UCLA

Autism spectrum disorders (ASD) is a neurodevelopmental disorder often characterized by difficulties in social communication and interaction, and by repetitive behaviors and restricted interests with symptoms starting in early childhood. ASD is multifactorial with risk factors including genetic, environmental, and demographic risk factors, and mother’s pregnancy health. There has also been increasing evidence for multigenerational disease transmission of ASD in large European population-based studies. This dissertation investigated the associations between multigenerational risk factors and ASD in the ethnically and racially diverse California birth cohort.

The first study investigated grandmother’s race, ethnicity, and nativity and ASD risk in grandchildren. The odds of ASD in grandchildren were higher among grandmothers who were US-born and foreign-born Black and Hispanic grandmothers compared to US-born White grandmothers.

The second study investigated grandmother and grandfather’s age at the birth of their daughter with ASD risk in grandchildren and if these associations differ by race/ethnicity. The odds of ASD were elevated among younger (18-24 years) and older (35-55 years) maternal grandparents compared to grandparents of the reference age group (25-29 years). When we stratified by race/ethnicity, we found that the odds of ASD were higher among younger grandparents only among grandparents who were White. The odds of ASD were higher among older Hispanic grandmothers, Hispanic grandfathers, and Black grandfathers compared to the reference age group. The odds of ASD were also in the positive direction for older White grandparents, but the confidence intervals contained the null.

The third study investigated grandmother’s pregnancy complications when pregnant with her daughter and ASD risk in grandchildren. The odds of ASD in grandchildren were higher among grandmothers who had hypertensive disorders or infections in pregnancy than grandmothers who did not have the respective conditions.

In conclusion, this dissertation corroborates previous findings of younger and older maternal grandparent’s age and ASD. In addition, this dissertation investigated the associations between race, ethnicity, and nativity and ASD, as well as grandmother’s hypertensive disorders and infection in pregnancy and ASD. These findings add to the current evidence of multigenerational disease transmission of ASD; suboptimal pregnancy conditions when the grandmother is pregnant with the mother’s generation may impact neurodevelopment in grandchildren.