Which lifestyle factors change tTG IgA?

tTG IgA is a biomarker for celiac disease. Lifestyle factors that can change tTG IgA levels primarily involve gluten intake: in individuals with celiac disease, gluten consumption raises tTG IgA, while a strict gluten-free diet lowers it. Infections (e.g., gastroenteritis) or other autoimmune conditions may also cause transient elevations. Evidence comes from clinical studies and guidelines, but is not present in the provided context, so the strength is moderate. Caveat: elevated tTG IgA alone is not diagnostic; duodenal biopsy remains the gold standard. If celiac disease is suspected, consult a physician before starting a gluten-free diet.