Table 1 Selected characteristics of the study population
Characteristic | HB study | Infant leukemia study a |
|---|---|---|
N (%) | N (%) | |
N children with samples | 412 | 392 |
Median DNA yield (μg) | 0.37 (0 – 139) | 0.15 (0 – 14) |
Child’s age at DNA collection | ||
0 – 2 years | 45 (11) | 75 (19) |
2 – 5 years | 151 (37) | 123 (31) |
> 5 years | 216 (52) | 194 (49) |
Child’s sex | ||
Male | 241 (58) | 183 (47) |
Female | 171 (42) | 209 (53) |
Case control status | ||
Case | 246 (60) | 223 (57) |
Control | 166 (40) | 169 (43) |
Storage (Child’s sample) | ||
0 – 3 days | 108 (29) | 121 (46) |
3 – 7 days | 99 (26) | 64 (24) |
7 – 14 days | 92 (24) | 54 (21) |
> 14 days | 79 (21) | 23 (9) |
Season of DNA collection | ||
Spring | 119 (29) | 117 (30) |
Summer | 117 (28) | 80 (20) |
Fall | 90 (22) | 109 (28) |
Winter | 86 (21) | 86 (22) |
Sample collection | ||
Cytosoft brush | 175 (42) | 341 (87) |
Epicentre brush | 202 (49) | 51 (13) |
Mouthwash | 35 (9) | |
N Mothers with samples | 446 | 489 |
Median DNA yield (μg) | 14 (0.02 – 401) | 14 (0.06 – 1209) |
Mother’s age at DNA collection | ||
< 30 years | 89 (20) | 104 (21) |
30 – 35 years | 117 (26) | 147 (30) |
35 – 40 years | 131 (29) | 134 (27) |
> 40 years | 109 (24) | 104 (21) |
Storage (Mother’s sample)a | ||
0 – 3 days | 110 (27) | 121 (38) |
3 – 7 days | 126 (31) | 104 (33) |
7 – 14 days | 100 (25) | 57 (18) |
> 14 days | 68 (17) | 35 (11) |
Maternal education | ||
< High School | 31 (7) | 26 (5) |
High School | 74 (17) | 104 (21) |
Some college | 115 (26) | 146 (30) |
College degree | 158 (35) | 152 (31) |
Advanced degree | 68 (15) | 61 (13) |
Maternal race | ||
White | 349 (78) | 411 (84) |
Black | 18 (4) | 19 (4) |
Hispanic | 50 (11) | 30 (6) |
Asian | 18 (4) | 16 (3) |
Other | 11 (2) | 13 (3) |
Income | ||
< $20,000 | 65 (15) | 73 (15) |
$20,000 -- $50,000 | 122 (28) | 183 (38) |
$50,000 -- $75,000 | 102 (23) | 110 (23) |
>%75,000 | 153 (35) | 122 (25) |
Season of DNA collection | ||
Spring | 128 (29) | 138 (28) |
Summer | 126 (28) | 100 (20) |
Fall | 98 (22) | 140 (29) |
Winter | 94 (21) | 111 (23) |