Year: 2017
Type: dissertation
Study design: Observational Study
Abstract: Background: The prevalence of celiac disease (CD) in Canadian adults is unknown, and the extent of adverse health effects associated with undiagnosed CD remains unclear. Gluten sensitivity in the absence of CD is also thought to exist; however, the physiological effects of gluten intake in those without CD remain poorly understood. Objectives: To determine the prevalence of CD seropositivity in Canadian adults, investigate whether undiagnosed CD is associated with altered biomarkers of health, and examine associations of gluten intake with proteomic biomarkers and genetic variants in those without CD using a multi-omics approach. Methods: Subjects were 2,832 men and women from the Toronto Nutrigenomics and Health and Toronto Healthy Diet studies. Fasting blood samples were collected for CD screening, biomarker assessment and DNA isolation. CD was assessed using self-reported diagnoses and positive tissue transglutaminase (tTG) serology. Dietary gluten intake was estimated using a 196-item food-frequency questionnaire. Results: The prevalence of CD seropositivity was 1 in 114 (0.88%; 95% CI, 0.57-1.30%), with the majority of cases being undiagnosed (87%). The prevalence of CD seropositivity, predisposing human leukocyte antigen risk variants, and average gluten intake was highest in Caucasians. Undiagnosed CD was associated with lower circulating HDL-cholesterol (p=0.008), apolipoprotein-AI (p=0.02), and retinol (p=0.006), but not widespread nutrient deficiencies. In individuals without CD, gluten intake was positively associated with plasma Îą2-macroglobulin (p=0.004), a protein with various immune-related functions. Îą2-Macroglobulin was associated with variation in ICOSLG (p=1.67x10-7), a T-cell stimulatory gene involved in cytokine release and gastrointestinal immune-related disorders; however, there was no significant interaction between ICOSLG and gluten intake on Îą2-macroglobulin. Conclusions: Approximately 1% of Canadian adults likely have CD. Undiagnosed CD is associated with less favourable lipid profiles and lower concentrations of certain fat-soluble vitamins. In individuals without CD, gluten intake may be associated with plasma proteomic biomarkers of immune function.
Source: TSpace (University of Toronto)
Author: Joseph Jamnik
Language: English
Subfield: Gastroenterology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2887263638