Open access article: https://www.sciencedirect.com/science/article/pii/S000291652400443X

Abstract

Food and nutrition-related factors have the potential to impact development of autism spectrum disorder (ASD) and quality of life for people with ASD, but gaps in evidence exist. On 10 November 2022, Tufts University’s Friedman School of Nutrition Science and Policy and Food and Nutrition Innovation Institute hosted a 1-d meeting to explore the evidence and evidence gaps regarding the relationships of food and nutrition with ASD. This meeting report summarizes the presentations and deliberations from the meeting. Topics addressed included prenatal and child dietary intake, the microbiome, obesity, food-related environmental exposures, mechanisms and biological processes linking these factors and ASD, food-related social factors, and data sources for future research. Presentations highlighted evidence for protective associations with prenatal folic acid supplementation and ASD development, increases in risk of ASD with maternal gestational obesity, and the potential for exposure to environmental contaminants in foods and food packaging to influence ASD development. The importance of the maternal and child microbiome in ASD development or ASD-related behaviors in the child was reviewed, as was the role of discrimination in leading to disparities in environmental exposures and psychosocial factors that may influence ASD. The role of child diet and high prevalence of food selectivity in children with ASD and its association with adverse outcomes were also discussed. Priority evidence gaps identified by participants include further clarifying ASD development, including biomarkers and key mechanisms; interactions among psychosocial, social, and biological determinants; interventions addressing diet, supplementation, and the microbiome to prevent and improve quality of life for people with ASD; and mechanisms of action of diet-related factors associated with ASD. Participants developed research proposals to address the priority evidence gaps. The workshop findings serve as a foundation for future prioritization of scientific research to address evidence gaps related to food, nutrition, and ASD.

Citation: Melissa Maitin-Shepard, Perrie O’Tierney-Ginn, Aletta D Kraneveld, Kristen Lyall, Daniele Fallin, Manish Arora, Alessio Fasano, Noel T Mueller, Xiaobin
Wang, Laura E Caulfield, Aisha S Dickerson, Rochellys Diaz Heijtz, Tomo Tarui, Jeffrey B Blumberg, Calliope Holingue, Rebecca J Schmidt, Johan Garssen,
Katherine Almendinger, Pi-I Debby Lin, Dariush Mozaffarian, Food, nutrition, and autism: from soil to fork, The American Journal of Clinical Nutrition, Volume 120, Issue 1,
2024, Pages 240-256

Open access article: (https://www.ingentaconnect.com/content/ben/cmc/pre-prints/content-bms-cmc-2023-157)

Abstract
Existing evidence indicates that environmental factors might contribute up to 50% of the variance in autism spectrum disorder (ASD) risk. This structured narrative review offers a comprehensive synthesis of current knowledge on environmental risk factors in ASD, including evaluation of conflicting evidence, exploration of underlying mechanisms, and suggestions for future research directions. Analysis of diverse epidemiological investigations indicates that certain environmental factors, including advanced parental age, preterm birth, delivery complications, and exposure to toxic metals, drugs, air pollutants, and endocrine-disrupting chemicals, are linked to an increased ASD risk through various mechanisms such as oxidative stress, inflammation, hypoxia, and its consequences, changes in neurotransmitters, disruption of signaling pathways and some others. On the other hand, pregnancy-related factors such as maternal diabetes, maternal obesity, and caesarian section show a weaker association with ASD risk. At the same time, other environmental factors, such as vaccination, maternal smoking, or alcohol consumption, are not linked to the risk of ASD. Regarding nutritional elements data are inconclusive. These findings highlight the significance of environmental factors in ASD etiology and emphasize that more focused research is needed to target the risk factors of ASD. Environmental interventions targeting modifiable risk factors might offer promising avenues for ASD prevention and treatment.

Citation: Yenkoyan Konstantin, Mkhitaryan Meri, Bjrklund Geir, Environmental Risk
Factors in Autism Spectrum Disorder: A Narrative Review,Current Medicinal
Chemistry, volume 31, issue 17, pages 2345-2360.

