(A) Association between long-term medication use (continuous use for ∼6.2 y) and wave3 vitamin B12 concentration among wave3 BPHRS participants. (B) Association between long-term medication use and wave3 vitamin B12 deficiency among wave3 BPHRS participants. Seven hundred eighteen participants with complete wave3 outcome and wave3 exposure data after adjusting for wave3 covariates. Exposure long-term ALA (∼6.2 y continuous use) adjusted for wave3 covariates: age, sex, alcohol frequency, smoking, BMI level, multivitamin, ACE inhibitor, metformin use, and serum creatinine. Exposure long-term PPI (∼6.2 y continuous use) adjusted for wave3 covariates: age, sex, alcohol frequency, smoking, BMI level, multivitamin, ACE inhibitor, H2RA and metformin use, and serum creatinine. Exposure long-term H2RA (∼6.2 y continuous use) adjusted for wave3 covariates: age, sex, alcohol frequency, smoking, BMI level, multivitamin, ACE inhibitor, PPI and metformin use, and serum creatinine. Exposure metformin (∼6.2 y continuous use) adjusted for wave3 covariates: age, sex, alcohol frequency, smoking, BMI level, multivitamin, ACE inhibitor use, PPI use, H2RA use, and serum creatinine. ALA, acid-lowering agent; BPHRS, Boston Puerto Rican Health Study; H2RA, histamine 2 receptor antagonists; PPI, proton pump inhibitor.