Healthy prenatal dietary patterns tied to lower risk of autism diagnosis in offspring: JAMA

The findings, published in JAMA Network Open, illuminate the link between prenatal dietary patterns and autism-related outcomes in offspring, contributing to advancing our understanding of autism's origins.

In the study comprising 84 548 mother-infant dyads in Norwegian Mother, Father, and Child Cohort (MoBa) and 11 670 mother-infant dyads in ALSPAC (Avon Study of Parents and Children), the likelihood of autism diagnosis was reduced by 22% in association with high adherence to healthy prenatal dietary pattern (HPDP), the researchers reported. However, there were no other consistent associations.

The potential causal relationship between prenatal diet and autism remains uncertain, given inconsistent findings and a scarcity of research utilizing small sample sizes and retrospective study designs. To fill this knowledge gap, Catherine Friel, University of Glasgow, Glasgow, Scotland, and colleagues aimed to investigate the associations of prenatal dietary patterns with autism diagnosis and autism-associated traits in 2 large prospective cohorts, MoBa, and the ALSPAC.

For this purpose, the researchers used data from MoBa and ALSPAC birth cohort studies performed across Norway and the Southwest of England, respectively.

The study enrolled individuals with singleton pregnancies who provided self-reported food frequency questionnaire responses. Recruitment for the MoBa cohort took place between 2002 and 2008, and for the ALSPAC cohort between 1990 and 1992, children were followed up until at least eight years of age. Recruitment rates were 41% for MoBa and 72% for ALSPAC. Data analysis was conducted from February 1, 2022, to August 1, 2023.

The researchers derived a healthy prenatal dietary pattern using factor analysis and modeled it as low, medium, and high adherence.

In the MoBa cohort, outcomes for offspring included autism diagnosis and higher social communication questionnaire scores assessed at 3 and 8 years of age, with additional examination of specific domains such as social communication difficulties and restrictive and repetitive behaviors. In the ALSPAC cohort, outcomes focused on elevated scores on the social communication difficulties checklist at eight years of age. Odds ratios (ORs) were calculated using generalized nonlinear models to estimate associations.

The researchers reported the following findings:

• MoBa included 84 548 pregnancies (mean age, 30.2 years; 51.2% male offspring), and ALSPAC had 11 760 pregnancies (mean age, 27.9 years; 51.3% male offspring).
• In the final adjusted models, high adherence to a healthy dietary pattern, compared with low adherence, was associated with reduced odds of autism diagnosis (OR, 0.78) and social communication difficulties at age three years in MoBa (OR 0.76) and age eight years in ALSPAC (OR, 0.74).
• There was no consistent evidence of association with the other outcomes.

"Additional research is needed to validate our findings, particularly in light of the variability observed in previous studies and across our assessments of autism-related characteristics. It would be beneficial to analyze combined and individual subdomains and investigate potential differences by food group. Furthermore, employing alternative study designs and exploring potential mediators are crucial steps towards establishing a causal link between prenatal diet and the associations identified in our study," the researchers concluded.

Reference:

Friel C, Leyland AH, Anderson JJ, Havdahl A, Brantsæter AL, Dundas R. Healthy Prenatal Dietary Pattern and Offspring Autism. JAMA Netw Open. 2024;7(7):e2422815. doi:10.1001/jamanetworkopen.2024.22815