Infantile Autism: The Incidence of National Groups in a New South Wales Survey

Perinatal and maternal risk factors for autism spectrum disorders in New South Wales, Australia

“…A previous Australian report of increased immigration rates among parents of children with autism (Harper & Williams 1976) found a predominance of parents from countries that were the major immigrant groups at the time, rather than south-east or north-east Asia born parents. The reasons why mother's country of birth is a risk factor for autism are not clear (Fombonne 2003), and several suggested theories such as increased vulnerability to intrauterine infections, overrepresentation of fathers with autistic traits seeking foreign brides (Gillberg & Gillberg 1996), possible 'deprivation as a consequence of familial stress both in terms of socio-cultural change and economic pressures' , and 'exposure to a confused and often severely limited language environment' (Harper & Williams 1976), remain untested. One previous study found an association between multiple birth and autism, using all surviving children as the denominator , but three others found no association (Hallmayer et al 2002;Hultman et al 2002;Larsson et al 2005).…”

“…In the overall analysis we included mothers born in the US, UK and Europe, but showed the risk for children was highest if their mother was born in south‐east or north‐east Asia. A previous Australian report of increased immigration rates among parents of children with autism (Harper & Williams 1976) found a predominance of parents from countries that were the major immigrant groups at the time, rather than south‐east or north‐east Asia born parents. The reasons why mother's country of birth is a risk factor for autism are not clear (Fombonne 2003), and several suggested theories such as increased vulnerability to intrauterine infections, over‐representation of fathers with autistic traits seeking foreign brides (Gillberg & Gillberg 1996), possible ‘deprivation as a consequence of familial stress both in terms of socio‐cultural change and economic pressures’, and ‘exposure to a confused and often severely limited language environment’ (Harper & Williams 1976), remain untested.…”

“…These factors were gestational age, birthweight, foetal growth, Apgar scores (as a marker of foetal distress) and multiple birth. In addition, there had been considerable interest about whether the risk of autism was increased if the child's parents were born outside the country of residence of the child (Harper & Williams 1976; Gillberg & Gillberg 1996), and during the course of the study and prior to statistical analysis, maternal age was reported as a risk factor (Tsai 1987; Croen et al . 2002; Glasson et al .…”

“…These factors were gestational age, birthweight, foetal growth, Apgar scores (as a marker of foetal distress) and multiple birth. In addition, there had been considerable interest about whether the risk of autism was increased if the child's parents were born outside the country of residence of the child (Harper & Williams 1976;Gillberg & Gillberg 1996), and during the course of the study and prior to statistical analysis, maternal age was reported as a risk factor (Tsai 1987;Croen et al 2002;Glasson et al 2004) and there was published debate about the role of birth order in risk factor estimation (Tsai & Stewart 1983;Lord et al 1991;Piven et al 1993), so these factors were also explored. Risk factors that had been explored in other studies were not included if they were only reported in one study at the time of analysis, were derived from multiple pieces of clinical information, were subject to different measurement methods and reporting, were not available in the population data available to this study or were thought to be 'proxy' measures of other risk factors.…”

Migration and autism spectrum disorder: population-based study

“…This inconsistency may be partly explained by differences between studies in their definitions of autism and the proportion of children with associated intellectual disability (online Table DS4). Other studies on this topic lacked individual-level control data 7,12,14,15,[25][26][27] and reported similar or increased risks of autism in children of migrant mothers, except one study from Israel 15 that found a reduced risk in Ethiopian migrants (online Table DS4).…”