Table 2. Demographic and biological baseline characteristics of first-degree relatives who seroconverted to persistent Ab+ according to age at seroconversion.
| Characteristic at seroconversion | Persistently Ab+ seroconverters (n = 118) | ||
|---|---|---|---|
| 0–9 years | 10–19 years | 20–39 years | |
| n (%) | 50 (42) | 39 (33) | 29 (25) |
| Age (years), P50 (IQR) | 6 (4–8) | 14 (12–16) | 29 (22–34) |
| Sex, n males/n females (ratio)a | 35/15 (2.33) | 22/17 (1.29) | 12/17 (0.70) |
| Relationship to type 1 diabetes, n (%)b | |||
| Parent | 0 (0) | 0 (0) | 19 (31) |
| Offspring type 1 diabetes mother | 12 (24) | 12 (31) | 6 (21) |
| Offspring type 1 diabetes father | 16 (32) | 12 (31) | 5 (17) |
| Sibling | 22 (44) | 15 (38) | 12 (41) |
| C-peptide (pmol/l), P50 (IQR) | 645 (374–943) | 731 (539–1,155) | 867 (583–1,162) |
| HLA-DQ2/DQ8, n (%) | 12 (24) | 8 (20) | 6 (21) |
| Ab type, n (%) | |||
| IAA+ | 26 (52) | 15 (38) | 10 (34) |
| GADA+ | 36 (72) | 29 (74) | 23 (79) |
| IA-2A+c | 11 (22) | 6 (15) | 0 (0) |
| ZnT8A+ | 7 (14) | 6 (15) | 0 (0) |
| Multiple Ab+, n (%)c | 21 (42) | 10 (26) | 4 (14) |
| Ablevelsd (% tracer-bound), P50 (IQR) | |||
| IAA+ | 1.3 (0.8–2.3) | 1.1 (0.8–2.0) | 0.9 (0.8–1.2) |
| GADA+ | 9.9 (4.8–36.1) | 15.1 (3.6–137) | 7.6 (3.6–79.7) |
| IA-2A+ | 6.9 (1.7–83.4) | 50 (1.1–82.1) | NA |
| ZnT8A+ | 5.2 (2.5–14.2) | 2.4 (1.7–12.4) | NA |
Threshold for significance: overall p < 0.05/14 or p < 0.0037, for differences among age groups: p < 0.05/3 or p < 0.017 (Bonferroni correction).
a
Overall p = 0.043;
b
overall p = 0.002;
c
overall p < 0.030
d
Only in relatives positive for that particular Ab
NA, not applicable; P50, median