Prenatal Diet

 In The Politics of Autism, I discuss various ideas about what causes the condition. 

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

Key Points

Question  What is the association between a healthy prenatal dietary pattern and offspring autism diagnosis and autism-associated traits in 2 large prospective cohort studies: the Norwegian Mother, Father, and Child Cohort (MoBa) and the Avon Study of Parents and Children (ALSPAC)?

Findings  In this cohort study including 84 548 mother-infant dyads in MoBa and 11 670 mother-infant dyads in ALSPAC, maternal consumption of a healthy dietary pattern was associated with reduced likelihood of offspring autism diagnosis (MoBa) and reduced likelihood of social communication difficulties (MoBa and ALSPAC). No other consistent associations were observed.

Meaning  These findings highlight the association between prenatal diet and offspring autism-related outcomes and contribute to the evolving understanding of autism etiology.

Abstract

Importance  Prenatal diet may be causally related to autism; however, findings are inconsistent, with a limited body of research based on small sample sizes and retrospective study designs.

Objective  To investigate the associations of prenatal dietary patterns with autism diagnosis and autism-associated traits in 2 large prospective cohorts, the Norwegian Mother, Father, and Child Cohort Study (MoBa), and the Avon Longitudinal Study of Parents and Children (ALSPAC).

Design, Setting, and Participants  This cohort study used data from MoBa and ALSPAC birth cohort studies conducted across Norway and in the Southwest of England, respectively. Participants were people with singleton pregnancies with self-reported food frequency questionnaire responses. MoBa recruited between 2002 and 2008, and ALSPAC recruited between 1990 and 1992, and children were followed-up until age 8 years or older. Recruitment rates were 41% (95 200 of 277 702 eligible pregnancies) in MoBa and 72% (14 541 of 20 248 eligible pregnancies) in ALSPAC. Data analysis occurred February 1, 2022, to August 1, 2023.

Exposure  A healthy prenatal dietary pattern was derived using factor analysis and modeled as low, medium, and high adherence.

Main Outcomes and Measures  In MoBa, the offspring outcomes were autism diagnosis and elevated social communication questionnaire score at ages 3 years and 8 years, with further analysis of the social communication difficulties and restrictive and repetitive behaviors subdomains. In ALSPAC, offspring outcomes were elevated social communication difficulties checklist score at age 8 years. Odds ratios (ORs) were estimated using generalized nonlinear models.

Results  MoBa included 84 548 pregnancies (mean [SD] age, 30.2 [4.6] years; 43 277 [51.2%] male offspring) and ALSPAC had 11 760 pregnancies (mean [SD] age, 27.9 [4.7] years; 6034 [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; 95% CI, 0.66-0.92) and social communication difficulties at age 3 years in MoBa (OR 0.76, 95% CI, 0.70-0.82) and age 8 years in ALSPAC (OR, 0.74; 95% CI, 0.55-0.98). There was no consistent evidence of association with the other outcomes.

Conclusions and Relevance  In this cohort study of mother-child dyads, adherence to a healthy prenatal dietary pattern was associated with a lower odds of autism diagnosis and social communication difficulties but not restrictive and repetitive behaviors.

This is a very long. growing, and probably incomplete list of other correlates, risk factors, and possible causes that have been the subject of serious studies: 

1. Inflammatory bowel disease;
2. Pesticides;
3. Air pollution and proximity to freeways;
4. Maternal thyroid issues;
5. Autoimmune disorders;
6. Induced labor;
7. Preterm birth;
8. Fever;  
9. Birth by cesarean section;
10. Anesthesia during cesarean sections;
11. Maternal and paternal obesity;
12. Maternal diabetes;
13. Maternal and paternal age;
14. Grandparental age;
15. Maternal post-traumatic stress disorder;
16. Maternal anorexia;
17. Smoking during pregnancy;
18. Cannabis use during pregnancy;
19. Antidepressant use during pregnancy;
20. Polycystic ovary syndrome;
21. Infant opioid withdrawal;
22. Zinc deficiency;
23. Sulfate deficiency;
24. Processed foods;
25. Maternal occupational exposure to solvents;
26. Congenital heart disease;
27. Insufficient placental allopregnanolone.
28. Estrogen in the womb;
29. Morning sickness;
30. Paternal family history;
31. Parental preterm birth;
32. Antiseizure meds
33. Location of forebears
34. Lithium
35. Aspartame
36. BPA
37. Brain inflammation
38. Maternal asthma
39. Infertility
40. Ultraprocessed foods
41. Household chemicals
42. Parental psychiatric disorders
43. Fluoride