Brief Report: Meta-analysis of Antacid Use and Alzheimer's Disease: Implications for the Aluminum Hypothesis.

Abstract

Exposure to aluminum remains a controversial risk factor for Alzheimer's disease. Antacids are aluminum-rich medications that are widely used in substantial amounts, but their association with Alzheimer's disease has not been systematically quantified. We conducted electronic searches of PubMed, Embase, and Cochrane Library up to January 2015 for case-control and cohort studies published in any language. Summary risk estimates were derived using random-effects models. Seven case-control studies (n = 5,468; 829 Alzheimer's disease cases) and two cohort studies (n = 842; 110 Alzheimer's disease cases) met the criteria for inclusion. Study quality was limited by imprecise characterization of the timing and duration of antacid use. Regular antacid use was not associated with Alzheimer's disease in either case-control (odds ratio = 1.0; 95% confidence interval = 0.8, 1.2) or cohort studies (relative risk = 0.8; 95% confidence interval = 0.4, 1.8). Sensitivity analysis including studies specifically examining aluminum-containing antacids did not reveal an association. Although the findings of this meta-analysis do not support an association between aluminum intake and Alzheimer's disease, prospective studies with longer follow-up and more precise characterization of exposure are required to definitively exclude an etiologic role for aluminum.