Gastrointestinal Symptoms in Children with Autism Open Access
Jaramillo, M. Elizabeth (Summer 2018)
Published
Abstract
Background: The classification and defining symptomology of autism has, historically, been controversial. Once considered a mental health disorder, today autism is known as a complex neurodevelopmental disorder with a heterogeneous presentation. It is diagnosed based on observation of hallmark behavioral symptoms. Comorbid conditions have been increasingly recognized. Gastrointestinal complications are perhaps among the most common co-occurring conditions. The etiology and pathophysiology of autism remains unknown and immeasurable. There has been much debate over whether symptomatic epidemiology may help us understand the pathophysiology and intervention options for children with autism.
Objective: This study aims to describe the change in the proportion of reported gastrointestinal symptoms among children with autism in a U.S.-based nationally representative sample, over the past decade. This study poses the question; does the association between gastrointestinal symptoms and autism stay constant from 2007 to 2016 in the National Health Interview Survey Data?
Methods: This secondary data analysis will produce descriptive statistics, including frequencies, unadjusted and adjusted odds ratios, calculated per individual year from 2007 to 2016 of the National Health Interview Survey Sample Child data. Autism prevalence as well as age distribution across the decade was also calculated. Variables that represent gastrointestinal symptoms are referred to digestive allergy, stomach illness and diarrhea/colitis, and defined by the survey question.
Results: This study cannot definitively conclude that there is not a pattern in the proportion of reported gastrointestinal symptoms (digestive allergies, stomach illness, and diarrhea/colitis) among children with autism, from 2007 to 2016 in the NHIS data. Based on odds ratios, the odds of having any of the three gastrointestinal symptoms hovered almost or right above significant over the decade, when compared to children without autism. Based on linear regression models, age and sex did not have an effect on the association between any of the three gastrointestinal variables and autism.
Conclusion: A gastrointestinal pathophysiology specific to autism may be plausible and children with autism may perhaps experience a higher incidence of gastrointestinal symptoms than children without autism. However, the connection between the gut-brain-axis and autism remains poorly understood. The results of this study show an oscillation in the significance of the likelihood of digestive allergies, stomach illness or diarrhea/colitis among children with autism, compared to those without. These results imply that there is insufficient evidence for the need for health care recommendations or interventions that target autism-specific gastrointestinal symptoms.
Table of Contents
INTRODUCTION ………………………………………………………………………………………………………………..…. 1
Overview
Background
Theories of Etiology
Rationale for Prevalence Increase
Changing Profiles in Autism Population
Conclusion
LITERATURE REVIEW ……………………………………………………………………………………………………………. 13
Gastrointestinal complications and autism
Is there an increased prevalence of GI in ASD?
Is the prevelance of GI in ASD changing over time?
Hypothesized Gastrointestinal-related Pathophysiology of Autism
Genetics and the mucoepithelial microbiota
Immune System and ASD
Celiac Disease and ASD
The Leaky Gut
Symptoms of autism and the gastrointestinal system
Behavioral
Linguistic
Conclusion
METHODS…………………………………………..………………………………………………………………………………. 25
Instrument
Data
Procecures
RESULTS ……………………………………………………………………………………………………………………………. 32
Frequencies and Odds Ratios
Logistic Regression
Summary
DISCUSSION ……………………………………………………………………………………………………………………….. 41
Limitations
Strengths
Future Research
CONCLUSION ……………………………………..…………………………………………………………………………..... 45
FIGURES AND TABLES ……………………………………………………………………………………………………………….
Figure A: Intellectual Disability: From Primary Symptom to Less Common Comorbidity 10
Figure B: Autism Prevalence (%) From 2007 to 2016 in the NHIS Data. 27
Table 1: Autism and Gastrointestinal Variables 31
Table 2: Unadjusted Odds Ratios for Gastrointestinal Variables among children
with autism compared to those without 32
Figure C: Digestive allergies- frequency and OR graphs 34
Figure D: Stomach Illness – frequency and OR graphs 35
Figure E: Diarrhea/Colitis – frequency and OR graphs 36
Table 3: Logistic Regression Model for Autism and Digestive Allergies, Adjusting for Sex and Age 38
Table 4: Logistic Regression Model for Autism and Stomach Illness, Adjusting for Sex and Age. 38
Table 5: Logistic Regression Model for Autism and Diarrhea/Colitis, Adjusting for Sex and Age. 38
Figure F: Various Gastrointestinal Symptoms Among Children with and without Autism 39
APPENDIX A. ……………………………………………………………..……………………………………………………………. 45
Expanded Definitions of Gastrointestinal Symptoms
Chronic diarrhea, chornic constipation, gastrointestinal reflux disease
Irritable bowel disease and inflamatory bowel disease (IBS)
Gut Brain axis and Gut microbiota
Food Allergy, food intollerace and food sensitivity
Immune System: Allergies and Immunoglobulins
Casein and gluten
Celiac Disease
Non-celiac gluten sensitivity
Terms
APPENDIX C. ……………………………………………………………..……………………………………………………………. 54
Frequency Tables for each gastrointestinal variable by survey year
REFERENCES ……………………………………………………………..………………………………………………….....…….…. 64
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