Hispanic white | 112 | 2.0 (0.0, 7.6) | 29% | ||
| Other | 14 | 3.0 (0.0, 7.7) | 36% | ||
| Smoking status | 0.52 | NAc | |||
| Ever smoked daily | 33 | 1.5 (0.0, 7.2) | 33% | ||
| Never smoked daily | 93 | 2.3 (0.0, 7.7) | 28% | ||
| Dietary supplement use | 0.13 | NAc | |||
| None | 52 | 2.1 (0.0, 7.9) | 35% | ||
| Vitamin A only | 11 | 2.0 (0.0, 7.2) | 27% | ||
| DHA only | 5 | 0.0 (0.0, 1.3) | 60% | ||
| Lutein only | 9 | 8.8 (1.8, 10.3) | 22% | ||
| Multiple supplements | 49 | 2.2 (0.1, 6.7) | 22% |
a
Continuous variable for DA 3.0 flicker amplitude was used as dependent variable.
b
Variable was analyzed as continuous.
c
Factors with P values > 0.05 in the stepwise selection process were not included in the final multivariable model.
d
One participant in the ARRP group was missing age of onset (a participant-reported field based on their awareness of visual symptoms) and duration of disease (computed based on age of onset and date of enrollment).