Table 1.
Characteristics of fetal-exposure cohort and childhood-exposure cohort from 1996–2016
| Fetal-Exposure Cohort | United States | Ontario, Canada | Total | |||
| n | Col % | n | Col % | n | Col % | |
| Total Children, n | 881,205 | 2,592,795 | 3,474,000 | |||
| Total Pregnancies, n | 867,279 | 2,550,318 | 3,417,597 | |||
| Total Singleton Pregnancies, n | 852,103 | 2,508,849 | 3,360,952 | |||
| Total Multiple Pregnancies, n | 15,176 | 41,469 | 56,645 | |||
| Total Unique Pregnant Women, n | 636,904 | 1,533,200 | 2,170,104 | |||
| Gestational Age at Birth (median, Quartile 1-Quartile 3) | 40 (38–40) | 40 (39–40) | ||||
| Gestational Age at Birth, n (%) | ||||||
| 24 – 36 weeks (pre-term) | 59,359 | 6.7% | 144,247 | 5.6% | 203,606 | 5.9% |
| 37 – 40 weeks (full-term) | 731,823 | 83.0% | 2,212,713 | 85.3% | 2,944,536 | 84.8% |
| 41 – 43 weeks (late-term) | 90,023 | 10.4% | 235,835 | 9.1% | 325,858 | 9.4% |
| Child’s Age at End of Follow-up (median, Quartile 1-Quartile 3) | 11 (6–16) | 10 (5–16) | ||||
| Child’s Age at End of Follow-up, n (%) | ||||||
| 0–5 years | 186,583 | 21.2% | 709,718 | 27.4% | 896,301 | 25.8% |
| 6–10 years | 223,687 | 25.4% | 637,189 | 24.6% | 860,876 | 24.8% |
| 11–15 years | 221,870 | 25.2% | 590,100 | 22.8% | 811,970 | 23.4% |
| 16–20 years | 249,065 | 28.3% | 655,788 | 25.3% | 904,853 | 26.0% |
| Child’s Calendar Year of Birth, n (%) | ||||||
| 1996 – 2000 | 167,510 | 19.0% | 584,528 | 22.5% | 752,038 | 21.6% |
| 2001 – 2005 | 214,598 | 24.4% | 610,178 | 23.5% | 824,776 | 23.7% |
| 2006 – 2010 | 224,593 | 25.5% | 638,610 | 24.6% | 863,203 | 24.8% |
| 2011 – 2016 | 274,504 | 31.2% | 759,479 | 29.3% | 1,033,983 | 29.8% |
| Child Sex, n (%) | ||||||
| Male | 451,396 | 51.2% | 1,330,593 | 51.3% | 1,781,989 | 51.3% |
| Female | 429,765 | 48.8% | 1,262,202 | 48.7% | 1,691,967 | 48.7% |
| Unknown | 44 | 0.0% | 0 | 0.0% | 44 | 0.0% |
| Child Race (U.S. only), n (%) | ||||||
| White | 387,681 | 44.0% | --- | --- | 387,681 | 44.0% |
| Asian | 149,187 | 16.9% | --- | --- | 149,187 | 16.9% |
| Black | 55,807 | 6.3% | --- | --- | 55,807 | 6.3% |
| Hawaiian/Pacific Islander | 15,555 | 1.8% | --- | --- | 15,555 | 1.8% |
| Native American | 4,312 | 0.5% | --- | --- | 4,312 | 0.5% |
| Other/Mixed | 1,736 | 0.2% | --- | --- | 1,736 | 0.2% |
| Unknown or Not Reported | 266,927 | 30.3% | --- | --- | 266,927 | 30.3% |
| Child Ethnicity (U.S. only), n (%) | ||||||
| Not Hispanic or Latino | 627,060 | 71.2% | --- | --- | 627,060 | --- |
| Hispanic or Latino | 153,850 | 17.5% | --- | --- | 153,850 | --- |
| Unknown or Not Reported | 100,295 | 11.4% | --- | --- | 100,295 | --- |
| Down syndrome, n (%) | 1,068 | 0.1% | 2,750 | 0.1% | 3,818 | 0.1% |
| Geocoded Median Household Income, n (%) | ||||||