Open access article:  (https://pubmed.ncbi.nlm.nih.gov/35238171/ )

Abstract

Prevalence estimates of autism are essential for informing public policy, raising awareness, and developing research priorities. Using a systematic review, we synthesized estimates of the prevalence of autism worldwide. We examined factors accounting for variability in estimates and critically reviewed evidence relevant for hypotheses about biological or social determinants (viz., biological sex, sociodemographic status, ethnicity/race, and nativity) potentially modifying prevalence estimates of autism. We performed the search in November 2021 within Medline for studies estimating autism prevalence, published since our last systematic review in 2012. Data were extracted by two independent researchers. Since 2012, 99 estimates from 71 studies were published indicating a global autism prevalence that ranges within and across regions, with a median prevalence of 100/10,000 (range: 1.09/10,000 to 436.0/10,000). The median male-to-female ratio was 4.2. The median percentage of autism cases with co-occurring intellectual disability was 33.0%. Estimates varied, likely reflecting complex and dynamic interactions between patterns of community awareness, service capacity, help seeking, and sociodemographic factors. A limitation of this review is that synthesizing methodological features precludes a quality appraisal of studies. Our findings reveal an increase in measured autism prevalence globally, reflecting the combined effects of multiple factors including the increase in community awareness and public health response globally, progress in case identification and definition, and an increase in community capacity. Hypotheses linking factors that increase the likelihood of developing autism with variations in prevalence will require research with large, representative samples and comparable autism diagnostic criteria and case-finding methods in diverse world regions over time.

Lay Summary

We reviewed studies of the prevalence of autism worldwide, considering the impact of geographic, ethnic, and socioeconomic factors on prevalence estimates. Approximately 1/100 children are diagnosed with autism spectrum disorder around the world. Prevalence estimates increased over time and varied greatly within and across sociodemographic groups. These findings reflect changes in the definition of autism and differences in the methodology and contexts of prevalence studies.

Citation: Zeidan J, Fombonne E, Scorah J, Ibrahim A, Durkin MS, Saxena S, Yusuf A, Shih A, Elsabbagh M. Global prevalence of autism: A systematic review update. Autism Res. 2022 May;15(5):778-790. doi: 10.1002/aur.2696. Epub 2022 Mar 3. PMID: 35238171; PMCID: PMC9310578.

Open access article: (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7408756/ )

Abstract

Autism spectrum disorders (ASD) constitute a public health concern with increasing prevalence worldwide. We aimed to estimate prevalence and age at diagnosis in Greece, where no large-scale prevalence study has ever been conducted. Aggregate data were collected on ASD diagnoses by gender and calendar year of diagnosis up to 2019, for children born in 2008 and 2009, from the Centers for Educational and Counseling Support, which evaluate children to receive special educational support in school. Coverage was 87.1% of centers and 88.1% of schoolchildren born in 2008–9. ASD prevalence overall was 1.15% (1.83% males, 0.44% females; ratio 4.14:1), ranging from 0.59% to 1.50% in Greece’s 13 regions. In five regions, prevalence differed significantly between centers. Overall, only 3.8% of diagnoses were made before the fourth year after birth and 42.7% before the sixth year, with considerable variation between regions. Approximate mean age at diagnosis was six years and one month, and about three months earlier for girls than for boys. Our results provide evidence-based information to guide service planning and development at national and regional levels. Particular attention should be paid to smoothing out inequalities regarding service accessibility and provision. Emphasis should be given to earlier identification and diagnosis of ASD.

Citation: Thomaidis L, Mavroeidi N, Richardson C, Choleva A, Damianos G, Bolias K, Tsolia M. Autism Spectrum Disorders in Greece: Nationwide Prevalence in 10-11 Year-Old Children and Regional Disparities. J Clin Med. 2020 Jul 8;9(7):2163. doi: 10.3390/jcm9072163. PMID: 32650567; PMCID: PMC7408756.

Open access article: (https://www.mednet.gr/archives/2022-3/pdf/308.pdf)

Abstract

Autism spectrum disorder (ASD) is a multifactorial neurodevelopmental disorder which has attracted the interest of researchers in many scientific fields. The prevalence of a disease or a disorder is important for healthcare and socio-economic reasons. According to the World Health Organization (WHO), currently, 1 in 160 children is born with ASD (0.63%), possibly a conservative estimate, as many studies have reported a prevalence higher than 1%. Even so, the WHO rate is approximately 14 times higher than that reported in the first epidemiological study on ASD, which was conducted in the UK 50 years ago. It is currently estimated that approximately 60 million people worldwide have ASD. Diagnosis and documentation of these individuals is challenging, due to the nature of the disorder and its broad spectrum. Many countries have no epidemiological data on ASD and several epidemiological studies on ASD record significant methodological limitations, but the currently available data indicate that the prevalence of ASD has risen over the years. The interpretation of this trend remains uncertain, but several factors have been documented that may have contributed to this apparent increase, including revision of the diagnostic criteria, overdiagnosis, scientific advances, accessibility to services, increase in social awareness, and improvement in the methodology applied in the epidemiological studies, in addition to environmental and other factors.

Citation: Depastas, C., Kalaitzaki, A. (2022). The epidemiology of autism spectrum disorder and factors contributing to the increase in its prevalence. A.Archives of Hellenic Medicine / Arheia Ellenikes Iatrikes . May/Jun2022, Vol. 39 Issue 3, p308-312. 5p.