Table 2.
Key demographic characteristics of participants in the 12 studies in the CLIC pooled analyses of home pesticide exposure and the risk of leukemia in the offspring
| ALL (12 studies) | AML (9 studies) | |||||||
|---|---|---|---|---|---|---|---|---|
| Case (n= 7,956) | Control1 (n = 14,494) | Case (n= 740) | Control2 (n= 10,847) | |||||
| n | % | n | % | n | % | n | % | |
| Sex | ||||||||
| Boy | 4,457 | 55.7 | 8,066 | 55.7 | 401 | 54.2 | 6,073 | 56.0 |
| Girl | 3,499 | 44.3 | 6,428 | 44.3 | 339 | 45.8 | 4,774 | 44.0 |
| Child's age (years)3 | ||||||||
| 0-1 | 867 | 10.9 | 2,149 | 14.8 | 220 | 29.7 | 1,724 | 15.9 |
| 2-4 | 3,731 | 46.9 | 5,764 | 39.8 | 138 | 18.6 | 4,101 | 37.8 |
| 5-9 | 2,319 | 29.1 | 4,225 | 29.1 | 180 | 24.3 | 3,112 | 28.7 |
| 10-14 | 1,038 | 13.0 | 2,326 | 16.0 | 200 | 27.0 | 1,906 | 17.6 |
| 15-16 | 1 | 0.0 | 30 | 0.2 | 2 | 0.3 | 4 | 0.0 |
| Child's year of birth | ||||||||
| 1970-1987 | 2,824 | 35.5 | 4,692 | 32.4 | 234 | 31.6 | 2,812 | 25.9 |
| 1988-1996 | 3,676 | 46.2 | 6,944 | 47.9 | 364 | 49.2 | 5,861 | 54.0 |
| 1997-2007 | 1,456 | 18.3 | 2,858 | 19.7 | 142 | 19.2 | 2,174 | 20.0 |
| Child's reference year3 | ||||||||
| 1980-1992 | 2,872 | 36.1 | 3,924 | 27.1 | 90 | 12.2 | 1,520 | 14.0 |
| 1993-1997 | 2,533 | 31.8 | 5,578 | 38.5 | 388 | 52.4 | 5,343 | 49.3 |
| 1998-2008 | 2,551 | 32.1 | 4,992 | 34.4 | 262 | 35.4 | 3,984 | 36.7 |
| Birth order | ||||||||
| 1st | 3,648 | 45.9 | 6,456 | 44.5 | 323 | 43.6 | 4,791 | 44.2 |
| 2nd | 2,706 | 34.0 | 5,067 | 35.0 | 246 | 33.2 | 3,849 | 35.5 |
| 3rd or more | 1,565 | 19.7 | 2,920 | 20.1 | 162 | 21.9 | 2,156 | 19.9 |
| Missing | 37 | 0.5 | 51 | 0.4 | 9 | 1.2 | 51 | 0.5 |
| Mother's age at child's birth | ||||||||
| <25 years | 2,222 | 27.9 | 3,563 | 24.6 | 222 | 30.0 | 2,596 | 23.9 |
| 25-34 years | 4,837 | 60.8 | 9,224 | 63.6 | 431 | 58.2 | 6,930 | 63.9 |
| >34 years | 876 | 11.0 | 1,682 | 11.6 | 83 | 11.2 | 1,296 | 11.9 |
| Missing | 21 | 0.3 | 25 | 0.2 | 4 | 0.5 | 25 | 0.2 |
| Child has Down Syndrome | ||||||||
| Yes | 97 | 1.2 | 6 | 0.0 | 39 | 5.3 | 3 | 0.0 |
| Highest level of education of either parent | ||||||||
| Did not finish secondary education | 1,409 | 17.7 | 2,491 | 17.2 | 173 | 23.4 | 2,226 | 20.5 |
| Completed secondary education | 3,312 | 41.6 | 5,694 | 39.3 | 274 | 37.0 | 3,985 | 36.7 |
| Tertiary education | 3,186 | 40.0 | 6,176 | 42.6 | 280 | 37.8 | 4,503 | 41.5 |
| Missing | 49 | 0.6 | 133 | 0.9 | 13 | 1.8 | 133 | 1.2 |
| Ethnicity | ||||||||
| White/Caucasian/European | 6,672 | 83.9 | 12,797 | 88.3 | 590 | 79.7 | 9,507 | 87.6 |
| Other | 1,248 | 15.7 | 1,615 | 11.1 | 145 | 19.6 | 1,295 | 11.9 |
| Indeterminate | 17 | 0.2 | 39 | 0.3 | 0 | 0.0 | 2 | 0.0 |
| Missing | 19 | 0.2 | 43 | 0.3 | 5 | 0.7 | 43 | 0.4 |
| Summary pesticide exposure data before conception | 2,785 | 35.0 | 3,635 | 25.1 | 173 | 23.4 | 1,789 | 16.5 |
| Any professional pest control exposure data in the 1-3 months before pregnancy | 2660 | 33.4 | 3120 | 21.53 | Not shown as only data from 1 study | |||
| Summary pesticide exposure data during pregnancy | 5,055 | 63.5 | 7,370 | 50.8 | 345 | 46.7 | 4,664 | 43.0 |
| Any professional pest control exposure data during pregnancy | 5,660 | 71.1 | 8,938 | 61.7 | 388 | 52.4 | 5,322 | 49.1 |
| Summary pesticide exposure data after birth | 4,162 | 52.3 | 5,179 | 35.7 | 198 | 26.8 | 2,655 | 24.5 |
| Any professional pest control exposure data after birth | 3,611 | 45.4 | 8,388 | 57.9 | 468 | 63.2 | 7,531 | 69.4 |
1
Includes controls from all studies with ALL cases (that is, all studies).
2
Includes controls from all studies with AML cases (that is, all studies except Australia, Canada, and COG-E15).
3
Age groups and reference years are based on the child's age at the censoring date. For case, this was the date at diagnosis and for controls, it was the date that the study investigators nominated (either the date of recruitment or the date of the questionnaire return).