| Q1 (lowest income) | 2,240 | 0.3% | 567,077 | 21.9% | ||
| Q2 | 58,510 | 6.6% | 517,035 | 19.9% | ||
| Q3 | 273,565 | 31.0% | 526,414 | 20.3% | ||
| Q4 | 389,417 | 44.2% | 536,126 | 20.7% | ||
| Q5 (highest income) | 119,894 | 13.6% | 433,579 | 16.7% | ||
| missing | 37,579 | 4.3% | 12,564 | 0.5% | ||
| Childhood-Exposure Cohort | United States | Ontario, Canada | Total | |||
| n | Col % | n | Col % | n | Col % | |
| Total Children, n | 931,120 | 2,793,512 | 3,724,632 | |||
| Child’s Age at End of Follow-up (median, Quartile 1-Quartile 3) a | 5 (2–9) | 11 (6–16) | ||||
| Child’s Age at End of Follow-up, n (%) | ||||||
| 0–5 years | 479,026 | 51.4% | 689,214 | 24.7% | 1,168,240 | 31.4% |
| 6–10 years | 239,349 | 25.7% | 704,793 | 25.2% | 944,142 | 25.3% |
| 11–15 years | 125,664 | 13.5% | 647,970 | 23.2% | 773,634 | 20.8% |
| 16–20 years | 87,081 | 9.4% | 751,535 | 26.9% | 838,616 | 22.5% |
| Child’s Calendar Year of Birth, n (%) | ||||||
| 1996 – 2000 | 192,169 | 20.6% | 672,300 | 24.1% | 864,469 | 23.2% |
| 2001 – 2005 | 235,641 | 25.3% | 676,021 | 24.2% | 911,662 | 24.5% |
| 2006 – 2010 | 246,005 | 26.4% | 698,931 | 25.0% | 944,936 | 25.4% |
| 2011 – 2016 | 257,305 | 27.6% | 746,260 | 26.7% | 1,003,565 | 26.9% |
| Child Sex, n (%) | ||||||
| Male | 477,699 | 51.3% | 1,432,892 | 51.3% | 1,910,591 | 51.3% |
| Female | 453,421 | 48.7% | 1,360,620 | 48.7% | 1,814,041 | 48.7% |
| Child Race (U.S. only), n (%) | ||||||
| White | 409,830 | 44.0% | --- | --- | 409,830 | 44.0% |
| Asian | 157,359 | 16.9% | --- | --- | 157,359 | 16.9% |
| Black | 53,366 | 5.7% | --- | --- | 53,366 | 5.7% |
| Hawaiian/Pacific Islander | 18,020 | 1.9% | --- | --- | 18,020 | 1.9% |
| Native American | 4,646 | 0.5% | --- | --- | 4,646 | 0.5% |
| Other/Mixed | 2,382 | 0.3% | --- | --- | 2,382 | 0.3% |
| Unknown or Not Reported | 285,517 | 30.7% | --- | --- | 285,517 | 30.7% |
| Child Ethnicity (U.S. only), n (%) | ||||||
| Not Hispanic or Latino | 633,822 | 68.1% | --- | --- | 633,822 | --- |
| Hispanic or Latino | 154,383 | 16.6% | --- | --- | 154,383 | --- |
| Unknown or Not Reported | 142,915 | 15.3% | --- | --- | 142,915 | --- |
| Down syndrome, n (%) | 1,209 | 0.1% | 2,935 | 0.1% | 4,144 | 0.1% |
| Geocoded Median Household Income, n (%) | ||||||
| Q1 | 2,242 | 0.2% | 633,317 | 22.7% | ||
| Q2 | 58,358 | 6.3% | 559,654 | 20.0% | ||
| Q3 | 274,831 | 29.5% | 559,670 | 20.0% | ||
| Q4 | 386,740 | 41.5% | 565,210 | 20.2% | ||
| Q5 | 118,648 | 12.7% | 459,046 | 16.4% | ||
| Missing | 90,301 | 9.7% | 16,615 | 0.6% | ||
a
Childhood-Exposure cohort had fewer years of fo low up as continuous enrollment was required in this cohort, whereas it was not required in the Fetal-Exposure cohort.