Table 2.
Diagnosis age outcomes for the total sample and analytic sub-samples by birth year and ART status
| Outcome and birth year | Total population of children with autism | Sample restricted for socio-demographic comparability | Sample further restricted to singletons | |||
|---|---|---|---|---|---|---|
| ART births | Non-ART births | ART births | Non-ART births | ART births | Non-ART births | |
| Mean age autism dx (year) | ||||||
| 1997–1999 | 4.6 | 5.3 | 4.7 | 5.1 | 4.9 | 5.1 |
| 2000–2002 | 4.2 | 4.6 | 4.2 | 4.5 | 4.0 | 4.5 |
| 2003–2004 | 3.7 | 4.1 | 3.6 | 4.0 | 3.9 | 4.0 |
| 2005–2006 | 3.6 | 3.7 | 3.7 | 3.7 | 3.8 | 3.7 |
| Total 1997–2006 | 4.0 | 4.5 | 4.0 | 4.4 | 4.1 | 4.4 |
| Median age autism dx (year) | ||||||
| 1997–1999 | 3.8 | 4.4 | 3.8 | 4.2 | 4.0 | 4.2 |
| 2000–2002 | 3.3 | 4.0 | 3.2 | 3.9 | 3.2 | 3.9 |
| 2003–2004 | 3.1 | 3.8 | 3.1 | 3.6 | 3.3 | 3.6 |
| 2005–2006 | 3.4 | 3.5 | 3.6 | 3.4 | 3.8 | 3.4 |
| Total 1997–2006 | 3.3 | 4.0 | 3.3 | 3.9 | 3.6 | 3.9 |
| % diagnosed at <4 years of age | ||||||
| 1997–1999 | 55.4 | 40.4 | 55.5 | 43.9 | 51.3 | 43.9 |
| 2000–2002 | 63.0 | 48.8 | 63.9 | 52.8 | 69.2 | 52.5 |
| 2003–2004 | 74.4 | 55.9 | 75.2 | 59.1 | 64.9 | 58.7 |
| 2005–2006 | 68.4 | 65.6 | 67.7 | 67.9 | 66.7 | 67.4 |
| Total 1997–2006 | 65.3 | 51.8 | 65.7 | 54.8 | 63.8 | 54.4 |
The sample restricted for socio-demographic comparability excludes children whose mothers were less than 20 years of age at the time of their birth, had less than a high school diploma, had prenatal care or delivery paid for by Medi-Cal or other public source, or had missing information on prenatal care, inadequate prenatal care or started prenatal care in the third trimester. The sample further restricted to singletons excludes all of the aforementioned children and additionally excludes all children born in twin or higher-order multiple birth deliveries