There was a statistically significant increase in the association of vitamin B12 deficiency with longer durations of use among all PPI users (P < .001 for trend) (Tables 2 and 3), although this was primarily attributable to the difference between nonusers and users; no significant trend was found with increasing duration among analyses confined to patients with 2 or more years of PPI use (P = .38 for trend). There was also no trend in association with increasing duration of H2RA use (P = .40 for trend).