Multivariable analysis of DP1 supertype, proxy measures for early life immune modulation (older sibling, daycare attendance, ear infection in infancy, and breastfeeding), and risk of childhood ALL, NCCLS, 1995-2008
| . | Non-Hispanic white . | Hispanic . | Pooled . | ||||
|---|---|---|---|---|---|---|---|
| Cases (%) . | Controls (%) . | OR (95% CI)* . | Cases (%) . | Controls (%) . | OR (95% CI)* . | OR (95% CI)* . | |
| Total† | 231 | 364 | 276 | 398 | |||
| Genetic factor | |||||||
| DP1 supertype | |||||||
| No copies | 191 (82.7) | 317 (87.1) | 1.00 | 227 (82.3) | 345 (86.7) | 1.00 | 1.00 |
| At least 1 copy | 40 (17.3) | 47 (12.9) | 1.32 (0.82-2.15) | 49 (17.8) | 53 (13.3) | 1.50 (0.97-2.33) | 1.41 (1.02-1.94) |
| Proxy exposure measure | |||||||
| Older sibling | |||||||
| No | 113 (48.9) | 134 (36.8) | 1.00 | 109 (39.5) | 143 (35.9) | 1.00 | 1.00 |
| Yes | 118 (51.1) | 230 (63.2) | 0.57 (0.40-0.82) | 167 (60.5) | 255 (64.1) | 0.85 (0.59-1.22) | 0.71 (0.55-0.92) |
| Daycare child-hours by age 6 months‡ | |||||||
| < 2000 | 212 (91.8) | 313 (86.0) | 1.00 | 265 (96.0) | 381 (95.7) | 1.00 | 1.00 |
| ≥ 2000 | 19 (8.2) | 51 (14.0) | 0.46 (0.25-0.85) | 11 (4.0) | 17 (4.3) | 1.19 (0.53-2.69) | 0.67 (0.41-1.07) |
| Ear infection during infancy | |||||||
| Not in infancy | 136 (58.9) | 198 (54.4) | 1.00 | 175 (63.4) | 232 (58.3) | 1.00 | 1.00 |
| At age < 6 mo only | 8 (3.5) | 23 (6.3) | 0.48 (0.20-1.15) | 18 (6.5) | 41 (10.3) | 0.52 (0.28-0.95) | 0.51 (0.31-0.83) |
| At age 6-11 mo only | 42 (18.2) | 81 (22.3) | 0.83 (0.52-1.30) | 42 (15.2) | 76 (19.1) | 0.67 (0.43-1.05) | 0.76 (0.56-1.04) |
| Both time periods | 45 (19.5) | 62 (17.0) | 1.36 (0.83-2.22) | 41 (14.9) | 49 (12.3) | 1.11 (0.68-1.78) | 1.20 (0.85-1.68) |
| Breastfeeding | |||||||
| No | 31 (13.4) | 37 (10.2) | 1.00 | 49 (17.8) | 60 (15.1) | 1.00 | 1.00 |
| Yes | 200 (86.6) | 327 (89.8) | 0.97 (0.55-1.69) | 227 (82.3) | 338 (84.9) | 0.89 (0.57-1.38) | 0.88 (0.62-1.23) |
| . | Non-Hispanic white . | Hispanic . | Pooled . | ||||
|---|---|---|---|---|---|---|---|
| Cases (%) . | Controls (%) . | OR (95% CI)* . | Cases (%) . | Controls (%) . | OR (95% CI)* . | OR (95% CI)* . | |
| Total† | 231 | 364 | 276 | 398 | |||
| Genetic factor | |||||||
| DP1 supertype | |||||||
| No copies | 191 (82.7) | 317 (87.1) | 1.00 | 227 (82.3) | 345 (86.7) | 1.00 | 1.00 |
| At least 1 copy | 40 (17.3) | 47 (12.9) | 1.32 (0.82-2.15) | 49 (17.8) | 53 (13.3) | 1.50 (0.97-2.33) | 1.41 (1.02-1.94) |
| Proxy exposure measure | |||||||
| Older sibling | |||||||
| No | 113 (48.9) | 134 (36.8) | 1.00 | 109 (39.5) | 143 (35.9) | 1.00 | 1.00 |
| Yes | 118 (51.1) | 230 (63.2) | 0.57 (0.40-0.82) | 167 (60.5) | 255 (64.1) | 0.85 (0.59-1.22) | 0.71 (0.55-0.92) |
| Daycare child-hours by age 6 months‡ | |||||||
| < 2000 | 212 (91.8) | 313 (86.0) | 1.00 | 265 (96.0) | 381 (95.7) | 1.00 | 1.00 |
| ≥ 2000 | 19 (8.2) | 51 (14.0) | 0.46 (0.25-0.85) | 11 (4.0) | 17 (4.3) | 1.19 (0.53-2.69) | 0.67 (0.41-1.07) |
| Ear infection during infancy | |||||||
| Not in infancy | 136 (58.9) | 198 (54.4) | 1.00 | 175 (63.4) | 232 (58.3) | 1.00 | 1.00 |
| At age < 6 mo only | 8 (3.5) | 23 (6.3) | 0.48 (0.20-1.15) | 18 (6.5) | 41 (10.3) | 0.52 (0.28-0.95) | 0.51 (0.31-0.83) |
| At age 6-11 mo only | 42 (18.2) | 81 (22.3) | 0.83 (0.52-1.30) | 42 (15.2) | 76 (19.1) | 0.67 (0.43-1.05) | 0.76 (0.56-1.04) |
| Both time periods | 45 (19.5) | 62 (17.0) | 1.36 (0.83-2.22) | 41 (14.9) | 49 (12.3) | 1.11 (0.68-1.78) | 1.20 (0.85-1.68) |
| Breastfeeding | |||||||
| No | 31 (13.4) | 37 (10.2) | 1.00 | 49 (17.8) | 60 (15.1) | 1.00 | 1.00 |
| Yes | 200 (86.6) | 327 (89.8) | 0.97 (0.55-1.69) | 227 (82.3) | 338 (84.9) | 0.89 (0.57-1.38) | 0.88 (0.62-1.23) |
ORs and 95% CIs were calculated using a single additive logistic regression model, including all variables listed in the table and additionally adjusting for age, sex, maternal age, maternal education, and annual household income. The pooled analysis was additionally adjusted for race/ethnicity (non-Hispanic white, Hispanic white, and Hispanic other).
Total numbers of cases and controls with complete data for DP1 supertype, all proxy exposure measures indicated in the table, and covariates, including age, sex, maternal age, maternal education, and annual household income.
The child-hours in each daycare setting were summed to obtain the total child-hours for each child. Child-hours = (number of months attending the daycare) × (mean hours per week at this daycare) × (number of other children at this daycare) × (4.35 weeks per month).